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Homemade CNC Router The Builders Guide (FREE!)

The Builder's Guide "Your homemade CNC router project begins here" Introduction So you've decided to build a homemade CNC router or maybe you re re just considering it, but where do you start? There are many advantages to owning a CNC router. Homemade CNC routers can cut and carve almost anything. For any hobbyist or DIY er, er, this opens many doors. The fact that you could own one for a fraction of the retail cost is even more enticing. ’

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Yes, you can build a CNC router that is just about as good as any other for a f r a c t i o n o f t h e r e t a i l p r i c e , and it s not that difficult! This is not a sales pitch, this guide is FREE its all bel ow. ’

There is also a great deal of flexibility when you design and build your own machine. You will be able to customize your machine to fit you needs best. Not to big, not to small, just right. There are many reasons people want to build their own homemade CNC router. It s usually because we simply can t afford to buy one off the shelf and that s as good of a reason as any other. Or you may be like me and enjoy working with your hand and creating something unique. You might simply be in it for the learning experience. For me personally, I think it was a little of both. ’

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My Experience When I first started to design and build my first homemade CNC router, I had it all figured out in about a day. I had my design ready to go. Then as I started to buy the parts, I did a little research. I found bits and pieces of information here and there, but it just lead to more questions.

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Do I really need ball screws or will ACME screws work fine? What kind of linear bearing is the best, and can I afford it? How big of a motor do I need, and should I use steppers or servos? Will this material flex too much over that span? Etc. “

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Luckily, some of my questions I could answer with my mechanical engineering background. However, many of the problems I would encounter could not be calculated . I just needed someone with experience and information on the subject. “

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So I researched the internet. The information available is scattered and hard to come by, and how do I know if it s valid. Most of the answers to my questions came through reading hundreds and hundreds of threads like CNCzone.com.. Which is a rood resource. I would post my questions and CNCzone.com wait for people who already have built a homemade CNC router to hopefully give me a good answer. ’

Of course I would get many answers to my questions from different people, many of which contradicted each other. Then I d have to read though a thread where people were bickering back and forth. Of course then I would have to research further to fi nd out which answers were worth while and which ones were garbage. ’

Every time I had a question that I didn t know, I would have to go through the same process. A lot of this was due to the fact I was on a budget and wanted the best design my money could buy. Which is the same situation many people building a homemade CNC router are in? ’

CNC router kits and plans Yes, there are homemade CNC router kits available, but I have yet to see one that gives any explanation as to what you are actually doing. It just says do these things and you are supposed to follow directions. But what if you do not have the parts available? Or you want your design to vary slightly. Then you are left to fend for your self. “

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Maybe you don t want to design your own, but still want to bui ld your own. That s where the kits and plans help you most, like the CNC router kits at www.solsylva.com . Plans are good for what they are, they are instructions. ’

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There are a lot of them out there and how do you know which one is the right one. No matter how good the instructions are, if it s a bad design it WILL be a bad machine. ’

That is why you need to be educated as to what you are building and what each part does! This Guide This is where this guide will help you. After designing and building several of my own homemade CNC routers, I would like to share the knowledge from my experiences, good and bad. I think it s sad that this information isn t out there, and I DON T think it should cost you anything. ’

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This guide aims to keep you for making some of the same mistakes that I



Do I really need ball screws or will ACME screws work fine? What kind of linear bearing is the best, and can I afford it? How big of a motor do I need, and should I use steppers or servos? Will this material flex too much over that span? Etc. “

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Luckily, some of my questions I could answer with my mechanical engineering background. However, many of the problems I would encounter could not be calculated . I just needed someone with experience and information on the subject. “

”

So I researched the internet. The information available is scattered and hard to come by, and how do I know if it s valid. Most of the answers to my questions came through reading hundreds and hundreds of threads like CNCzone.com.. Which is a rood resource. I would post my questions and CNCzone.com wait for people who already have built a homemade CNC router to hopefully give me a good answer. ’

Of course I would get many answers to my questions from different people, many of which contradicted each other. Then I d have to read though a thread where people were bickering back and forth. Of course then I would have to research further to fi nd out which answers were worth while and which ones were garbage. ’

Every time I had a question that I didn t know, I would have to go through the same process. A lot of this was due to the fact I was on a budget and wanted the best design my money could buy. Which is the same situation many people building a homemade CNC router are in? ’

CNC router kits and plans Yes, there are homemade CNC router kits available, but I have yet to see one that gives any explanation as to what you are actually doing. It just says do these things and you are supposed to follow directions. But what if you do not have the parts available? Or you want your design to vary slightly. Then you are left to fend for your self. “

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Maybe you don t want to design your own, but still want to bui ld your own. That s where the kits and plans help you most, like the CNC router kits at www.solsylva.com . Plans are good for what they are, they are instructions. ’

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There are a lot of them out there and how do you know which one is the right one. No matter how good the instructions are, if it s a bad design it WILL be a bad machine. ’

That is why you need to be educated as to what you are building and what each part does! This Guide This is where this guide will help you. After designing and building several of my own homemade CNC routers, I would like to share the knowledge from my experiences, good and bad. I think it s sad that this information isn t out there, and I DON T think it should cost you anything. ’

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This guide aims to keep you for making some of the same mistakes that I



made costing me precious time, money, and frustration. We will walk through ever component down to the bolts, looking at advantages and disadvantages of every type of each component. I will discuss every aspect of designing and building your own homemade CNC router. It will take you through the mechanics to software and everything in between. If you still want to use a homemade CNC router plan or kit, you can find CNC router plans here. Keep in mind, homemade CNC Router plans offer little in the way of explaining concepts. This often leads to a "sloppy" design or unsatisfactory machine performance. That is why I suggest I you read through this guide first. By the end, you should be talking CNC like a pro! This will give you a real heads up when you go to build and design your homemade CNC router. Regardless if you are using your plans or someone else's. L ET S GET STAR STAR TED ’

Step 1: Key Design D ecision s This section covers the the follow ing: Identifying the right design for you Required cutting area Space availability Materials Tolerances Constructing Methods Available tools Budget Step 2: The Base an d X-axis Fram e This section covers the the follow ing: Designing and Building the main base or x-axis base A breakdown of different designs Fully Supported Frames Partially Supported Frames etc. STEP 3: The The Y - Axis Gantry Design This section covers the the follow ing: Designing and Building the Y-axis Gantry A breakdown of different designs Forces and Moments on the Gantry Do's and Don't etc.

STEP 4: The ZZ- Axis A ssembly Design This section covers the the follow ing: Designing and Building the Z-axis Assembly Forces and Moments on the Z-axis Assembly Linear rail/rods and bearing spacing The Plunge arm Design etc. http://www.cncroutersource.com/homemade-cnc-router.html http://www.cncroutersource.com/ho memade-cnc-router.html (3 of 5) [8/6/2008 12:52:12 AM]


STEP 5: The The Lini ear Motion System This section covers the the follow ing: Detailed Overview of linear motion systems Choosing the right system for your machine Designing and building your own Linear Shaft and bushings Linear Rails and Guide Blocks etc. STEP 6: Mechanical Drive Components This section covers the the follow ing topics: Detailed overview of the drive components Choosing the right components for your design Stepper and Servo motors Lead screws and ball screws Drive nuts Radial and thrust Bearings Motor coupling and mounting Direct drive vs. Geared Rack and Pinions Lead screw motor sizing etc. STEP 7: The Cutting Table design This section covers the the follow ing: The Cutting table designs overview T-slot Table Vacuum Table Perforated cutting bed The Cutaway bed Designing and Building your own etc.

STEP 8: The Spindle Options This section covers the the follow ing: CNC Spindles overview Types and features Pricing and costs Mounting and cooling options Coolant systems Building your own How to calculate chip load and cutting force How to find optimal feed f eed rates etc.



STEP 9: The Electronics This section covers the the follow ing: CNC Electronics overview The Control panel Wiring and Fusing Buttons and switches MPG's and Jog wheels Power Supplies etc.

STEP 10: The CNC Controller options This section covers the the follow ing: The CNC Controller overview Controller selection Options available Closed loop vs. Open loop systems Best priced controllers Building your own from scratch etc.

STEP 11: Selecting Selecting the Softw are This section covers the the follow ing: The CNC related Software overview What software will I need CAM software CAD software NC Controller Software Best choices Free ware etc.

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CNC Plans ~Solsylva Home Page~

CNC Router Plans

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Plans Home Page Plans for low cost CNC machines

The tables were designed to be: Inexpensive to build Simple to assemble Accurate for the cost ●

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Table parts

Primarily off-theRack and Pinion or Leadscrew 24 x 48 Inch Cutting Area shelf from home centers and department stores. Part descriptions and sources for the other components are provided in the plans. This site gives a list of software, stepper and drive suppliers. Manuals There are two plan books.

One manual is for the single table shown above. This manual covers a variety of options including rack and pinion and/or leadscrews for the X and Y axes.

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Dual Leadscrew Table 25 x 37 Inch ( 640 x 950 mm) Cutting Area

The other manual includes plans for the 5 machines shown below. Both plan sets include hundreds of images and dimensioned CAD drawings, with step by step written instructions. All machines were designed around the drive, stepper and power supply packages sold by Xylotex and HobbyCNC. These cost $250 to $600 depending on the desired features. Tables' cost (Not

including the above drive packages) Fixed gantry table: Less than $100 Smaller blue tables: Less than $250 Belt drive, and rack and pinion tables: Less than $600 and up depending on the components used.

Belt Drive Table 27.5 x 64 Inch Cutting Area

Cutting areas

Belt Drive Table X 64" Y 27.5" Z 7" Rack/Leadscrew Table X 48" Y 24" Z 8" Dual Leadscrew Table X 37.5" Y 25.5" Z 6.5" http://www.solsylva.com/ (2 of 4) [8/6/2008 12:53:15 AM]


Small Blue Tables X 20" Y 17.5" Z 4" Fixed Gantry Table X 13" Y 13" Z 5" Footprint Size

Belt Drive Table 3' x 6' Rack and Pinion Table 3' x 5' Dual Leadscrew Table 36" x 49" Small Blue Tables 31" x 33.5" Fixed Gantry Table: 18" x 25" Fixed Gantry Table 13 x 13 Inch Cutting Area

Accuracy Very

good for the cost. Pictures are worth thousands of words. Stepper Size 200 oz.in. for the 13" x 13" and 17 x 20

inch prototypes. . . . 269 to 425 oz.in. for the 25 x 37 inch prototype, the Belt Drive table and the Rack/Leadscrew table. Speed 35+ inches per minute rapid, 30 ipm cuts on

the small tables, and up to 300+ ipm rapids on the rack and belt drive tables. The machines were all designed to use the stepper and drive systems from Xylotex and HobbyCNC. The recommended software is Mach3 or TurboCNC. These suppliers work with the Do It Yourself market, and supply documentation and help forums for their products.



These are all real machines that have been built and tested in this shop. Small Dual Leadscrew Table 17 x 20 Cutting Area

All of the machines were designed around standard sizes of lumber and hardware store components. This keeps construction simple and prices low. Suppliers for the other parts, such as belts and pulleys, are listed in the manuals. Though the machines are similar, each was designed to meet specific goals. The smaller machines use a minimum of Small Overhead Leadscrew Table components, 17 x 20 Cutting Area are inexpensive, and are simple to build. The large machines were designed to move quickly with a larger cutting area. The Rack and Pinion/Leadscrew machine is designed to carry a full sized router. It can use racks or leadscrews on the X and Y axes; the plans address the multiple versions.

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CNC Router Plans: Download free CNC router plans

CNC Router Plans CNC router plans are a great starting point for anyone wanting to build a CNC router. They give valuable insight on how these machines work. Many of us are very visual people and it helps to see examples of these machines laid out on paper. Some plans are thorough enough to act as a complete blueprint from start to finish while others only offer bits of information. You may prefer to design and build your own machine. However, CNC router plans can still be a valuable resource. Plans can give you great ideas. You may like the linear motion system on one design but prefer the cutting bed design on another. They may also uncover aspects of your design that may or may not work. This is why we want to provide you with as many free plans and blueprints as possible. There several companies devoted to providing plans you can buy. Some are worth while, and others are not. At the moment, we are working on several free plans complete with pictures, 3D and 2D downloads, and even videos. Even if you decide to use plans, we strongly suggest you read through the Builder s Guide There you will find in depth information regarding all the components and their function. ’

For now, feel free to check out the plans below. These designs have been tested and built by many CNC router enthusiasts. CNC Router P lans Dow nload Center

JGRO s

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This design is very popular among the DIY CNC router community. This set of plans is very detailed and contains dimensions on all parts. This is a mobile gantry type designed around a wood or MDF construction utilizing skate bearings for the linear motion system. http://www.cncroutersource.com/cnc-router-plans.html (1 of 2) [8/6/2008 12:54:06 AM]

CNC Router Plans: Download free CNC router plans

This build can be very sturdy if built correctly. The set of plans also contains a complete BOM (bill of materials). Download JGRO s Design in PDF format ’

Download JGRO s Design in DXF format ’

Pl e as e n o t e , t h a t b y d o w n l o a d i n g t h i s p l a n , y o u a r e u n d e r t h e a g r e em e n t t h a t t h e y a r e n o t t o b e r e so l d o r u s e d f o r co m m e r c ia l p u r p o s e . Pe r s o n a l u s e O N L Y!

Joe s 2006 R-1

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Design

This is another very popular design. This design is also a mobile gantry CNC router, designed around a wood or MDF structure. The linear motion system is also design around skate bearings. However, the xaxis employs dual rods and each side instead of one. This design is very ergonomic looking and employs antitorsion framing and slanted gantry side arms to account for CG location. This set of plans are in a 3D format which can be viewed, rotated, and dimensioned using a free E-drawing viewer that you may download here. Download JOE s 2006 design in EASM format ’

Download the free EASM viewer here Pl e as e n o t e , t h a t b y d o w n l o a d i n g t h i s p l a n , y o u a r e u n d e r t h e a g r e em e n t t h a t t h e y a r e n o t t o b e r e so l d o r u s e d f o r co m m e r c ia l p u r p o s e . Pe r s o n a l u s e O N L Y!

MORE PLANS ARE COMING VERY SOON!!!! If you have any question or would like to submit a set of your own CNC router plans to be reviewed and posted, feel free to contact us.

Return to Homepage from CNC Router Plans

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The Hobby CNC Router: Builders Guide Step 1

Building a Hobby CNC Router Step 1 As we discussed earlier, there are numerous advantages to designing and building a hobby CNC router. Designing and building any machine has the potential of being a good or bad experience. This is also the case wen designing and building a CNC router. The concepts of CNC routers are fairly straight forward, but you can quickly become overwhelmed in the process. Don t let this stand in the way. ’

That s why this guide is here; to keep you from making mistakes that might cost you time, money, and performance. ’

Although this guide is primarily focusing on hobby CNC routers, the concepts may be applies to most any CNC linear motion system. For example, you could use these same concepts to build a CNC plasma cutter. If you are thinking of building your own machine, there is a good chance you already have a design in mind. This is to be expected. After all, it s your machine. This guide does not aim to subtract from any of your ideas but rather supplement your project with valuable information. I wish that I had known a lot of this stuff bef ore my first machine. It would have saved me many headaches and money. ’

One last comment before we jump in head first. I am assuming you know some very CNC basics, such as what CNC means etc. If you do not, then you may wish to start at the CNC router Basics.

Let s Get Started: ’

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1) Choosing your design There are two primary styles of the hobby CNC router. This may seem contradictory as every design is unique. However, there are two overall designs types that you will encounter. 1) Stationary Gantry, Mobile bed 2) Mobile Gantry, stationary bed Here you can see an example of each.

Let s take a look at these two designs in detail. ’

The Mobile bed This type of design is less prominent in the hobby CNC router community than the mobile gantry design. However, there are reasons for choosing the mobile bed design type. The mobile bed design is typically found on smaller CNC machines such as a PCB or engraving machines. For this size machine, the mobile bed design works well.



Another advantage of this design is that creating a sturdy gantry that will not flex under load is much easier. This is because the gantry is stationary and does not have to be light or conform to a certain size to fit your linear bearings. With a mobile gantry, you must take into consideration the weight of the gantry itself and the size, in regards to the linear bearings on the x axis. With the mobile bed design, the gantry itself does not move, therefore you have more breathing room in regards to the weight, size, and structural design. There are disadvantages with this type of design as well. As the length of the x-axis increases the mobile bed design become less eff icient. If you are unfamiliar with the x, y, and z, axis notation, take a look at the picture below labeling each. As we discuss the hobby CNC router, the x, y, and z axis will always be this configuration.

With the mobile bed design, as you increase the x axis length your design become less efficient due to the size of the bed. When you see a mobile bed design employed on a hobby CNC router, the total x axis travel i s usually between 12-36 inches. I have seen l arger, however the design becomes increasingly complicated. If you made an extended x axis with a mobile bed, the actual size of the object you could cut would still be relatively small because the bed itself is still relatively small. As a side note, the y and z axis usually changes very little between the mobile bed and mobile gantry designs. In conclusion, the mobile bed design i s for you if you want a smaller machine that is compact and relatively easy to build, offering rigid a gantry but limiting on the overall size. Now let s look at the mobile gantry. ’

The Mobile Gantry The mobile gantry design accounts for probably 95% of the hobby CNC routers. This design type is similar to the mobile bed except the whole gantry moves along the x axis. This is advantageous because the overall size virtually limitless. It can be tricky to design a gantry that is lig ht enough for your design and still offer little flex under load. Not to mention, you must design it to be mobile and fit some sort of linear bearing assembly. The mobile gantry design is very versatile. If you are building anything other than a small machine, I suggest this be your design choice. Of course, we will go into greater detail on both designs later.



For now, you need to decide which design will fit your needs be st. Now lets move on to some other considerations. 2) The Cutting Area The cutting area is the total distance the machine can cut along each axis. Keep in mind, this is one of those decisions that is likely to change as you search for parts. The linear bearings will probably be you primary restrictions. After all, most of us want as big of a machine as we can get away with. We will look at sizing in more depth later when we look at the structural considerations. Right now it s a good idea to have an idea of the size of piece you want to be able to cut. Later you may find that you are limited to a certain size due to materials and parts. For example, some linear systems and materials may flex excessively over a certain span, which could also limit the cutting area. ’

The cutting area is also called the machine travel for each axis. The travel is not the overall machine size, which brings us to our next consideration. 3) The Machin e Size Most of us want as big of a machine as we can get, however, you may be limited due to shop space or some other f actor. So if you have a machine footprint limitation, keep this in mind as you design your machine. You do not want to have wasted space in your hobby CNC router design. For example, if your limitation is 36 x24 , then your ideal travel for that machine is 36 x24 . Although, it is unlikely you will achieve the maximum travel for your machine size, working towards getting as much travel as possible is worth the effort. ”

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4) The Machine Tolerance One of the most important considerations when designing or building a hobby CNC router is the accuracy and precision of the machine. Don t get accuracy and precision confused. Take a look at the illustration below. ’

You want to design and build your machine to hold a certain accuracy and precision. For example, you machine may be able to cut a piece that is within .0001 of an inch but the repeatability may be .1 inch. Many people design and build a hobby CNC router and live with the results, or keep adjusting to get the results they want. However, there are ways to design machine to hold a certain tolerance. For example, if you know you only need a tolerance of .01 inch and you know that all you will ever need, http://www.cncroutersource.com/hobby-cnc-router.html (4 of 6) [8/6/2008 12:54:41 AM]


you can save a lot of money by designing for that requirement. On the other hand, if you want a machine to hold a tolerance of .0001 inch repeatable, then there are some design requirements that must be met to get the required performance. Typical hobby CNC routers hold a tolerance of .001 to .0001 inch. However, this is up to you. At this point all you need to do is have an idea as to what kind of tolerance you require. Keep in mind the larger the machine, the more costly it is to hold tight tolerances. 5) Materials and Tools The tools and materials can define your design almost as much as any other factor. Hobby CNC routers are constructed from all types of materials. I have seen machines made out of plastic, wood, MDF, aluminum, steel, and others. The material from which you construct your machine should be based on 3 criteria, budget, tools you have to work with, and materials available. It is hard to say which material is best as it varies with the design. I have seen machines made from MDF that hold better tolerances than those constructed of solid metal. That is why it is crucial to choose your materials ahead of time. Of course, your hobby CNC router will probably integrate many materials. However, you will have a certain material that will make up the bulk of your machine. The right design for a wood machine is not the right design for an aluminum or steel machine. The tools you have may also define the type of material you must use. If you do not have access to a milling machine or heavy metalworking equipment, then it may be hard to build your design correctly out of metal. This will eventually lead to a poor overall machine. On a piece of paper right down all the tools you have to work with, and then think of the material you can use. Keep in mind, I have seen machines built with as little as a drill motor and a hand saw. So there is no need to think that because you have limited tools you can not create a hobby CNC router. A popular method is to build a basic CNC router and then use that to build a nicer one. This method works well if you have limited tools. Do not take on a job that you do not have the tools for. We will look at properties of material later. There we will cover how to calculate deflection and other mathematical models with relative ease. This will help you design your machine to the load ratings you specify. 6) Budget Last but not least is the budget. For most of us, this is the one factor that will determine many of our decisions. After all, if we had the money, we would just buy one. Well maybe we would just buy really nice parts and bolt them http://www.cncroutersource.com/hobby-cnc-router.html (5 of 6) [8/6/2008 12:54:41 AM]


together. I suggest you have an overall budget in mind and keep track of how much you spend. Below you will find an excel spreadsheet that you may download. It breaks down all the components of a hobby CNC router and parts you will need. This will help you stay organized and see where you should spend the bulk of your money. I also included information on what you should expect to pay. As a warning, the bul k of your budget should go towards the linear motions system and the drive system. We will cover this in greater detail in later steps. Summary of Step 1 So by now you should have the following decisions made or understand them at least. 1) 2) 3) 4) 5) 6)

Mobile bed or mobile gantry Required cutting area Machine size requirements Tolerance requirements Materials and Tools Budget

Now that we have the major decisions worked out, let con Building a hobb y CNC router Step 2

View and Down load a Sample Expense sheet Back to the Builders Guide Index Homepage


Build your own CNC router Step 2: The frame

Build your own CNC router Step 2 The Frame and Base When you design and build your own CNC router, one of the first considerations is the base and frame. Although another practice is to actually design from the top down, but well start at the bottom and work our way up. The Base and Frame Overview The base and frame of a CNC router is the main structural element of your machine.The base and frame is what holds everything together. This is what will determine your motor placement and lead screw placement along with everything else. The frame and base design will be determined partially by the materials and supplies that you have, the number of lead screws lead screws , and motors your budget allow etc. However, we need to b ecome familiar with different designs so that you may buy parts that fit your design. If you can not find or can t afford the parts for the design you would like. Then it s back to the drawing board to optimize the design for the materials you do have. This will likely happen a lot when you build your own CNC router. ’

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When you look at other homemade CNC router designs, you may notice that almost ever unit is different. Although this is true, you can break down these designs into categories. The X-Axis Base and Frame When you build your own CNC router, the X-axis frame should also act as the base for the machine as the X-axis should be the axis closest to the ground. This portion of the machine will perform 3 primary tasks. 1) Act as the base for the machine 2) Support the X axis linear motion system 3) Support the cutting table

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Lets look at the most common designs for the base. Fully Supported Frame The fully supported base is one of the best designs and is the design used on most industrial or professional routers.

The image above shows only the base and does not show the gantry. Pay no attention to the type of linear bearings. The fully supported design means that both the Y and X axis may rest on the floor or some other structure. There is nothing connecting the gantry across the Y-axis. This allows for a very sturdy design and is not susceptible to the cutting table or the structure itself flexing under its own or e xternal weight. In order for this system to flex or deform, the material itself would need to compress. Keep in mind we are not talking about massive amounts of flex. This all ties back in to the Step 1 on how to build your own CNC router. Where you should already have some idea as to the desired precisions and accuracy you want your machine to hold. A deformation of 0.001 is acceptable if you only expect 0.010 accuracy from your machine. ”

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There are drawbacks with this design, the cost. You will need and extra lead screw, lead nut, and motor. You may employ a fully supported frame design with one motor using a pulley and belt system, but you will need to make sure you motor is up to the task. We will cover how to calculate that in the CNC drive system section. With this design you can get away with a lighter material as it will be supported against the ground or some other structure. Now let s look at another design. ’



Fully Supported Frame vs. Fully Supported Bearing Rods/ Rails When we say fully supported in this section, we mean that there is nothing obstructing sweeping across that axis during operation. “

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Later we will discuss fully and end supported l inear bearing systems, but that is not the focus in this section. We are focusing on the frame itself. It is possible to have a fully supported linear bearing system and not have a fully supported frame. You can see this in the Solsyva design below.

Partially Supported X-axis Fully Supported Y-axis Frame The more common design with most hobby CNC routers out there is the partially supported X or Y-axis.

The

image above illustrates a supported Y-axis and a end supported X-axis frame. This is the most common design. The gantry would have an undercarriage that would connect the gantry to the l ead screw. With this setup you could have a fully supported linear rails or rods “


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setup. . However, the rods or rails would still be able to flex with the frame itself. You may only support the frame on the ends since there must be clearance between the ground and the frame to allow the gantry undercarriage to move along the X-axis. In the image above, the Y-axis would be considered supported since you could have a frame that would not interfere with the gantry movement. The frame across the Y-axis would prevent flexing for that axis. This would mean the cutting bed would be very rigid in the Y-axis but could flex or deform along the X-axis. With the design above, even if the frame were made of solid aluminum measuring 1-1/2 by 4-1/2 and the X-axis span were 60 inches, the frame would sag .01 inches in the center, just under its own weight. That does not include the weight of the gantry or anything else. ’’

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You can understand that this would be an issue if I m trying to design a machine to hole a tolerance of 0.001 in the Z-axis. It is true that the machine would flex as a whole and could be compensated. However, the machine could vibrate and bounce when cutting creating lines in the work. If your machine has a relatively small X-axis span, this design works well and is probably the e asiest to setup. There are other solutions. ’

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Partially Supported Y - axis Fully Supported X-axis Let s say I have only one motor and lead screw for the X-axis and still wish to maintain a high tolerance on my machine. I could move the Y-axis gantry assembly inside the frame which would allow me to fully support the X-axis because the gantry would not cut under the X-axis frame. However in that situation, the Y-axis frame would not be fully supported. ’



As you can see in this design, the longer X-axis is fully supported (on the ground), however the gantry would cut through any frame in the Y-axis inside the cutting area. This means that no matter how much weight I put on the gantry or cutting table (not pictured), the X-axis frame would only deform if the material itself deformed. With this design, the cutting bed would need to have its own frame and could sag in the center. However, he machine itself would be constant and once the cutting bed is installed, you could true the cutting table surface by plain the surface with the machine.

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The cutting bed would then be true to the machine. When you design or build your own CNC router, you need to decide which is more important. Have the machine remain constant or have the cutting bed and the machine flex together. We will cover this more when we discuss the cutting bed. Alternatives There are other alternatives when you build or design your own CNC router. One way to obtain a fully supported router is to do away with the gantry undercarriage and have the lead screw connect at the top of the gantry or have 2 lead screws high on each side. You may see this application in the Solsyva designs. They offer these blueprints on how to build your own CNC router. However, with a single lead screw up high above the gantry, it makes access to the cutting bed somewhat difficult. This design works well for smaller machines that you wish to be mobile. For instance, a CNC router designed to carve shapes on wood flooring. http://www.cncroutersource.com/build-your-own-cnc-router.html (5 of 7) [8/6/2008 12:55:24 AM]


The Mobile bed design

The mobile bed or movable bed design approaches the CNC router frame differently. With a mobile bed CNC router, like the one pictured above, you may have a f ully supported frame and bearing system for the X-axis without compromising any structural framing. With this design you also only require one motor and lead screw for the X-axis. Because the lead screw attaches to the bed itself and there is no undercarriage for the gantry, the bearings and frame would not be in the way. This is advantageous because if you want design and build your own CNC router, the chances are you want to save as much money as possible. The bed must also only support its weight and the weight of the material you will be cutting. It does not hold the weight of the gantry itself. However, this design may be inefficient for larger designs as we discussed in step one.

Other Considerations When you design and build your own CNC router, the material you use to construct the frame will play a big role in the design of the frame. Different materials will deform differently. Keep the material consideration in mind as you choose a frame design. Most popular materials are: 1) MDF 2) Plywood 3) Aluminum Stock 4) 80/20 Structural aluminum.



5) Steel Keep the materials in mind as you think of how to build your CNC router. In later sections of this guide we will discuss bearing pl acement, lead screw and motor placement, and other design features. All of which should be considered when you build your own CNC router. For now just review and consider your options for the base and X-axis. When you design or build your own CNC router, you may decide to employ some elements from each design. If you try to rush the process and forget to consider these design issues when you build your own CNC router, then you may be setting yourself back. Before you set anything in stone, let s take a look at the Y-axis gantry and the Zaxis frame assemblies. ’

Go back to Step 1: How to build a CNC router

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Do it yourself CNC router: Design Considerations, the Gantry

The "Do It Yourself CNC router" The Gantry Design Considerations Now that we have looked at the X-axis frame designs and considerations in a do it yourself CNC router design, let s look at the Y-axis gantry assembly. ’

The gantry design is the most popular design in the do it yourself CNC router community. It is popular for a reason, it works. When you build a CNC router, it is important to keep the design trade offs in mind. No matter your budget, the parts you have, or the material you use, there is a design that is best for you. The gantry design is a proven design for "do it yourself CNC routers." However, there are still many things that you should be aware of. From a design standpoint, you want your gantry to be stable and balanced. Design the CNC gantry to meet the forces that it will encounter. This will prevent excess stress and strain on you bearings, lead screw, motor, etc. In order for you to be able to design and build your gantry to meet the required forces, you first need to identify and understand the forces involved. ’

Let s take a look at the forces evolved with a do it yourself CNC router gantry.

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The above image illustrates a side view of a typical do it youself CNC router gantry.

Take a minute to look over the image, there is a lot there. Now let s discuss what is happening. It may seem confusing at first but it s rather simple once you understand what is taking place. We will discuss. ’

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Center of gravity/mass Forces Moment Let quickly identify the labels above: D1 = the distance between the cutting tool (the router bit) and the center between the http://www.cncroutersource.com/do-it-yourself-CNC-router.html (2 of 5) [8/6/2008 12:56:07 AM]


two Y-axis linear bearing rods/rails (D3). D2 = distance between lead screw/ linear bearings and the bottom Y-axis linear bearing rail/rod. D3 = distance between the lower and upper Y-axis linear bearing rods/rails. D4= distance between the 2 linear bearings that sit on the X-axis linear bearing rods/ rails. Now we will look at the forces evolved. The Technical Explanation: CNC Router Forces (scroll down for the short Version) The image above illustrates a gantry that is moving from left to right as you look at the screen. It is being pulled or pushed by the CNC drive system at the bottom. Now, the router spindle at the bottom. Now, the router spindle is lowered and it starts cutting. The cutting action apposes the movement of the gantry resulting in a cutting force. The cutting force varies according to the gantry acceleration, spindle RPM, and the chip load. The chip load depends on the bit you use, the RPM, and the material. We will get into these details when we discuss the CNC router spindle. For now just know you have a cutting force apposing the movement of the gantry. Just so you know, a force is equal to mass of multiplied by its acceleration. The units of force are lb-f (pounds of force) in the English system or the Newton in the SI system. The cutting force results in a moment, which is moment A in the figure above. A moment results when you have a force applied at a distance. A moment has units of lbfin or N-m, we usually call a moment force torque. Moment A, in the image above, is the result of the cutting force being applied at the distance D1. Moment A = D1 x Cutting force Example: If the distance D1= 12 inches and the cutting force is 5 lb of force. Then the Moment A would be 5lb x 1ft = 5 ft lb of force. ( I converted 12 inches to 1 foot) You can see that even if the cutting force remains the same, the longer the distance of D1 the larger the moment will be. Moving on, the Moment A results in 2 forces on the Y-axis linear bearing rods/rails. These resulting forces are forces A and B in the figure above. Force A and Force B are equal to each other Force A = Force B. Force A = Moment A divided by 2 divided by ½ of D3 this equals to Force A = Force B = Moment A / D3 You can see that as the vertical distance between the two linear rods/rails (for the Yaxis linear bearings) grows, the resulting forces A and B shrink which is good. Why is this good? It reduces the amount of centralized torque that is on the gantry itself.



Moment B will decrees as force A decreases. Moment B = D2 x Force A Moment B is what causes the whole gantry to rock or want to rotate due to the cutting force. This is not a good thing. You want to decrease Moment B as much as possible. Why? You want to make have equal amounts of force on your set of linear bearings as possible. This will reduce deformation and chatter in your machine. There are two ways to reduce Moment B. 1) Reduce Force A 2) Reduce the D3 A well designed machine keeps force C and force D to be as equal as possible. And that is the goal. Force C and D are the sum of the weight of the machine and resulting forces that occur do to moment B. We also need to consider the weight of the gantry and try and calculate or guess where the center of gravity will be and keep that directly in the center between the two separated bearings (½ D4). The center of gravity is the point at which the machine would balance. That is why you often see the gantry upright side arms slanted backwards an a do it yourself CNC router. This compensated for the weight of the spindle which hangs our over the Y-axis linear bearings. When you build a do it yourself CNC router, you want the center of gravity of the whole gantry assembly to be directly between the two linear bearings. Or if you have a stationary gantry and a mobile bed, you want center of gravity to be in the center of the bottom of you gantry side arms. This assures that your machine is balanced and could stand own its own. This applies equal load on your bearings. The short answer (summary) When you design or build a do it yourself CNC router, keep the following in mind: Try and keep the distance between the X-axis lead screw and linear bearings, as close as possible to the bottom Y-axis linear bearing rods/rails. Or as close to the center distance between the top and bottom Y-axis linear rods/rails. (Minimize D2) Keep the spindle plunge arm on the Z-axis assembly as short as possible and make that arm out of rigid material to prevent flexing. A normal Z-axis arm travel is anywhere from 3 to 6 inches. (Minimize D1) Calculate or estimate where the center of gravity of the gantry will be located, including the spindle. Design your gantry side arms to compensate and place the center of gravity (CG) between the front and back X-axis linear bearings per arm. (CG should be located at ½ D4 and as close to X-axis lead screw as possible) Maximize the distance between the upper and lower Y-axis linear bearing rods/rails but http://www.cncroutersource.com/do-it-yourself-CNC-router.html (4 of 5) [8/6/2008 12:56:07 AM]


still allow for clearance under the bottom rod/rail for your max Z travel. (Maximize D3) Other considerations A good gantry design is one of the most crucial factors for a quality do it yourself CNC router. As with all DIY CNC routers, budget is a concern which means material are also a concern. Try and visualize and estimate the forces evolved and make your do it yourself CNC router design work with the materials you have. If you would like a more thorough analysis you may consult us. We offer free engineering design analysis of your machine. We can help you find: Specific CG location Material stress and strain analysis Dynamic simulation of your machine Material selection And more Remember, we will discuss more on the gantry design in later section. Topics such as lead screw placement, motor placement, linear bearing at tachments, etc. Which are all important consideration with a do it yourself CNC router project. Now let s take a look at Step 4: the Z-axis assembly design for th e do it yoursel f CNC router. ’

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Building a CNC Router Step 4: The Z-axis assembly

Building a CNC Router Step 4: The Z-axis assembly So far we have looked at the first three steps in building a CNC router Step 1: Key Design Decisions Step 2: The Base and X-axis Frame Step 3: The Y-axis Gantry Assembly Now let s look at the 4th step, ’

The Z-axis assembl y Below you can see two examples of Z-axis assemblies with the Y-Axis CNC Router Gantry in the background.

http://www.cncroutersource.com/building-a-cnc-router.html (1 of 8) [8/6/2008 12:56:26 AM] Building a CNC Router Step 4: The Z-axis assembly

As with the previous discussions, when designing or building a CNC router it is important to consider the forces that are evolved. That way, you can adjust your design and verify that it will meet your design requirements . However, in order to design and build your machine to meet your requirements, you first need to understand the forces evolved.


As with the previous discussions, when designing or building a CNC router it is important to consider the forces that are evolved. That way, you can adjust your design and verify that it will meet your design requirements . However, in order to design and build your machine to meet your requirements, you first need to understand the forces evolved. Forces on the Z- Axis Assembly



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Le t s interpret the above image. The following explains the dimensions: D1 = the vertical distance between the upper and lower Y-axis linear bearing rods/rails. http://www.cncroutersource.com/building-a-cnc-router.html (3 of 8) [8/6/2008 12:56:26 AM] Building a CNC Router Step 4: The Z-axis assembly

D2 = the vertical distance between the upper and lower sets of Z-axis l inear bearings. D3 = the length of the spindle attachment plunge arm. D4 = the width of the Z-axis assembly. D5 = the horizontal distance between the Z-axis linear bearing rods/rails. D6 = the thickness of the plunge arm D7 = the distance between the cuttin g force (approx, tip of the cutting tool) and 1/2 D2. ’

Now that we understand what the dimensions are, let s analyze the forces and moments. Forces and Momen ts on the Z-Axis Assembl y Building a CNC router can be easy or hard. Some people over analyze and some people just build it and see if it works. I think the best approach is a mix of the two methods. So let s first try and understand what is happening. ’

The above image illustrates an example of a Z-axis assembly shown in a front view and a side view. Look at the front view and notice that the Z-axis assembly is moving to the right while it rides on the Y-axis linear bearing rails/rods. The plunge arm is at max Z travel and is cutting into a material as it moves from left to right. This cutting action produces a cutting f orce that apposes the movement of the Z-axis assembly.


D2 = the vertical distance between the upper and lower sets of Z-axis l inear bearings. D3 = the length of the spindle attachment plunge arm. D4 = the width of the Z-axis assembly. D5 = the horizontal distance between the Z-axis linear bearing rods/rails. D6 = the thickness of the plunge arm D7 = the distance between the cuttin g force (approx, tip of the cutting tool) and 1/2 D2. ’

Now that we understand what the dimensions are, let s analyze the forces and moments. Forces and Momen ts on the Z-Axis Assembl y Building a CNC router can be easy or hard. Some people over analyze and some people just build it and see if it works. I think the best approach is a mix of the two methods. So let s first try and understand what is happening. ’

The above image illustrates an example of a Z-axis assembly shown in a front view and a side view. Look at the front view and notice that the Z-axis assembly is moving to the right while it rides on the Y-axis linear bearing rails/rods. The plunge arm is at max Z travel and is cutting into a material as it moves from left to right. This cutting action produces a cutting f orce that apposes the movement of the Z-axis assembly. The cutting force is a variable of spindle RPMs, the number of flutes on the cutting tool, the feed rate, and the material that is being cut. You can learn more on how to calculate cutting force here . When building a CNC router an important decision to make is what types of material you would like to be able to cut, which was covered in step 1. For now, just understand that there is a force in the opposite direction than the Z-axis assembly is moving. Now let s see what happens because of this cutting force. ’

The cutting force creates a moment, which is illustrated in the image above as Moment A. A moment is just a force that is applied at a distance. We covered moments in greater details in Step 3. Moment A = D6 x Cutting Force. http://www.cncroutersource.com/building-a-cnc-router.html (4 of 8) [8/6/2008 12:56:26 AM] Building a CNC Router Step 4: The Z-axis assembly

Moment A torques the plunge arm in the opposing direction of the cutting force, which torques the whole Z-axis assembly. br> This moment results in resultant forces that are applied to the Z-axis linear bearing rails/rods and the Z-axis linear bearings themselves. (Yellow arrows)


Moment A torques the plunge arm in the opposing direction of the cutting force, which torques the whole Z-axis assembly. br> This moment results in resultant forces that are applied to the Z-axis linear bearing rails/rods and the Z-axis linear bearings themselves. (Yellow arrows)

As D5 and D2 increase in length, the resulting forces decrease. You can see that when you are designing or building a CNC router, it is important to maximize the horizontal distance between the Z-axis linear rails rails (D5), and the vertical distance between the Z- axis linear bearing blocks.

The Plunge Arm D2 also has an effect while cutting along the X-axis. Take a look at the image to the bellow. The cutting force causes another moment; Moment B. http://www.cncroutersource.com/building-a-cnc-router.html (5 of 8) [8/6/2008 12:56:26 AM] Building a CNC Router Step 4: The Z-axis assembly

Moment B is the result of the cutting force being multiplied by the distance between the cutting force and ½ D2. This moment will apply resulting forces on the Z-axis bearings. As the distance between these bearings (D2) increase, these forces will decrease. That is why it is best to maximize D2. As a rule of thumb when building a CNC router, D2 should never be any less that half the length of the plunge arm. Also, you want the thickness if the plunge arm (D6) to be thick enough to not flex under your maximum cutting force.


Moment B is the result of the cutting force being multiplied by the distance between the cutting force and ½ D2. This moment will apply resulting forces on the Z-axis bearings. As the distance between these bearings (D2) increase, these forces will decrease. That is why it is best to maximize D2. As a rule of thumb when building a CNC router, D2 should never be any less that half the length of the plunge arm. Also, you want the thickness if the plunge arm (D6) to be thick enough to not flex under your maximum cutting force.

The flex will depend on the maximum cutting force you are designing your machine around, the thickness of the material (d6), plunge arm length (D3), and the material it is made of. If you need help calculating your desired cutting force or the amount of deformation a certain material and size will have, you may contact us We offer free design consultation and other engineering services.


Summary Keep the following in mind when you design or build a CNC router: Maximize D1, reduces the forces due to torque c aused by the cutting force in the X-axis. Maximize D2 reduces the forces due to torque ca used by the cutting force in the X-axis. Minimize D3, but still allow for your desired Z-axis travel. Maximize D4, reduces the forces due to torque c aused by the cutting force in the Y-axis. Other Considerations In later sections of the building a CNC router guide , we will discuss other features such as lead screws, motor placement, linear bearings etc. ’

Don t forget that you may contact us with any questions regarding CNC machines in general or your design. We will try and help any way possible. The motor mount that is used in the above image may be bought pre-fabricated from K2CNC.com for a variety of router spindles. Conclusion So far we have looked at the first 4 steps when building a CNC router,


Summary Keep the following in mind when you design or build a CNC router: Maximize D1, reduces the forces due to torque c aused by the cutting force in the X-axis. Maximize D2 reduces the forces due to torque ca used by the cutting force in the X-axis. Minimize D3, but still allow for your desired Z-axis travel. Maximize D4, reduces the forces due to torque c aused by the cutting force in the Y-axis. Other Considerations In later sections of the building a CNC router guide , we will discuss other features such as lead screws, motor placement, linear bearings etc. ’

Don t forget that you may contact us with any questions regarding CNC machines in general or your design. We will try and help any way possible. The motor mount that is used in the above image may be bought pre-fabricated from K2CNC.com for a variety of router spindles. Conclusion So far we have looked at the first 4 steps when building a CNC router, Step 1: Key Design Decisions Step 2: The Base and X-axis Frame Step 3: The Y-axis Gantry Assembly Step 4: The Z-axis Assembly Now let s continue to one of the most important features when designing or building a CNC router system, the linear motion system. Building a CNC router Step 5: The linear Motion System ’


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CNC Linear motion: Everything you need to know

CNC Linear Motion Systems The linear motion system plays a vital role in any linear CNC machine, and CNC routers are no exception. Without these systems coupled with a drive system, a CNC


CNC Linear Motion Systems The linear motion system plays a vital role in any linear CNC machine, and CNC routers are no exception. Without these systems coupled with a drive system, a CNC router would be of little use. The LM system is responsible for three primary tasks. 1) Support Machine Components 2) Guide the machine in a precise linear motion with minimal friction 3) Support secondary loads (Torque, Lateral Loads, etc) A LM system is composed of some type of linear b earing and the linear bearing guides. There are a number of types of bearings and guides, each with advantages and disadvantages. Because of the importance of this system, it is vital for a buyer a bui lder to be knowledgeable about the LM components. For the Buyer The linear motion system can make or break a machine. For people buying new CNC routers today, there should be little concerns regarding these components. The quality and performance of linear motion slides have drastically improved over the last few years. Almost all of the new CNC router machines are using quality linear bearing systems. This holds true for mid-range to high-end models. . If you are buying hobby CNC routers or low end machines, it is still important for you to be able to identify quality systems. Some manufacturers do not specify what types of components are installed and you should know how to identify faulty systems.For those interested in buying a used system, you need to know what types of linear system are installed and be able to identify faults or at least know the right questions ask. It can cost $10,000 or more to replace a full set of linear bearings http://www.cncroutersource.com/linear-motion.html (1 of 3) [8/6/2008 12:56:40 AM]


(depending on the system). If the system is older, the companies may no longer sell the parts. If you must replace a part you could be dead in the water. So it is important to be able to identify the components, know what faults to look for, and know whether or not the replacements are still in production. For the Builder The LM system can be one of the most expensive and difficult features of a machine. That is why it is imperative to get it right the first time. If you are here following the step 3 in the builder's guide then I suggest your read through all the sections and not just the section on b uilding your own. This guide will go through the many options you have for linear systems. It will discuss advantages and disadvantages of each and also show you how to build your own if you so choose. It will also include information on how to mount rails, linear shafts, and much more, including money saving tips and tricks. If you have any questions regarding LM systems, don t hesitate to contact us. ’

Sections

Linear Mo tion Systems Overview This Section covers: Categories of LM systems Rating and Terminology How LM systems work Etc. Rails and Guide Blocks This Section covers: How rails and guide blocks work Terminology Types and features Manufacturers Where to Buy and Buying Tips Etc. Rods and Bushings This Section covers: How rods and bushings work Supported and Unsupported shaft Shaft types and features Plain and ball bearing bushings Manufacturers Where to Buy and Buying Tips Etc. V-Groove Wh eels and Track Rollers This Section covers: How V-groove wheels and track rollers work Types and features Manufacturers Where to Buy and Buying Tips http://www.cncroutersource.com/linear-motion.html (2 of 3) [8/6/2008 12:56:40 AM]


Etc. Homemade Linear Motion Systems This Section covers: Homemade LM systems overview Skate bearing systems Plain Bearing systems Linear Surfaces Mounting Linear bearing rails Linear Rods Other Linear Bearing Systems Etc. “

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The Builder's Guide Step 6

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CNC Drive Components: Stepper Motors, Servo Motors, Leadscrews Etc.

Your Guide to CNC Drive Components So wh at are CNC drive components? The drive components are the mechanical components that "drive" the CNC machine along its axis. The most common components associated with a drive system, are the motor and lead or ball screw. The whole idea of a drive system is to convert controlled rotary motion to controlled linear motion with the help of a CNC Controller . The idea of a CNC drive system is a fairly simple one. However, the actual mechanics evolved can be complicated. This is where many "DIY CNC'ers" get lost. The drive system is a direct correlation to the machines capabilities. By understanding the CNC drive system you have a much better understanding of a CNC machine. Just by changing a few components you can control the machines cutting speed, cutting force, precisions, and accuracy; which should be taken into consideration. If you are buying a CNC machine, it is best to know what type of drive components are installed. For example, if someone quotes a precision of .0001 inch and then informs you they have standard ACME screws and no anti-backlash nut installed, then they are probably over stating the machines capabilities. Again, this is especially true if you are buying a used machine. You need to know what kind of components are installed, how much wear they have, and could you buy replacement parts if needed .

What w ill this guide do? This guide offers detailed information on every component that makes up a CNC drive system. If you are building a CNC router, we will discuss money

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saving tips and options as well as assembly. If you are interested in Buying CNC drive parts , then visit our store or take a look at our links page. There you will find a list of recommended places to buy each part.

1. Stepper Motors and Servo Motors A CNC machine wouldn't be a CNC machine without some sort of motor. Stepper motors or Servo motors both perform the same task, which is take in electrical power and convert it to rotational motion. Think of the motors as the workhorse for the machine, however, they need to be told what to do, which is the job of the CNC controller. This section will take you though the ins and outs of CNC motors. 2. Leadscrews and Ballscrews The first step to converting the rotational motion supplies by the motors to linear motion, is the lead screw or ball screw. With the help of a CNC drive nut, you can have a great amount of linear force with little torque. Just like the jack on your car. Try to lift your 2000 lb vehicle without the aid or your jack and see how far you get. However, there are many different types of leads crews and ball screws. This guide will walk you through the pros and cons of each type and also discuss alternative solutions for CNC machines on a budget. 3. CNC Drive Nuts The drive nut is the one link between the lead or ballscrew and the actual machine. Therefore it is often discussed in direct relation with the leadscrews. However, you may have the nicest system money can buy and less than par drive nuts, and not be able to hold a tolerance of .01 inch. That is why I am devoting a full section to drive nuts. This one component will make or break your machine. We will discuss the types of drive nut, backlash and much more. If you are building a CNC router, you MUST read this section. The CNC drive system is a vital part of your machine. I will discuss how to obtain some very nice anti-backlash nuts for very cheap. 4. Rack and pinion Rack and pinions are less pronoun than their leadscrew counterparts. However, there are some applications where it is the only solution so that close tolerances can still be held. Many hobby CNC'ers completely overlook this option, primarily because of cost. However, there are ways to come out even cheaper than alternative solutions. 4. Radial, Thrust bearing and Couplers This section covers some of the minor components in a CNC drive system. Things such as radial and thrust bearings for leadscrews and and shaft couplers. Although, these are "minor" pieces in the whole system, they still play a vital role. After all, a machine is only as good as it weakest link. If you are buying a CNC router then you have nothing to worry about as these parts are usually all the same. However, if you are building a CNC machine, this section will cover vital information that will save major headaches down the path. 5.Direct drive vs. Geared or Pu lley Systems There are two main ways of coupling your electric motor to the other CNC



drive components. The first being direct drive via use of a anti-backlash shaft coupler discussed above, and secondly, the use of either pulleys or gears. We will cover the reasons for having each and also the pros and cons as usual. This is another one of those things that people often overlook.

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The CNC Router Table Top, Where the magic happens

The CNC Router Table Top The CNC router table top is where the cutting magic happens. The table top, also called the cutting bed, can make the life of a CNC router operator enjoyable or a nightmare. Many times when buying a CNC router, the type of table top is often overlooked or the significance underestimated. I assure you there is a design that will fit your needs best. For example, if you are in the prototyping business, you will probably be working with all kinds of materials and shapes. This would probably push you towards a T-slot style, which offers numerous clamping options. On the other hand, you might produce the same type of product on a daily basis which would push you towards a different style. On higher end CNC router router tables now days, you may find a combination of different types of cutting table tops. However, it is best to be knowledgeable about what kind of CNC router table will be best for you. If you are building your own CNC router , your options are limited unless your budget allows. However, there is still a lot of material to be covered regarding the cutting board. This information should be very helpful to your design.

The T-Slot table top The T-slot table is often seen on traditional CNC milling machines. However, these are usually made of tooling steel and are extremely heavy. The T-slot tables found on CNC routers are usually made of extruded aluminum. There are many advantages to the T-slot type table. However this style can be very... The Vacuum table top

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The CNC Router Table Top, Where the magic happens

The vacuum style CNC router table top is often f ound on higher end models. They can be very useful for many applications. However, there are drawbacks. For example the... The Perfor ated table top Similar to the vacuum table in appearance, the perforated table top is simple yet affective. Much cheaper than a T-slot style bed, yet offe rs similar performance. The perforated table offers a lot as far as... The "Disposable" table top The "The "Disposable" table top is actually one of my favorites. Especially if you are new to operating a CNC router. This table style, usually composed of one or two sheets of high density MDF board, are very useful even if you have some other table top installed. I can't tell you how awful it makes you feel when you cut into your brand new t-slot or vacuum table. Yes I know there are limit switches, touch off pad and sensors to prevent that type of mistake. However, you would be surprised at how often we "bypass" those features. The disposable bed can also... Building your ow n CNC router table top The CNC router table top on a homemade machine is a very important considerations. The budget usually pushes towards the MDF style cutaway table top, which I actually think is best because of its versatility. However, design of the table support and structure should NOT be overlooked. Continue this section for step 6 of the builders guide. Continue to The builders gui de: Step 7 Spindle Selection

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The CNC Router Spindle: Your ultimate resource

The Router Spindle So what is the router spindle? Don't be confused by the "fancy" terminology. The spindle is simple the actual motor doing the cutting, with the help of a cutting tool of course. In other words it’ s the actual router of CNC router. Like most everything else involving CNC routers, there are a variety of spindle types out there. Some made for wood, some made for metal, etc. As usual there are many factors involved when choosing a spindle for either your pre-build machine, or your homemade CNC machine. If you are buying an industrial CNC router , then you should be well informed as to the capabilities of the spindle before you buy. Most companies who sell CNC routers do a pretty good job of displaying the spindle capabilities. The reason being, this information is easily understood and appeals well to the reader. For example, “our machine offers a 7 HP router.” Most people readily understand these figures much more than linear bearings and lead screw information and make a direct link to the machines capabilities, which is somewhat true. There are, however, many other important considerations. Such as, RPM, load ratings, power requirements, and the collet type and size to say the least. If you are building a CNC machine, then you also need to make important decision regarding the router spindle. Ag ain, I realize a lot of hobbyists are bound by budget which I respect. After all, that’ s part of the challenge. However, there are many choices to choose from within the same price bracket. One of the most important decisions for the hobbyists , I believe, is the noise level. If you are anywhere near neighbors or your own house, then this is a huge consideration. You don’ t want to be running an extremely load machine for hours at a time, unless you want angry neig hbors. This section will go into detail regarding all aspects of spindles of all types. Well look at types and features, price ranges , mounting issues, and much more.

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The CNC Router Spindle: Your ultimate resource

The Rou ter Spindle: Types and Features There are as many tpes of spindles as there are types of CNC routers out there. We'll take a look at all types, from... Spindle Prices and Costs We'll look at general pricing of different types of spindles. This assures you aren't getting ripped off by... Mountin g and Cooling Options There are many ways to mount a spindle head, but there are very few ways to do it right. Cooling the spindle and the cutting tool is a major issue for some applications. The one way to make a bad... Building your own For the mechanically minded enthusiasts out there, there are ways to make your won spindle that is specific to your needs. Although I view this as an extra project and not a necessity as it would be hard to make something cheaper than what is available commercially. Alternatively, there are ways to crop parts from other machines to build a rather robust router spindle that is… Calculating Cutting Force While designing, building, or operating a CNC router, you will probably run across terms such as cutting force or chip load. This section will describe how to calculate relative cutting force, chip load, optimal feed rates and spindles speeds... Continu e to: The Buil ders Guide Step 8

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CNC Electronics: MPG's, Buttons, Switches, Controle Panel

CNC Electronics CNC electronics are a vital part of any CNC machine. Aside from the motors and CNC controllers , there are many electronic components that assist in the machine operation. In this section we will cover all the electronics involved with a CNC router. Many people feel more threatened by the electrical components than the mechanics of a machine. This doesn t have to be the case. Whether you are building or buying a CNC router , this section will help inform you on the electronic systems found on a CNC router and help you understand how they come together with other components to create a fully working machine. ’

For the buyer If you are purchasing a CNC router , you will probably know right from the start if something is wrong with the electronics. This should be checked before ever committing to buying a CNC router. Of course for a new machine, this should be of little concern. If you are buying a new machine, everything should be in tip top shape and if not, send it back or have them fix it. However, if you are buying a used machine, it would be highly recommended to check all the systems before hand. The control panel buttons, limit switches, wiring, etc. For high end CNC routers, i n any case you should always have a professional inspect the machine if you find something to be faulty. The chances of you shorting out other systems are not worth the risk of trying to fix it yourself or having the Maytag repair man look it over. For lower end models and hobby CNC routers , the electronics are usually very straightforward but if you don t feel comfortable, have someone else do it. “

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For the Builder There are many electronic aspects of a CNC router that are vital to its function. Things such as limit and proximity switches, motor wiring, correct cable sizing and selection etc. These features are, in my op inion, vital to building a reliable machine. Yet many peopl e neglect these feature http://www.cncroutersource.com/cnc-electronics.html (1 of 3) [8/6/2008 12:57:48 AM]


because of lack of know how or budget . Many of these add-ons cost only pennies to install and could save either your machine or the piece you are working on. For the most part, adding these components is by no means difficult. “

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There are also some CNC electronic features that are not often requi red. Such as manual pulse generators, home and e-stop buttons, touch-off tool sensors etc. These things may or may not be essential to the machine, depending on the user, but do increase user friendliness. Not to mention, increasing the overall look and feel of the machine. With a few CNC electronic add-ons and a well constructed user panel, you can make you homemade CNC routers seem like one off the shelf.

The Follow ing Section Covers

The Control Panel Layout and Overview Features Building Your Own Buttons and Sw itches Overview E-stop Buttons Home Switches Misc. Switches Limit and Proximity switches Overview Limit Switches Normally On vs Normally Off Proximity Switches Manual Pulse Generators/ Jog Wheels Overview True MPG Wheels Jog Wheel Other Options Wiring and Fusing Overview Wiring Your System Cable Selection Fuses Do s and Don ts Cable Tracks ’

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Connectors Overview Motor Connectors http://www.cncroutersource.com/cnc-electronics.html (2 of 3) [8/6/2008 12:57:48 AM]


DB9 Connectors DB25 Connectors Misc. Connectors

Lighting Overview Lighting your Work Shop Lighting Nifty Ideas Pow er Supplies (PSU s) Overview Stepper/Servo PSU Controller PSU Building your Own DC PSU Shop Power Requirements ’

Tool Sensors Overview Digital Tool Sensors Analog Tool Sensors Build a Touch off pad Breakout boards Overview Applications Options Build your Own Troubleshooting Need Help? Contact Us We will try and help you or provide you with someone who can assist you.

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The CNC Controller: Everything you need to know buildone or buy one

The CNC Controller The CNC controller is the heart of any CNC system. Without a controller, there would be no CNC as we know it. A controller completes the all important link between a computer system and the mechanical components of a CNC machine. A controller s primary task is to drive electric motors that in turn drive a CNC machine, with the help of a mechanical drive system. Before the advent of microprocessors or computers, NC controllers held the stage. Computerized Numerically Controlled (CNC) controllers are sometimes still refereed to as Numerically Controlled (NC) controllers. Although this term is still technically correct. The term NC controller is usually used when describing older controllers. ’

A Brief History NC controllers were introduced in the late 19 40 s and early 1950 s. An NC controller receives a set of sequenced instructions, the program, consisting of alpha and numeric characters. The controller then uses this set of instructions to direct the motions of a machine tool (such as a milling machine, lathe, or flame cutter), much like the controllers today. ’

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The program was edited and programmed with the very basic computers of the time. The program would then be transported to the controller via a tape.

This permitted the program instructions to be read by the controller's tape reader only once and then stored in the controller's memory. Magnetic tape recorders and floppy disk drives were also being used for program recording and storage. There were no direct links between the computer and controller on early systems. Debugging an N/C program before the advent of the computerized NC required making a new tape, trying out the new tape, finding the next error, making another tape, and so on. The process of debugging a new program could require making a dozen or http://www.cncroutersource.com/cnc-controller.html (1 of 3) [8/6/2008 12:57:58 AM]

The CNC Controller: Everything you need to know buildone or buy one

more punched tapes until an error free program was achieved. Engineering changes required a new tape to be made and debugged. Modern Controllers Today, with the use of powerful microprocessors and computer systems, the NC controller now communicated directly to a computer system with a real time. This is the CNC controller that most of us are familiar with. The controllers today do far more than drive motors. Some controller systems have the capabilities to detect and control limit switches , spindles speeds, coolant flow, and more. Modern controllers still require operators to create a program for the controller to follow. Operators today receive help from CNC Software Software such as Computer-Aided Design (CAD) packages and ComputerAided Manufacturing (CAM) software along with the controller software to are used to create the necessary numerical code such as G-code. The controllers today range from professional standalone system, with their own keyboard and user interface , to hobby use CNC controllers that require a personal computer. ’

Types of Controllers CNC Controllers can be broken down into two broad categories. 1) Open Loop Systems 2) Closed Loop Systems Further more, controllers can be broken down into two categories with respect to cost and abilities.

Pr ofessional Controller Systems - found on high end machine, are usually standalone systems that offer their own user interface panel and many features. This section will discuss features and types of controllers that fit into this category. We ll also look at some general pricing. ’

Hobby CNC Controller systems - are generally much cheaper and usually require an external computer system and do not come with a user interface system. In this section we ll look at all types of CNC controllers that fit in this category, including pricing, feature, brands, and more. This section continues the Builder s Guide section . We ll discuss what ’

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