Contents NO. TITLE
PAGE
1
OBJECTIVE
2
INTRODUCTION
3
SAFETY
3
4
DRAWING
4
5
PROCEDURE
6
OBSERVATION
7
RESULT
8
CONCLUSION
12
9
REFERENCES
12
1
1-2
5–8
9
10 - 11
OBJECTIVE 1. To know the working principles of lathe machine. 2. To identify the most common operations can be carried out on a lathe process. 3. To know the major parts of lathe machine.
INTRODUCTION Lathe machines are capable of cutting or grinding symmetrical shapes into materials such as wood and metal. There are countless practical applications associated with lathe machines. The definition of a lathe is a machine that shapes objects by rotating them while a shaping tool such as a chisel is applied to its surface. To avoid injury, care should be taken while operating lathe machines. The function of lathe machine can be used to create symmetrical shapes into a piece of wood, metal or other material. Lathe machines offer cutting, grinding and even milling options. Lathes grip a work piece and spin it along an axis. Shapes are created after running a cutting tool or grinding tool against the rotating work piece. Cutting tools can be held in place and moved by the operator or by the machine itself depending on the type of lathe machine in use. In essence, wood turning and metal spinning lathes do not have cross slides, but have "banjos", which are flat pieces that sit crosswise on the bed. The position of a banjo can be adjusted by hand no gearing is involved. On a woodworking lathe, the cutting tools are usually hand-held against a support and are moved in and out and back and forth along the surface of the work by hand to form a shape such as a table leg. On metalworking lathes, the cutting tools are held rigidly in a tool holder that is mounted on a movable platform called the carriage. The tool is moved in and out by means of hand cranks and back and forth either by hand cranking or under power from the lathe. The result is that material can be removed from the work piece under very precise control to produce shapes that are truly precision made. Because of the inherent rotational nature of a lathe, the vast majority of the work produced on it is basically cylindrical in form.
The types of Lathe Machine are Speed lathe, Bench lathe, Engine lathe, Tool room lathe, Capstan and turret lathe Automatic lathe Special purpose lathe
All lathes require several basic components to function properly. Some of the essential components to a lathe machine include a saddle, bed, cross slide, top slide, apron, headstock, tool rest, lead screw, tailstock, gears, headstock, countershaft and a chuck. The chuck contains the spindle and jaws, which grip and spin the work piece. A carriage houses the cross slide, top slide and saddle while the apron houses the gears involved. The bed is the foundation of the lathe machine where all components come together. The headstock is employed to allow the spindle to rotate at variable speeds. The tailstock holds the end of the work piece that is not gripped by the spindle and chuck. APPARATUS
FIGURE 1: LATHE MACHINE
SAFETY 1. Always wear eye protection such as goggles preferably industrial quality safety glasses with side-shields. The lathe can throw off sharp, hot metal chips at considerable speed as well as spin off spirals of metal that can be hazardous.
2. Wear short sleeve shirts or shirts with snugly fitting cuffs if long sleeve. Loose sleeves can catch on rotating work and quickly pull your hand or arm into harm's way. 3. Wear shoes preferably leather work shoes to protect your feet from sharp metal chips on the shop floor and from tools and chunks of metal that may get dropped.
4. Remove wrist watches, necklaces, chains and other jewelry. It can catch on rotating work and severely damage your ring finger and hand. 5. Tie back long hair so it can't get caught in the rotating work. It can catch on rotating work 6. Double check to make sure your work is securely clamped in the chuck or between centers before starting the lathe 7. Remove the chuck key immediately after use. The chuck key can be a lethal projectile if the lathe is started with the chuck key in the chuck. 8. Keep your fingers clear of the rotating work and cutting tools.
PROCEDURE Facing
Clamp the workpiece tightly in the 3-jaw chuck.
Clamp the cutting tool in the tool post and turn the tool post so that the tip of the cutting tool will meet the end of the workpiece at a slight angle.
Clamp the toolpost in place and advance the carriage until the tool is about even with the end of the workpiece.
Press the half-nut lever down to engage the half-nut with the leadscrew.
Use the compound handwheel to advance the tip of the tool until it just touches the end of the workpiece.
Use the cross feed crank to back off the tool until it is beyond the diameter of the workpiece.
Adjust the speed to 370 RPM and switch on the lathe.
Slowly advance the cross feed handwheel to move the tool towards the workpiece. When the tool touches the workpiece it should start to remove metal from the end. Continue advancing the tool until it reaches the center of the workpiece and then crank the tool back in the opposite direction.
Cut both side of the workpiece until it is 70mm in length.
Diameter Cutting/Turning Process
Clamped safely the work piece into 3 jaws chuck.
Clamp the cutting tool in the tool post and turn the toolpost so that the cutting tool will meet the end of the workpiece at a slight angle. It is important that the cutting tool be right at the centerline of the lathe
Vernire caliper was used to measure the work piece and was marked to undergo machining.
The work piece is switched inversely from back to front.
The steps was repeated until workpiece get the dimension.
Chamfer
Clamped safely the work piece into 3 jaws chuck.
Clamp the cutting tool in the tool post and turn the tool post so that the cutting tool will meet the end of the workpiece at 45 degrees.
Adjust the speed to 370 RPM and switch on the lathe.
Feed the tool into the workpiece to remove the unwanted material until the correct size is achieve.
Taper Turning
Clamped safely the work piece into 3 jaws chuck.
Clamp the cutting tool in the tool post and turn the tool post so that the cutting tool will meet the end of the workpiece at 45 degrees.
Adjust the speed to 370 RPM and switch on the lathe.
Feed the tool into the workpiece to remove the unwanted material until the correct size is achieve.
Grooving
Clamp the workpiece tightly in the 3-jaw chuck.
Set the parting tool on center and square
Clamp the grooving tool in the tool post and then measure the grooving.
Set the speed of lathe to 58 RPM and switch it on.
Slowly feed the tool bit into the workpiece using the cross feed handle. Continue the grooving process until the diameter reaches 28mm.
Drilling
Clamped safely the work piece into 3 jaws chuck.
Firmly seated the drill chuck into the tailstock.
Choose a center drill with a diameter similar to that of the hole that you intend to drill.
Insert the center drill in the jaws of the tailstock chuck and tighten the chuck until the jaws just start to grip the drill.
Slide the tailstock along the ways until the tip of the center drill touches the surface of the workpiece and tighten the tailstock clamp nut.
Set the speed of the lathe to180 RPM and then switch it on. Use the tailstock crank to advance the drill slowly into the end of the workpiece and continue until the conical section of the center drill is about 3/4ths of the way into the workpiece. The purpose is just to make a starter hole for the regular drill. Back the center drill out and stop the lathe.
Loosen the tailstock clamp nut and slide the tailstock back to the end of the ways.
Remove the center drill from the chuck and insert a regular drill and tighten it down in the chuck. Slide the tailstock until the tip of the drill almost touches the workpiece and then lock the tailstock in place.
Switch on the machine and start the drilling process until the depth is 27mm then stop the machine.
Boring
Clamped safely the work piece into 3 jaws chuck.
Firmly seated the drill chuck into the tailstock.
Choose a center drill with a diameter similar to that of the hole that you intend to drill.
Insert the center drill in the jaws of the tailstock chuck and tighten the chuck until the jaws just start to grip the drill.
Slide the tailstock along the ways until the tip of the center drill touches the surface of the workpiece and tighten the tailstock clamp nut.
Set the speed of the lathe to180 RPM and then switch it on. Use the tailstock crank to advance the drill slowly into the end of the workpiece and continue until the conical section of the center drill is about 3/4ths of the way into the workpiece. The purpose is just to make a starter hole for the regular drill. Back the center drill out and stop the lathe.
Loosen the tailstock clamp nut and slide the tailstock back to the end of the ways.
Remove the center drill from the chuck and insert a regular drill and tighten it down in the chuck. Slide the tailstock until the tip of the drill almost touches the workpiece and then lock the tailstock in place.
Switch on the machine and start the drilling process until the depth is 15mm then stop the machine.
Clamp the boring tool bar in the tool post.
Set the speed of the lathe to 58 RPM and switch it on. Use the tailstock crank to advance the boring bar slowly into the end of the workpiece and continue until the diameter of the bore is 30mm.
Knurling process
Clamped safely the work piece into 3 jaws chuck.
Set the lathe speed to 58 RPM.
Select the proper knurling tool (1mm pitch, spiral angle 30 degrees and profile angle 90 degrees).
Mount the tool in the tool post then center and square the knurling tool to the work piece. Check the tracking of the knurling tool, adjust the tool if it is cross-tracking.
Engage the longitudinal feed, and let the tool feed across the work piece to the desired length then stop the machine.
Tapping
Clamp the workpiece to the table clamp
Choose the correct size of tap and clamp it to the threading die.
A tap enters the workpiece axially through existing 15mm hole.
Turn the threading die clockwise.
Continue the tapping process until it is finish.
Machine Shut Down
Switch off machine main power followed by power supply switch.
Cleared all the chips by using brush and broom.
OBSERVATION Lathe machine can be used for facing process, diameter cutting process, tapping process, groving process, drilling process, boring process, knerling process and chamferad process. On metalworking lathes, the cutting tools are held rigidly in a tool holder that is mounted on a movable platform called the carriage. The tool is moved in and out by means of hand cranks and back and forth either by hand cranking or under power from the lathe. The result is that material can be removed from the work piece under very precise control to produce shapes that are truly precision made. Because of the inherent rotational nature of a lathe, the vast majority of the work produced on it is basically cylindrical in form. Before operating the machine students should check the machine whether it is safe and appropriate by clean and lubricate the machine. Be sure all guards are in position and locked in place. Turn the spindle over by hand to be sure it is not locked nor engaged in back gear. Then, move the carriage along the ways. There should be no binding. Check cross slide movement. Mount the desired work holding attachment. Adjust the drive mechanism for the desired speed and feed. Besides, clamp the cutter bit into an appropriate tool holder and mount it in the tool post. Do not permit excessive compound rest overhang as this often causes tool "chatter" and results in a poorly machined surface. Lastly, mount the work. check for adequate clearance between the work and the various machine parts. There were many precaution steps that must be taken. Firstly, Wear personal protective equipment. Remove the chuck wrench immediately after adjusting the chuck. Make sure the forward/ reverse lever is fully disengaged before using the chuck wrench. Then, aways let the chuck come to a complete stop before touching the part or the chuck. If in some instances flying chips are unavoidable, please use a curtain to prevent other operators from being subjected to burns. Be very careful while filing, emerying and when using a deburring tool. Do not operate the lathe wearing loose clothing, finger rings or other jewelry. Long hair must be tied up or tucked under the hard-hat. Never attempt to remove chips by hand, turn off the lathe and use a chip hook or a brush. Never polish a part with emery cloth wrapped around your hand, hold the emery cloth using your thumb and forefinger only. Finally,when emerying a threaded part use a course grit sandpaper to minimize the surface to surface contact, which will reduce the tendency for the emery cloth to want to grab.
RESULT
CONCLUSION
By the end of the project, we can know the working principles of the Lathe Machine. In a lathe machine the operations, which are done is defined as a job. The job is held in a chuck or between centers and rotated about its axis at a uniform speed. The cutting tool held in the tool post is fed into the workpiece for a desired direction. Since there exists a relative motion between the work-piece and the cutting tool, therefore the material is removed in the form of chips and the desired shape is obtained. In our project, it was based on the lathe. The most common operations which can be carried out on a lathe that we should know are facing, drilling, turning, boring, knurling, chamfer,taper turning and tapping. Facing is almost essential for all works. In this operation, the work piece is held in the chuck and the facing tool is fed from the center of the work piece towards the outer surface or from the outer surface to the center, with the help of a cross slide. The major parts of lathe machine are bed, headstock, tailstock, carriage, it have five major parts. They are a saddle, cross-slide, compound rest, tools post, apron. Lastly, power feed and thread cutting mechanism. As we know, practice made things perfect. To get the best results of the project, we must practice all out before starting our project. Besides, we needed extra time to finish the project to get the best results. This will give us more experienced about lathe process.
REFERENCES
1) http://www.scribd.com/doc/17390328/Introduction-to-Lathe-Operations 2) http://www.mini-lathe.com/ 3) http://en.wikipedia.org/wiki/Turning
