Lathe Report

BTPU 1223 MANUFACTURING PRACTISE LABORATORY LATHE MACHINE

Contents NO TITLE

PAGE

1

OBJECTIVE

1

2

INTRODUCTION

1

3

APPARATUS

3

4

PROCEDURE

7

5

RESULTS

12

6

DISCUSSION

14

7

CONCLUSION

15

8

REFERENCES

16

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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, woodturning 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.

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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. Wood lathe machines are employed by manufacturers to create such objects as legs for tables, baseball bats and billiard cues. Metal lathe machines are utilized to cut, grind, drill, bore and ream harder, heavier materials such as metal. Screws and some types of drill bits are fabricated with the aid of metal lathes. Some metal lathes can be modified to create a machine capable of executing milling applications. APPARATUS:

FIGURE 1: LATHE MACHINE

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FUNCTION OF FIGURE 1: ITEM Apron Bed Carriage Carriage Hand wheel Center Drill

Chuck

Compound

Compound Hand wheel Cross Feed

Cross-slide Cross-slide Hand wheel Dog

Faceplate Gib

Half nut

FUNCTION Front part of the carriage assembly on which the carriage hand wheel is mounted Main supporting casting running the length of the lathe Assembly that moves the tool post and cutting tool along the ways A wheel with a handle used to move the carriage by hand by means of a rack and pinion drive 1. A short, stubby drill used to form a pilot hole for drilling and a shallow countersunk hole for mounting the end of a work piece on a center. 2. The process of drilling a work piece with a center drill A clamping device for holding work in the lathe or for holding drills in the tailstock. Movable platform on which the tool post is mounted; can be set at an angle to the work piece. Also known as the compound slide and compound rest. A wheel with a handle used to move the compound slide in and out. Also known as the compound feed. A hand wheel or crank that moves the cross-slide by turning a screw. Also the action of moving the cross slid using the cross feed hand wheel. Platform that moves perpendicular to the lathe axis under control of the cross-slide hand wheel A wheel with a handle used to move the cross-slide in and out. Also known as the cross feed. Used to clamp a work piece and apply rotational force to it while the work piece is mounted between centers along with a faceplate. The dog engages with a hole in the faceplate to apply the force to the work piece. A metal plate with a flat face that is mounted on the lathe spindle to hold irregularly shaped work. A length of steel or brass with a diamond-shaped cross-section that engages with one side of dovetail and can be adjusted by means of screws to take up any slack in the dovetail slide. Used to adjust the dovetail for optimum tightness and to compensate for wear. A nut formed from two halves which clamp around the lead screw under control of the half nut lever to move the carriage under power driven from the lead screw.

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Half nut Lever Headstock Jacobs Chuck

Lead screw

Saddle

Spindle

Tailstock

Tailstock Hand wheel Taper

Tool Tool Blank

Toolpost Turning

Ways

Lever to engage the carriage with the lead screw to move the carriage under power The main casting mounted on the left end of the bed, in which the spindle is mounted. Houses the spindle speed change gears. A common style of drill chuck that uses a geared outer ring along with a chuck key that engages with the geared ring to hold a drill bit very tightly. Prior to the introduction of "keyless" chucks, these were universally used on handheld power drills and drill presses. Precision screw that runs the length of the bed. Used to drive the carriage under power for turning and thread cutting operations. Smaller lead screws are used within the cross-slide and compound to move those parts by precise amounts. A casting, shaped like an "H" when viewed from above, which rides along the ways. Along with the apron, it is one of the two main components that make up the carriage. Main rotating shaft on which the chuck or other work holding device is mounted. It is mounted in precision bearings and passes through the headstock. Cast iron assembly that can slide along the ways and be locked in place. Used to hold long work in place or to mount a drill chuck for drilling into the end of the work. A wheel with a handle used to move the tailstock ram in and out of the tailstock casting. A smooth gradual change in the diameter of a work piece; also the procedure for cutting a work piece to produce a tapered diameter. May also refer to a tapered end of a tool that conforms to an industry-standard configuration such as a Morse Taper or Jacobs Taper. A cutting tool used to remove metal from a work piece; usually made of High Speed Steel or carbide. A piece of High Speed Steel from which a cutting tool is ground on a bench grinder. Typically 5/16" square by 2 1/2" long for mini-lathe use. A holding device mounted on the compound into which the cutting tool is clamped A lathe operation in which metal is removed from the outside diameter of the work piece, thus reducing its diameter to a desired size. Precision ground surfaces along the top of the bed on which the saddle rides. The ways are precisely aligned with the centerline of the lathe.

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Varnier calliper

large T-clunch

Small T cluch

L-spanar

Spanar Open

Allen key

Live centre

Threading die

Grease oil

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PROCEDURE: 1. Sharpening Tools a) Used as cutting tool for turning process. b) Grinder machine was used to sharp tool. c) All PPE (personal protective equipment) have been worn before do the process. d) The step for sharpening tool has been followed correctly as to shape it like the figure 1.

Figure 1 2. Set Up Machine a) The machine was switch on followed by power supply to machine main power switch. b) Changed machine speed to 625rpm or appropriated for machining process. c) Rotation of spindle have been determined (clockwise / counterclockwise) d) The machines have been checked before running it. 3. Datum Setting a) Life centre/death centre have been slot in into tailstock. b) Cutting tools (HSS) have been installed to turning tool holder. Screw was loosening by using tool post key. c) Turning tools holder have been installed to tool post. d) Tool post key have been used to loosening the screw of tool post so that the tool post can be rotated into 45 degree and perpendicular it to life centre / death centre. e)

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4. Turning Process a) Work piece have been clamped safely into 3 jaws chuck by using key chuck like shown at figure 2.

Figure 2 b) 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 c) Set the lathe to its lowest speed and turn it on. Doing work facing in both grounds until get 40mm measure. d) A tool with a sharp pointed tip will cut little grooves across the face of the work and prevent you from getting a nice smooth surface. e) Venire caliper was used to measure the work piece and was marked to undergo machining. Shown at figure 3.

Figure 3

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Figure 4

f) Turning process was proceed to get the diameter of the round bar aluminum ( figure 4 ). This process continuously proceeds until every part get the dimension. Step to feed are : 

Move y axis to front (negative). Make sure that there will be no crashed when y axis is moving.



Make sure the value of federate is compatible with spindle speed.



With slowly and carefully, move the Z axis to spindle (negative) and start cutting the work piece.

g) After side A undergo machining, the work piece switched inversely from back to front. h) Step ( f ) was repeated until work piece get the dimension.

5. Turning angle process a) Rotating tools post according to measure prepared to 45 degrees. b) Open rotor for x axis which work and doing cutting from thing coner work 9ntil hit to line have been marked c) After finish doing cutting for 45 degrees, doing once again according to work method that is same (b) but exchange degree to 60 degrees to get 30 degree deduction where 90 deg – 60 deg = 30 deg.

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Figure 5 6. Knurling process a) Set the lathe to the slowest spindle speed. Mount the work between centers, lubricate the tail stock center. b) Select the proper knurling tool, 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. c) Engage the longitudinal feed, and let the tool feed across the work piece to the desired length. Apply cutting oil during the knurling operation. d) Every third pass, run a clean-up pass by not increasing the pressure on the cross-slide.

7. Cutting external threads process a) The bolt (round stock) is vertically clamped into the vice between - jaws, attachments or clamping jaws for round stock; with this, only the part of the material which is to be worked shall project over the clamping device in order to reduce the springing of the bolt.

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b) In order to be able to put the tool in an angular position on the bolt, a chamfer must be made at the head of the bolt. This can be done with the help of a file or by a grinding machine. The chamfer shall have an inclination of approximately 45° and a width of at least 0.5 mm.

Figure 6 c) According to the nominal diameter of the thread, a threading die or diestock is used.

Figure 7 d) After thread cutting, the chips and rests of oil are removed from the thread flanks by compressed air or brush.

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8. Finishing Process a) To get good surface, sharp cutting were used b) Slow down the speed rate to get smooth surface.

9. Machine Shut Down a) Switch off machine main power followed by power supply switch. b) Keeps all tools in the box. c) Cleared all the chips by using brush and broom.

RESULTS: 1. Actual drawing

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2. Finish good drawing

Part

Actual Dimension

Actual Diameter

Diameter

Result

Tolerance

Dimension/

(±)

Angle

Result Diameter

1

4.00mm

-

0.5mm

30.00 deg

-

2

4.00mm

-

0.5mm

45.00 deg

-

3

10.00mm

22.00mm

0.5mm

9.50mm

22.00mm

4

2.00mm

16.00mm

0.5mm

3.00mm

16.00mm

5

10.00mm

8.00mm

0.5mm

10.00mm

8.00mm

6

10.00mm

6.00mm

0.5mm

10.00mm

6.80mm

Table 1- Result finish good

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DISCUSSION: From the table 1, it shown that all result was in tolerance where the tolerance is was ± 0.5mm. The highest inaccurate result is at part 5 diameter. The surface of good finish product was smooth although there got line marking at the surface. It may be due to the vibration of cutting tools. On the other hand, because of the three jaws spindle, the surface also got marking. Apart from that, there were no discontinuities at the work piece. 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.

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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.

CONCLUSION:

By the end of the laboratory, we can know the working principles of 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 work-piece 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 and parting. 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. Drilling is an operation of making a hole in a work piece with the help of a drill. In this operation, the work piece is held in a chuck and the drill is held in the tailstock. The drill is fed manually into the rotating work piece, by rotating the tailstock hand wheel. Turning is an operation of producing various steps of different diameters in the work place. This operation is carried out in the similar way as plain turning. At the end of the laboratory, 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.

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REFERENCES: 1) http://www.scribd.com/doc/17390328/Introduction-to-Lathe-Operations 2) SOME BOOKS IN LATHE (JOURNAL OF INDUSTRIAL TECHNOLOGY). 3) http://www.mini-lathe.com/ 4) http://fie-conference.org/fie2008/papers/1706.pdf 5) Pearson book : Manufacturing and engineering technologys

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Lathe Report

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