Machine Shop Lab Manual GENERAL INSTRUCTION

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Duane Payne
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1 Machine Shp Lab Manual GENERAL INSTRUCTION 1. Every student shuld btain a set f instructin sheets entitled manufacturing prcesses Labratry. 2. Fr reasns f safety, every student must cme t the labratry in shes. it is unsafe fr the students t cme t the labratry wearing garments with parts that that hang abut lsely. Students shuld preferably Use half-sleeve shirts. The Students shuld als ensure that flr arund the machine is clear and dry (nt ily) t avid slipping. 3. An aprn will be issued t each student. Students nt wearing an aprn will nt be permitted t the wrk in the labratry. 4. Instruments and tls will be issued frm the tl rm. Every student must prduce his identity card fr the purpse. Tls, etc. must be retuned t the tl rm n the same day. 5. The student shuld take the permissin f the Lab Staff / Tutr befre handling any machine. 6. The student shuld nt lean n the machine when it is wrking. 7. Pwer t the machines will be put ff 10 minutes befre the end f labratry sessin t allw the students t return the tls. 8. Students are required t clear ff the chips frm the machine and lubricate the guides etc. at the end f the sessin.

2 MACHINING PROCESSES Machining is ne f the prcesses f manufacturing in which the specified shape t the wrk piece is imparted by remving surplus material. Cnventinally this surplus material frm the wrkpiece is remved in the frm f chips by interacting the wrkpiece with an apprpriate tl. This mechanical generatin f chips can be carried ut by single pint r multi pint tls r by abrasive peratins these are summarized belw: Machining Prcesses Single pint tl peratins Multi-pint tl peratins Abrasive peratins 1. Turning 1. Milling 1. Grinding 2. Bring 2. Drilling 2. Lapping 3. Shaping 3. Tapping 3. Hning 4. Planing 4. Reaming 4. Super-finishing 5. Hbbing 6. Braching 7. Sawing The prcess f chip frmatin in metal cutting is affected by relative mtin between the tl and the wrkpiece achieved with the aid f a device called machine tl. This relative mtin can be btained by a cmbinatin f rtary and translatry mvements f either the tl r the wrkpiece r bth. The kind f surface that is prduced by the peratin depends n the shape f the tl and the path it traverses thrugh the materials. When the wrkpiece is rtated abut an axis and the tl is traversed in a definite path relative t the axis, a surface f revlutin is generated. When the tl path is parallel t the axis, the surface generated is a cylinder as in straight turning r bring peratins. Similarly, planes may be generated by a series f straight cuts withut rtating the wrkpiece as in shaping and planning peratins (Fig.3). In shaping the tl is reciprcating and the wrk piece is mved crsswise at the end f each strke. Planning is dne by reciprcating the wrkpiece and crsswise mvement is prvided t the tl. Surface may be machined by the tls having a number f cutting edges that can cut successively thrugh the wrkpiece materials. In plane milling, the cutter revlves and mves ver the wrk piece as shwn Fig. 4. The axis f the cutter is parallel t the surface generated. Similarly in drilling, the drill may turn and be fed int the wrkpiece f the wrkpiece may revlve while the drill is fed int it (Fig.5). The machine tls, in general, prvide tw kinds f relative mtins. The primary mtin is respnsible fr the cutting actin and absrbs mst f the pwer required t perfrm the machining actin. The secndary mtin f the feed mtin may prceed in steps r cntinuusly and absrbs nly a fractin f the ttal pwer required fr machining. When the secndary mtin is added t the primary mtin, machine surfaces f desired gemetric characteristics are prduced.. Cnsider a situatin where bth the cutting mtins as well as the feed mtin (prvided at the end f each strke) are rectilinear but perpendicular t each ther. Here the machined surface prduced is a plane. The line generated by the primary mtin (cutting mtin) is called the generatrix, while the line representing the secndary mtin (feed mtin) is called the directrix (Fig. 6a).

Depending upn the shapes f the generatrix and the directrix and their relative rientatins. Varius gemetries can be prduced n the wrkpiece.

It is clear that in this situatin the surface prduced will be a cylinder (Fig. 6b).

6c), lines are generated which results in a plain surface when a number f generatrices and directrices are placed side by side in the directin perpendicular t the plane f the generatrix.

3 Depending upn the shapes f the generatrix and the directrix and their relative rientatins. Varius gemetries can be prduced n the wrkpiece. Cnsider anther case when the generatrix is a circle and the directrix is a line perpendicular t the plane f the generatrix. It is clear that in this situatin the surface prduced will be a cylinder (Fig. 6b). A tapered surface can be prduced by merely changing the angle that the directrix makes with the plane f the generatrix. When the directrix is in the plane f the circular generatrix (Fig. 6c), lines are generated which results in a plain surface when a number f generatrices and directrices are placed side by side in the directin perpendicular t the plane f the generatrix. In actual practice, the cutting is perfrmed by cutting edge and nt a pint. Thus,a series f generatrix directrix cmbinatins are invlved and the relative mtin prduces a surface rather than a line. Basically there are tw methds f prducing new surfaces, the tracing methd and the generatin methd. In the tracing methd the surface is btained by direct tracing f the generatrices and when the surface prduced is the envelpe f the generatrics the prcess is knwn as generatin. Figs. 6(a) & 6{b), the plane and the cylindrical surfaces are btained by direct tracing, while in Fig. 6(c) the final surface gemetry is the envelpe f the generatrices

(c) Cncept f generatrix and (c) Directrix in the plane f

4 directrix. (a) Rectilinear generatrix and directrix. (b) Directrix perpendicular t the plane f generatrix. (c) Cncept f generatrix and (b) Directrix perpendicular t the plane f generatrix. (c) Directrix in the plane f generatrix.

5 INTRODUCTION TO LATHE MACHINE AND EXERCISE ON TURNING PART (A) OBJECTIVE : T study the characteristic features f lathe. i) Run the machine at lw speed and bserve the mtins, which cntrl the shapes f the surfaces prduced. Nte particularly the features, which cntrl the gemetrical frm f the surface. ii) Learn the names f the majr units and the cmpnents f each machine. Recrd these details (Table A). (Please ensure that the main islatr switch is ff and check that the machine. cannt be inadvertently started. D nt remve guards). Use the manufacture's handbk fr details that cannt be inspected. iii) Recrd the btainable speed and feed values (Table B). iv) Nte dwn the special features f the speed and feed cntrl n each machine. v) Pay attentin t the fllwing : a. Size specificatin f varius machine tls. b. Machine tl structures and guide ways I slide ways. c. Drive mechanism fr primary (cutting) mtin. d. Drive mechanism fr secndary (feed) mtin.

OBSERVATIONS : (a) Recrd the fllwing in a tabular frm: Machine Tl Type & Specificatins Make (Table A) Machine Size Speed given t Feed given t T l Wr k Tl Wrk Type f Surface Prduced lathe Type & Make

6 OBSERVATIONS : (a) Recrd the fllwing in a tabular frm: Machine Tl Type & Specificatins Make (Table A) Machine Size Speed given t Feed given t T l Wr k Tl Wrk Type f Surface Prduced lathe Type & Make Size Speed given t Feed given t T l Wr k lathe Tl Wrk Type f Surface Prduced OBJECTIVE : T make the part shwn in the sketch frm a mild steel rd n a Lathe. EQUIPMENT: List all tls and instruments used. Hld the bar in a three jaw chuck and face the end with a right hand facing tl. Make central hle with a center drill. Repeat these' peratins fr the ther end f the bar. Replace the chuck by a dg plate (Center plate) and hld the jb in a carrier between centers. Turn the bar t the required diameter with rugh cuts. Face the steps and finishes the diameters t the required sizes. Machine the rts and the

7 grve with frm tls. Machine the taper with the help f the crss-slide swiveling arrangement. Knurl the required surface. Cut the threads. OBSERVATIONS (a) Measure all dimensins (up t secnd decimal place) n the specimen turned by yur grup. Make a neat sketch and indicate all measured dimensins. (b) Discuss briefly hw tapered prtin was turned. (c) Shw the calculatin f the required gear rati fr thread cutting. (d) Sketch the main drive unit f 'the- lathe and shw hw the speed steps are btained. Questin Bank fr labratry quiz (ME Lab.) All answers must be brief and t the pint. Sketches must be neat and self-explanatry. 1. What are the units f cutting speed and feed n machine tls? 2. What is the use f back gear arrangement in a lathe headstck? 3. Hw is the rtatin imparted t a part, which is t be turned between centers? 4. What are the different ways f munting the wrk n a lathe? 5. What is the use f Center drilling? 6. What is the functin f chasing dial? 7. What is the difference between the lead and the pitch f a multistsrt thread? 8. Calculate the gear rati between the spindle and the lead screw fr cutting a screw with X threads per mm. The lead screw pitch is mm. 9. Why is the main spindle f a lathe hllw? 10. List the type f surfaces prduced by turning. 11. Sketch the plan/tp view f different types f cutting tls yu have used during the lathe exercise and indicate their respective names. 12. What are the instruments fr measuring the diameters f turned shafts? 13. What is the instrument nrmally used fr-measuring lengths f varius parts? 14. Explain hw yu can determine the taper angle f a taper pin. 15. Calculate the time required fr single pass straight turning f a cylindrical bar (diameter D1 length L) at a spindle speed f N rpm and feed f in apprpriate units. 16. Main scale f a Vernier has 10 divisins/cm and the least cunt f the instrument is 0.01mm. What shuld be the length f each divisin n the Vernier scale? 17. Hw are the spindle speeds changed? 18. What is the relatin between spindle speed and cutting speed? 19. What is the relatin between feed rate (mm/rev.) and spindle speed? 20. Are the back gears used t get lwer r higher spindle speeds? 21. Draw figures f left hand and right hand turning tls. 22. Hw is the size f lathe specified? 23. Why are fllw-rest and steady-test used? 24. What is Live Center and Dead center f the lathe?

8 MILLING: INTRODUCTION AND PRACTICE PART (A) OBJECTIVE: T study the characteristic features f Milling machine. i) Run the machine at lw speed and bserve the mtins, which cntrl the shapes f the surfaces prduced. Nte particularly the features, which cntrl the gemetrical frm f the surface. ji) Learn the names f the majr units and the cmpnents f each machine. Recrd these details (Table A). (Please ensure that the main islatr switch is ff and check that the machine cannt be inadvertently started. D nt remve guards). Use the manufacture's handbk fr details that cannt be inspected. jii) Recrd the btainable speed and feed values (Table B). iv) Nte dwn the special features f the speed and feed cntrl n each machine. v) Pay attentin t the fllwing: a. Size specificatin f varius machine tls. b. Machine tl structures and guide ways I slide ways. c. Drive mechanism fr primary (cutting) mtin. d. Drive mechanism fr secndary (feed) mtin. OBSERVATION : Recrd the fllwing in a tabular frm: Machine Tl Specificatins (Table A) Machine Type & Make Size Speed given t Feed given t T l Wr k Milling m/c Tl Wrk Type f Surface Prduced

SHAPING: INTRODUCTION AND PRACTICE PART (A) OBJECTIVE: T study the characteristic features f Shaper. i) Run the machine at lw speed and bserve the mtins, which cntrl the shapes f the surfaces prduced.

9 SHAPING: INTRODUCTION AND PRACTICE PART (A) OBJECTIVE: T study the characteristic features f Shaper. i) Run the machine at lw speed and bserve the mtins, which cntrl the shapes f the surfaces prduced. Nte particularly the features, which cntrl the gemetrical frm f the surface. ii) Learn the names f the majr units and the cmpnents f each machine. Recrd these details (Table A). (Please ensure that the main islatr switch is ff and check that the machine cannt be inadvertently started. D nt remve guards). Use the manufacture's handbk fr details that cannt be inspected. iii} Recrd the btainable speed and feed values (Table B). iv) Nte dwn the special features f the speed and feed cntrl n each machine. v) Pay attentin t the fllwing: a. Size specificatin f varius machine tls. b. Machine tl structures and guide ways I slide ways. c. Drive mechanism fr primary (cutting) mtin. d. Drive mechanism fr secndary (feed) mtin. OBSERVATION Recrd the fllwing in a tabular frm: Machine Tl Specificatins (Table A) Machine Type & Make Size Speed given t Feed given t T l Wr k Shaper M/c. Tl Wrk Type f Surface Prduced

10 EQUIPMENT List all tls and instruments used. Hld the wrk piece in a vice and machine the bttm surface shwn in the sketch. Invert the casting in the vice and machine the tp surface till the desired height is btained. Machine the inclined faces using right and left hand tls. Finally machine the grve. OBSERVATIONS (a) Measure all dimensins (up t secnd decimal place) n he specimen machined by yur grup. Make a neat sketch and indicate all measured dimensins. (b) Calculate the machining time fr the bttm surface f the specimen. (c) Explain -the quick return mechanism. (d) Explain the use f clapper bx n the machine. Questin Bank fr labratry quiz (ME Lab.) All answers must be brief and t the pint. Sketches must be neat and self-explanatry. 1. What is the driving mechanism n the shaping machine? 2. Why is quick return effect imprtant? 3. What happens t the quick return rati when the strke length is reduced? 4. Hw is feeding dne n a shaping machine? 5. Why is clapper bx prvided n a shaper? DRILLING AND FITTING PART (A) OBJECTIVE: T study the characteristic features f Drilling machine. i) Run the machine at lw speed and bserve the mtins, which cntrl the shapes f the surfaces prduced. Nte particularly the features, which cntrl the gemetrical frm f the surface. ji) Learn the names f the majr units and the cmpnents f each machine. Recrd these details (Table A). (Please ensure that the main islatr switch is ff and check that the machine cannt be inadvertently started. D nt remve guards). Use the manufacture's handbk fr details that cannt be inspected. jii) Recrd the btainable speed and feed values (Table B). iv) Nte dwn the special features f the speed and feed cntrl n each machine, v) Pay attentin t the fllwing: a, Size specificatin f varius machine tls, b, Machine tl structures and guide ways I slide ways. c. Drive mechanism fr primary (cutting) mtin, d. Drive mechanism fr secndary (feed) mtin.

11 OBSERVATION Recrd the fllwing in a tabular frm: Machine Tl Type & Size Speed given t Feed Specificatins Make given t (Table A) T Wr Tl Wrk Machine k l Type f Surface Prduced Drilling m/c EQUIPMENT : List all tls and instruments used. File all the sides f the mild steel wrk piece ensuring with a trisquare that all the angle are 90. Mark the centers f the hles. Mark the circle fr the diameters t be drilled. Punch at the center and at tw pints n the periphery f the required hle. Drill and ream the hles as required. Tap the hle using a set f three taps. OBSERVATIONS (a) Measure all dimensins (up t secnd decimal place) n the specimen made by yur grup. Make a neat sketch and indicate all measured dimensins. (b) Explain hw pwer is transmitted frm drill spindle t drill shank.' (c) Sketch a reamer and shw its main features. (d) Explain why a set f three taps was used. Questin Bank fr labratry quiz (ME Lab.) All answers must be brief and t the pint. Sketches must be neat and self-explanatry. 1. T which elements (tl and wrk) the speeds and feeds are prvided n 2. Lathe (ii) Milling machine (m) Shaper and (iv) Drilling machine. 3. What type f speed variatin mechanism is prvided in the drilling machines yu have studies? 4. What material is generally selected fr the machine tl structure? 5. What types f guides are used fr the main sideways f the basic machine tls? 6. Hw are the sizes f varius basic machine tls specified? 7. Why are square threads used n driving screws f machine tls? 9. Which f the fllwing prcess are intermittent? (a) Milling (b) Drilling (c) Shaping (d) Turning 10. What makes the simultaneus rtatin f the spindle and the feed mtin pssible n drilling machines? 11. What are the functins f flutes n a twist drill? 12. Explain hw pwer is transmitted frm the drill spindle the drill shank? 13. Why are drilled hles generally slightly larger than drill diameter? 14. What is the primary purpse f reaming? 15. Sketch a twist drill and name its principle pats. 16. Name the principal kinds f reamer. 17. Hw is the diameter f a drilled hle measured? 18. What is the apprximate rder f magnitude by which hle diameter increases after reaming? 19. What will happen when the drilling is dne with dull drill? 20. What are the types tapes in a hand perated tap set? 21. What is a curse file used fr sft wrk materials? 22. Describe very briefly the imprtant features f files? 23. Why the number f flutes n a reamer always even? 24. Hw is the drill held in spindle? 25. Why is the cutting fluid generally nt used during drilling cast irn? 26. Hw are the files classified? 27. Distinguish between secnd cut and duble cut files. 28. What is a scraper? 29. Des a saw blade cut n a return strke? 30. What peratin ther than hle drilling can be perfrmed n drilling machine?

INSTALLATION INSTRUCTIONS

Lad with min. 5 kg 405000090 405070090 INSTALLATION INSTRUCTIONS CONTENT: 1. Imprtant safety instructins. 2. Specificatins and main dimensins. 3. Parts included. 4. Installatin. 5. Adjusting the strke