M A N U F A C T U R I N G P R O C E S S E S ME A S S I G N M E N T

Transcription

1 H.- J. Steinmetz, Jan M A N U F A C T U R I N G P R O C E S S E S ME A S S I G N M E N T To compress seeds and collect the oil for experiments a small machine shop has to manufacture 1000 presses which have to be manualy operated in a bench mounted hand press. The assembly drawing shows 3 parts. The plug and the piston have to be machined on a CNC Lathe using a bar stock feeder. To machine the cylinder a conventional Lathe is used. These parts have to be cut on a band saw, which has a saw blade width of 2mm, to a length of 107mm to have enough material for a finishing facing pass on both ends. The 16 ϕ1.0mm holes are drilled using a milling machines dividing head. For these small holes it is necessary to use first a center drill to make sure the ϕ1.0mm drill does not slip of the wall and break when it touches the circular outside diameter. The machine shop has no CAM software, therefore CNC programs have to be manually written and all start and endpoint calculations for the CNC programs are manually calculated. The machine shop has 3 machinists earning each $24.20/hour including all benefits and one shop foreman. His wage is $34.00/hour including all benefits. The overhead cost for administration and engineering for this small shop is 45%. The energy cost = $0.18kW/hr. The delay time, tv, is 10% of tg for all time calculations. Material for all 3 parts: AISI 4140 (Ck45 V) low alloy steel solid bar stock ϕ50.8mm and 12 feet long - $17.80/foot, g/cm3n/mm2density=7.85, Kc = The exponent table shows the following machining parameters for this material: C=280; F=-0.11; E=-0.25 and G= The flank wear factor for all external tools and boring bars is 0.3 mm. Leave an equal amount (DOC= 0.5 mm) of material for all finishing pathes. Parameters for the CNC Lathe and the tools to be used: Max power 12 HP, nmax=4000, E=0.85. Use the home positions from the lab manual and hard ground jaws. The replacement cost for this machine = $144, Cost for space Cs=$2,200.00/year. The maintenance cost Cm=$1,200.00/year. Tool and insurance cost Co = $3,400.00/year. The Lathe is used in 1 eight-hour shift 5 days a week, for 52 weeks each year, for a utilization time of 6 years with an 8% interest rate. Use all tools in the sequence listed for RH or D.O.C. f LH tool W Xset Zset Vc n Rs max machining Tool# ID# (mm) (mm) (mm) (m/min) (rpm) (mm) (mm) (mm/rev) External roughing, Reference Tool External finishing Cut off tool LH LH ? LH Parameters for the conventional Lathe and the tools to be used: Max power 5 HP, nmax=2000, E=0.80. The replacement cost for this machine = $36, Cost for space Cs=$1,100.00/year. The maintenance cost Cm=$ /year. Tool and insurance cost Co = $1,000.00/year. The Lathe is used in 1 eight-hour shift 5 days a week, for 52 weeks each year, for a utilization time of 8 years with an 8% interest rate. The following rpm s are available: The positioning time for drilling ttb=0.8min. The hourly rate for the band saw to cut 1000 workpieces to machine the cylinders is $ RH or D.O.C. f LH tool D Xset Zset Vc n Rs max Tool Tool# ID# (mm) (mm) (mm) (m/min) (rpm) (mm) (mm) (mm/rev) External facing tool RH ? Drill RH ? 0.22 Internal roughing Tool RH ? Internal finishing RH ? ? Int. 15degr. Chamfer RH ? ME328 Assignment 2012, Page 1

2 Parameters for the milling machine and the tools to be used: ttb=0.4min moving the dividing head 22.5 degr., ttb=0.6min chucking time (in & out), Max power 3 HP, nmax=6000rpm, E=0.80, tr=20min. Hourly rate $ The positioning time for the center drill and for the 1mm dril is 0.2min/hole and tool. RH or D.O.C. f LH tool D Xset Zset Vc n L max Tool Tool# ID# (mm) (mm) (mm) (m/min) (rpm) (mm) (mm) (mm/rev) Center drill RH ? Drill RH ? THE LAB REPORT HAS TO INCLUDE THE FOLLOWING TASKS IN SEQUENCE: 1. Calculate the amount of bar stock needed to machine all 3000 parts and the material cost. How many bars do we have to order? 2. Use the template-2011.dwg to make two CNC set up sheets. (one for the plug and one for the piston). 3. Calculate the workpiece datum and the reference points for both parts. The safety distance for the tool change position u=25.0 mm. PLUG (CNC Lathe) 4. Calculate the N.O.C., the D.O.C and all start and endpoints for the roughing passes on the PLUG. Show all calculations and the geometry. 5. Calculate all start and endpoints for the finishing passes on the PLUG. Show all calculations and the geometry. 6. Calculate all start and endpoints for the part off tool on the PLUG. Show all calculations and the geometry. 7. Calculate the federates for the surface finish required for the PLUG and the PISTON. 8. Write a CNC program for the PLUG. Use CNC-Space to format the text and use CNC-Plot to check your program for errors. Debug and optimize the program. 9. Calculate the maximum Power and the Tool life for the external roughing tool 10. Calculate the machining rate C and the hourly rate for the CNC lathe. 11. Calculate the tr and te for the PLUG. PISTON (CNC Lathe) 12. Calculate the N.O.C., the D.O.C and all start and endpoints for the roughing passes on the PISTON. Show all calculations and the geometry. P6 P5, 12 P11 P10 P9,18 P17 P16 P15 P1 P7 P4,13 P8 P P3 P2 2 ME328 Assignment 2012, Page 2

3 13. Calculate all start and endpoints for the finishing passes on the PISTON. Show all calculations and the geometry. P10 P9 P8 P7 P6 P1 P5 P4 P3 P Calculate all start and endpoints for the part off tool on the PISTON (INCL.GROOVING). Show all calculations and the geometry. Tool 3 Tool 3 2mm bar stock 50.8 P10,17 P mm P1,3,6 P12 P13 P7 P4 P14 P15 P5,8 P11 P2 Ø40mm Z=0 P Write a CNC program for the PISTON. Use CNC-Space to format the text and use CNC-Plot to check your program for errors. Debug and optimize the program. 16. Calculate the maximum Power and the Tool life for the external roughing tool 17. Calculate the tr and te for the PISTON. CYLINDER (Conventional Lathe) 18. Find tr and te for the band saw. The workpiece has to be 107mm long to leave approximately 1mm on each side for a finishing pass. 19. Calculate tr and te for the manual lathe operation on the CYLINDER. Show all calculations. Follow the exercise we did in class. 20. Calculate the maximum power for the drill used for conventional machining. 21. Calculate the machining rate C and the hourly rate for the conventional lathe. Milling machine 22. Calculate te for center drilling and drilling the 16 holes. 23. Fill in a Job Card using the Template_Jobcard.dwg for each of the 4 manufacturing processes. 24. Tabulate the total time and cost for these manufacturing processes. ME328 Assignment 2012, Page 3

4 Surface finish Ra 16 m (Ra 5 m) All dimensions in mm ISO Tolerance 0.1mm Break all sharp edges 0.3x45 o Ra 5 m Ra 5 PLUG Material 4140 Designer H.-J. Steinmetz Jan Scale: N.T.S. PISTON Material 4140 Designer H.-J. Steinmetz Jan Scale: N.T.S. Ra 5 Surface finish Ra 16 m (Ra 5 m) All dimensions in mm ISO Tolerance 0.1mm Break all sharp edges 0.3x45 o CYLINDER Material 4140 Designer H.-J. Steinmetz Jan Scale: N.T.S Surface finish Ra 16 m (Ra 5 m) All dimensions in mm ISO Tolerance 0.1mm Break all sharp edges 0.3x45 o O-Ring, ID 36.5, W 2.5 A A F ASSEMBLED SEED PRESS Material Designer H.-J. Steinmetz Jan Scale: N.T.S. View A - A ME328 Assignment 2012, Page 4

5 External roughing tool ID# 5, Rs=1.2mm External finishing tool ID# 15, Rs=0.4mm Part off tool ID# 130, Rs=0.2mm W=4.0mm, B=3,0mm Internal roughing tool ID# 300, Rs=0.8mm Internal finishing tool ID# 305, Rs=0.4mm HSS Drill diam. 30mm 15 degr. Chamfer bar Drillchuck with center drill Drillchuck with a 1mm drill ME328 Assignment 2012, Page 5

6 ME328 Assignment 2012, Page 6 1. PLUG Round Barstock PISTON Round Barstock CYLINDER Round Barstock D (inch) L (inch) D (inch) L (inch) D (inch) L (inch) d (mm) L (mm) d (mm) L (mm) d (mm) L (mm) d (cm) 5.08 d (cm) 5.08 d (cm) 5.08 L (cm) 2.40 L (cm) L (cm) V V V W = grams W = grams W = grams W = kg W = kg W = kg W = 0.84 lb W = 4.42 lb W = 3.82 lb Part off tool W=4mm Part off tool W=4mm Band saw blade width = 2mm Facing pass R & F = 2mm Facing pass R & F = 2mm Finishing facing = 1mm x 2 L=18+2+4=24mm L= =126mm L= =109mm 1000 Plugs need 24000mm 1000 Pistons need mm 1000 Cylinders need mm 112'*12"* barmmmmPlugsLLmmbar WPbarsWP 112'*12"* barmmmmPistonsLLmmbar WPbarsWP 112'*12"* barmmmmCylindersLLmmbar WPbarsWP Order ( ) = bars Material cost = $17.80/foot * 12feet * 72 bars = $ cm 2 d 2 cm 3 / cm g 3 cm 2 d 2 cm 3 / cm g 3 cm 2 d 2 cm 3 / cm g

7 2. ME328 Assignment 2012, Page 7

8 3. REFERENCE POINT CALCULATION for CNC - PROGRAM No. O 2012-PLUG DATE 02-Jan-12 What is the ZW to use for these calculation? ZW = mm How long is the workpiece? LW = mm What is the safety distance? u = mm X home mm TOOL DIMENSIONS Z home mm X-set Z-set REFERENCE TOOL ID # Tool # X-set Z-set W L max Rs D Ext LH roughing 5 T Ext LH finishing 15 T Cutt-off tool 130 T /4 CALCULATION of WORKPIECE DATUM (W) X = Z = mm mm CALCULATION of REFERENCE POINT (RP) for TOOL CHANGE REFERENCE TOOL RP X = mm RP Z = mm CALCULATION of REFERENCE POINT (RP) for TOOL CHANGE T01 RP X = mm RP Z = mm T02 RP X = mm RP Z = mm T03 RP X = mm RP Z = mm ME328 Assignment 2012, Page 8

9 REFERENCE POINT CALCULATION for CNC - PROGRAM No. O 2012-PISTON DATE 02-Jan-12 What is the ZW to use for these calculation? ZW = mm How long is the workpiece? LW = mm What is the safety distance? u = mm X home mm TOOL DIMENSIONS Z home mm X-set Z-set REFERENCE TOOL ID # Tool # X-set Z-set W L max Rs D Ext LH roughing 5 T Ext LH finishing 15 T Cutt-off tool 130 T /4 CALCULATION of WORKPIECE DATUM (W) X = Z = mm mm CALCULATION of REFERENCE POINT (RP) for TOOL CHANGE REFERENCE TOOL RP X = mm RP Z = mm CALCULATION of REFERENCE POINT (RP) for TOOL CHANGE T01 RP X = mm RP Z = mm T02 RP X = mm RP Z = mm T03 RP X = mm RP Z = mm ME328 Assignment 2012, Page 9

10 (()) PLUG Ø50.8 Bar stock D d' D = 41 mm Atan*0.5A2tan *0.5A 2= = d = D - 2(A3+0.5) + 2(A2) = 41-2( ) + 2( ) = mm Barstock diameter = 50.8mm d = smallest diameter = mm D.O.C. max = 3.0 mm tan15*3mm= N.O.C. = Barstock d ' = 2* D. OC..max = 1.94 cuts 2 cuts 2*3.0 D.O.C. = Barstock d ' = 2* N. OC.. P1 without safety distance, Rs=1.2mm Final D=40mm Rs0.5XD2tan15*32 2Rs38 tan = 2.91 mm 2*2 Zmm.6012L3tan7.5*Rs0.5R 1 s X=41.00 Z= X= Z=18.5 P1 with a 2mm safety distance, Rs=1.2mm Rs2XD2.5tan15*32 2Rs3 tan52.5 mm X= P2 Rs=1.2mm Z=20.5 L=18.0 ME328 Assignment 2012, Page 10

11 ME328 Assignment 2012, Page 11 P2P1 P1 with a 2mm safety distance, Rs=1.2 L=Z=20.5mm XmmP1 without a 2mm safety distance, Rs=1.2 L=Z=18.5mm XmmP2 3(tan7.5*) ZLRsRs X = 40.0mm 5. External finishing pass P2P1 P1 with a 2mm safety distance, Rs=0.4, L=Z=18+2=20mm(tan15(32))2(tan37.5*) XDRsRs P2 Rs=0.4, D=X=40mm, L=18mm 3(tan7.5*) ZLRsRs

12 ME328 Assignment 2012, Page 12 2mm Ø50.8 Bar stock 0.3mm Rs=0.4 Rs=0.2 From Lab manual page 61 figure 4 451tan0.41tan22ZXRs mm *0.32XX (0.3)-2(0.2343)=49.731mm 1Z 10mm Xmm ZZ =7.4657mm Or 250.8Xmm Zmm6. Part off tool From Lab manual page 61 figure 4 451tan0.21tan22ZXRs mm (2)X 54.8mm 120.3ZZ = mm *0.32XX (0.3)-2( )= mm Z2=0.0mm 7. Calculate the theoretical federates for the final surface finish required for the PLUG and PISTON. *0.4* thRsRammfrev use 0.2mmfrev *0.4* thRsRammfrev use 0.1mmfrev

13 8. CNC Program PLUG % O2012 N001 G00 G28 U0.0 W0.0 N002 G99 G21 N003 G50 X Z S4000 N004 G00 T0100 N005 G00 Z50.8 N006 X300.0 N007 G50 X300.0 Z50.8 S4000 N008 G96 S200 M04 N009 X54.8 Z18.5 T0101 M08 N010 G01 X-3.0 F0.35 N011 G00 U4.0 W2.0 N012 X44.98 N013 G04 X1.5 N014 G01 Z10.5 N015 X50.8 N016 G00 Z20.5 N017 X N018 G01 X41.0 Z N019 Z10.5 N020 X44.98 N021 M09 N022 G00 X300.0 Z50.8 T0100 M05 N023 G00 U0.0 W0.0 T0202 N024 G50 X296.8 Z50.5 S4000 N025 G96 S280 M04 N026 G00 X41.0 Z18.0 M08 N027 G01 X-1.5 F0.2 N028 G00 U4.0 W2.0 N029 G00 X N030 G04 X1.5 N031 G01 X40.0 Z N032 Z10.0 F0.1 N033 X F0.2 N034 X54.8 Z7.466 N035 G00 X200.0 M09 N036 X296.8 Z50.5 T0200 M05 N037 G00 U0.0 W0.0 T0303 N038 G50 X299.7 Z43.0 S4000 N039 G96 S80 M04 N040 G00 Z0.0 M08 N041 X54.8 N042 G01 X48.8 F0.08 N043 G00 X54.8 N044 Z2.417 N045 G01 X Z0.0 N046 X0.0 N047 G00 X200.0 M09 N048 X299.7 Z43.0 T0300 M05 N049 G28 U0.0 W0.0 N050 M30 % ME328 Assignment 2012, Page 13

14 DO *09. Power and Tool Life calculation for T01 DOC * f * kc * Vc Turning P= 3 VBa 60*10 * E = 31*5*60*10.8* = kw = HP VcC*Tool life DOC f kc Vc VB E Powe r Power kw HP CfT**FEGDOC f Vc Exponent Table Tool life (mm) (mm/rev) (m/min) C F E G min Calculate the machining rate C and the hourly rate for the CNC and conventional lathe. GIVEN: number of workers 3 number of shop foreman $/hour Overhead cost (%) 45 8 hrs. 5days*52weeks 1 working hours / day days weeks hours/year Replacement cost=start Value($) Interest rate % 8.00 Utilization time (years) 6.00 Cost for space (Cs) $ Cost for maintenance (Cm) $ Cost for insurance (Co) $ Energy cost KW/hour 0.18 Efficiency 0.85 CNC operator, Machinist $/hour Power ( HP ) Calculations: Ce = $ Cw = $ Mv = $ Year Sv Mv Rv Interest Start Value Mean Value Remaining Value f(mean Value) 1 144, , , , , , , , , , , , , , , , , , , , ME328 Assignment 2012, Page 14

15 6 24, , Ci = $ C = $ Wages Mach. Rate C Foreman Sum Overhead cost ($) Interest 34, Hourly Rate $ THE CUTTING TIME FOR THE CNC PROGRAM C:\2012-PLUG.TXT JANUARY The cutting time for each tool is minutes. Tool # Tool # Tool # The total cutting time is... The rapid traverse time is... The total tool change time is.. The total dwell time is minutes minutes minutes minutes. The overall production time is. ttu = 0.96 minutes. Chucking time (in and out) ttb = 0.60 minutes. tg = ttu + ttb = = tv = te = tg + tv = 1.56 minutes minutes minutes. tr = (3 * tg) + (4*number of tools) tr = (3*1.59) + (4*3) = tr= 25 minutes T = tr + ( te * m ) = 25 + ( * 1000 ) = 1741 minutes 12. PISTON Barstock diameter = 50.8mm d= smallest diameter = 2(16.707)=33.414mm D.O.C. max = 3.0 mm N.O.C. = Barstock d ' = 2* D. OC..max *3.0 = cuts 3 cuts ME328 Assignment 2012, Page 15

16 P6 P5, 12 P11 D.O.C. = Barstock d ' 2* N. OC.. = = mm 2*3 P10 P9,18 P17 P16 P15 P1 P7 P4,13 P8 P P3 P2 2 x=0.497 P15 a=2.793 x=0.497 P14b P14a P2 P Code X Z P1 G P2 G P3 G P P5 G P P7 G P P9 G P P P P13 G P P15 G P P P P14a X=2( x Rs ) = Z= P14b X= Z= P14b X= 36.0 Z= z = Piston finishing pass Code X Z P1 G P2 G P3 G P P5 G P P P P ME328 Assignment 2012, Page 16

17 P10 P9 P P8 P7 P6 P1 P5 P4 P3 P Grooving and parting off 2mm Tool 3 Tool 3 bar stock 50.8 P12 P10,17 P13 P14 P15 P11 P9 4.0 P1,3,6 P7 P4 P5,8 P2 2mm Ø40mm P16 Z=0 Code X Z R P1 G P2 G P3 G P P5 G P6 G P P8 G P9 G P P11 G P12 G P P14 G P15 G P16 G P17 G ME328 Assignment 2012, Page 17

18 15. CNC CNC Program PISTON % O2013 N001 G00 G28 U0.0 W0.0 N002 G99 G21 N003 G50 X Z S4000 N004 G00 T0100 N005 G00 Z152.8 N006 X300.0 N007 G50 X300.0 Z152.8 S4000 N008 G96 S200 M04 N009 X54.8 Z120.5 T0101 M08 N010 G01 X-3.0 F0.35 N011 G00 U4.0 W2.0 N012 X N013 G04 X1.5 N014 G01 Z-3.0 N015 X50.8 N016 G00 Z122.5 N017 X N018 G01 Z53.7 N019 X41.0 Z N020 Z-3.0 N021 X N022 G00 Z122.5 N023 X N024 G01 X36.0 Z N025 Z54.8 N026 X N027 X Z53.7 N028 M09 N029 G00 X300.0 Z152.8 T0100 M05 N030 G00 U0.0 W0.0 T0202 N031 G50 X296.8 Z152.5 S4000 N032 G96 S280 M04 N033 G00 X40.0 Z120.0 M08 N034 G01 X-1.5 F0.2 N035 G00 U4.0 W2.0 N036 G00 X N037 G04 X1.5 N038 G01 X35.0 Z N039 Z54.3 N040 X N041 X40.0 Z N042 Z-1.5 F0.1 N043 X42.0 F0.2 N044 M09 N045 G00 X296.8 Z152.5 T0200 M05 N046 G00 U0.0 W0.0 T0303 N047 G50 X299.7 Z145.0 S4000 N048 G96 S80 M04 N049 G00 Z14.0 M08 N050 X44.0 N051 G01 X36.5 F0.08 ME328 Assignment 2012, Page 18

19 2.9*1953**0.N052 G00 X44.0 N053 Z N054 G01 X Z N055 G00 X N056 Z N057 G01 X Z N058 G00 X N059 Z0.000 N060 G01 X N061 G00 X N062 Z2.000 N063 G01 X Z0.700 N064 G03 X Z0.000 R0.7 N065 G01 X3.0 N066 G00 X200.0 M09 N067 G00 X299.7 Z145.0 T0300 M05 N068 G28 U0.0 W0.0 N069 M30 % 16. Power and Tool Life calculation for T01 DOC * f * kc * Vc Turning P= 3 VBa 60*10 * E = 3*0.3560* = kw = HP 20T01 Power requirement for turning Answers VcC*Tool life DOC f kc Vc VB E Power Power Input kw HP Equation T01 DOC*f*TFEGTool life Answers DOC f Vc Exponent Table Tool life (mm) (mm/rev) (m/min) C F E G min Input ME328 Assignment 2012, Page 19

20 THE CUTTING TIME FOR THE CNC PROGRAM C:\2012-PISTON.TXT JANUARY The cutting time for each tool is minutes. Tool # Tool # Tool # The total cutting time is... The rapid traverse time is... The total tool change time is.. The total dwell time is minutes minutes minutes minutes. The overall production time is. ttu = 1.95 minutes. Chucking time (in and out) ttb = 0.60 minutes. tg = ttu + ttb = = tv = te = tg + tv = 2.55 minutes minutes minutes. tr = (3 * tg) + (4*number of tools) tr = (3*1.59) + (4*3) = tr= 25 minutes T = tr + ( te * m ) = 25 + ( * 1000 ) = 2830 minutes CYLINDER, conventional lathe 18. Find tr and te band saw From Table 7: tr = 5 min, te = 1.10 min, L material = 107 mm 19. Find tr and te for the conv. Lathe trg1 = Get DWG and Job card + Study DWG + get Tools + time for each tool = ( 5 tools * 0.5 min ) 8.5 min trg2 = Set up 3-Jaw chuck 2.0 min trg3 = Change inserts, int. roughing, ext. & int. finishing, 15 degr. chamfer 4.0 min trg4 = Set tools on center, int. roughing, int. finishing, 15 degr. Chamfer 1.2 min Sum trg 15.7 min tr = 16 min Chucking time IN Pos. finishing facing tool ttb = 0.3 min ttb = 1.1 min Find L and n for a finishing facing pass D5LRs 2 m mmL28m2nVc*939.89rpmn d* 50.8* rpmME328 Assignment 2012, Page 20

21 ME328 Assignment 2012, Page 21**800*50.8* minnDmVc min*800*0.2Ltunf Pos. Drill ttb = 0.8 min Find L and n for drilling finalLWPammLmm 3* *30*Vcnrpmnrpmd **240*30* minnDmVc min*240*0.22Ltunf 1 st Pos. Internal roughing bar ttb = 1.0 min 2 nd Pos. Internal roughing bar ttb = 0.3 min 3 rd Pos. Internal roughing bar ttb = 0.3 min Drill diameter = 30 mm Final roughing diameter = 39 mm D.O.C. max = 1.5 mm N.O.C. = 2*...max Final diameter Drill diameter D OC = *1.5 = 3 cuts 3 cuts finalLWPmmLmm 31* *33*Vcnrpmnrpmd 32* *36*Vcnrpmnrpmd 33* *39*Vcnrpmnrpmd 3*3* min*400*0.25Ltunf Pos. Internal finishing bar ttb = 1.8 min L = 109 mm, d = 40 mm

22 ME328 Assignment 2012, Page 2231* *40*Vcnrpmnrpmd *0.4* thRsRammfrev use 0.1mmfrev min*600*0.1Ltunf Pos. Internal 15 degr. bar ttb = 1.3 min L = 109 mm, dmax = mm 31* *41.624*Vcnrpmnrpmd 0.08givenmmfrev min*600*0.08LtunfChucking time for a finishing facing pass on the 2 nd side, IN & OUT ttb = 0.6 min Pos. finishing facing tool ttb = 1.1 min Find L and n for a finishing facing pass DdLRsmmLmm 3* *50.8*Vcnrpmnrpmd 80.05min*800*0.2Ltunf Chucking time OUT ttb = 0.3 min

23 24.662mi*30*02*1953* *1*08ttb ttu Operation min min Chucking time IN 0.3 Pos ext. facing tool 1.1 Facing pass Pos Drill 0.8 drill diam st Pos. Internal roughing bar nd Pos. Internal roughing bar rd Pos. Internal roughing bar internal roughing passes Pos. Internal finishing bar 1.8 finishing boring pass Pos. Internal 15 degr. bar 1.3 Mach. 15 degr. Slope Chucking time IN & OUT for 2nd facing pass 0.6 Pos ext. facing tool 1.1 Facing pass Chucking time OUT tg = ttb + ttu = tv = te = T=tr+(te*m) tr= 16 min m= 1000 Conventional machining (Lathe) T = min 20. Calc. the max power for the drill vc0nfind n d * *reduce to n=240rpm n*d*240*30*vc rpmmnPD*f* 412*10K*cEVc.0.= 3.03 KW = 4.06 HP ME328 Assignment 2012, Page 23

24 21. Calculate the machining rate C and the hourly rate for the Conventional lathe GIVEN: number of workers 3 number of shop foreman $/hour Overhead cost (%) 45 8 hrs. 5days*52weeks 1 working hours / day days weeks hours/year Replacement cost=start Value($) Interest rate % 8.00 Utilization time (years) 8.00 Cost for space (Cs) $ Cost for maintenance (Cm) $ Cost for insurance (Co) $ Energy cost KW/hour 0.18 Efficiency 0.80 Machinist $/hour Power ( HP ) 5.00 Calculations: Ce = $ Cw = $ Mv = $ Year Sv Mv Rv Interest Start Value Mean Value Remaining Value f(mean Value) 1 36, , , , , , , , , , , , , , , , , , , , , , , , , , , , Interest 11, Ci = $ C = $ 4.94 Wages Mach. Rate C 4.94 Foreman Sum Overhead cost ($) Hourly Rate $59.00 ME328 Assignment 2012, Page 24

25 min07minMILLING MACHINE 22. Calc te for drilling 16 holes GIVEN: tr = 16 min Chucking time IN + OUT ttb = 0.6 min Moving the dividing head 1/16 of a revolution (22.5 degr.) ttb = 0.3 min Chucking time IN & OUT ttb = 0.3 min Pos. for center drilling ttb = 0.2 min Pos. for drilling ttb = 0.2 min L for center drilling diam 1 = 3 mm nl for drilling diam 1 = 8 mm 30Vc*7639.4rpmn d* 1* 10240rpmL13tuCenter drill 16 holes n*f 60*0.2 6*L18tuDrill 16 holes n*f 60*0.2 6*ttb ttu ttu or Operation min times min ttu Chucking time IN Rotate dividing head for center drilling Pos center drill Center drill 1mm deep Rotate dividing head for center drilling Pos Drill Drill diam 1mm through Chucking time OUT tg = ttb + ttu = tv = te = ME328 Assignment 2012, Page 25

26 23. Fill in a Job card for this process showing all set-up times and machining times. Date: 2012-Jan Description: PLUG Part Number: Name: H-J.S Material: 4140 V4 Quantity: Dimensions: Diameter 50.8 mm 1000 mm Work Seq. No. Center Text, Fixture, Jig, Tool tr te 5 CNC Lathe Use bar stock material diam 50.8 Load Program PLUG to mach. Workpieces Inspection Total Process Time (min) T= 1741 Date: 2012-Jan Description: PISTON Part Number: Name: H-J.S Material: 4140 V4 Quantity: Dimensions: Diameter 50.8 mm 1000 mm Work Seq. No. Center Text, Fixture, Jig, Tool tr te 5 CNC Lathe Use bar stock material diam 50.8 Load Program PLUG to mach. Workpieces Inspection Total Process Time (min) T= 2830 ME328 Assignment 2012, Page 26

27 Date: Jan Description: CYLINDER Part Number: Name: H-J.S Material: 4140 V4 Quantity: Dimensions: Diameter 50.8 mm 1000 mm Seq. No. Work Center Text, Fixture, Jig, Tool tr te 5 Band Saw Cut material L= 107mm Conv Lathe Machine Cylinders Ext. finishing facing tool Drill diam. 30mm Int. roughing boring bar Int. finishing boring bar Int. 15 dgr. Tool 10 Inspection Total Process Time (min) T= Date: 2012-Jan Description: CYLINDER Part Number: Name: H-J.S Material: 4140 V4 Quantity: Dimensions: Diameter 50.8 mm 1000 mm Seq. No. Work Center Text, Fixture, Jig, Tool tr te 10 Milling mach. Drill 16x1mm holes Set up dividing head Center Drill Drill diam. 1 mm 10 Inspection Total Process Time (min) T= ME328 Assignment 2012, Page 27

28 24.. Tabulate total production time and cost for this job m tr te h/rate T Cost min min $ min $ Material $15, Saw Cylinder $ CNC Lathe Plug $2, CNC Lathe Piston $3, Conv. Lathe Cylinder $17, Milling Mach. Cylinder $31, Total $71, hours ME328 Assignment 2012, Page 28