1 MANUFACTURING PROCESSES WE REVIEW IN MME2259a DESIGN FOR MANUFACTURING (DFM) 1.Machining - is the process of removing or separating pieces of material from a workpiece (i.e. material removal). 2.Forming - is the process of giving shape to a workpiece without adding material to, or removing material from, the workpiece (i.e. material deformation, casting, and injection molding). 3.Joining - is the process of fastening workpieces together, permanently or semi- permanently. 4.Finishing - is the process of modifying a workpiece surface for the purposes of protection and/or appearance (i.e. surface treatment).

2 run out.sldprt WHAT IS WRONG?

3 ball.sldprt WHAT IS WRONG?

4 inclined.sldprt

5 WHAT IS WRONG? large surface.sldprt

6 channel.sldprt WHAT IS WRONG?

7 chamfer.sldprt WHAT IS WRONG?

8 half bar.sldprt WHAT IS WRONG?

9 thread.sldprt WHAT IS WRONG?

10 1.Hole depth/diameter ratio 2.Inaccessible features 3.Linear and angular tolerance rules 4.Mill sharp internal corners 5.Partial hole rule 6.Deep pocket/slot 7.Hole entry/Exit surface 8.Holes with flat bottom 9.Conform to standard drill sizes 10.Fillets on outside edges 11.Hole intersects cavity

11 Are any dimensions missing?

12 MANUFACTURING PROCESSES WE REVIEW IN MME2259a DESIGN FOR MANUFACTURING (DFM) 1.Machining - is the process of removing or separating pieces of material from a workpiece (i.e. material removal). 2.Forming - is the process of giving shape to a workpiece without adding material to, or removing material from, the workpiece (i.e. material deformation, casting, and injection molding). 3.Joining - is the process of fastening workpieces together, permanently or semi- permanently. 4.Finishing - is the process of modifying a workpiece surface for the purposes of protection and/or appearance (i.e. surface treatment).

13 DESIGN GUIDELINES FOR CASTING AND MOLDING DON’TDO Avoid sharp corners

14 DON’TDO Maintain uniform section thickness DESIGN GUIDELINES FOR CASTING AND MOLDING

15 DON’TDO Stagger ribs to prevent hot spots DESIGN GUIDELINES FOR CASTING AND MOLDING

16 DON’TDO Facilitate flow of molten material DESIGN GUIDELINES FOR CASTING AND MOLDING

17 DON’TDO Provide draft angle to be able to remove part from mold DESIGN GUIDELINES FOR CASTING AND MOLDING

18 Avoid abrupt changes in section thickness DON’TDO Better Best DESIGN GUIDELINES FOR CASTING AND MOLDING

19 Design bosses with uniform thickness DON’TDO DESIGN GUIDELINES FOR CASTING AND MOLDING

20 [Boothroyd et al 1994] Avoid deep narrow ribs DON’TDO DESIGN GUIDELINES FOR CASTING AND MOLDING

21 [Boothroyd et al 1994] Design with mold flow considerations in mind DON’TDO DESIGN GUIDELINES FOR CASTING AND MOLDING Flow hinders die fillingFlow aids die filling

22 [Boothroyd et al 1994] Avoid staggered split lines DON’TDO DESIGN GUIDELINES FOR CASTING AND MOLDING

23 Avoid using “sliders” in mold design DON’T DO DESIGN GUIDELINES FOR MOLDING

24 DESIGN GUIDELINES FOR MOLDING [Boothroyd et al 1994] Use uniform wall thickness DON’TDO

25 DESIGN GUIDELINES FOR MOLDING [Boothroyd et al 1994] Use uniform wall thickness DON’TDO

26 DESIGN GUIDELINES FOR MOLDING Do not design sharp corners, they create stress concentrations and obstruct material flow, … but do not design too large radii either. DON’T DODON’T

27 DESIGN GUIDELINES FOR MOLDING Keep section thickness uniform around bosses. Attach bosses to walls with ribs. DON’T DO

28 DESIGN GUIDELINES FOR MOLDING Keep rib thickness less than 60% of the part thickness to prevent voids and sinks. Space out ribs as shown. DON’T DO Sink mark

29 WHAT IS WRONG? pulley.sldprt

30 WHAT IS WRONG? boss.sldprt

31 box.sldprt WHAT IS WRONG?

32 WHAT IS WRONG? t beam.sldprt

33 ribs.sldprt WHAT IS WRONG?

34 WHAT IS WRONG? plate with boss.sldprt Cross section

35 WHAT IS WRONG? sprocket.sldprt

36 WHAT IS WRONG? slider.sldprt Cross section

37 DESIGN GUIDELINES FOR SHEET METAL pipe support.sldprt

38 DESIGN GUIDELINES FOR SHEET METAL tutorial.sldprt

39 DON’T A narrow web will cause bulging. Provide an ear in the blank or include the hole as a notch. DESIGN GUIDELINES FOR SHEET METAL

40 DON’T DO Offset bends DESIGN GUIDELINES FOR SHEET METAL

41 A cut-out is needed to bend flange DESIGN GUIDELINES FOR SHEET METAL

42 Use separated flanges when possible DESIGN GUIDELINES FOR SHEET METAL

43 Undesirability of having sharp internal and external corners. [Bralla 1992] DON’T DO No radiiRadii ½ of T or more DESIGN GUIDELINES FOR SHEET METAL

44 [Bralla 1992] DON’T DO Undesirability of having sharp internal and external corners. DESIGN GUIDELINES FOR SHEET METAL

45 sheet.sldprt WHAT IS WRONG? unfolded folded

46 sheet metal 02. sldprt WHAT IS WRONG?

47

48 Drilling

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51 Milling

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54 Turning

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57 Sheet metal

58 Sheet metal

59 Sheet metal

60 Sheet metal

61 Sheet metal