1. DESIGN FOR MANUFACTURING (DFM) DESIGN FOR ASSEMBLY (DFA)

2. … but, correct decisions require knowledge of manufacturing process
Casting ?
Stamping ?
… but, correct decisions require knowledge of manufacturing process

3. DECISIONS AGAIN; HOW TO MANUFACTURE A FORK?
[Andreasen 1988]

4. DESIGNERS’ KNOWLEDGE OF MANUFACTURING PROCESSES
[Boothroyd et al 1994]

5. DESIGNERS’ KNOWLEDGE OF MANUFACTURING PROCESSES
Some of manufacturing processes for plastic products:
GRP - glass reinforced plastics
SMC - Sheet Molding
BMC - Bulk Molding
LFT - Long Fiber Thermoplastic Molding GMT - Glass Mat Thermoplastic Molding
Thermoforming
HIP - Hot Isostatic Pressing
…. + vast number of other technologies

6. EXAMPLES OF SOME “EXOTIC” MANUFACTURING PROCESSES
                                                                    
Loading: The blank is loaded in the form die.  The hot press heats the die and the blank to the material super-plastic temperature.
                                                                                                                  
Forming: Once the temperature is reached, it is accurately controlled, while the gas pressure slowly inflate the blank.
                                                                                
Forming: The gas keeps inflating the part to fit the die.  The material at the super-plastic temperature can allow up to 500% elongation
                                                                           
Release: At the end of the forming cycle, the part perfectly conforms with the die, even in its smallest details.
SUPERPLASTIC FORMING
This method consists in hot forming up to 1000° Celsius superplastic alloys by using an inert gas pressured up to 50 bars. Combined with diffusion bonding, this process allows honeycomb structures made of several sheets in a single operation.

7. EXAMPLES OF SOME “EXOTIC” MANUFACTURING PROCESSES
Thixomolding® is the injection molding of thixotropic metal alloys (magnesium to date) in a semi-solid or plastic-like state. The process takes place in a specially designed machine resembling a plastic injection-molding machine. Click here
to see the schematic of a Thixomolding® machine.

8. EXAMPLES OF SOME “EXOTIC” MANUFACTURING PROCESSES
Spinning
Shear molding
Flow molding
Process classification

9. EXAMPLES OF SOME “EXOTIC” MANUFACTURING PROCESSES
Metal spinning
Note that “exotic” does not necessarily mean “new”, it may be just forgotten.

10. DIRECT LABOR COSTS – UNITED STATES
Process Processing Cost ($/hr in 1998 dollars)
Injection Molding T (where T is the tonnage of the machine)
Die casting 30.00
Machining 50.00
Powder Metal
Sheet Metal 30.00
Manual Assembly 30.00
Electrical work (assembly, PCB) 30.00
Finishing (paint, labeling) 30.00

11. SHAPES AND COMMON METHODS OF PRODUCTION
[Boothroyd et al 1994]

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).
Joining - is the process of fastening workpieces together, permanently or semi-permanently.
Finishing - is the process of modifying a workpiece surface for the purposes of protection and/or appearance (i.e. surface treatment).

13. 1. MACHINING PROCESS - SAWING
TYPE
DESCRIPTION
EXAMPLES

14. 1. MACHINING PROCESS - SHEARING
TYPE
DESCRIPTION
EXAMPLES

15. 1. MACHINING PROCESS - MILLING
TYPE
DESCRIPTION
EXAMPLES

16. 1. MACHINING PROCESS - TURNING
TYPE
DESCRIPTION
EXAMPLES

17. 1. MACHINING PROCESS - DRILLING
TYPE
DESCRIPTION
EXAMPLES

18. TYPE DESCRIPTION EXAMPLES
[Lindbeck 1995]
1. MACHINING PROCESS - SHAPING
TYPE
DESCRIPTION
EXAMPLES

19. 1. MACHINING PROCESS ABRADING
TYPE
DESCRIPTION
EXAMPLES

20. 1. MACHINING PROCESS ELECTRO - CHEMICAL
TYPE
DESCRIPTION
EXAMPLES

21. 2. FORMING PROCESS - DRAWING
TYPE
DESCRIPTION
EXAMPLES

22. 2. FORMING PROCESS - WIRE DRAWING
TYPE
DESCRIPTION
EXAMPLES

23. TYPE DESCRIPTION EXAMPLES
2. FORMING PROCESS CHART - BENDING
TYPE
DESCRIPTION
EXAMPLES
WORK PIECE

24. TYPE DESCRIPTION EXAMPLES
2. FORMING PROCESS CHART FORGING
TYPE
DESCRIPTION
EXAMPLES
Hot or cold

25. 2. FORMING PROCESS - CASTING
TYPE
DESCRIPTION
EXAMPLES

26. 2. FORMING PROCESS - ROLLING
TYPE
DESCRIPTION
EXAMPLES

27. 2. FORMING PROCESS - EXTRUDING
TYPE
DESCRIPTION
EXAMPLES

28. 3. JOINING AND FASTENING - MECHANICAL
TYPE
DESCRIPTION
EXAMPLES

29. 3. JOINING AND FASTENING - ADHESIVE
TYPE
DESCRIPTION
EXAMPLES

30. 3. JOINING AND FASTENING - COHESIVE
TYPE
DESCRIPTION
EXAMPLES

31. 4. FINISHING PROCESS - MECHANICAL
TYPE
DESCRIPTION
EXAMPLES

32. 4. FINISHING PROCESS - COLORING
TYPE
DESCRIPTION
EXAMPLES

33. 4. FINISHING PROCESS COATING
TYPE
DESCRIPTION
EXAMPLES

34. Manufacturing Aluminum Cans
[Lindbeck 1995]

35. DESIGN GUIDELINES FOR MACHINING
Allow for run-out for tool
[Boothroyd et al 1994]

36. DESIGN GUIDELINES FOR MACHINING
Avoid completely spherical surfaces

37. DESIGN GUIDELINES FOR MACHINING
Use rectilinear shapes
Use co-planar surfaces
Minimize machined areas
Break-up large surfaces

38. DESIGN GUIDELINES FOR MACHINING
DON’T DO
Poor design
(no thread run-out)
Thread run-out

39. DESIGN GUIDELINES FOR MACHINING
DON’T DO
Provide boss to avoid drilling into an inclined surface
[Boothroyd et al 1994]

40. DESIGN GUIDELINES FOR MACHINING
DON’T DO
Do not design very difficult (or impossible) to machine hollows or overhangs

41. DESIGN GUIDELINES FOR MACHINING
DON’T DO
R = 0
impossible
Design for reasonable internal pockets radii

42. Φ = 10.57mm Φ = 10 mm DESIGN GUIDELINES FOR MACHINING
DON’T DO
Φ = 10.57mm
Φ = 10 mm
Use standard dimensions

43. DESIGN GUIDELINES FOR MACHINING
DON’T
Avoid long narrow holes

44. DESIGN GUIDELINES FOR MACHINING
DON’T DO
Avoid thin wall, they break when machining

45. DESIGN GUIDELINES FOR MACHINING
DON’T DO
Place holes away from edges

46. DESIGN GUIDELINES FOR MACHINING
DON’T DO
Provide access for tools

47. DESIGN GUIDELINES FOR MACHINING
DON’T
Avoid deep pockets that require long tools and cause tool vibration

48. DESIGN GUIDELINES FOR MACHINING
DON’T
Difficult to hold DO
Easy to hold
Design parts that are easy to fixture (hold)

49. DESIGN GUIDELINES FOR MACHINING
DON’T
Avoid long thin sections that cause vibration when machined

50. DESIGN GUIDELINES FOR MACHINING
DON’T DO
Remember that holes can’t change directions

51. DESIGN GUIDELINES FOR MACHINING
DON’T DO
Avoid external rounds which are difficult to machine, use chamfers instead