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

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

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

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

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

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 MoldingGMT - Glass Mat Thermoplastic Molding • Thermoforming • HIP - Hot Isostatic Pressing • …. + vast number of other technologies

EXAMPLES OF SOME “EXOTIC” MANUFACTURING PROCESSES http://www.cyrilbath.com/plasticforming_process.html

EXAMPLES OF SOME “EXOTIC” MANUFACTURING PROCESSES http://www.jsw.co.jp/en/mg_f/mg_tixo_f/mg_tixo_proce.htm

EXAMPLES OF SOME “EXOTIC” MANUFACTURING PROCESSES Process classification

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

DIRECT LABOR COSTS – UNITED STATES Process Processing Cost ($/hr in 1998 dollars) Injection Molding 30 + 0.06T (where T is the tonnage of the machine) Die casting 30.00 Machining 50.00 Powder Metal 40.00 Sheet Metal 30.00 Manual Assembly 30.00 Electrical work (assembly, PCB) 30.00 Finishing (paint, labeling) 30.00

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

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 withoutadding material to, or removing material from, the workpiece(i.e. material deformation,casting, and injection molding). • Joining-is the process of fastening workpiecestogether,permanently or semi-permanently. • Finishing - is the process of modifying a workpiece surface for thepurposes of protection and/or appearance (i.e. surface treatment).

1. MACHINING PROCESS - SAWING TYPE DESCRIPTION EXAMPLES

1. MACHINING PROCESS - SHEARING TYPE DESCRIPTION EXAMPLES

1. MACHINING PROCESS - MILLING TYPE DESCRIPTION EXAMPLES

1. MACHINING PROCESS - TURNING TYPE DESCRIPTION EXAMPLES

1. MACHINING PROCESS - DRILLING TYPE DESCRIPTION EXAMPLES

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

1. MACHINING PROCESS ABRADING TYPE DESCRIPTION EXAMPLES

1. MACHINING PROCESS ELECTRO - CHEMICAL TYPE DESCRIPTION EXAMPLES

2. FORMING PROCESS - DRAWING TYPE DESCRIPTION EXAMPLES

2. FORMING PROCESS - WIRE DRAWING TYPE DESCRIPTION EXAMPLES

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

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

2. FORMING PROCESS - CASTING TYPE DESCRIPTION EXAMPLES

2. FORMING PROCESS - ROLLING TYPE DESCRIPTION EXAMPLES

2. FORMING PROCESS - EXTRUDING TYPE DESCRIPTION EXAMPLES

3. JOINING AND FASTENING - MECHANICAL TYPE DESCRIPTION EXAMPLES

3. JOINING AND FASTENING - ADHESIVE TYPE DESCRIPTION EXAMPLES

3. JOINING AND FASTENING - COHESIVE TYPE DESCRIPTION EXAMPLES

4. FINISHING PROCESS - MECHANICAL TYPE DESCRIPTION EXAMPLES

4. FINISHING PROCESS - COLORING TYPE DESCRIPTION EXAMPLES

4. FINISHING PROCESS COATING TYPE DESCRIPTION EXAMPLES

Manufacturing Aluminum Cans [Lindbeck 1995]

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

DESIGN GUIDELINES FOR MACHINING Avoid completely spherical surfaces

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

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

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

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

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

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

DESIGN GUIDELINES FOR MACHINING DON’T Avoid long narrow holes

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

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

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

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

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

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

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

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