Material - Process Selection Polycarbonate? Aluminum? Stainless steel? Die cast? Forged? Stamped? Molded? CRS? Nylon 6? Zinc? Poli, C., Design for Manufacture: a structured approach, 2011, 1st Ed, Butterworth-Heinmann

Decisions Decisions Decisions Proposed replacement part Original 5-part assembly Question: Should we replace the original 5-part assembly with a single part? Question: If so -what material should the part be made of? -what process should be used to make the part? Question: Should we choose the material first? Should we select the process first?

Materials First Approach Consider application information such as stresses, environment, codes, disposal, etc. Based on this information, select feasible material classes Now select associated process types Now consider application information such as stresses, environment, codes, disposal,etc. Select feasible process and material

Process First Approach Consider part information such as size, shape, production volume, etc Based on this select feasible process types Select associated materials classes Now consider application information such as stresses, environment, codes, disposal,etc. Select feasible process and material

Properties of Selected Cast Alloys

Properties of Selected Wrought Alloys

Properties of Selected Plastics

Concurrent Engineernig Team Product Design Process Design Production Control Marketing Production Shipping Involve Everyone (Team Approach)- from beginning to end / from cradle to grave Product and process design done simultaneously rather than sequentially

Taxonomy of the kingdom of materials, process and their attributes

Preliminary Material-Process Selection Cast Metals

Preliminary Material-Process Selection Thermoplastics

Preliminary Process and Material Selection - Wrought Processes

Preliminary Process and Material Selection - Casting Processes

Preliminary Process and Material Selection - Plastic Processes

Level I: Metals vs Plastics Can be formed into almost any shape with no finishing Resist corrosion better Better insulators Plastics less dense Less costly

Level I: Metals vs Plastics - continued Metals have better mechanical properties Better thermal and electrical conductivity; higher temp. capabilities Can be processed by a fast process - stamping!

Level II - Cast vs Wrought To choose must know: - How easily can the material be shaped? - Mechanical and physical properties. Complex shapes - Easy to cast - Difficult to forge Castings: - small voids - pockets of impurities (inclusions) - large grain structure - poorer mechanical properties Forgings: - start with cast billet that was then rolled/drawn/extruded - squeeze between die halves - formed using 2-3 stages - better mechanical properties

Level II - Cast vs Wrought - continued Mechanical properties (ductility and strength) are improved by wrought processes. For alloys of the same composition - wrought better than cast By choice of composition - high carbon steel casting better properties than low carbon steel sheet Specify desired mechanical properties- producer adjusts composition.

Level II - Cast vs Wrought - continued Consider casting process/alloy - complex/hollow shapes - large parts - when several parts can be combined Consider wrought alloys/processes - simple geometry - fast process such as stamping or extrusion can be used

Level II- Thermoplastic vs Thermoset Thermoplastics faster and easier to process Thermosets have higher flexural modulus => more rigid

Level III: Ferrous vs Non-ferrous Ferrous more resistant to corrosion Easier to fabricate due to lower tensile and yield strengths Better thermal and electrical conductors Lighter in weight Non-ferrous better mechanical properties; stiffer

Level III: Steels Strength, hardness, wear resistance increases As carbon content increases, ductility (%elongation) decreases structural shapes, forgings,plates hammers, dies, tool bits Resist corrosion, high strength

Polycarbonate has highest impact resistance Level III: Plastics Nylon has low coefficient of friction => used for bearings, bushings, gears, etc Polycarbonate has highest impact resistance Plastics with fillers have improved mechanical properties, electrical and thermal conductivities and cost more

Injection molded: polycarbonate Level IV At the parametric stage of design we pick the specific alloy or resin Die cast: aluminum A380.0 Injection molded: polycarbonate Stamped: CRS ASTM A606

Example 1

Example 2