Material Process Selection Polycarbonate Aluminum Stainless steel Die

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, 1 st Ed, Butterworth-Heinmann

Decisions Original 5 -part assembly Proposed replacement part • 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 Product Design Marketing Production Team Process Design Production Control 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 Resist corrosion better Can be formed into almost any shape with no finishing Plastics less dense Less costly Better insulators

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

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 Castings: - small voids - pockets of impurities (inclusions) - large grain structure - poorer mechanical properties - Difficult to forge 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 propertiesproducer 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 Easier to fabricate due to resistant to corrosion lower tensile and yield strengths Better thermal and Lighter in weight electrical conductors 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

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

Level IV • At the parametric stage of design we pick the specific alloy or resin Injection molded: polycarbonate Stamped: CRS ASTM A 606 Die cast: aluminum A 380. 0

Example 1

Example 2