Injection Molding - MIT

← Back to document page

Injection GutowskiD. Roylance1V-6 air intake manifoldWater control valveBrass Vs Injection history of plastics1866 Celluloid1891 Rayon1907 Bakelite1913 Cellophane1926 PVC1933 Polyethylene1938 Teflon1939 Nylon stockings1957 velcro1967 The Graduate 1970 Earth Day recycling 3Ref Kalpakjian and SchmidMcCrum, Buckley, Bucknall4OutlineBasic operationCycle time and heat transferFlow and solidificationPart designToolingNew developmentsEnvironment530 ton, fl oz (45 cm3) EngelInjection Molding Machinefor wheel fabrication6Process & machine schematics** Source: *Schematic of thermoplastic Injection Molding machine7Process OperationTemperature: barrel zones, tool, die zonePressures: Injection max, holdTimes: Injection , hold, tool openingShot size: screw window8Typical pressure/temperature cycleTime(sec)Cooling time generally dominates cycle timeTime(sec)* Source: **9Ca

Part design rules Simple shapes to reduce tooling cost No undercuts, etc. Draft angle to remove part In some cases, small angles (1/4 ) will do Problem for gears Even wall thickness Minimum wall thickness ~ 0.025 in Avoid sharp corners

  Design, Injection, Molding, Injection molding