Plastic Injection Molding

Injection molding is a manufacturing process, which is making semi-finished parts of certain shapes by pressurizing, injecting cooling and separating molten thermoplastic.
Validate and optimize your tool design
 Challenges
 Design phases
 Simulation methods
 Summary and question
Many factors and decisions for molded components
 Continual change
Part geometry, process type, material design, mold design
 Application criteria
Function, cosmetics, volume, economics, life cycle
 Variations
Lot-2-material, machine ware, machine cloning, mold ware
Process and analysis types
 Gate location analysis
 Molding window
 Filling
 Runner balancing
 Fiber orientation
 Packing
 Design of experiment
 Venting analysis
 Crystallization analysis
 Core shift analysis
 In-mold label
 Wire sweep paddle shift
 Cooling and heating analysis…………steady state, transient, multi cycle, conformal
 ‘repaid heating and cooling…………water, steam electrical or induction
 Warpage and shrinkage analysis
 Thermoplastic injection molding
 Two-shot sequential, insert molding over-molding, IMD
 Gas-assisted injection molding
 Injection compression molding
 Bi-injection molding
 Microcellular injection molding
 Birefringence
 Structural reaction injection molding
 Rubber, liquid silicone injection molding
 Multiple-barrel reactive molding
 Reaction injection molding
 Microchip encapsulation and underfill encapsulation
 Export as-manufactured properties to FEA
 Defect visualization
The Best opportunity for the design process
 Part design
Concept, select material, prototype, estimate cost…..
 Mold design
Quoting, concept, initial layout, during fabrication…….
 Process development
Develop a stable process, optimize quality criteria, and minimize cycle time
 Production troubleshooting
Oops…….. I did it again
Product development cycle
 Lower costs through upfront insight into the part and mold optimization
 Reduce time to market and avoid warranty issues and recalls
 Have confidence that the design is the right
Part design
Normal wall thickness
 Thickness variation
 Traffic-light display
 Plastic design rule: thickness changes no more than 30% of nom. Wall thickness
Draft angle
 Draft variations
 The Draft is acceptable locations
 Suitable undercuts
Molding window analysis
 Take the guess work out of your process window
Helps determine process window and optimum conditions
 Full range of mold, melt temperature
 Pressure limit
 Temperature drop through part
Define the size of window by
 Number and location of gates
 Per geometry
 Material – can compare several materials
Mold design
 Runner system
 Venting
 Steel types
 Cooling and heating
Cooling and heating
Revised design
• Range 72 – 105 degree
• Difference 33 degree
• Average tem 89.1 degree
Original design
• Range 55 – 119 degree
• Difference 64 degree
• Average tem 88.2 degree
Variable coolant inlet temperature and coolant during a cycle:
• Heating phase
• Air purge
• Cooling phase
• Air purge
Mold heated by:
• Water, steam, electrical or induction
Heating and cooling phase:
• Time or temperature (thermocouple) controlled
The design is choice of your
• Mold design
• Part geometry
• Process type
• Material
Validate and optimize your design
• Part simulation
• Runner simulation
• Venting simulation
• Cooling and heating simulation
• Design of experiment