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
Agenda
 Challenges
 Design phases
 Simulation methods
 Summary and question
Challenges
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
DFM
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
Undercut
 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
Summary
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

Rapid Injection Molding

What is More Convenient the Regular or Rapid Injection Molding

Plastic molding has been known as the most popular way of processing and creating plastic. There are three types of molding machines that is commonly used by most of the industrial companies nowadays. These are the electric, hydraulic, and the hybrid but there are two main processes that can be used in processing plastic these are the regular way and the rapid injection molding.

The regular way of injection molding involves the process of pouring plastic granules into the hopper and it slowly passes into the barrel where it is being heated and melted. The large screw passes the melted plastic into the mold where it is being cooled and finally hardens. Once the plastic has been solidified it will be ejected from the mold. However, the rapid injection molding uses the method of prototyping and conventional injection molding.

Compared to the regular process, the rapid injection molding is cost-effective and of course fast that will allow you to fix any problem encountered if the product design is not right. It uses an aluminum mold, which is unlike the hardened tool use in the regular process. The molds used in rapid injection molding consists of the A-side, which is also known as the cavity side, and the B-side, also known as the core side.

When choosing a design that will be used in the rapid process, make sure to avoid adding small features into the steep walls. Similar to the regular process, it is important that the mold has enough thickness that is equally distributed to avoid any damage into the product. There are different parts that are made from rapid injection molding and an example of this are some of the medical devices that is being used by most of the medical companies. medical companies need the medical plastic molding parts for the business as well.

Both of the processes have their advantages, but the best thing that you must do is to choose the one that will best meet to your needs.