Injection moulding details Flashcards
(12 cards)
What are some typical materials for injection moulding?
ABS
Nylon
What are some advantages of injection moulding?
High efficiency
Cost effective
Multiple materials can be used at the same time
Low scrap loss
High tolerance (accuracy) so it can be repeatable
Internal details/ in mould decoration
What are some disadvantages of injection moulding?
Expensive tooling cost
Expensive machine setup and installation
Parts must be designed before (DFM)
How long is the process of injection moulding?
2 seconds to 2 minutes (varies)
What are the 4 main processes for injection moulding?
Clamping
Injection/ packing and holding
Cooling
Ejection
How does clamping work?
Both halves of the mould are closed together ensuring the two halves align perfectly together
How does injection/ packing and holding work?
Plastic pellets are fed into the machine (through the hopper)
Plastic melts and then is injected under high pressure
Once filled the machine injects more materials into the tool to compensate for shrinkage during the cooling stage
How does cooling work?
Longest part of the process as it cools from outside in
It must be solidified before being removed
How does ejection work?
An ejection system removes the product
The product may shrink in the tool which makes it harder for the ‘grab’ tool to release the product
What machinery and tools are used in injection moulds?
Injection mould machine
Mould tool
DFM/ CAD
Material used
Diagram of machine
How to ensure accuracy in injection moulding?
High tolerance due to holding stage
Use CAD to produce the mould
Ensure the injection mould machine is clamped
How to ensure consistency in injection moulding?
Quality control - check quality of batch every 10 products
Use batch number
Make sure they all have the same amount of time to cool
