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The thermoforming process involves the following steps:
- Extrusion of sheet
- Place the sheet on a mould
- Draw the sheet into the shape of the mould by heat and negative
force (vacuum).
Raw Materials
Most thermoplastics are usable. Must be in sheet form.
Tooling
Generally, machined aluminum is used, although poured composites and
even wood can be used for short runs.
Cost
Tooling costs are generally low and piece prices are strictly dependent
upon the speed of the machinery.
Examples of
Application
Covers, displays, blister packaging, trays, drinking cups & food
packaging.
Some of the possible advantages of thermoforming over injection
molding include
- Large surface-area parts formed on inexpensive molds andmachines,
due to low pressure and temperature requirements
- Easy formation of very thin-walled parts that are difficult to
make by other techniques.
- Very high rates of production of thin-walled parts atrelatively
low capital investment.
Advantages
- Extremely adaptive to customer design needs
- Rapid prototyping development
- Material and process is optimized for cost effectiveness
- High-speed production allows for just-in-time shipments
- Flexible tooling design offers a competitive advantage
- On-the-fly product enhancements with low additional costs
- Visually pleasing appearance
- Weight savings for consumer and manufacturer
- Wider design scope
- Lower tooling costs
- No anticorrosion spray necessary
- Paintable and colored plastic availability
- Fully integrated process with limitless flexibility for small to
large product designs
Disadvantages
- High initial equipment investment
- High startup and running costs possible
- Part must be designed for effective molding
- Accurate cost prediction for molding job is difficult
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