1.15 Polymer Processes Flashcards
State two features of vacuum forming
Moulds are relatively easy to make but need a draft angle, air holes, and rounded corners
Not cost effective for one-off manufacture
Small-scale batch and mass production
State two features of thermoforming
Like vacuum forming, except an additional mould is pressed on the surface of the polymer sheet at the same time as the vacuum is applied
Good for fine details such as moulding in logos
Slow process, used in industrial production
State two features of calendering
Heated rollers squash and stretch the polymer to make it thinner
Industrial production method, carried out by specialist manufacturers
Used for continuous production
State two features of line bending
Uses an electrically heated element that provides heat along a line
Quite slow and labour intensive used in school or college workshops
Suitable for one-off or limited batch production
State two features of lamination (lay-up)
Requires a former to mould around
Polyester resin used as the polymer
A top gelcoat is applied which may contain pigment
CFRP requires an autoclave for the product to ‘cure’
State two features of injection moulding
Complex 3D shapes can easily be made
Fast industrial production method
High initial tooling cost
Used for large-scale mass or continuous production
State two features of blow moulding
Produces hollow thin-walled components
High initial tooling cost
Used for continuous production
State two features of rotational moulding
Seamless hollow components with a large wall thickness
Mould continuously rotated through heating and cooling
Large-scale batch or mass production
State two features of extrusion
Like injection moulding expect polymer is forced through a die
Industrial production method
Continuous position
State two features of compression moulding
Uses a pre-weighted ‘slug’ of polymer
Polymer removed from moulds
Large-scale batch production
