Polymer finishing

Question 1

What is an over moulding?

Answer 1

moulding second polymer over specific parts of a product

Question 2

What kind of plastic is often used for over moulding?

Answer 2

thermoplastic elastomer

Question 3

Why are over mouldings used?

Answer 3

provide areas of grip or texture

highlight different colours for different component parts

Question 4

What are the two types of over moulding methods?

Answer 4

two injection moulding moulds

twin-shot injection moulding

Question 5

Describe the two injection moulding moulds method

Answer 5

one mould for the products and one for the grip areas
product is injection moulded then placed into second mould where over moulding polymer is injection moulded on to the body

Question 6

Describe the twin shot injection moulding process

Answer 6

very fast , continuous cycle

injection moulding machine has mould designed to produce the product in one cycle
mould has 2 separate component cavities and can be rotated through 180 degrees so that they line up with the twin injection points
1. main product created then mould slight opens and rotates to the secondary position
2. mould closes and second injection applies the oversold

Question 7

Give an example of a product that might use over moulding

Answer 7

razor - grip

Question 8

What are some o the benefits of acrylic spray paints?

Answer 8

fast-drying, water -soluble paint that becomes water resistant when dry
improves aesthetics
can provide additional protein against effects of UV light and weathering

Question 9

Why is it impractical for mass customised products to be pigmented?

Answer 9

manufacturer would have to keep changing the granules on an injection moulder - expensive as well

Question 10

At what two points during production can pigments be added?

Answer 10

during manufacture process or manufacture of stock form