Fig. 2 shows an acrylic sheet being shaped using a strip heater. The polymer has been chosen for its specific properties including its ability to be formed ...
Question 1 Report
Fig. 2 shows an acrylic sheet being shaped using a strip heater. The polymer has been chosen for its specific properties including its ability to be formed into shape. Modern manufacturing processes allow polymers to be produced in large quantities efficiently. The choice of polymer depends on the required properties of the finished product.
The parts are all the same size. It is safe to use. It is made in a shop.
The plywood provides adequate hardness while keeping the overall weight low.
(a) Name the process shown in Fig. 2. [1]
(b) Explain why the acrylic must be heated before it can be bent. [2]
[Total: 3 marks]
Answer Details
(a) Name the process shown in Fig. 2 [1]
The process is line bending (also called strip bending). A strip heater contains a long, narrow heating element that heats the acrylic along a single line. Once the material softens along that line, it can be folded to the required angle. [1]
(b) Explain why the acrylic must be heated before it can be bent [2]
Acrylic is a thermoplastic polymer [1]. At room temperature its polymer chains are locked in position, making it rigid and brittle. Heating it above its softening point (approximately 160 degrees Celsius) gives the polymer chains enough energy to slide past one another, allowing the sheet to become pliable and bend without cracking or snapping [1]. Once it cools, the chains lock into the new shape and the acrylic becomes rigid again.
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