Design and Technology (D&T) KS3: Line bending

Line bending is used to make straight, precise folds in plastic components. Items like mobile phone stands are made using this process.

Before we get started here's what you'll need:

A sheet of plastic (usually acrylic is best)

Access to a hotwire heater or strip heater

And a right angle or adjustable jig

Cut the plastic sheet to the size and shape you need for your design. If you are using a CAD/CAM method then use a laser cutter., but you can also use a jig saw or coping saw and sand and finish the edges.

There are a few different options for heating plastic to bending point.

For this example, we are using a hot wire heater, but the process is the same for a strip heater.

Set the hot wire heater to the correct temperature for the type and thickness of your plastic. Acrylic like this softens at 160 degrees Celsius, but high impact polystyrene would soften at 80 to 90 degrees.

Heat the plastic until it bends easily in your fingers.

If the plastic is over 6 mm thick, it will require a cooler wire and a longer heating time and will need be turned during heating to ensure that it doesn't burn.

Using an appropriate angle or adjustable jig, hold the plastic at your desired angle until its cool.

Our 3 mm thick sheet will need to be held in position for two minutes, but thicker plastics would need to be held for longer.

In general, you'll need about 2 minutes for every three millimetres of thickness.

Once it's cooled, then you're ready to finish your plastic product.

Check out the 'Explain This...Finishing Plastic' in this series for more detail.