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FOLDING PLASTICS ON A STRIP HEATER

V. Ryan © 2005 - 2009

 

Plastics such as acrylic can be formed (shaped) in different ways. One of the most popular methods of shaping plastic materials like acrylic is to fold (bend) it on a ‘strip heater’, at different angles. An example of a strip heater is shown below. A heating element extends along the length of the strip heater and gives off intense heat when it is turned on.

The desk organiser seen opposite has a steel wire frame and plastic shelves. The selves have been folder on a strip heater. This heats the plastic along a line so that it becomes soft and flexible. It can then be folded to almost any angle. Thermoplastics such as Acrylic (Perspex) are most suitable for this type of product as they can be shaped when heated.

The diagram below shows the ‘disassembled’ desk organiser. The shelves have been removed to reveal the steel frame behind it. When the shelves clip back on to the frame, the organiser it forms can ‘free stand’ on a desk. The desk organiser can be used to hold folders and paper etc.....

   

   

 

   

STAGES IN THE MAKING OF A SHELF

   

STAGE ONE: The position of the fold is marked with a china-graph pencil. With this type of pencil line can be removed easily later.

   

STAGE TWO: The plastic is placed across the rests, above the heating element

STAGE THREE: The strip heater is turned on and the plastic is turned over every 30 seconds - one minute. This stops the heat rising from the element damaging the surface of the plastic.
   
 
   

STAGE FOUR: When the plastic becomes flexible it is placed in a ‘jig’. The jig is made to the correct angle, 90 degrees in this case. A square section block is then pressed against the plastic to hold it in position as it cools.

   

STAGE FIVE: A second line can be drawn on the plastic with a china-graph pen, heated and folded in the same jig. The shelf is complete.

   
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QUESTIONS:

1. Using diagrams and notes, describe the stages involved in the use of the strip heater.

2. Explain the safety rules you feel are necessary for the use of this 'hot' equipment.

   

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