Cox Wokingham Plastics Limited

Thermoforming Process

Thermoforming is the general term for a group of processes where a heated sheet of plastic is drawn, pulled or pressed over or into a tool to form a shape.

The main types of forming used by Cox Wokingham Plastics are:

• Vacuum Forming
• Press Forming
• Drape or Bench Moulding
• Line Bending
• Free Blowing

Vacuum Forming is a machine based process which forms simple or complex 3 dimensional shapes by using a tool made from aluminium, wood or resin.

WP can produce vacuum formed parts up to 2400 x 1400 x 600 mm using a range of modern vacuum forming machines.

Pictured here is a medium size vacuum forming machine with 260 independent quartz heaters for accurate zoned temperature control over the whole sheet. The process is automatically controlled and monitored by computer to ensure the parts are consistent and reliable.

See the Media page for animation and video

High Definition Thermoforming This process is a development of the vacuum forming process, where dedicated tools and equipment, often with female tools, possibly using articulated sections can form more complex shapes and re-entrant (undercut) details, fine details on text/logos, etc.

Press forming is commonly used for sign and lighting applications using Acrylic materials.

Drape or Bench Moulding is used for simple forms. The material is heated in an oven and placed on a former, there is usually another former or cloth drape which holds the material in position while it cools. This process is used when the shape is simple and the complexities of a press tool are unnecessary.

Line Bending or Hot Wire Bending produces straight bends in plastic sheet, commonly used for acrylic covers and shelves. The material is positioned in a machine which heats a single strip of material which can then be bent to the desired angle.

Free Blowing is where a heated sheet is clamped around the edges and then air pressure is applied under the centre to form a bubble. The shape of the clamping ring determines the shape of the bubble. The parts produced by this method are ideal when a high level of clarity is required as there is no tool contact.