Bend and shape plastic sheets

Plastic panels have become established in many areas as a professional construction material for craftsmen and DIY enthusiasts. Typical processes to be done with plastic sheets include bending and forming plastic sheets. Below you will find valuable tips on how to shape and bend different plastic sheets.

Thermoplastics or plastomers - thermoformable plastics

Plastics with a low physical bond of linear carbon chains can be bent and deformed by heating. This process can be repeated as often as desired, so it is reversible. These plastics are also referred to as thermoplastics or plastomers. There are different plastics with these properties. Following are the most important thermoplastics for DIY enthusiasts:

  • Acrylonitrile butadiene styrene (ABS)
  • Polyamides (PA)
  • Polymethyl methacrylate (PMMA, also acrylic or colloquial Plexiglas)
  • Polycarbonate (PC)
  • Polyethylene (PE)
  • Polypropylene (PP)
  • Polystyrene (PS)
  • Polyvinyl chloride (PVC)

The processing of different plastic plates

Of these, polycarbonate (PC) and polymethyl methacrylate (PMMA) are among the most widely used plastics for processing. Effortlessly, these plastic sheets can be cut or milled, but also hot-formed. In the case of polycarbonate, you can even cold-form these plastic sheets to a certain degree. For more information, see "Makrolon Bend". But even the acrylic glass bending is bound to individual requirements.

Bend and shape plastic sheets: bend

The temperature during bending and deformation of plastic sheets

The biggest challenge in bending is the uniform heating to the necessary temperature. For PMMA, this temperature range is around 150 degrees Celsius, for polycarbonate as well, while that of PVC starts at already 110 degrees Celsius. However, it should be ensured that the heating takes place uniformly. If it comes to a point higher heating, the plastic plates in this area can be very soft to viscous, whereby the structure is destroyed.

Equipment for heating the plates

Depending on how large the plate is that you want to bend or deform, you should resort to different heating sources:

  • Hot air blower: up to a maximum of 30 to 40 cm
  • Oven or correspondingly large heating lamp from 30 to 40 cm
  • special oven for heating plastics

Each plastic can be bent in a different temperature range

Especially in extreme bending, for example, bending at 90 degrees, the temperature range must fit perfectly. Regardless of whether you bend plastic or metal - on the inside, the bent plate is always compressed while being pulled out at the outside. If the heating temperature is too low for a plastic plate, these stress cracks occur. The same thing happens if the plate is heated too much. Some plastics even have other effects. For example, ABS starts to become wavy.

Plastics are pushing back into their old position with varying degrees of force

In addition, all substances, including plastics, have the property of at least partially withdrawing back into their original form. Explicitly when cold forming PC, this effect is good to observe. But even during hot forming, some plastics tend to go back a bit towards their original position. Therefore, such plastics should always be bent slightly beyond what is necessary.

Aids for bending and shaping

Freehand bending and deformation is not recommended for any plastic. Instead, you can make gauges or negative molds into which the heated plastic plate is pressed. To maintain the shape, it can be fixed with collets or stones. If you want to bend curves, offers a good heat-conducting and soft metal such as copper or aluminum, which you acquire as desired rod or cylinder or edit accordingly. It is recommended for some plastics such as PVC to heat the copper cylinder as well. For other plastics such as PMMA, you should cool down your negative mold as soon as possible.

Tips & Tricks

Depending on which plastics you want to bend - you will find detailed instructions for bending and forming in the House Journal. Acrylic glass (polymethyl methacrylate or PMMA) is also colloquially referred to as Plexiglas. However, "Plexiglas" is a brand name of Evonik Röhm GmbH for acrylic glass. Likewise, polycarbonate plastic sheets are often referred to by consumers as "Makrolon". But that is again a Markmann name of Bayer for plastic sheets made of polycarbonate (PC).

Video Board: How to Bend Acrylic and Plexiglass - 3 Easy Ways