Cold Forming Plastic Sheet

Modify the timing as necessary.

Cold forming plastic sheet.

This article uses a sheet about 1 4 thick so all times are about 10 to 15 minutes per step. Cold forming plexiglas sheet can be cold formed bent at room temperature in a smooth arc and held to a radius by forcing the material into a curved channel support. Spectar supposedly looks and handles much like acrylic but with the surprising property that it can be cold formed without breaking or whitening and exhibits a memory effect holding a cold bend until reheated. The recommended radius of curvature should be a value greater than 180 times the thickness of the sheet for plexiglas g sheet and 300 times the thickness for plexiglas mc sheet see table below recommended minimum radii of curvature for cold formed plexiglas sheetnominal sheet thickness recommended.

Amorphous plastics like abs and polycarbonate generally have wide processing windows and good melt strength making them easy to thermoform. It can be formed into a permanent shape without heating avoiding the use of ovens or strip heaters. Polycarbonate is good for cold working. This is a type of vacuum forming where thin or thick gauge plastic sheet is placed over a die heated to a temperature that allows the material to become pliable then is stretched over the surface of the die while vacuum pressure pulls the sheet down and into its final shape.

For thicker sheets it will take longer and for thinner sheets it will take less time. Styrene thermoform plastic sheets high impact styrene is an inexpensive thermoform plastic that is easy to work with and produces excellent vacuum forming results making styrene the perfect beginner plastic for folks who are new to vacuum forming. It sandwiches the sheet between the mold and the plug. Any of the amorphous sheet plastics can be heated and formed.

Uk educational supply center centre mindsets online sells variously sized 3mm thick sample sheets of eastman s spectar copolyester at not completely outlandish prices. It can also shorten the time required to transport the heated sheet from the oven to the forming equipment thus minimizing the possibility of cold forming. Cold formed plastic cfp looks like acrylic but has a toughness approaching polycarbonate. Clamping and unclamping sheets preparatory to forming.

The design of the unit permits the operator to open all the clamps at once by simply opening a valve on the air line. It is also a shape memory polymer which will return to its original flat form on application of moderate heat such as immersion in very hot water. Thermoforming is useful for clamshell packaging. In this procedure after heating the polycarbonate sheet to its forming temperature the sheet is lowered to the mold followed by the plug.