How cast acrylic sheet is made

Roehm America LLC manufactures ACRYLITE® cast (GP) acrylic sheet by the cell cast method. Essentially, liquid monomer (unreacted acrylic) is poured between two panes of glass which are separated by a gasket to control the thickness of the sheet. For each sheet made, a gasketed glass cell must be assembled. The cells are stacked on a vertical rack and put into an autoclave (a steam pressurized oven) for a given amount of time, based on the thickness, for reaction and curing. When the reaction has completed, the two panes of glass are separated from the acrylic sheet and the sheet is inspected for optical clarity and proper thickness. The sheets are then masked for protection and packaged for shipment.

The advantages of producing material by the cell cast method include better optical clarity than a material produced by any other method, and the flexibility to produce smaller quantities to allow for custom colors, textures, or other special features. When cell cast material is produced, the high optical quality results because it is manufactured by a static process, that is, one in which there is no movement of the sheet during the curing process, unlike, for instance, extruded type material. The distortion in cell cast acrylic is very minimal, even when viewed at very low angles. The light transmission is a consistent 92% throughout the sheet. The 8% loss is due to reflection at the sheet surfaces. Interior defects or light-scattering artifacts should be minimal. Special grades of sheet are available if you require material inspected to a higher standard to ensure the lowest possibility of defects.

Die cutting unmodified acrylic at room temperature is not recommended because the material is prone to cracking. Acrylics are notch sensitive materials and therefore cannot be die cut at room temperature without difficulties. Laser cutting or CNC routing may be better options for sizing parts. If the acrylic is heated to temperatures near to its softening point, then die cutting is possible. Heating and cooling of the parts must be well controlled to avoid introducing stress and distortion into the parts. Hot stamping is also possible as many of our customers successfully hot stamp materials.