PMMA acrylic glass XT / GS / Continuous Cast
Acrylic glass (PMMA, Plexiglas®) possesses good optical and mechanical properties. The crystal clear thermoplastic PMMA, the abbreviation for polymethyl methacrylate, is used for ophthalmic and other types of lenses, greenhouses, and skylights. Acrylic glass is popular in model making due to its versatility and transparency. The name Plexiglas as a term for acrylic glass originated with its inventor, Otto Röhm. This brand name has become part of everyday language.
ACRYLIC GLASS XT (extruded) is manufactured by melting acrylic pellets and subsequently forming the molten mass into sheets, rods or tubes. 'XT' stands for 'extruded'. During extrusion, micro-granules are transported in a machine through a rotating screw for melting; the resulting acrylic molten mass is then processed through nozzles into the desired shape.
Acrylic glass XT has the following properties: hardness, stiffness, good tensile, compressive and fatigue strength and low susceptibility to scratches. In addition, it is colourless and very transparent. For exterior use, it is lightfast and ageing and weather resistant and isn't subject to yellowing.
PLEXIGLAS® GS (moulded) results when the raw materials are brought together in a mould, for example, between two glass plates, where they react to the polymer.
Moulded acrylic glass has the advantage of being more easily processed by machining. Acrylic glass XT, on the other hand, melts more quickly during processing, thus clogging drills and saws and retaining a white cutting edge. It is of course less expensive, since extrusion is less costly than moulding between glass plates.
PMMA GS is hard and stiff and has good tensile, compressive and fatigue strength. For a plastic, it has the advantage of having low susceptibility to scratches.
PMMA GS is absolutely colourless and has high light transparency.
Extruded acrylic glass can be used on a sustained basis at temperatures up to 70 °C; acrylic glass GS can be used as high as 80 °C.
The manufacture of ESLON-DC sheets of PMMA/acrylic glass occurs during continuous casting. When the sheets have a low thickness, it has similar properties to extruded PMMA; with thicker sheets, its behaviour approximates that of moulded PMMA. If parts made of PMMA are to be glued or moulded into domes, the parts should be tempered before processing in order to reduce internal stresses in the material and to achieve a better dimensional stability.
Acrylic glass at J. Schwarz
J. Schwarz processes acrylic glass by warm working using a blade or hot wire bender. In addition, lasing, milling and diamond and flame polishing are possible. Six laser cutting machines are available with a processing area of up to 3000 mm x 1500 mm.