Our supply: Special order material
Thickness: Available in 3mm, 5mm, 10mm, 20mm
Sheet sizes: 2400×1200mm, 2000×1000mm, 1500×1000mm, 1000×1000mm, 1000×500mm, 500×500mm, 500×250mm
Your supply: If preferred, you can also supply your own acrylic at any thickness up to 25mm, any sheet size up to 3000×2000mm
Black cast acrylic is a thermosetting plastic with a superior surface finish, flatness and optical properties. It is also a hard and brittle material which is sensitive to stress concentrations. This is most evident if parts are small or thin.
Black acrylic sheet is supplied to us with a protective plastic film on both sides. When only laser cutting is required, we leave the plastic film on. This helps to reduce heat marks and protects the surface from scratches.
As a benchmark, we recommend that minimum cut widths be no smaller than the corresponding thickness of the material. For example, if cutting from 3mm acrylic, its best not to allow anything less than 3mm in width. We can go smaller (see cut width image above) but this can make your components quite fragile which might not be suitable for your application. See more on cut widths and Kerf.
Acrylic laser cuts with a highly polished edge. We achieve this using a high laser frequency (ppi. pulses per inch ) that melts the edges as it cuts. If you look closely at the edge it is not entirely smooth and is made up of lots of tiny vertical lines. This is caused by the pulses of the laser which is more evident on thicker acrylic.
As with all materials thicker than 10mm we use a longer focus lens to help the laser maintain a clean cut. Thicker acrylic has a slightly different appearance than thinner acrylics where the pulsing of the laser is more evident. Read more about laser focal points and cut edge appearance.
For volume orders that require engraving from uniform sizes of rectangular or square acrylic sheets we also offer a diamond polishing service. Get in touch to find out more.
We have established optimised engraving settings for all our supply materials. For acrylic the marking is a shallow cosmetic light surface scratching. All cast acrylic engraves with a milky white finish.
If you just require vector engraving / scoring and cutting, we leave the protective film on both sides and engrave though the top layer of film into the acrylic surface. This helps to protect the top and bottom surface from heat marks from cutting.
As a standard we remove the top layer of protective backing when any raster engraving is required. We always leave the reverse side of the plastic film on to prevent any reverse markings when cutting is also required.
When raster engraving is required alongside cutting we need to remove the protective film to to engrave the surface. The downside of this is that the surface is more exposed when cutting. Very slight white heat marks can occur around the edge of the cuts. This is very minimal and usually unnoticeable. Markings tend to get slightly stronger when cutting and engraving acrylic thicker than about 8mm due to the slower speeds and higher powers required. Heat marks can be cleaned off using acrylic cleaner.
Since our standard engraving settings for acrylic are very shallow, no heat marks occur around the surrounding engraved areas. We can engrave deeper but bare in mind that due to the slower speeds and higher power required, there is a higher risk of heat marks. Residues also tend to build up on the surface.
Engraving at slower speeds is also more time consuming and therefore more expensive to process. Up to 2mm is considered deep for acrylic. Bear in mind that raster engraving is not an absolute science in terms of depth specification. It is therefore not suitable for making mechanical grooves or any features requiring precise depths. A depth of engraving will always be within a tolerance of +/-0.2mm.
When your engraving covers a large surface area the engraver can produce lines within the engraved surface. This is caused by the pulsing of the laser.
Cast PERSPEX is manufactured in accordance with ISO7823-1, which means for the thickness range of 2 to 25mm, a manufacturing tolerance of +/-10% plus 0.4mm (e.g. 8mm cast sheet could vary from 6.8mm to 9.2mm).