Acrylic Transport Services

Acrylic surfaces are softer than polycarbonate and scratch from contact with materials that would not mark either glass or polycarbonate. A single scratch across the face of a clear acrylic sheet is visible in the finished display or sign face from any viewing angle that allows reflected light from the scratch to reach the viewer's eye. Those scratches cannot be removed without optical polishing equipment that affects surface flatness, and on large-format sheet, optical polishing a scratch repair to an imperceptible level is effectively not achievable in a production fabrication shop environment.

Cast acrylic sheet and extruded acrylic sheet have different internal stress states and different handling sensitivity profiles that require different transport approaches. Cast acrylic is produced with low internal stress and is more dimensionally stable during temperature change but more susceptible to stress cracking from localized mechanical loading. Extruded acrylic has higher internal stress from the extrusion process and is more susceptible to stress cracking at edge damage locations, particularly after thermoforming operations that relax the extrusion stress. Handling both cast and extruded acrylic with the same approach creates different damage modes on each product type.

Acrylic is susceptible to stress cracking that initiates at edge damage and surface scratches when the sheet is under stress. A corner chip that appears to be minor cosmetic damage on a freshly delivered sheet can initiate a stress crack during thermoforming or during installation when the sheet is under thermal or mechanical stress. For fabricators who thermofrom acrylic into retail fixtures and display components, incoming edge condition is a production quality input that determines whether the sheet will thermofrom without cracking at the damaged locations.

Standard acrylic sheet without UV stabilizer yellows on extended UV exposure, though more slowly than polycarbonate. For clear acrylic in display applications where water-clear optical quality is the specification, UV-induced yellowing from a long open haul creates a perceptible tint that the display fabricator cannot attribute to anything other than the material's incoming condition. For UV-filtering acrylic used in museum display applications, UV exposure during transport consumes UV absorber content from the surface layer that was specified to protect the exhibits behind the acrylic.

Acrylic sheet ships from the manufacturer with protective masking film applied to one or both surfaces. The masking adhesive is selected for compatibility with acrylic and for clean removal. However, acrylic is more susceptible to masking adhesive migration than polycarbonate during hot-condition storage and transport, because acrylic's surface energy and its response to elevated temperature promote adhesive penetration into the surface layer. Masking left on acrylic during a hot summer haul and removed at the fabrication shop can leave an adhesive ghost pattern on the acrylic surface that requires solvent cleaning before fabrication can proceed.

Acrylic sheet for precision laser cutting, CNC routing, and close-tolerance fabrication applications requires dimensional flatness within the tolerances that the fabrication equipment's hold-down system can accommodate. A sheet with thermal bow from a constrained summer haul, or with permanent distortion from improper stacking support, cannot be held flat by the fabrication equipment's vacuum table, resulting in dimensional errors in the cut parts that trace back to the incoming sheet flatness condition.