Akruit — Acrylic Sheet Properties and Use | akruit.com
Cast acrylic has better thermal stability, higher resistance to crazing and a wider thermo-forming range; the choice should follow the process, not the price.
Cast acrylic is poured as liquid monomer between mould plates and cured slowly, which gives it a more relaxed molecular structure. The result is better thermal stability and a wider thermo-forming window than extruded sheet.
Extruded sheet is pushed through a die, which holds tight thickness tolerance but locks in residual orientation. That orientation is what makes extruded stock more prone to crazing when an aggressive solvent meets a stressed surface.
For solvent bonding, cast is the default: it resists crazing better than extruded, so dichloromethane joints on cast sheet are less likely to open a crack network along the seam.
On narrow screens, swipe or scroll the plate sideways.
Thermo-forming also favours cast. The wider forming range means deeper draws without whitening or blistering, which is why deep display housings and light fittings are usually specified in cast stock.
Unmodified PMMA scratches more easily than glass regardless of the casting route, and many grades therefore carry scratch-resistant coatings. Where handling is frequent — retail fixtures, machine guards — specify a coated sheet.
Before buying, match the sheet to the process: solvent-bonded and thermo-formed parts in cast stock, flat tolerance-critical panels in extruded, and any laser-cut part annealed before it meets a solvent.
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