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[Leo Bernard]

Hi, I’m producing clear polycarbonate panels for a machine safety enclosure, cut from 4 mm sheet with small mounting holes and tight internal radii. Optical clarity and edge integrity matter more than cosmetics. From your experience, does laser cutting hold up well for this thickness, or is it safer to default to routing or waterjet for parts that will be bolted and see vibration?

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[Raphael Dubois]

I’m cautious with laser cutting PC, especially for this context. You can laser-cut 4 mm PC, but the heat input leaves residual stress that’s more prone to crazing and cracking. Laser edges can look fantastic, almost “flame polished”, but that’s exactly the sign you’ve melted/reflowed the edge. It’s especially bad if there’s any chemical/solvent exposure or cyclic vibration. Generally, routing is the safer default. Routing with a sharp O-flute and good fixturing gives you a cooler cut and lower stress. Internal radii are limited by tool diameter, so plan radii around that.

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[Jules Richard]

Waterjet is also a good option for PC in that thickness. You can get a slightly frosted edge and taper if the shop isn’t careful about multi-axis compensation. Also, watch fixturing – thin plastics can flutter. If you must laser: use the right wavelength/system (some lasers behave better than others), avoid ultra-tight radii, keep holes away from edges, and consider annealing after cutting to relax stresses. Also, use shoulder washers or grommets and don’t over-torque fasteners. But for bolted safety panels with vibration, I’d default to routing (or waterjet if routing geometry is awkward) and treat laser as a last resort unless you can validate with stress/chemical exposure testing.

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