Polycarbonate earns its place in custom work for one reason: it absorbs impact that would crack or shatter acrylic. Machine guards, high-abuse glazing, service-counter barriers, parts that get hit — that’s polycarbonate’s territory, and nothing else clear competes with it there. But a buyer who has been specifying acrylic for years tends to write polycarbonate drawings as if only the material line changed. It didn’t. The process plan, the edge menu and the handling rules all changed with it. Here is what to unlearn.
Cutting: saw and CNC, never the laser
Polycarbonate cannot be laser-cut. Where the beam leaves a clean, glossy edge on acrylic, sheet manufacturers’ own fabrication guidance rules the laser out for polycarbonate — the material scorches and discolors along the cut — so there is no laser route for a polycarbonate part in this shop: it is cut with a saw and machined on the CNC. Both produce accurate parts; what they don’t produce is the laser’s as-cut gloss edge, which matters for how you specify edges (below) and for cost expectations on intricate profiles, since detailed geometry that the laser would cut in one pass becomes CNC time instead. The guarding comparison walks through what that means on the polycarbonate part buyers ask about most.
Edges: the flame-polish callout doesn’t transfer
Flame polishing is an acrylic method — it is not used on polycarbonate. A polycarbonate edge is machined and sanded; what it is not is flowed to a watch-crystal gloss by a flame, and a drawing that copies an acrylic edge callout onto a polycarbonate panel is specifying something that can’t be built. The practical approach: name the faces and edges that are actually seen, specify a clean machined or sanded finish for them, and spend the attention saved on the material grade decision instead. The Edge Finishing Standards define the method vocabulary; on polycarbonate, the usable subset is simply smaller.
Forming: real, and its own discipline
We thermoform polycarbonate, including formed bends — a formed polycarbonate guard with a return flange, a wrapped cover, a bent sash panel are all buildable. What changes from acrylic is preparation: sheet manufacturers’ forming guides call for drying polycarbonate before heat forming, because moisture in the sheet turns into defects at forming temperature. Build that into schedule expectations for formed polycarbonate parts, and treat forming geometry the way formed acrylic is treated — as a process with its own dimensional behavior, not a bent version of the flat drawing.
Joining: bondable, but stress-aware
We bond polycarbonate — to other polycarbonate pieces and to other materials. The difference from acrylic is sensitivity: sheet manufacturers’ fabrication guidance treats polycarbonate as the more vulnerable material around solvents and concentrated stress, so joint design carries more of the load than it does in acrylic work. The same guidance is consistent on fasteners: oversize the holes, keep hardware torque controlled, and never let a screw become the thing that locks stress into the panel. If your assembly mixes bonded and fastened connections, say which joints do which job on the drawing — the bonding methods post covers how those choices get made on acrylic, and the logic transfers even where the chemistry doesn’t.
Grades: the material line is longer than “polycarbonate”
Polycarbonate sheet comes in more than one form. We have worked with abrasion-resistant coated sheet — for parts whose soft surface would otherwise scratch into cloudiness — and with multiwall sheet, where weight and stiffness trade differently; UV-stabilized grades are the other form real specs name, for parts that live near windows or outdoors. The grade belongs on the drawing. “Polycarbonate” alone leaves the most consequential decision to whoever reads the material line later — and a coated sheet, once specified, also constrains which processes can touch which face.
What the drawing should say differently
Five lines separate a polycarbonate drawing that quotes cleanly from one that comes back as questions:
- Material grade — polycarbonate, plus the qualifier the application needs (UV-stabilized, abrasion-resistant coated, multiwall), not the bare word.
- Process-true callouts — saw and CNC language, no laser references carried over from an acrylic template.
- An edge spec from the polycarbonate menu — machined or sanded, named per visible edge; no flame-polish callouts.
- Hole and slot sizing for the hardware — clearance and torque notes where the panel is fastened.
- Tolerances by the process that cuts it — the published fabrication tolerance ranges are written for acrylic, but the per-process principle transfers: a saw-cut part should carry a saw-appropriate range, not a blanket figure borrowed from another process. State the range per feature and we’ll confirm it at quote.
Where polycarbonate sits against the alternatives — acrylic for optics and finish, PETG for forming economics — is the material-selection question, and the processes guide holds the full process map this post is one column of. If the part in front of you is polycarbonate because something will hit it, send the drawing as it stands — the unlearning above is exactly what a file review is for.
