Most process questions that stall a quote have the same shape: a drawing written for one material carries a callout that belongs to another. A flame-polished edge specified on a polycarbonate panel. A laser-cut profile called out on PVC. A solvent-bonded joint drawn into an HDPE tray. None of these can be built — not because the shop lacks the machine, but because the material refuses the process. This post is the reference table we wish every drawing were checked against before it reached the quote desk.
One thing to say plainly before the table: this is a statement of our shop’s practice with the materials we fabricate, not an industry standard. Different shops draw these lines in different places. Ours are below.
The matrix
| Material | Laser cut | Flame polish | Solvent bond | Heat / line bend | Thermoform | UV print |
|---|---|---|---|---|---|---|
| Acrylic | Yes | Yes | Yes | Yes | Yes | Yes |
| Polycarbonate | No — saw and CNC | No | Bonded — ask about the joint | Yes | Yes | |
| PETG | No | Yes | ||||
| HDPE | No | No — mechanical joints or welding | ||||
| PVC (incl. expanded) | No — never | No | Yes | |||
| MDF | — | — | — | — |
A blank cell is deliberate. It means “ask us about your part” — not yes, not no. A dash means the process doesn’t apply to the material at all.
Why each “no” exists
The blank cells are shop practice — the no’s are not. Each “no” traces to the material’s chemistry, and the sheet manufacturers’ own fabrication guidance draws the same lines.
Polycarbonate and the laser. Polycarbonate cannot be laser-cut. Where the beam vaporizes acrylic cleanly and leaves a presentable edge, polycarbonate responds by scorching and discoloring along the cut. A polycarbonate part is cut with a saw and machined on the CNC instead — which is why a polycarbonate drawing should carry saw and CNC callouts, and why the machine-guarding comparison treats cutting route as part of the material decision.
PVC and the laser. PVC is never lasered, in any form — rigid sheet or expanded. Burning PVC releases corrosive chlorine-bearing gas that attacks the machine and worse; sheet manufacturers’ guidance is unambiguous on it, and so is our standing rule. PVC parts are cut and machined by other methods.
Flame polishing is an acrylic method. The flame that flows an acrylic edge into a clear gloss does not produce that result on other materials, so flame polishing is used on acrylic alone. The Acrylic Edge Finishing Standards place it among six defined methods, and an edge callout that names it is an acrylic callout by definition.
HDPE and solvent cement. The solvent bonding that makes bonded acrylic construction possible has no purchase on HDPE — polyethylene’s surface energy is low enough that solvent cements don’t bite, a limitation the sheet manufacturers document rather than one any fabricator can work around. HDPE assemblies are designed around mechanical joints instead — fasteners, and geometry that locates parts without adhesive — or welded, which we do.
Where the “yes” cells carry conditions
Heat and line bending runs across the materials that tolerate it — acrylic, polycarbonate, PETG and PVC — so a bent-flange part has options the laser column doesn’t offer. We thermoform acrylic and polycarbonate over molds; how forming works and what it does to tolerances is its own subject. Bonding on polycarbonate is real work with its own rules: sheet manufacturers’ fabrication guidance treats polycarbonate as the more solvent- and stress-sensitive material, so joint design and bonding practice shift with the material rather than carrying over from acrylic.
And a yes is a process answer, not a grade answer. Laser-cut, saw-cut and machined edges each land differently against a finish specification — the comparison between CNC and laser cutting covers why the same profile can leave two different edges to finish.
What to do with the table
Use it at the CAD stage, before the callouts are written. The drawing’s process and edge language has to match the material line: an acrylic-style “flame-polished laser edge” on a polycarbonate part is a spec that can’t be built, and it will come back as a question instead of a price. If the part is moving between materials during design — acrylic to PETG, acrylic to polycarbonate — re-read every process callout against the new column, because the geometry survives the material change and the process plan usually doesn’t.
The full process vocabulary — cutting, forming, bonding, finishing, and where each belongs — lives in the fabrication processes guide. For the blank cells, or a material that isn’t in the table at all: ask with the part in hand. The honest answer depends on what the part needs the process to do.
