Guide · Composites
Delamination shows up after the cut, when the panel is already scrap. This guide covers the mechanics of ply separation and the blade condition, pass strategy, backing and feed discipline that keep laminates together.
In a carbon-fiber laminate the weak plane is the resin-only interface between plies. Any cut that pushes or pries rather than shears loads exactly that plane, and the plies separate. Heat adds a second failure path: a softened matrix weakens the interface and smears resin over the fibres, which also degrades secondary bonding later.
The exit side is always worst. The last ply has nothing supporting it from below, so fibres push out and fuzz, or the ply lifts along the cut. This is why the same blade and feed that look fine on the top face still delaminate the bottom — judge every test cut on the back face first.
A worn edge raises cutting force silently — and rising force is what opens plies. So blade state belongs in the feed discussion, not just the maintenance one. Fresh, sharp tungsten carbide is the baseline; fuzzing that appears "suddenly" is usually an edge that wore out gradually. Replace at the first sign of fuzzing, and log when it happened.
Class follows stack thickness. Single fabrics and thin plies are drag-knife work. Stacks want vibration or oscillating blades — common vibration-class blades run about 2.5–3.0 mm wide — and heavier stock goes to router-class tooling. Match the class to the stack, then verify the holder against the machine nameplate; the oscillating & vibration collection lists the reference classes.
Multiple shallow passes beat one deep pass. Each pass keeps thrust low and lets the backing carry the exit fibres of that layer. Set pass depth by test cut on your layup — it depends on the stack and the matrix, not on a universal number.
Slow into corners and at lead-in and exit; keep speed constant in the straight runs instead of hunting. Dwell is the enemy: a blade that pauses under load pushes heat and force into one spot, and that spot is exactly where the laminate fails.
Put a sacrificial backing board directly under the layup so exit fibres are supported to the last ply. Pull vacuum close to the cut line, not only at the panel edge — the laminate must not be able to lift locally as the blade passes. For trim operations on finished parts, support the back face along the whole path, including overhangs. The summary stack:
Carbon dust is electrically conductive and respirable. That makes extraction, filtration and machine housekeeping part of cutting quality: conductive dust finds electronics, and fine residue on tables and rails shows up as tracking and sensor faults. Treat extraction maintenance with the same discipline as blade replacement. This is general practice guidance — follow your machine manual and local safety requirements for specifics.
Send the layup, thickness and defect photos — we verify the tool class against your machine nameplate before quoting anything.
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