Laser cutting, engraving and marking of foams

Cutting, engraving or marking: define the expected result

Cutting aims to separate material along a contour, for example to create a tool compartment in an insert. Engraving aims to remove material locally; marking mainly aims to create a visible reference. On a cellular structure, check that the operation does not compromise the intended function: protection, fit, sealing or filtration.

To prepare a suitcase insert project with NWS LASER, specify the contours to be cut and the desired markings. These objectives must be assessed using the exact foam reference and the equipment being considered; they do not constitute a guarantee of feasibility.

Polymer foams: start with the actual formulation

The designations PE for polyethylene, PES for polyester and PUR for polyurethane identify polymer families, not laser suitability. To define an NWS LASER solution, the exact formulation must be checked against the permitted materials and safety conditions of the equipment under consideration. No general compatibility can be inferred from the polymer name alone.

Request the technical data sheet and safety data sheet, or SDS, when available. Also identify coatings, adhesives and additives. Do not begin testing on foam containing PVC, PTFE or other halogenated compounds. Adhesives, resins and flame-retardant treatments also require an analysis of their composition and risks. A “flame-retardant” label therefore does not mean “laser-compatible”.

Metal and ceramic foams: a separate study

For metal foam, the alloy, thickness, porosity and any surface treatments must be specified. A fiber laser may be considered for this type of material, but feasibility and process parameters must be determined on a case-by-case basis. It is therefore not appropriate to state a general maximum thickness or guarantee a marking result without prior testing on the specific material reference.

Ceramic foams, on the other hand, are somewhat fragile and may be susceptible to cracking during cutting. Cutting, engraving and marking must therefore be evaluated separately, based on the composition and precise characteristics of the ceramic. A color change or controlled material removal cannot be guaranteed without prior process validation.

Qualify a sample before production

Once the composition and safety conditions have been reviewed, a supervised test on a representative sample can be used to assess the result against the requirement. Record the material reference, its density and thickness, as well as the machine model and the operation being evaluated. Do not extrapolate the result to a different formulation without verification.

• Check dimensions and fit after cutting.
• Examine the edges, deposits, deformation and visible damage.
• Check the marking’s legibility or the usable depth of the engraving.
• Check that the part retains its intended function.

Fumes and fire: include prevention in the process selection

Depending on the composition, laser-material interaction can generate hazardous gases, vapors or dust. Source capture and emissions treatment must therefore be assessed for the material and the machine, together with the risk-prevention personnel. An extractor does not make a material excluded by the manufacturer acceptable.

Never leave a laser operation on foam unattended, and avoid the accumulation of combustible residues. Follow the monitoring, maintenance and fire-response instructions specific to your installation. INRS notes that prevention must be based on risk assessment and the manufacturer's documentation, with beam containment and operator training.

Further reading

Sources and documentation

• BAuA — TROS Laserstrahlung, Part 3: indirect risks and protective measures
• Emory University TechLab — Materials prohibited for laser cutting
• University of Wisconsin–Madison — Laser cutter safety
• INRS — Optical radiation: Laser radiation