Polyester (fabric)

Physical properties

Laser processing

Melting and combustion of polyester (PET) releases acetaldehyde, acrylic acid and other irritating volatile organic compounds. Fumes have a characteristic burnt plastic odour. Extraction with activated carbon filter required. Not classified as highly toxic but ventilation is essential.

CO₂: Excellent CO2 laser cutting: the laser heat simultaneously melts and seals the edges of polyester fibres, definitively preventing fraying. This is one of the main advantages of CO2 laser over mechanical shears. Power 15–25W at high speed to avoid excessive melting.

Diode: Acceptable on dark fabrics. Polyester reflects part of the blue diode laser wavelength: on light-coloured fabrics multiple passes or temporary darkening treatments may be needed.

Fiber: Not applicable.

CNC / milling processing

Not machinable on CNC with rotary bits: fibres instantly wrap around the tool, tearing the fabric. The flexible structure does not allow any kind of hold-down on the worktable suitable for milling.

Plotter and thermoforming

Excellent workability with rotary or deep-cut blade plotter. Polyester fabric requires high-adhesion mats to keep it taut during cutting. The slippery surface of polyester tends to slide more than cotton.

Post-processing

Sanding: Not sandable.

Gluing: Bondable with adhesives specific for synthetic fabrics or heat-bonding films. The low hydrophilicity of polyester makes water-based adhesives less effective: prefer polyurethane-based or contact adhesives.

Over time: Polyester is very stable over time: resistant to mould, insects and moisture. Colours withstand washing well but degrade with prolonged UV exposure. Sublimation printing keeps colours vivid for a long time.

Common defects

• Excessive melting on laser edges with too-high power or too-low speed — creates a hard, plastic-like edge instead of a clean sealed one
• Build-up of electrostatic charges during processing that attracts dust and residues
• Difficult to dye with standard natural fibre dyes — requires specific disperse dyes

Safety

Polyester melts before burning. In case of fire it produces droplets of molten incandescent plastic that can spread the fire. Monitor laser processing and keep air assist active.

Availability and formats

Commercial formats: fabric by the metre, flags and banners, sportswear material

Related materials

Sources

• ISO 1833 — Textiles quantitative chemical analysis
• Manuali operativi FabLab di manipolazione tessile sintetica