HDPE (PE-HD)
Frequently asked questions
Can HDPE (PE-HD) be laser cut?
No: HDPE (PE-HD) is not suitable for laser cutting. Adequate extraction/ventilation is required.
Can HDPE (PE-HD) be CNC machined?
Yes: HDPE (PE-HD) can be CNC machined.
Is HDPE (PE-HD) food safe?
Yes, HDPE (PE-HD) is food safe even in its raw state.
Physical properties
| Density | 940.0–970.0 kg/m³ |
|---|---|
| Tensile strength | 28.0 MPa |
| Melting point | 120.0–130.0 °C |
| Glass transition (Tg) | -120.0 °C |
| Thermal expansion | 150.0 µm/m·K |
| Moisture absorption | Negligible |
Laser processing
Although chlorine- and nitrogen-free, incomplete combustion of polyethylene releases aliphatic hydrocarbons, aldehydes, and fine particulate. Not toxic in the strict sense, but irritating to the respiratory tract. Thermal processing always requires ventilation.
CO₂: Absolutely not cuttable or engravable with CO2 laser. HDPE does not vaporize: it melts and crosslinks, producing fused edges, plastic drips, and dense fumes. Never a recommended process.
Diode: Not applicable for the same reasons as CO2 laser: the material melts without vaporizing.
Fiber: Not applicable in maker contexts. Fiber laser marking is technically possible but produces poor quality results.
CNC / milling processing
Excellent CNC machinability. Produces clean ribbon chips. The main concern is the low melting temperature: the bit must cut, not rub. Use single-flute or two-flute bits with high positive rake angle, high feed rate, and moderate spindle speed. A compressed air blast prevents chip buildup and localized overheating. Liquid coolant not required.
Plotter and thermoforming
Post-processing
Sanding: Sandable but with modest results: the surface tends to fray. For a smooth finish, prefer rapid flame polishing with a torch or heating with a hot air gun, which re-melts the surface layer and levels scratches.
Primer: mandatory. Surface notoriously difficult to paint or bond due to very low surface energy. Requires corona treatment, flame treatment, or polyolefin chloride primer (CP primer) specific for polyolefin plastics before any painting.
Gluing: Nearly impossible to bond with conventional adhesives. The extremely low surface energy prevents adhesion. The only reliable method is thermal welding with HDPE rod or welding piston, or the use of specific structural adhesives (Loctite 4861 or similar) on a pre-flamed surface.
Over time: Exceptional resistance to chemicals, moisture, and UV (if stabilized). Does not rust, absorbs no water, resists concentrated acids and bases. Prone to creep (slow deformation under constant load) at high temperature.
Common defects
- Chip melting and welding to the cutter if feed rate is too low (characteristic whitish burn marks)
- Dimensional creep in structural parts under prolonged loads at elevated ambient temperature
Safety
Recommended PPE: eye_protection
Non-toxic and inert material in its solid form. No significant risks during mechanical processing with adequate ventilation for chip removal. Never process with laser.
Availability and formats
Commercial formats: sheets 3–100mm, round and square bars, thermoforming sheets, cutting boards and panels
Related materials
Sources
- ISO 1872-1 — Plastics polyethylene (PE) moulding and extrusion materials
- ASTM D4976 — Standard Specification for Polyethylene Plastics Molding and Extrusion Materials
- Datasheet tecnico HDPE/PE300 Rocholl GmbH
Information on compatibility, processing parameters and safety is purely indicative. MakerSpecs accepts no liability for damage to persons or property arising from the use of this data. Always check the safety rules and the manufacturer's official manuals before carrying out any processing.