LDPE (PE-LD)
Frequently asked questions
Can LDPE (PE-LD) be laser cut?
No: LDPE (PE-LD) is not suitable for laser cutting. Adequate extraction/ventilation is required.
Can LDPE (PE-LD) be CNC machined?
With some limitations: LDPE (PE-LD) can be CNC machined.
Is LDPE (PE-LD) food safe?
Yes, LDPE (PE-LD) is food safe even in its raw state.
Physical properties
| Density | 910.0–940.0 kg/m³ |
|---|---|
| Tensile strength | 12.0 MPa |
| Melting point | 105.0–115.0 °C |
| Glass transition (Tg) | -110.0 °C |
| Thermal expansion | 200.0 µm/m·K |
| Moisture absorption | Negligible |
Laser processing
Combustion of LDPE releases aliphatic hydrocarbons, aldehydes, and volatile waxes. Not toxic like chlorinated plastics, but irritating to eyes and respiratory tract. Avoid burning or thermal processing without ventilation.
CO₂: Not laser-processable. LDPE melts instantly without vaporizing, producing irregular fused edges and plastic drips. Fumes contain irritating hydrocarbons. No viable laser application.
Diode: Not applicable.
Fiber: Not applicable.
CNC / milling processing
LDPE is very soft and rubbery: it tends to stretch and wrap around the bit rather than producing clean chips. Difficult to achieve quality finishes. If necessary, use very sharp single-flute bits with high positive rake angle and high feed rate. HDPE or POM are far more suitable choices for structural CNC milling.
Plotter and thermoforming
Cuttable with blade plotter on thin sheets and films (0.05–0.3mm). Use Roland 45° or 60° blades, low pressure. LDPE film is the typical application in screen printing and packaging. Very common material for masking and temporary protection.
Post-processing
Sanding: Sanding LDPE is practically useless: the surface frays and the sandpaper clogs from friction heat. This is not a material intended for mechanical finishing.
Primer: mandatory. Like all polyolefins, LDPE has very low surface energy and cannot be painted without corona treatment, flame treatment, or adhesion promoter primer (CP primer). In practice, painting LDPE is not a common maker application.
Gluing: Virtually impossible to bond with standard adhesives. Hot-air thermal welding (plastic welder with PE rod) is the only reliable method for joining LDPE parts. Alternatively, friction welding (ultrasonic or friction) is possible.
Over time: Excellent chemical resistance to acids, bases, and polar organic solvents. Good UV resistance if stabilized with antioxidants. Tends to deform under load over time (creep). Non-UV-stabilized LDPE bags become brittle and crumble after 1–2 years of sun exposure.
Common defects
- Cannot be milled to clean finishes due to the rubber-like nature of the material
- Gluing and painting impractical without dedicated surface treatments
- Rapid UV embrittlement in unstabilised films
Safety
Non-toxic and inert material in solid form. No significant risks during handling. Avoid burning: fumes from incomplete combustion are irritating.
Availability and formats
Commercial formats: film 0.03–0.3mm (bags, packaging), flexible tubes, thermoforming sheets, blow-moulded containers
Related materials
Sources
- ISO 1872-1 — Plastics polyethylene (PE) moulding and extrusion materials
- ASTM D882 — Standard Test Method for Tensile Properties of Thin Plastic Sheeting
- Datasheet LDPE Basell Polyolefins
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.