Polyethylene (PE) is one of the most versatile and widely used thermoplastics in the world. While often associated with high-volume production methods like injection molding, its excellent machinability makes it a prime candidate for CNC machining. This process is ideal for creating high-precision prototypes, functional components, and low-volume production parts where the cost of molding is prohibitive.
CNC machining of PE allows for rapid turnaround and exceptional design flexibility, enabling the production of complex geometries and tight-tolerance parts directly from solid stock or near-net-shape blanks. From chemical-resistant fixtures to low-friction bearings, machined PE components offer a unique combination of performance, durability, and cost-effectiveness.
KEY BENEFITS
Machining PE offers distinct advantages over other manufacturing methods and materials, providing a balance of performance and practicality.
| Material Property Benefits | CNC Machining Advantages |
|---|---|
| Excellent Chemical Resistance: Highly resistant to a wide range of acids, bases, and solvents, making it perfect for harsh environments. | Rapid Prototyping: Quickly produce functional prototypes for testing and validation without the need for expensive tooling. |
| Low Coefficient of Friction: Provides natural lubricity, ideal for bearings, wear pads, and sliding components. | Design Freedom: Create complex geometries, intricate features, and undercuts that are difficult or impossible with molding. |
| High Impact Strength: Remains ductile and tough even at low temperatures, resisting shock and impact loading. | Cost-Effective for Low Volumes: Eliminate mold costs, making it economical for small batches, custom one-offs, and pre-production runs. |
| Good Electrical Insulator: Excellent dielectric properties for electrical and electronic applications. | Excellent Dimensional Stability: Achieve tight tolerances and consistent part quality with precise CNC control. |
| Lightweight & Low Water Absorption: Minimal moisture uptake ensures stable performance and contributes to a high strength-to-weight ratio. | Material Versatility: Machine from various PE grades (HDPE, UHMW-PE) to precisely match the application requirements. |
APPLICATIONS
The properties of PE make it suitable for a diverse range of industries and functional parts. Here are some common applications.
| Industry | Specific Parts & Components |
|---|---|
| Industrial Machinery | Bearings, wear strips, guide rails, conveyor chain guides, fixtures, jigs, and machine guards. |
| Chemical Processing | Tank liners, seals, gaskets, valve seats, chemical-resistant spacers, and flow meter components. |
| Food & Beverage | Cutting boards, food conveyor components, packaging machine guides, and non-contaminating wear surfaces. |
| Automotive | Bumpers and impact absorbers for low-speed vehicles, bushings, battery trays, and custom spacers. |
| Marine & Aquatic | Dock bumpers, boat fenders, marine bearings, and components for freshwater applications. |
| Medical & Laboratory | Non-toxic trays, handling jigs for devices, low-wear components, and bases for sensitive equipment. |
| Consumer Products | Prototypes for containers, custom gears for light-duty applications, and low-stress structural parts. |
TECHNICAL SPECIFICATIONS
This table provides key technical data for the most commonly CNC machined Polyethylene grades. Note: Values are typical and can vary by specific manufacturer and grade.
| Property | Test Method | HDPE (High-Density PE) | UHMW-PE (Ultra-High Molecular Weight PE) | Unit |
|---|---|---|---|---|
| Density | ASTM D792 | 0.952 – 0.965 | 0.93 – 0.935 | g/cm³ |
| Tensile Strength (Yield) | ASTM D638 | 26 – 33 | 21 – 24 | MPa |
| Elongation at Break | ASTM D638 | 10 – 1200 | 200 – 500 | % |
| Impact Strength (Izod Notched) | ASTM D256 | 20 – 200 | No Break | J/m |
| Hardness (Shore D) | ASTM D2240 | 66 – 73 | 60 – 67 | – |
| Coefficient of Friction | ASTM D1894 | 0.2 – 0.3 | 0.10 – 0.22 | – |
| Continuous Service Temperature | – | -50 to +80 | -150 to +80 | °C |
| Dielectric Strength | ASTM D149 | 18 – 20 | 28 – 32 | kV/mm |
| Water Absorption (24 hrs) | ASTM D570 | < 0.01 | < 0.01 | % |
Key Takeaway: HDPE offers a great balance of stiffness, strength, and chemical resistance. UHMW-PE is the superior choice for extreme wear resistance, high impact strength, and the lowest coefficient of friction, making it a “performance” grade for demanding applications.