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UHMWPE parts design guide

Ultra-high molecular weight polyethylene (UHMWPE) is widely used in machinery manufacturing, food processing, medical equipment, automobiles, aerospace, mining and other industries due to its excellent properties such as wear resistance, low friction, impact resistance and chemical corrosion resistance. Reasonable design can improve the performance and service life of UHMWPE parts while reducing production costs.

1. Key points in the design of UHMWPE parts

·1.1 Size & shape

Consider the thermal expansion of the material: UHMWPE has a high thermal expansion coefficient, and sufficient clearance should be left during design to avoid dimensional changes affecting installation.

Thickness selection: Thin plates (<5mm) are easy to deform and are suitable for gaskets; medium thickness (5-20mm) are suitable for structural parts; thick plates (>20mm) are suitable for high-strength load-bearing parts.

Avoid sharp corners & sharp edges: rounded corners (R ≥ 3mm) are recommended to prevent stress concentration and cracking.

·1.2 Tolerance & Precision

Standard tolerance:

Machining accuracy: ±0.1 ~ ±0.5 mm (normal accuracy), ±0.05 mm (high accuracy).

Aperture tolerance: Try to use H7-H9 level to ensure assembly accuracy.

Screw hole/slot spacing: The influence of thermal expansion should be considered, and the spacing should be appropriately widened to prevent deformation or expansion and jamming during use.

·1.3 Connection & Assembly

Threaded connection:

Direct tapping is not recommended. It is recommended to use metal inserts or nut seats to enhance thread durability.

If tapping is necessary, it is recommended to use coarse threads (M8 and above) and control torque to avoid thread slippage.

Welding & Bonding:

UHMWPE cannot be effectively bonded, but can be connected by hot melt welding and ultrasonic welding.

The use of latch and snap-on structures reduces reliance on bonding.

·1.4 Wear-resistant & low-friction design

Optimize contact surface: If UHMWPE parts are used as sliding parts (such as guide rails, bearing seats, sliders), the surface should be kept smooth. It is recommended to polish to Ra 0.2-0.8μm to reduce friction.

Add lubrication grooves: For high-friction occasions, lubrication grooves can be designed to reduce the friction coefficient and extend the service life.

Wall thickness uniformity: Avoid excessive thinness that leads to increased local wear, and try to ensure uniform force during design.

·1.5 Load & Strength

UHMWPE material has moderate strength, avoid overload design:

Force direction: Try to design along the fiber direction to improve tensile strength.

Add reinforcement ribs: For large-area force-bearing parts, reinforcement ribs (such as wave-shaped and grid-shaped) can be added to increase strength while reducing material consumption.

Avoid concentrated loads: The force points are evenly distributed to reduce the risk of local deformation.

2. Typical UHMWPE machining parts design cases

>Sliding guide rails

Rounded corner design to avoid stress concentration.

Lubrication groove design to reduce friction and improve wear resistance.

Standardized slot size for easy installation and replacement.

>Bearing bushings

Add metal inserts to prevent thread stripping.

Optimize wall thickness to prevent deformation due to excessive thinness.

Polish the inner surface to reduce the friction coefficient.

>Conveyor chain guide rails

Add lubrication channels to reduce friction resistance.

Reinforce rib structure to improve pressure resistance.

Adopt a detachable design for easy maintenance and replacement.

3. UHMWPE processing methods