Custom NVH Solutions

Custom Polyurethane Bushings Manufacturer & Supplier

Superior durability, vibration damping, and load-bearing capacity. We engineer custom PU bushings that outperform rubber in the most demanding automotive and industrial applications.

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Durometer Selection Guide

70A – 80A

Soft / Flexible

Best for vibration isolation and noise reduction (NVH). Acts closer to rubber but with better oil resistance.

85A – 90A

Firm / Structural

The “Sweet Spot” for suspension bushings. Excellent balance of stiffness for handling and compliance for ride quality.

95A – 75D

Hard / Rigid

Replaces metal bearings or nylon. High load capacity, zero deflection, but transmits more vibration.

Engineered for Performance

Oil & Grease Resistant

Unlike natural rubber, PU does not degrade or swell when exposed to oils, road grime, or hydraulic fluids.

Load Bearing

PU handles higher compressive loads without permanent deformation (set), maintaining alignment geometry longer.

Abrasion Resistance

Outlasts rubber 5:1 in gritty environments. Ideal for off-road and mining suspension components.

Custom Design Configurations

Bonded Bushings

PU chemically bonded to inner/outer metal sleeves for maximum torque transfer and zero slip.

Floating (Free)

Separate inner sleeve (crush tube) allows the PU to rotate freely, reducing torsional stress.

Split Design

Two-piece “top hat” style for easy installation into housing eyes without a hydraulic press.

Grooved ID

Internal diamond or spiral grooves (knurling) to retain grease and prevent squeaking.

Technical Specifications

Property	Typical Range	Test Standard
Hardness	60 Shore A to 75 Shore D	ASTM D2240
Tensile Strength	20 – 50 MPa	ASTM D412
Ultimate Elongation	300% – 600%	ASTM D412
Compression Set	20% – 35% (Method B)	ASTM D395
Operating Temp	-40°C to +80°C (Peaks to 100°C)	–
Dimensional Tolerance	±0.15mm (Molded), ±0.05mm (Machined)	ISO 3302-1 Class M2/M1

Manufacturing Approach

We utilize open-cast molding for flexibility in low-to-medium volumes. For high-precision requirements, we post-machine molded blanks to achieve tight tolerances that standard molding cannot match.

Validation & Test Plan

Durometer Check: Verified on every batch post-cure.
Bond Strength: Push-out tests for bonded sleeves.
Dimensions: CMM inspection of critical OD/ID fits.

Post-cure inspection ensures consistent rebound and hardness.

Common Design Mistakes

Ignoring Swell

While oil resistant, PU can swell slightly in water over long periods. Fix: Specify hydrolysis-resistant ether-based PU for wet apps.

Too Hard = Noise

Choosing 95A for a suspension bush transmits all road noise. Fix: Stick to 80A-90A for suspension; keep >90A for pivots only.

The Squeak Factor

PU rubs against metal housing causing squeaks. Fix: Use internal grease grooves and marine-grade grease during assembly.

Sharp Corners

Sharp internal corners are stress risers leading to tears. Fix: Always include generous radii in the mold design.

FAQ: Polyurethane Bushings

What is the difference between Ether and Ester based PU?

Ester-based PU has better abrasion and oil resistance but degrades in water. Ether-based PU has excellent hydrolysis (water) resistance but slightly lower abrasion resistance. We can mold both.

Do you make molds in-house?

Yes, we design and machine our own aluminum molds for rapid turnaround and cost control on custom projects.

Can you match a specific color?

Yes. While natural PU is amber/translucent, we can pigment it Red, Black, Yellow, Blue, or Orange to match your brand or identify hardness levels.

What is the minimum order for custom PU bushings?

Since we cast, setup is lower than injection molding. We can do runs as small as 50-100 pieces, though unit cost improves significantly at 500+.

How do I prevent PU bushings from squeaking?

Proper lubrication is key. We recommend silicone-based grease (Super Lube) or marine grease. We also machine internal grease reservoirs into the bushing ID.

Is PU temperature resistant?

PU is generally good up to 80°C (176°F). It can handle intermittent spikes to 100°C, but for continuous high heat, we recommend High-Temp Urethane or switching to PTFE/PEEK.

Can you bond PU to metal?

Yes, we sandblast and prime metal sleeves/cores before casting to ensure a bond strength that often exceeds the tear strength of the urethane itself.

Do you offer 3D printed prototypes?

We can 3D print molds for very fast prototyping (1-3 days) to cast real PU parts for testing before cutting metal tools.

What hardness should I use for motor mounts?

Typically 70A-80A for street use (vibration absorption) and 85A-95A for race/track use (engine stability but more vibration).

Can I machine PU bushings?

Soft PU is hard to machine (it deflects). We usually grind it or freeze it to machine. Harder grades (>90A) can be turned more easily.

Engineer Your Solution

Don’t settle for off-the-shelf rubber that fails. Get custom-engineered polyurethane bushings built for your specific load and environment.

info@rapidaccu.com

Rapidaccu Manufacturing

Rongli Industrial Park, Dalang

Longhua District, Shenzhen, China