Urethane Springs Characteristics
Century Spring's stock inventory of urethane compression springs was designed primarily for special applications where our steel wire springs are not as well suited. For example, these springs are useful in applications where corrosion, vibration, and magnetism prevent the use of conventional steel springs. Also, urethane springs have proven to be the safest, most efficient and reliable compression material for punching, stamping and drawing dies.
As compared to conventional springs, the advantages of the urethane material include the following:
- High load-carrying capability
- High dielectric strength and non-magnetic
- Protection against marring/galling
- Longer life
- Abrasion resistance
- Oil and solvent resistance
- Low noise
- Vibration damping and shock absorbence
- 100% load-bearing surface
- Bondable to mating parts
- Effectiveness between -30° F and 180° F
Century Spring's urethane spring material is a polyether-elastomer that reacys similarly to an incompressible fluid. The volume of material moved by compression is displaced laterally in the form of bulging sides. An approximation to the change in diameter of one of our standard cylindrical urethane springs can be made by increasing the diameter by the inches of compression.
Example: A 1.00" long spring is to be deflected 15%, or .15". The diameter will then also increase roughly by .15". This material's lateral expansion much be considered for many applications.
The recommended maximum free (unloaded) length is 2 1/2 times the spring's outside diameter, although springs may be stacked with guide rods and washer-shaped spacers.
Pounds to produce 1/8" deflection
|Conventional heavy-duty die spring||Up to 500 lbs.|
|Urethane springs||Up to 2,600 lbs.|
|Urethane bar stock||Up to 90,000 lbs.|
|Urethane slab stock||Unlimited|
Suggested Maximum Cyclic Frequency & Deflection Percentage of Free Length
|Maximum Deflection||Cycles Per Hour|
|Slow speeds / short runs||less than 25%||200|
|Intermittent||up to 25%||700|
|Continuous||up to 15%||12,000|