Metal Forming Applications Using Urethane

Why Use K•Prene® Urethane in Forming Applications?

There are several families of urethane elastomers, but not all of them will perform equally well. Even within one grade of a given urethane formulation, cured properties can vary widely. K•Prene® urethane is specifically compounded and processed by Acrotech Inc. to maximize the characteristics desired for optimum tool and die operation. Some of the major advantages of urethane are non-compressibility, resiliency, and the ability to form and hold metal without marring its surface finish. It behaves similar to a solid fluid with a memory; under force it will change its shape, but its volume will remain constant. Urethane will produce high, uniform and continuous counter pressure under load. And, when the load is removed, it quickly returns to its original shape.

Application Examples where K-Prene® Urethane Can Be Used

	Radius Forming with Deflector Bars Urethane die with deflector bars positioned under pad. Bars are graduated in size to control deflection of urethane. This helps form the difficult bends.
	Compound Bends Difficult forms like these can be made with a standard urethane. die pad (definition is best with lighter gauges). Deflector bars beneath die pad provide air space to permit greater penetration into pad.
	Over-forming Unique adaptation of urethane pad to over-form flanges. Here, the pad is cast or machined-to-shape because greater pressures are required. This design provides compensation for springback.
	Bulging Punch In bulging applications, urethane. offers much longer service life than rubber, and is very cost effective compared to expanding/shrinking steel punches. Displacement of urethane punch under compression forces metal outward into desired shape. Amount of bulge is determined by depth of stroke. When ram is raised (after stroke), urethane resumes its normal shape and bulged part can be easily removed.
	Stripping Pad for Punching A standard urethane pressure pad machined to fit around punch. This is an easy, economical method of constructing a durable, oil resistant, high pressure stripping pad.
	Roll Bending A rotating steel shaft coated with K•Prene® working with another steel shaft positioned directly above, results in round parts with little or no flats on the leading or trailing ends.

The information and suggestions in this brochure are based upon the best laboratory and technical information available to us. Any recommendations or suggestions are made without warranty or guarantee, since the conditions of use are beyond our control. Nothing contained herein shall be construed to imply the nonexistence of any relevant patents nor to constitute a permission, inducement or recommendation to practice any invention covered by any patent owned by Acrotech Inc. or by others, without authority from the owner of the patent.