A corrugated cavity featured in some heart-shaped bend dies to force the wrinkling of the inside radius of the tube bend into a regular pattern. In the past the wrinkle control was used in the production of aftermarket automotive exhaust systems. However, that has declined because of the increased rate of corrosion failure and impeded exhaust flow that resulted from products with controlled wrinkles instead of the smooth surfaces of mandrel-bent products.
FREE Tube-Bending Guide Download:
A complete guide to the principles of the 4-Step set-up for tube-bending tools
This is a printable handbook showing how to implement in four standardized steps the “forward mandrel” set-up for rotary-draw tube-bending machines and establish process control over the so-called black art. The procedure is based upon the guiding principle that the tools make the bend and takes advantage of the inserted design of modern mandrel tooling.