The flattening the extrados of the tube during the bending process. Reduction is in tension with wall thinning. Generally, to the extent that reduction is decreased, wall thinning is increased. Using assist pressure (or in extreme situations, boost pressure) mitigates both reduction and wall thinning by causing material to flow from the back tangent into the arc of the bend. Excessive direct pressure and other causes of drag will exacerbate reduction.
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.