A long tubular part, especially as a component of a heat exchanger, that is characterized by a pattern of 180-degree bends alternating in two planes of bend that are 180 degrees apart in orientation. While the bends of a serpentine application are typically not intrinsically difficult to form — indeed, the “D” of bend is usually generous — they often must be formed without a mandrel, because the great length of the tube needed for the finished part exceeds the length of the bed of the bending machine. Setting the wiper at zero-rake and increasing the assist pressure can compensate for the absence of a mandrel if the bend specifications are not otherwise extreme.
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.