Thin walled material, at or below 18 gauge (.049), is commonly specified for tube bending projects. This medium is desirable for applications in the automotive, aerospace, food and beverage and recreational industries, where the weight of component parts must meet specific requirements for the products’ end use.
To achieve an accurate bend, proper tooling and setup are critical. Thin walled tubing requires a mandrel, a bronze alloy or chrome plated metal insert that supports the pipe or tube from the inside during bending. Use of a mandrel helps to prevent the tube from collapsing and wrinkling, and to minimize ovality.
Normally a regular ball mandrel is used; however the higher the wall factor, the more likely that a closed pitch mandrel will be needed. For aluminum material, a chrome mandrel is used and for stainless steel an aluminum-bronze mandrel is preferred. This is done to reduce any type of interference, sticking or scraping of the metals.
Wiper tip and mandrel nose placement must be precisely set to ensure the tube is supported inside and out through the bend process. Use of lubricants helps reduce friction between the metals to ensure a smooth bend without wrinkles or ribboning.
Based on the project being completed, the pressure and clamp die will also need to be adjusted to accommodate the thinner wall during setup and possibly after the first run.
As the “D” of bend increases, the difficulty decreases but wall factor must still be considered. In most cases, on a 2D or 3D bend with thin walled material does not need to be annealed, or softened prior to bending, while a 1D bend may need this treatment, based on the type of material specified for the project.
In terms of material, 6061-T6 aluminum and hot-rolled and DOM steel may need to be annealed in order to bend out on a tighter radius. Exotic materials, such as Inconel, may also need to be treated prior to bending.
For each bending project, it is important to share as much specification information with your vendor when discussing the RFQ. This data helps to determine costs, lead time and overall requirements for the project, as well as any secondary options that should be considered.
For more information or questions on this topic, please contact us.
This blog was co-authored by Marshall Arndt, manufacturing engineer. Marshall can be reached at marshalla@sharpeproducts.com.