Tube and pipe benders

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Tube and pipe benders are machines which bend tube, pipe and solid metals from 0-180 degrees, in most cases. Pipe bending machines can either be human powered, hydraulic assisted, or hydraulic motor driven

Rotary draw benders

Rotary draw benders (RDB) are precise in that they bend using tooling or "Die Sets" which have a constant Center Line Radius (CLR). The die set consists of two parts: The former die creates the shape to which the material will be bent. The counter die does the work of pushing the material into the former die while traveling the length of the bend. Rotary draw benders can be programmable to store multiple bend jobs with varying degrees of bending. Often a Positioning Index Tabel (IDX) is attached to the bender allowing the operator to reproduce complex bends which can have multiple bends and differing planes.

Rotary draw benders are the most popular machines for use in bending tube, pipe and solids for applications like: handrails, frames, roll cages, handles, lines and much more. RDB bends are aesthetically pleasing when the right tooling is matched to the application.

Mandrel benders

Mandrel benders (MB) are machines designed to bend tube to tight a radius with little to no change in the shape of the tube. Typically a mandrel bender is needed when bending thin wall tubing to a radius much tighter than the material can bend without collapsing or distorting. The word mandrel refers to the part of the tooling set up which is inserted into the tube and remains inside the tube during the bend process. This internal mandrel helps to support the shape of the wall when bending. Performance exhaust pipe is a common application for a mandrel bender.

Roll benders

Roll benders use three rolls (typically) to bend solids, extrusions and tube and pipe to various diameters by adjusting one or two rolls. The pyramid style roll benders have one moving roll, usually the top roll. Double pinch type roll benders have two adjustable rolls, usually the bottom rolls, and a fixed top roll. Large arcs, circles and spirals are typical applications for roll benders.

Bending Springs

These are strong but flexible springs with diameters slightly less than the internal diameter of the pipe to be bent. They are only suitable for bending 15mm and 22mm soft copper pipe. The spring is pushed into the pipe until its center is roughly where the bend is to be. A length of flexible wire can be attached to the end of the spring to facilitate its removal. The pipe is generally held against the flexed knee, and the ends of the pipe are pulled up to create the bend. To make it easier to retrieve the spring from the pipe, it is a good idea to bend the pipe slightly more than required, and then slacken it off a little. They are less cumbersome than rotary benders, but are not suitable for bending short lengths of piping when it is difficult to get the requires leverage on the pipe ends.

10mm copper pipe can be easily bend using an external spring which slides around the outside of the pipe.

References

• Ed Holmes (2006)

Manufacturers

• BendPak Inc. http://www.bendpak.com
• Unison Tube Bending Machines
• Horn Machine Tools, Inc.
• BLM GROUP USA
• SMT Industries Inc
• Baileigh Industrial Inc
• Winton Machine Company
• JD Squared, Inc.
• Howron Industries
• Advanced Fabricating Machinery
• Hader Industries Inc.
• Pro-Tools
• JMR Manufacturing