Tube Bending Aids

Suggestions on tool set up

Bend Die: Make sure it is securely tightened down. Use a cheater bar if necessary.

Mandrel: Position the front of the shank at the tangent point.

Clamp Die: Position it within .005 - .010 of the bend die insert. Make sure there is no slippage during the bend. This is the main cause of wrinkling.

Wiper Die: Position the tip to as close to the tangent as possible while not creating a negative rake angle. Start out with the wiper die as perfectly aligned with bend die insert as possible. (Use a straight edge to verity)

Mandrel Rod: Is used to adjust the position of the mandrel.

Pressure Die: Bring the pressure die in against the tube, retract it, and then adjust it in a little more. The pressure die should travel at the same speed as the tube when being bent.

Addressing Bend Quality Issues

Hump at the end of a bend

Adjust mandrel slightly back from tangent until hump is barely visible. This is also a good process to find the best location for the mandrel.
Adjust in the program the mandrel retract at xx degrees before the finish of the bend. (Recommend starting at 5 degrees)
Increase force on the pressure die assist.

Wrinkling throughout the bend

Advance wiper die closer to tangent
Decrease rake angle of the wiper die. (Note: the rake angle is the how much the back of the wiper die is adjusted away from the center line of the tube)

Deep scratches throughout the bend and in the wiper die area

Increase rake angle on the wiper die.
Check for an undersized mandrel.
Increase pressure die force (or pressure) only after checking wiper fit and mandrel location.
Reduce the force (or pressure) on the pressure die assist.
Use more or better mandrel lubricant.

Tool marks on the centerline of the bend in the clamp and pressure die area.

Reduce pressure die and clamp die forces.
Check the tube for proper OD. Make sure it fits in the tooling cavity properly.
Check and adjust the heights of the pressure die and clamp dies.

Excessive collapse with or without wrinkling throughout entire bend

Advance mandrel toward tangent until slight hump occurs (most mandrels need to be adjusted ahead of tangent a very short distance.)
Install more balls on the mandrel assembly.

Mandrel ball humps

There may be too much drag on the tube; back off pressure die force and increase wiper die rack angle.
The mandrel may be required to be close pitch.
The tubing material may be too soft. (especially dealing with T0 Aluminum)
Increase force on the pressure die assist.

Wrinkles throughout the bend area with the wiper and mandrel in known proper position

Check for undersized mandrel.
Increase pressure die force only after double checking wiper die fit and rake angle and mandrel location.
Reduce force on pressure die assist.

Bad mark at the start of the bend

Bend die insert not matched properly to the bend die body.
Clamp die not parallel to the key way. (positioned at an angle).

Heavy wrinkles through bend area only and linear scratches in grip area indicating clamp slippage.

Reduce pressure die force.
Check location of mandrel and wiper die.
Increase pressure on clamp die. (note: benders with toggle linkage on the clamp die can be adjusted too far in which reduces clamp force.)

Mandrel Lubricant Sample

PREMIUM GEL - MANDREL BENDING LUBRICANT (5 GALLON) Part No. 471091

*Premium Gel Mandrel Bending Lubricant is specially formulated for bending all types of materials: Steel, Stainless Steel, Aluminum, Copper and Titanium. It is used to lubricate the inside of the tube and the bending mandrels or to lubricate the outside diameters inside radius of the tube and wiper die, reducing friction during the tube bending process. Decrease scrap material and increase tool life. Premium Gel is also water soluble and washes out easily with water, Premium Gel will not cause smoke or toxic fumes when welding or at start up (Automotive applications).

**Premium Gel is easily pumped though all lubrication delivery systems lubricating mandrels and wiper dies during the mandrel bending of round, square and rectangular tubing.If you would like to try this lube and would like to have a free sample, please let us know. Or if you would like to purchase a 5 gal pail of it, let me know. I can also provide you a MSDS if you would like.

PREMIUM GEL - MANDREL BENDING LUBRICANT (5 GALLON) Part No. 471091

P & R Industrial Sales, LLC.

P & R Industrial Sales, LLC.

CASE HISTORY

Tube Bending Trouble Shooting Guide

See the Results

Mandrel and Wiper Die Selection Guide

Mandrel and wiper die engineering data

standard pitch

Close pitch mandrel

close pitch thin wall

Square back wiper die

square back wiper

Typical Interlocking Mandrel Tooling Set Up