Applications and Recommendations

Recommendation:

Use interlocked and lipped tooling. This will help keep the tooling aligned and will reduce marking on top and bottom of tube in bend area.
For extreme applications when bending Aluminum or Stainless Steel, use different tooling material. These tools don't last as long as steel, but can further reduce marking.
- Aluminum: Delrin tools.
- Stainless Steel: Aluminum bronze (AB) pressure dies.

Recommendation:

Redesign final part to use a bigger radius and a thicker wall thickness.
Use mandrelless (pinch groove) tooling as long as the application has a difficulty factor of 10 or less. This will deform the tube.
- Formula for difficulty factor: OD/Wall = wall factor (WF) and OD/D of bend = D of bend factor. WF/D = Difficulty Factor.
Use the mandrel and wiper die selection chart or guide on OMNI-X website at www.OMNI-X.com to determine if the application is a mandrelless application or not.
Tool steel is highly recommended when bending without a mandrel.

Recommendation:

Using interlock and lip tooling will help keep tooling aligned and help contain the material from flowing between the tools.
Use a thin wall or ultra thin wall mandrel with a lipped wiper die. Use our online calculator to determine style of mandrel and quantity of balls.
Make sure the mandrel has a tight fit to the tube.
Check the wall with calipers or micrometer to verify wall thickness of tube is correct.
Tubing should be tightly toleranced with low ovality.
The wiper die should not have any rake or very little to help support the material through out the bend.
Use collet and pressure die assist to help feed more material into the bend which will relieve some thinning and expansion on the OSR that could lead to material breaking.

Recommendations:

There are different tooling styles for this application: single finger, split and actuated, or tapered finger.
- Single Finger - OMNI-X Standard, clamp and pressure dies have a finger to support the top or bottom of the tube. Allows the tube to be easily removed from the bend die.
- Split Actuated - Cosmetic bending, requires actuator system to open and close the die vertically.
- Tapered Finger (Leaf) - Heavy duty bending, uses a tapered finger to clamp the tube vertically as well as horizontally.
Design bends with a large inside radius and ensure the material has high elongation. D of bend should be over 2D (ISR/Tube Horizontal Dim).
If bending a part tighter than standard tooling will allow (~1.5D ISR), crush style tooling might be required to allow the tube to deform to relieve the compression and expansion forces. Crush bending uses a large bump feature in the center of the bend die groove that deforms the ISR of the tube and allows material on the outside of the bend to collapse.
- Formed mandrel can be used upon request to support the OSR from caving in if necessary.

Recommendations:

Use standard tooling with straight grips for the long straight sections, and compound grips for the short DBB bends.
Compound grips hold part of previous bend and straight DBB section allowing the part to have bends closer together. The degree of bend and plane of bend rotation will need to be evaluated to determine if there are any issues with machine interference.
Compound tooling is part specific and generally not useable for other parts unless they have common bending data (angle/degree, rotation, and DBB). It is necessary to review part prints with XYZ's to determine tooling requirements and feasibility.
Bending with compound tooling works best with a stack bending machine.
- Use compound grips with quick change inserts on a single stack bending machine but it will take longer to complete the finish bent product compared to a stack bending machine.

Recommendations:

Dies may be made Split Actuated, Single Finger, Rolled or Standard depending on the part configuration.
To reduce marking or deformation there are a few options depending on the part: Wiper, Mandrel, Wiper guide or UHMW strip.
Ensure the tube material has a high elongation.
When providing tooling for extreme applications it is best to send full detailed prints to OMNI-X. Application evaluation will determine if the part can be bent , what tooling is needed, possible deformation and part design suggestions that can ease manufacturing.

Recommendations:

The main issue with bending tubes with fittings or end forms is that after bending the fitting or end form may not allow the part to be removed from the bend die.
There are several die designs that can help eliminate this issue: Clam Shells, Split and Actuated, or custom design.
- Clam Shells - Used for parts with fittings that are close together. Dies clamp up vertically rather than horizontally.
- Split Actuated - Dies can spring open to allow fittings to clear. Can be used when small amounts of clearance are needed.
- Custom - At OMNI-X we have made some out of the box solutions for various parts, please reach out to us to see if we have a solution for your issue.
It is best if you have a long straight between the fitting or end form to tangent.
When providing tooling for extreme applications it is best to send full detailed prints to OMNI-X. Application evaluation will determine if the part can be bent, what tooling is needed, possible deformation and part design suggestions that can ease manufacturing.