Embracing the Wrinkle

How turning the tables on an unwanted wrinkle can be profitable. 

There has been a lot of time and money spent on removing unwanted wrinkles. I’m not talking about the botox industry. I’m talking about those unwanted ones that have a tendency of appearing on the inside of a bent tube. Maybe you have caught yourself saying: “If I could just get rid of the wrinkles, I could ship these parts”. Or “If the customer would just increase the wall thickness, production would be run a lot smoother”. It goes on and on.


The quest to eliminate the wrinkles continues to generate cash flow all over the world… all in an effort to accomplish one or more of the following: 
• Improve the flow of a liquid or gas thru the tube 
• Improve the cosmetic look of the tube 
• Pacify the perception of the customer regardless of the fact that the tube may not be seen by the end user and/or the presence of a wrinkle may not have a significant effect on the flow inside the tube 

In a large number of cases, the presence of wrinkles is not good. For example, a light fixture hanging in a dining room that sported random wrinkles could easily conger up the impression of low quality. Or imagine a very tight bend radius used on a car’s exhaust pipe that has wrinkles. The additional back pressure caused by the wrinkles could easily equate to fewer miles per gallon. 

If you can’t Beat’em – Join’em 
You may have an option here. Consider sharing with your customer as to the benefits of a controlled wrinkle. That’s right. Embrace the wrinkle! Get rid of the wiper die (and maybe the mandrel but that is a different story). 

A controlled wrinkle not only looks good but has benefits. Consider the following when moving to a controlled wrinkle design: 
• No wipe die needed which can translate into lower COGS over the course of a year’s production 
• The internal flow for some applications may not be affected significantly being that a controlled wrinkle protrudes outwards and not inwards 
• A controlled wrinkle would make for a good grab handle on a public bus 

If you think a controlled wrinkle may be for you, consult your bend tooling provider. They should be able to look at your application and make suggestions about what you can expect. Nevertheless, at the end of the day if you can save on your COGS and pass some of the saving onto your customer, the implementation of a controlled may be a win-win situation. 
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Controlling the Wrinkle 
The feature to control a wrinkle is machined into the bend die. How the bend die is machine takes into account, at a minimum, the tube OD, wall thickness, tube material, and bend radius. 

Once these factors are established, the details on how to impart the controlled wrinkle features into the bend die start to become evident. 




About the Author

George Winton, P.E. designs and builds CNC tube fabrication equipment for Winton Machine in Suwanee, GA. He can be reached at gwinton@wintonmachine.com or 888.321.1499

About the Machines We Build 

All of our semi-rigid coax and tube fabrication machines at Winton are designed, manufactured, and tested in-house.  We have a large line of standard products as well as the ability to engineer the best solution for our customer’s needs.  Our experienced sales staff makes sure that our customers can justify their capital equipment investment by offering a solution that is exactly what they need in order to manufacture their parts.  Please contact us today to discuss your project.