The tao of forming order

Working with the current to bend peacefully with press brakes

THE FABRICATOR® JUNE 2007

June 12, 2007

By:

Is the starting position of the flat part facing the wrong way or upside down to your natural flow? Are you working from left to right when your natural motion is right to left? If you are, you're fighting the current rather than letting the current do the work. Set up the press brake in such a manner that you work with your natural flow; by not interrupting your "chi."

Part forming machine

The Emperor's guard was patrolling the river near the base of the Great Falls when the scout came running back down the bank. He was short of breath, too excited to speak.

The Captain of the Guard's attention was drawn to the excitement. "Report the cause of this commotion, soldier!"

"Ahead there's an old man bobbing in turbulent waters at the base of the falls. A rescue must be mounted immediately if we are to save his life!"

"Make it so!" replied the Captain of the Guard.

But, as the rescuers approached the falls, the small old man walked up out of the deep pool of water and onto the shore.

The captain approached the old man and asked, "Are you a spirit? A ghost? No man could swim to shore or survive against the power of the water."

"Precisely," answered the old man. "I am not a ghost or a spirit; I have no magical powers. I simply did not resist the power of the water; I saved my energy and let the wash take me to shore."

Fighting the Current

How often are you scrapping parts because one is formed backward or bent on the wrong tool set? It could be that you are fighting against the current, the natural flow of things.

In other words, is the starting position of the flat part facing the wrong way or upside down to your natural flow? Are you working from left to right when your natural motion is right to left? If you are, you're fighting the current rather than letting the current do the work. Set up the press brake in such a manner that you work with your natural flow; by not interrupting your chi.

Setup Sheets

Depending on how you use press brake setup sheets, they have some good aspects and some bad. When they are used for reference only, setup sheets are excellent tools. Punch and V-die relationships remain constant by achieving a consistent bend deduction, producing a consistent inside bend radius. If all of the necessary data is on the setup sheet, everyone—whether you are a beginner or an experienced operator—will have enough information to complete the task correctly.

Setup sheets become a problem when they are seen as absolutes. By having the opportunity to modify the setup, even if just a little, over time you will learn more about your craft. Trying variations taps your creativity and gives the prima donna instincts common to all press brake operators a place to manifest ... "That's my setup!"

Also, if the setup sheet is not rigid, another thing happens: You will tend to set up the brake consistently using tooling that matches the bend characteristics, such as inside bend radius, bend allowance, and tonnage; in other words, making the setup and setup sheets work with your natural movements and flow. By doing so, you will avoid making many basic mistakes, such as flipping the part when it shouldn't be flipped.

Forming Order

You may even consider modifying the forming order—work left to right, or right to left; put step three before step two, if it flows better for you, as long as the change does not affect the completion of the part. This kind of change should be done at the time of setup, and not in the middle of a run.

Modifications should be made prudently, however, in the world of air forming. If every aspect of the setup becomes a variable (especially the punch and die), complete chaos could easily occur, and the same blank could turn out to be a completely different part.

V-die Changes

Whether you air-form or bottom-bend the part, V-die changes affect the results. In bottom bending they affect the tonnage; in air forming, V-die changes can lead to inconsistent bend angles as well as tonnage variations. Tooling variations in an air form, such as a change in V-die width, will change the inside bend radius. Of course, changing the inside bend radius changes the bend deduction.

Once a setup is established, the tooling set should not be changed without a valid reason, and then only if you are very experienced, for example, changing to—or from—a sharp bend to a radius bend. This minor change in the relationship between the press brake punch and the material thickness could have a profound effect on the resulting part, so again, it is not advisable to change V-die openings randomly.

It's a zen thing!



ASMA LLC

Steve Benson

President
ASMA LLC
2952 Doaks Ferry Road N.W.
Salem, OR 97301-4468
Phone: 503-399-7514
Fax: 503-399-7514
Steve Benson, a member and former chair of FMA's Precision Sheet Metal Technology Council, is the president of Asma LLC.

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The FABRICATOR® is North America's leading magazine for the metal forming and fabricating industry. The magazine delivers the news, technical articles, and case histories that enable fabricators to do their jobs more efficiently. The FABRICATOR has served the industry since 1971. Print subscriptions are free to qualified persons in North America involved in metal forming and fabricating.

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