Press Brake

The hidden yet important differences in press brake tooling

Question: Machine vendors often tout the importance of buying precision-ground tooling instead of planer tooling for machines that boast high levels of accuracy. Beyond the accuracy argument, though, are there implications regarding setup time, especially when it comes to staging multiple toolsets in a single setup?

Answer: As an instructor, I can’t count the number of times I’ve watched operators struggle endlessly trying to get a staged tooling setup to run correctly. By staging the press brake tooling, I mean using multiple toolsets down the length of the bed. With long setup times and mixed results, staging the tooling often doesn’t seem to pay off. To be fair, staged setups aren’t easy. Many times the various tools do not match in both their heights and centers. 

In “Phaedrus,” Plato writes of a conversation between Socrates and Phaedrus. During the dialogue, Phaedrus makes the following point: “Things are not always what they seem; the first appearance deceives many; the intelligence of a few perceives what is hidden.”

There’s a considerable amount of wisdom in that statement. Allow me to show you how that wisdom applies to press brake operation and, to a great extent, how it explains why some skilled craftspeople can stage a setup and have the press brake up and running quickly, while others don’t seem to get it.

“Things are not always what they seem; the first appearance deceives many; the knowledge and intelligence of a few perceive what is hidden.” OK, so I added one word. What do you want me to say? But in all seriousness, adding “knowledge” takes us a bit closer to what this ancient wisdom was trying to convey, at least in 21st-century terms.

What in the “Hades” Am I Talking About?

The information that I’m about to share directly applies to your issue and is specific to traditional planer and precision planer press brake tooling.

As you know, precision-ground tooling is manufactured by grinding tool blanks toward the centerpoint. Traditional planer tooling is ground from an X-Y coordinate. This little bit of information is part of that “common knowledge” that almost all of us are aware of, but few perceive the significance. 

Things are not always what they seem. The tools look similar and in some cases look the same, as in the case of precision planer and precision-ground tooling. The first appearance deceives many. They look the same, function the same, and both types fit in a press brake. But they achieve very different results when it comes to producing parts, especially if tool staging is involved. 

The knowledge and intelligence of a few perceive what is hidden. We all know the difference in the method used to manufacture the tooling, but few can see it, much less define “that which is hidden” and apply that wisdom to the everyday operation of a press brake. Recognizing that which is hidden and using hidden knowledge is the difference between the average craftsmen and those craftsmen in a league of their own. “That which is hidden” also explains why two craftsmen using the same traditional planer toolset don’t achieve the same quality or the same setup and run times. 

Perceiving That Which Is Hidden

Because precision-ground tools are ground toward the center of the tool, they are symmetrical around the center axis. Take two pieces of the precision-ground die and place them facing opposite directions front to back and back to front, and the tooling will maintain a common center when aligned with a precision-ground punch. Setups are quick, clean, and easy, even with eight or 10 sets of tooling. 

Now try that with planer tooling and see what happens. It doesn’t work so well. Why? Again, planer tooling is manufactured from an X-Y coordinate rather than toward the center, and this means all planer toolsets must face the same way in the machine—either all forward or all backward. If you mount planer tools so that they face opposite directions, what happens? Because they’re manufactured from an X-Y coordinate, they lose center alignment from die to die. 

There is still more to perceive. Consider the cutting of press brake tools. 

A precision-ground tool comes in lengths of around 3 feet and in shorter, sectionalized pieces, so shops rarely need to cut a tool to length. On the other hand, traditional planer tools come in long sections of 10, 12, 14 ft., or more. You need to cut the tool to the appropriate length for a specific flange or part. That’s fine, if you remember to mark both sides of each cut with a number and direction (1-1, front and back of the tool). 

When you cut the tooling yourself and do not mark them, you will find it very difficult, when incorporating them into a longer die, to get the pieces of tooling back in order and correctly mated again. The variation can be a number of thousandths’ difference over 20 ft. 

You might be successful bending a long flange using an uncut, 20-ft.-long planer tool. But if you cut that tool into 20 segments, good luck making an accurate bend by mating cut No. 1 and cut No. 20, facing opposite directions front to back . Sure, you might have only a few thousandths of an inch variation, but then again, it only takes a few thousandths of an inch to change a degree of bend angle or change a dimension. 

Another reason for careful numbering of cut-to-length planer tools has to do with residual stress. When you cut your tooling, it releases the residual stress within the original metal stock or from processes performed during the tool’s creation. The stress and strain within the die or punch are released by the act of cutting the tool, causing twist and bow to appear in the tool, which causes even further mating and alignment problems. 

Trying to mix and match tooling is complicated enough with a single planer toolset. You will find that it’s not very productive to try to mate tooling from another unique toolset. They do not mix, match, or play well with others. On the other hand, precision-ground tooling is quite social.

Nothing Wrong With Traditional Planer Tools

Traditional planer tools have their place, just as precision-ground tools do. Each has its own strengths, including cost and the type of work they perform best. That said, note that “precision planer tools” are not precision-ground tools. They are planer tools cut in a precision-ground-tool profile. A precision planer tool will suffer all the issues as all planer tools do. All planer tools—be they traditional planer or precision-planer—are available in lengths greater than 3 ft. 

Note that you also have “precision-ground planer tools,” which are a kind of precision-ground tool, ground to the center, but to planer profiles. Like any precision-ground tool, they come only in short lengths.

Socrates said, “Things are not always what they seem; the first appearance deceives many; the intelligence of a few perceives what is hidden.” Add our knowledge to that sentiment, and we will perceive many hidden things. 

What are you seeing? It might take a little thinking, and sometimes you will see what is hidden. It might even take a mentor to point it out. Either way, it feels great to discover something new and then apply it. It can make your day and, in this case, improve your setup times, run times, and overall quality.Take a minute to look deeper. You’ll find there is much that is yet to be discovered and applied. Be the intelligent one, the one who genuinely perceives that which is hidden.

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