Tooling: The heart of choosing a press brake

When you are selecting a new press brake, consider first and foremost the tooling style and forming method. If you don’t begin here, you’ll make some costly mistakes.

Will your new machine have new tooling, and will it be the same style you currently have, or are you going to change it up with a new tooling style? For many, the most disruption comes from changing from American traditional planed tooling and bottom bending to precision-ground European or New Standard and air forming.

Many specialty forming methods and tooling systems are available for press brakes, such as rotary, wiping, and folding tools, but in this article I’ll focus on the major tooling styles and look at what constitutes each tooling group and their attributes. I don’t mean to promote or detract from any brand or style. Rather, I only seek to compare each tooling style with others. Therefore, I will address only in general terms how each tooling group and style relates to your decision—that is, whether to keep the status quo or to face a brave new world. Your decision about tooling should influence your decision about which press brake is right for you.

American Traditional, Precision-Planed

The word traditional says it all. Other than the leaf style of press brake, this style of tooling was our first and still is one of our basic forms of tooling for the powered press brake.

These tools were developed by companies such as the Cincinnati Shaper Company (which would become Cincinnati Incorporated) in the early 1890s, Chicago Dreis & Krump in 1899 (eventually to become Muratec), and Perfection Machine & Tool in 1917. Manufacturers of sheet metal cutting and hand-forming (that is, manual folding) machines and tooling, these companies grew from their leaf brake beginnings to offer mechanical press brakes and V-forming machines in the early 1920s.

The mechanical press brake design gave us the coining and bottoming methods we know today. These forming methods are well-suited for traditional planed tooling. The tools are manufactured in lengths of up to 20 feet and then cut to length by the end user.

These tools have a small amount of error inherent in planing anything of length. For some manufacturers, that error could be as much as 0.005 inch over 20 ft. Ultimately, this means that the tools must be kept in the order cut when being installed together in the machine; they also must face the same direction (front to back), because the centerline may be inconsistent. If they are mismatched, there could in some cases be as much as a 0.010-in. difference between two tools.

Even if slightly mismatched, such tools still can produce a decent part if you are coining or bottoming, though it’s not ideal. The tool’s inherent error, however, makes it unconducive to air forming, as a thousandth or two of variation from tool to tool can change the bend angle. This does not mean that air forming cannot be done with traditional planed tooling, but it will take a lot of operator skill to produce tight-tolerance pieces. This is also true for precision-planed tooling, as these are still long planed tools with those same inherent issues as other “you cut it to length” tooling; they just have a European-style profile.

Nonetheless, as a general-use basic shop tool, this style of tool is perfect. It’s functional and inexpensive.

European Precision-Ground

This style of tooling came along in the late 1970s with the numerically controlled (NC) press brake. To make these NCs efficient required a new and very precise punch and die set.

Toolmakers accomplished this by precision-grinding the tools from short lengths of preshaped tool steel blanks. They are ground to a tolerance as close as ±0.0005 in. in profile accuracy and in height, while holding a consistent centerline. These tools allow the “numerical control” of CNCs to work their magic.

They are through-hardened to 48-52 Rockwell C, with a surface hardness of up to 70 HRC, a very high value that gives the tooling extra wear protection. This also makes these tools brittle; if they’re overloaded, they could explode and throw shrapnel—unlike their planed cousins, which are only 28-32 HRC.

Also, the precision-ground tool profile usually requires spacer blocks, which need to be specialized to adapt this style of tooling to a press brake designed for planed tooling. The tool costs substantially more than a planed tool, and its value would be lost on mechanical and non-CNC machines.

On a press brake designed for precision-ground tooling, the tools are quick and easy to install, and because of the “floated” lower rail for the die, they are the most versatile tooling style. It is an excellent choice for both prototype production as well as for tight-tolerance production forming.

New Standard

New Standard tools have all of the precision of the European precision-ground, as they are ground to the same tight specifications. They are, however, designed for, and really expected to be used in, specialty tool clamping systems.

Like its European cousin, New Standard has a center that is fixed and consistent with a known location; that is, it has a fixed reference point for the CNC to work from. Inserted into an auto-clamping system, this style mounts directly into the ram or bed and is drawn to its center position or reference point.

New Standard is designed for quick tool changes in a production operation. But again, it requires a specialized clamping system, making this style incompatible with other machines not designed for it. Still, this tooling style remains a good choice for quick tool changes.

Get More Tonnage Than You Need

One more note from personal experience: When you are looking at the maximum tonnage rating of your new press brake, get at least 20 percent more than you think you’re going to need. You never want to use any piece of equipment at or beyond its rated capacity. It’s dangerous to the operator and very detrimental to the long-term viability of the press brake and tooling.

Why Does This Stuff Matter?

This is only a brief overall review of the three major styles of tooling: the good, the bad, and the most common applications for each type. They are general observations for you to consider.

Is a new purchase going to be worth your time and money—such as switching from planed to precision-ground tooling? What will the learning curve be, especially when moving from bottoming to air forming? Will these changes be cost-effective if you’re fabricating one-off plate parts with ±1⁄16-in. tolerance? Probably not.

Are you a precision shop? Then perhaps changing from European to New Standard or vice versa may improve your operation. With these newer tooling styles, converting from one to the other can be straightforward, other than perhaps learning the new controller. Even changing from one modern press brake and controller to another isn’t too arduous. It’s certainly easier than changing the fundamental bending method from bottoming to air forming.

Also think about the acceptance factor: How will employees accept changes? It’s easy to talk a good game, but pay attention to the reality on the shop floor. Will your staff find the new methods too difficult to use, because of the “that’s not the way we do things here” attitude? If so, they may continue to use the old machines instead of the new equipment. It’s a problem more common than you would think. Most craftspeople aren’t comfortable with change and will try to avoid it as best they can.

Nonetheless, it might be a good idea to discuss tooling, forming methods, and press brakes with your staff first. Try to get a feel for how they will react to change. How will they receive the new press brake, tooling, or bending method?

Before you can make a decision about effecting changes in the press brake department, review where your shop is headed within the industry. Is upgrading necessary within your market segment?

Weigh the cost of the upgrades, along with the costs of learning new ways of forming, against the cost of not upgrading your equipment and keeping to the old ways. This information could make or break your decision to purchase a new press brake and its ultimate integration into your operation.

Once you can answer those questions about the tooling, you can then decide which press brake you truly need and purchase only those bells and whistles that will actually improve your operation.