Additive tech takes on short-run press brake tooling

Nothing can beat steel tooling for long-run press brake jobs, but additive-built tools can benefit prototype and short-run work

Metal additive manufacturing (AM), while an intriguing technology, is often well beyond the scope of most metal fabricating businesses. The cost of the technology, with applications more in line with machine shop needs, limits its appeal.

However, 3D-printed parts made of plastics or carbon fibre composites are a different story. For short-run press brake tooling and the production of peripheral assembly items, AM has found a niche.

Wilson Tool International Inc. and Cincinnati Incorporated are leading the charge in this space, the two taking slightly different approaches in encouraging further adoption of 3D printing as a way to access tooling quickly and inexpensively when there is an urgent need. The question for fabricators is how they perceive their shops: Do they have the in-house knowledge to build tools themselves, or are they simply interested in having access to less expensive tooling for short-term needs? Whichever camp you fall in, options are available to you.

Building Parts In-House

Cincinnati launched its Small Area Additive Manufacturing (SAAM) in 2017.

“We have been working on the idea of 3D-printed tooling for a number of years,” said Mark Watson, press brake product specialist at Cincinnati. “During our testing we saw that side by side with metal tooling with the same geometry, the printed tooling performed surprisingly well. It wasn’t quite up to the standard of the metal tooling, but it encouraged us to pursue the research further.”

At the time the company was using stronger plastics, taking the approach that any tooling producer would – a tool that is harder and stronger than the material being bent will always be the best answer.

“But at some point we decided to see what benefit we could get out of the weakest material that we print,” said Watson. “What we found was that for air bending steel, the bottom line is you’re pressing materials down into a cavity without bottoming out in the cavity. The material itself is the only thing that is resisting you in your depth. We discovered that on mild steel up to about 12 gauge, we never broke one of these plastic tools. That was using polylactic acid (PLA) material, which is essentially a hobbyist’s 3D thermoplastic material. It demonstrated to us that if a DIY guy had a small 3D printer, he could do this.”

Watson stressed that printing a tool isn’t going to produce an item that is more accurate or durable than metal tooling; it’s also not the only way to make a tool that won’t mark up a part.

“The benefit, really, is that you can get to market very fast if you don’t yet own the tool you need,” he explained. “If it’s a geometry that needs some sort of cutaway, a traditional fabricator is going to consider how long it is going to take him to get the new tool. Or he is going to consider modifying a tool he already has in the shop and then buy a replacement for the tool that has been modified. The printed tooling allows you to design, print, and run the tooling promptly. Eventually, if you have a long-running job, you’re going to buy a metal tool.”

Here we see a 3D-printed press brake tool in action. Image courtesy of Cincinnati.

The tooling built in the SAAM generally can perform about 1,000 hits before it needs to be replaced. So you could make around 250 parts if that part had four bends in it.

“It’s useful if you are only running that number, or if you hope to prove out a concept before buying your metal tooling,” said Watson.

As the team was proving out its concept of a machine designed to print tooling in the shop, they found that 3D-printed parts could solve other press brake issues as well.

“Backgauge fingers are another item that makes sense to print like this,” said Watson. “If you have a really awkward gauging scenario on a part, you can now print fingers that might match a contour that you couldn’t match before. And by matching that contour, you might to hold a tolerance you couldn’t hold when you had to gauge the part from the other side. Not only could this improve tolerances, but it could also change the bend sequence, allowing you to use a common tool rather than something more complicated.”

Watson also raised the concept of printing a 3D fixture that might have a slot to drop a part into to ensure the part is accurate.

“By using a 3D fixture, we can check not only the angles and lengths of the flanges on a part, but we can also test that the inside radius is also correct,” said Watson. “If you are working toward standardized work and parts, a 3D fixture can detect that where a contour fixture won’t.”

Shallow parts can also be time-consuming to measure properly. Again, having a 3D fixture the part can be slid into can quickly alert you to any errors.

There are other things you could make with a 3D printer that could come in handy, Watson enthuses – for instance, tongs for gripping very small parts to better manage operator safety.

“Having the machine on the floor gives you a tool you can use for any number of purposes,” said Watson. “The tooling and gauges are simply the most obvious examples of how it can be applied initially.”

Watson is straight up about the applicability of this machine to most shops.

Additive inserts are being used here to help reduce sheet marking. Image courtesy of Wilson Tool.

“If you don’t have solid-modelling capabilities in your shop yet, this isn’t a machine that will be useful to you,” he explained. “You can’t run these machines without being comfortable with solid modelling. The ideal adopter of this is the person who says, ‘I can design this stuff, but I just can’t produce it in my shop.’ That’s when it makes sense. It allows you to quickly make things and try them out.”

The SAAM and the PLA are essentially engineered to run at an ideal speed and temperature together. The stronger carbon fiber nylon (CarbonX) is also very well suited to the parameters of the SAAM machine. The machine has an optional part unloader, which removes the finished product from the substrate and unloads it from the machine without an operator being present. In this way two pieces of tooling that might take 11 hours to build can be completed overnight. The machine is not fast, but compared to waiting weeks for steel tooling, it’s very quick.

The SAAM HT (for “High Temperature”) is a more advanced model the company offers for customers who wish to make more advanced products using thermoplastics and composites. The machine prints in Ultem®, PEEK, polycarbonate, and any thermoplastic up to 500 degrees C. These materials are much more expensive to print, however.

“We were demonstrating a 16-gauge part, a 6-in.-long part with a relieved straight punch,” said Watson. “The die was a half-inch bottom die. Using PLA it only cost $20 for the material. Because the punch was a little more intricate, it took six hours to print and the die took five, so 11 hours of preparation. If you were going to use a carbon fibre, the price would be three to five times more expensive. Using Ultem would put you in the $200 range for the material, and it would take longer.”

On-demand Tooling

Many fab shops might look at the idea of printed tooling but consider it outside their core competencies to make it themselves. But a short-run, promptly delivered, 3D-printed tool could still be of value to them. This was the perspective that Wilson Tool took when it decided to launch its Wilson Tool Additive™ product lines, Bend3D™ and Solv3D™, in October 2018.

“We had been printing jigs, fixtures, and workholding-type tools in our own facility for some time when we decided to see whether we could extend those services to our customers,” said Bryan Rogers, senior additive manufacturing engineer, Wilson Tool. “We spent a good deal of time analyzing what materials would work best for what we wanted to do, especially on the sheet metal forming side, narrowing down the parameters for that technology. We looked at materials, resin systems, fused deposition modelling (FDM) systems [3D printers that produce industrial thermoplastic parts], and metal powder deposition systems to see the best fit for what we want to do in the market.”

Wilson Tool currently uses machines built by two companies, California-based Carbon and Massachusetts-based Markforged. The Carbon 3D machine Rogers considers their primary machine, on which they run epoxy or rigid polyurethane materials. The Markforged machine is used when more rigidity is required, in which case they use carbon fibre-reinforced materials.

“We look at an application carefully first to ensure that it meets the criteria for additive-built tooling,” said Rogers. “Sometimes on paper a project will look like a perfect fit, but if it’s a hardened material like a sprung steel or half-hardened stainless, that’s not a good application for an additive-built tool because it doesn’t have the strength to make the application profitably and safely. Once we’ve determined that a part is a good fit for this technology, we look at three things when deciding what material to use for a tooling job. We look at the material thickness of the part being formed, how big the form is, and what the bend radii are. If a customer is doing a V form or a raised bead with the tool we’re making, we want a size ratio generally about 10 times the material thickness, and the bend radius we want to be up to four times the thickness to the radius, depending on what the application is.”

Designing a short-run tool for a customer gives Rogers’ team a chance to test and run the tool to ensure it’s exactly the right fit before they deliver it. This might mean the tool goes through a couple iterations. Sometimes, because of the constraints of the tooling material, design changes are encouraged.

These images show additively manufactured tooling being used to bend 10 clips at one time. Image courtesy of Wilson Tool.

“For instance, we were working with a refrigerator manufacturer that wanted to do a 16-gauge stainless steel using a very deep draw form,” Rogers said. “We were able to accommodate that, but they had to change some of the design parameters of the prototype. The advantage was that we were able to get the tooling to them within a week, whereas a steel tool would have taken anywhere from four to 12 weeks. The price of the tool might also be half of what the steel tool would have cost.”

The goal for the tooling Wilson is making is to reach 1,000 bends accurately. With thick material, a company could expect to make fewer bends, but in thin gauge this goal is manageable.

“Based on the customers we have surveyed, most jobs fall well within that limitation,” said Rogers. “For that reason, this tooling also makes sense. There’s no point spending a large sum on a tool you only need for perhaps 100 parts.”

While the company’s Bend3D service initially saw the most business, those same customers are beginning to see the value of sourcing small parts they may have purchased from an injection mould company previously. This is the Solv3D piece of the additive business at Wilson Tool.

“Sometimes companies need perhaps 1,000 pieces of one part but don’t want to invest in a mould,” said Rogers. “This is where additive manufacturing is becoming a real benefit to our customers.”

Rogers noted that, even internally, this part of the business has become a real boon.

“We have 30 or more different part numbers, standard parts, that are now straight-up production end-use parts we make,” said Rogers. “We do our tapping tool on our Carbon machine. We have our pneumatic clamping system that has a lot of additive-produced parts built into it. We’ve stopped making parts using injection moulding and converted all of that over to the additive machines. The economics of that just makes sense for us.”

It's clear that many shops can benefit from 3D-printed tools. The choice to be made is simply how involved in their creation they wish to be.

Editor Robert Colman can be reached at rcolman@canadianfabweld.com.

Cincinnati Incorporated, www.e-ci.com

Wilson Tool International Inc., www.wilsontool.com

About the Author
Canadian Fabricating & Welding

Rob Colman

Editor

1154 Warden Avenue

Toronto, M1R 0A1 Canada

905-235-0471

Robert Colman has worked as a writer and editor for more than 25 years, covering the needs of a variety of trades. He has been dedicated to the metalworking industry for the past 13 years, serving as editor for Metalworking Production & Purchasing (MP&P) and, since January 2016, the editor of Canadian Fabricating & Welding. He graduated with a B.A. degree from McGill University and a Master’s degree from UBC.