3D-Printed Press-Forming Tools Dos And Don’ts

Press-forming is a versatile metal forming technique that can quickly and easily turn sheet metal into finished parts. But there’s a lot of time and money tied up in the tooling needed, which can make it hard for the home-gamer to get into. Unless you 3D-print your press-form tooling, of course.

Observant readers will no doubt recall our previous coverage of press-forming attempts with plastic tooling, which were met with varying degrees of success. But [Dave]’s effort stands apart for a number of reasons, not least of which is his relative newbishness when it comes to hot-squirt manufacturing. Even so, he still came up with an interesting gradient infill technique that put most of the plastic at the working face of the dies. That kept print times in the reasonable range, at least compared to the days of printing that would have been needed for 100% infill through the whole tool profile.

The other innovation that we liked was the idea to use epoxy resin to reinforce the tools. Filling the infill spaces on the tools’ undersides with resin resulted in a solid, strong block that was better able to withstand pressing forces. [Dave] didn’t fully account for the exothermic natures of the polymerization reaction, though, and slightly warped the tools. But as the video below shows, even suboptimal tools can perform, bending everything he threw at them, including the hydraulic press to some extent.

It sure seems like this is one technique to keep in mind for a rainy day. And hats off to [Dave] for sharing what didn’t work, since it points the way to improvements.

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Forming Sheet Metal Parts With 3D Printed Dies

Using 3D printed forms to bend sheet metal isn’t exactly new. We’ve seen several people create custom dies for their brakes, and the results have shown the concept has merit for small-scale production. But that’s usually where the process ends. A bend here or there is one thing, but the ability to form a complex shape with them has always seemed like asking too much. But judging by his recent experiments, [Shane Wighton] is very close to changing that perception.

The process at work here is, relatively speaking, pretty simple. You print out the upper and lower die, put a piece of sheet metal between them, and then smash them together with a hydraulic press. If everything works correctly, and your CAD skills hold true, the metal will take the desired shape.

Of course, that’s vastly oversimplifying things. As [Shane] explains in the video after the break, there are many nuances to forming sheet metal like this that need to be taken into account, and iteration and experimentation are basically unavoidable. So it’s a good thing you can rapidly redesign and reprint the dies.

Which isn’t to say that the dies themselves didn’t come with their own unique set of challenges. The first ones shattered under the pressure, and it took a few design revisions and eventually a switch to a stronger resin before [Shane] got a set of dies that could form the desired piece. Even still, he’s had a lot of trouble getting the printed parts to survive multiple uses. But he’s confident with some more refinements he could get a repeatable process going, and thinks ultimately producing runs of up to 100 parts on a set of printed dies isn’t out of the question.

Logically, it would seem plastic isn’t an ideal choice for punching and shaping metal. Frankly, it’s not. But if you’re doing in-house manufacturing, the ability to produce complex tooling quickly and easily can help make up for any downsides it might have.

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3D Printed Tooling Punches Above Its Weight With Added Hardware

Reddit user [thetelltalehart] has been making brake press tooling with 3D printed PLA, and recently shared an interesting picture of a hybrid brake press punch, shown here on the right, in blue.

Printed in PLA, with 80% infill and 12 walls, the tool (right) failed at 5 tons.

In a press, material such as sheet metal is formed into a shape by forcing the material around the tooling. Some types of tooling can be 3D printed, and it turns out that printed tools are not only fast and economical, but can be surprisingly resilient. You can see such tools in action in our earlier coverage of this approach here and here.

[Thetelltalehart]’s previous work was printed at 80% infill and 12 walls, and failed at 5 tons. The new hybrid tool adds some common hardware that has the effect of reinforcing the tool for very little added expense or complexity. The new tool made it up to 7 tons before failure. It’s a clever idea, and an apparently effective one.

The goal with these 3D printed tools is twofold: doing short-run work, and reducing costly rework when developing “real” tooling. Having to re-cut a tool because it isn’t quite right in some way is expensive and costly, and it’s much easier and cheaper to go through that process with 3D printing instead of metal.

3D-Printed Tools Turn Bench Vise Into Expedient Press Brake

Chances are pretty good that most of us have used a bench vise to do things far beyond its intended use. That’s understandable, as the vise may be the most powerful hand tool in many shops, capable of exerting tons of pressure with the twist of your wrist. Not taking advantage of that power wouldn’t make any sense, would it?

Still, the clamping power of the vise could sometimes use a little finesse, which is the thinking behind these 3D-printed press brake tools.  [Brauns CNC] came up with these tools, which consist of a punch and a die with mating profiles. Mounted to the jaws of the vise with magnetic flanges, the punch is driven into the die using the vise, forming neat bends in the metal. [Braun] goes into useful detail on punch geometry and managing springback of the workpiece, and handling workpieces wider than the vise jaws. The tools are printed in standard PLA or PETG and are plenty strong, although he does mention using his steel-reinforced 3D-printing method for gooseneck punches and other tools that might need reinforcement. We’d imagine carbon-fiber reinforced filament would add to the strength as well.

To be sure, no matter what tooling you throw at it, a bench vise is a poor substitute for a real press brake. Such machine tools are capable of working sheet metal and other stock into intricate shapes with as few setups as possible, and bring a level of power and precision that can’t be matched by an improvised setup. But the ability to make small bends in lighter materials with homemade tooling and elbow grease is a powerful tool in itself.

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Build A Sheet Metal Brake With No Welding Required

Sometimes, there’s a job to be done and the required tools don’t fall easily to hand. [Bob] found himself in just such a position, needing to get some window flashing made up despite lacking a sheet metal brake. After waiting far too long for someone else to do the job, [Bob] elected to simply make the tools and do it himself instead (Youtube link, embedded below).

The project came about simply because [Bob] needed to bend 42″ sections of flashing, and couldn’t find a decent deal on a sheet metal brake above 36″ wide. The build starts with some angle iron and simple hinges, bolted together to form a basic brake design. With some rectangular hollow section bolted on for handles, the brake is then clamped to the bench and is ready for action.

It’s a build that any experienced hacker could whip up in an afternoon and be pumping out basic sheet metal parts by sundown, and requires no welding to boot. To learn more about bending sheet metal, check out our primer on the subject. Video after the break.

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Building A Plate Reverb On The Cheap

For those who don’t spend their free time creating music with experimental audio effects, a plate reverb is essentially a speaker. It just happens to be, by design, a rather poor one. Rather than using a paper cone for a diaphragm like a traditional speaker, the plate reverb uses as you might guess, a metal plate. As the plate vibrates along with the source audio, a set of piezoelectric pickups convert that to an output. The end result is that audio fed into the plate reverb comes out with a nice echo effect.

But despite their relative simplicity, a plate reverb costs thousands of dollars. They’re so expensive that the majority of people just emulate the effect in software. But it doesn’t have to be that way. [Sammartino] and an audio engineer friend recently came up with a detailed guide for building a plate reverb that cost about 10% of commercially available models.

The construction is fairly simple. A wooden frame is built, and eight hooks are installed around the edges. The plate is suspended between these hooks using guitar strings, which holds it tight but with enough give to vibrate along with the tunes. Another board is attached across the center of the frame to support the electronics: a transducer to vibrate the plate, and two piezo pickups to convert that to an audio signal, and a couple jacks and some wiring to tie it all together.

For a different take on the DIY plate reverb, check out this one we covered all the way back in 2013. If you’re in the market for something a bit larger, we’ve got you covered there as well.

Incremental Sheet Forming With A CNC Machine

If you want to form a piece of sheet metal into a shape, you’ll probably think about using a die. That’s certainly a great way to do it, but it presupposes you can create or purchase the die, which may be a showstopper for small projects. [Dardy-7] has worked out how to use a lesser-used technique — incremental sheet forming — to get similar results with a CNC machine. The idea is to trace out the form on the sheet metal with a round blunt tool.

He got good results using an inexpensive dapping tool, although he’s seen other use heated titanium ball bearings. In addition, he’s worked out how to adapt existing tool paths, like the ones you might download from the Internet, to use with this technique. You can see a video of the workflow below.

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