Electric press brakes: the 5 criteria of choice - Metal Interface

Folding is an essential operation that conditions the workflow in a sheet metal workshop. The challenges are numerous: productivity, precision of folded parts, safety of the operator, etc.

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Almost all sheet metal plants use press bending machines at this production post. Two main technologies are proposed by the manufacturers: machines with hydraulic drive and those with electric drive by servomotors.

The main advantage of hydraulic press brakes is to offer very large folding capacities. On the other hand, despite the higher purchase cost of electric press brakes, the use of servomotors instead of hydraulic cylinders brings productivity, energy, flexibility and maintenance gains. And the capacities of electric press brakes can be of up to 4 meters of folding and a force of 300 tons.

Mauricio Gutierrez Matta, Export Manager, SafanDarley, builder-developer of hydraulic and electric press brakes, agreed to enlighten us.

There are 5 axes of differentiation between electric press brakes and hydraulic press brakes:

On average, 60% of the operating time of a hydraulic press brake is used for adjustment and maintenance operations: programming, changing of tools, handling of parts to be bent, oil change, etc.

The productivity of the equipment is strongly impacted. The hydraulic system works continuously even when the machine does not bend. This results in considerable and unnecessary electricity consumption (oil to heat, machine idle, etc.).

Mauricio Gutierrez Matta indicates that, on the other hand, "the energy consumption is very low on an electric press brake, because the servomotors consume energy only during its operation!"
 

The bending is a deformation of the slider which is observed on all machines with hydraulic drives. Most manufacturers of hydraulic press brakes offer mechanical or hydraulic "de-bending" systems. There are actually solutions that consist in compensating for this phenomenon by a reverse force in the worktable. The adjustment is manual or automatic, according theoretical bending rules.

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"We have invented and patented for our electric press brakes a system of pulleys and belt that avoids bending in 99% of situations"adds Mauricio Gutierrez Matta.. "The force is distributed all along the sheet to bend evenly. The removal of the bending allows an improvement in the precision of the bent parts."

 

The manufacturer who invests in a press brake determines the capacity of the machine according to the largest part to bend and the thickest material to be bent. However, on a hydraulic press brake, energy consumption will be similar from one piece to another. On an electric press brake, servomotors consume only the energy required to bend the work piece. It has therefore to be taken into account in the choice.

 

Folding operator safety on press brakes is often considered by industry as a brake on productivity.

"The protection system installed on most machines reduces productivity. This is a passive solution that works according to the height of the tooling. It must be set at each tool change left and right. A wrong setting defaults the machine." »detailed Mauricio Gutierrez Matta.

And to add that« "SafanDarley has integrated in its machines a security system that requires no adjustment or use of a pedal. The descent of the slider can even be done in high speed up to 1 mm of the sheet. It's a security system that increases productivity instead of decreasing it!"

 

Hydraulic press brakes require regular maintenance, especially on the hydraulic part such as valves, tanks, pumps, filters and seals. In addition, the loss of pressure in the cylinders causes the loss of oil, which spreads around the machine. The challenge is to be able to reduce maintenance costs, without accident and without having to immobilize the press brake.

As a conclusion, Mauricio Gutierrez Matta differentiates the two technologies by stating that "the electric press brake is the most relevant solution up to lengths of 4 meters. The economic gains are very important because of the reduction of the energy expenses of about 30%, the reduced maintenance and the flexibility which makes it possible to increase the productivity."

 

For more Electric Press Brakeinformation, please contact us. We will provide professional answers.

I do fabrication work part time at my home shop as a hobby, with the occasional paying job that supplements my racing habit. In the past six months or so I picked up a customer that started off with a few small projects that have steadily increased in size and frequency. My most recent project includes a cabinet fabricated from 14 gauge mild steel, which has not been a fun thing to do with my apron brakes. They're rated for 14 gauge, but that's with the angle installed, so you lose the capability to do return flanges. It's also not fun to operate a box and pan brake at full capacity...stuff that's easy in 18 gauge is a challenge in 14. Assuming I keep him happy, it's likely more work of this nature is coming my way, plus the added capability wouldn't hurt on my own projects and might allow me to find some more outside work.

So, I have started doing some research on press brakes. Being that this is a sideline for me, I'm definitely going to be looking at used equipment. In the limited research I've done so far, it looks like a DiAcro 14-72 would be about the ideal machine for my application. I'm not looking to do huge quantities of heavy stuff, but the 35 tons would give me the ability to do limited amounts of 10 gauge or 3/16" for brackets and the like, as well as 14 gauge full width. I certainly would not turn down a 16-72 or 14-48 if I happened across one, either. I like the idea of the hydro-mech system on the DiAcro brakes, it seems like a good blend of hydraulic and mechanical characteristics.

Now I'm looking to answer some questions, like:

1. Are there other brakes out there I should be looking at besides DiAcro? I have seen a couple mechanical Niagara's and Wysong's with similar capacity. I doubt a real modern brake is going to fit in my price range, which is definitely less than $10K, and probably closer to $5K.

2. Since I'm buying used, what do I need to look for in a used press brake to tell if it's worth buying or not? I have quite a bit of experience with my apron brakes and jump shear, but I've never run a press brake beyond the attachment I've made for my press. It sounds like the DiAcro system is prone to leaks at the hydraulic motor that are annoying but not terminal. Are there other quirks with these that I need to watch for? What are signs of guaranteed abuse that mean I should keep looking for another machine?

3. How tough are these to move? It looks like a 14-48 DiAcro is about lbs and a 14-72 is closer to . Obviously there's a fair amount of that weight up high. I have moved both of my apron brakes (big one is a 10' x 14 gauge Chicago) and my 8' jump shear, as well as my mill and lathe, so I have a clue about moving equipment, but a press brake appears to be a whole different animal.

Thanks in advance for reading, and any advice you might have for me.

dkmc, I've read your thread. The frame with fork pockets sounds like a good thing. Does your brake seem reasonably well balanced when you move it? That's the biggest issue with my shear...with the back gauge on it, it's not only top heavy, but rear-heavy, making it tough to balance when putting skates under it. It sounds like a 14-48 would move reasonably easily with a pallet jack on your frame setup.

I would say yes, reasonably balanced, but then again, it doesn't matter as much with the fork pockets.
I've gone over uneven spots with it on the forks, and had it
'clang' a bit IN the pockets....somewhat UN-nerving, but
it stays captured nicely. I'm also probably a bit overconfident and reckless when moving it as a result...
Most times I put at least a 1" ratchet strap around the top and around the mast too. Going carefully with a helper steadying it on a pallet jack should be NO problem.

My very old Niagara 8ft x 16ga shear......whole different
animal as you say. The couple times I've moved that SOB even a short distance it caused me more stress and extended bullshit than any other machine in the shop.
Way top AND rear heavy, and every time it clears the ground you're sure it gonna crash. I end up with all sorts of chains and 2" straps around it to keep it from 'rolling' on the forks.
And then it still likes to 'slip' sideways and be all unpredictable!

What that shear REALLY needs is some sort of frame underneath to keep it from flexing, and as a lifting point. I do not want to have to shim and level it, and bolt it down to my old uneven barn floor. I'm trying to decide what to use for the frame. 4" or 6" U channel? Has to be stiff corner to corner so the legs of the shear don't twist. Hum....I'm starting another thread on this right now!

Curious question: What type of racing??