Thread: graphical reference showing parts a press brake can make a finger brake cannot

Oke
Let us take your first example
You had to design that second flange shorter Otherwise it would interfere with the bottem die
On a folder one can do this peace with the second flange all the lengt of the first flange
Also the deep U can be produced With sharp corners even with the right tooling Perhaps not the same gauge but the shape yes
Also for your last excample
And very important, especialy with SS, without scratching the material
Thicker material That is where a press brake excells So in that regard more universal

Peter

First pic of my last post. The deep bends had plenty of room to be much deeper. But only need a hanger for a 2x6. Press brake can also bend with minimal or no scratching if using roll V dies. Same roll V dies can bend flanges with cutouts very close to bend line with no problem, also form a radius with correct punch. CNC folders are in another $$$ world.
Really cannot compare a box/pan finger brake with a 6 axis CNC press brake with sectional European spec tooling. Better comparison would be to a bottom bending press brake with manual back gauge and solid full length tooling. Air bending not so accurate, bending to a sharpie mark?
I have 10 feet and often have multiple punches/dies set up across that for the same part.
The rejected 10 gauge part was for a punch/die storage cabinet. I decided not to compensate for side to side part thickness. Bent the parts and compensated by other means (big friggin hammer), and some welded in "correction" coupons. 8 drawers on 500# slides. European spec sectional tooling is +- .0004? And not cheap. Top 6 drawers are filled and may need to fabricate another soon. Cabinet can be picked up with a pallet jack from front, or diagonal for going through doors. But it aint moving until I quit moving.

I didn't see if this has been touched on but I've never seen a proper back gauge on a finger brake. I was comparing notes with some university engineering shop colleagues here and since we are all followers of Dan Gelbart (and because his halo supports funding for this stuff in our local scene) we all have variants of the Atek 12 and 24 ton press brakes with manual or CNC back gauges. It emerged in conversation with the gang that while a 24 ton would definitely be better, and good Z control would really be better, a CNC back gauge was the first most important thing in letting you do complex bends with reasonable efficiency.

OK, the point of all this was to illustrate geometries that a new designer might see or think of, which could be made on a press brake (all around us), but cannot be made on the finger brake likely to be found in low-tech shops in poor countries. One solution, if they have electric power, of course a cnc-press brake and/or a stamping press with the right tooling. But in the mean time, arranging designs so that they *can* be easily made on a finger brake is a challenge, and I'm trying to make a document to help people understand these limits. A related topic is designing for low available accuracy - yes in the dev shop we can waterjet and bend and it will all line up. In the developing world shop, at least to start with, better to make designs that are more forgiving...

As for back gauges, right now my greatest wish for my little hand powered di-acro is for a working and accurate punch depth stop. It's plenty wide, has plenty of power for the projects at hand, but is very hard to use repeatably (probably part of why in this market segment finger brakes rule.)

Originally Posted by bryan_machine

the finger brake likely to be found in low-tech shops in poor countries.

I resemble that remark.

Are you considering magnetic box/pan brakes, or just conventional? Because the magnetic brake can do a lot that a conventional brake can't. Here's a promo video from Baileigh:
Baileigh BB-4816M Magnetic Box and Pan Brake Sheet Metal Bending Machine - YouTube

Just conventional metalmagpie. I actually had a magnetic brake - and while it can do more, it's a royal pain to use, and unlikely to be found in the developing world shops we care about. (Though one of them it turns out has a hydraulic press brake - you literally never know from one place to the next.)