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Davek0974
02-20-2015, 10:16 AM
I need to fold small qty's of steel in 1 - 3mm thcknesses, I have a 20t hydraulic press which does nothing most weeks ;)

I was looking to knock up the usual style of brake tool using angle-irons for the Vee and tool but then I realised i could not make hooks and close bends etc.

Research took me swan-neck tooling for pro machines.

My question is would i be better spending a little on these parts and building myself a frame to take them...

http://www.ebay.co.uk/itm/171136969914?_trksid=p2055119.m1438.l2649&var=470291165499&ssPageName=STRK%3AMEBIDX%3AIT

and

http://www.ebay.co.uk/itm/181434806527?_trksid=p2055119.m1438.l2649&var=480406669447&ssPageName=STRK%3AMEBIDX%3AIT

The lengths are perfect and the vee is a usable size and being a standard tool means i can get other sizes to suit my jobs and available tonnage.

Would that be a better plan??

darryl
02-21-2015, 01:14 AM
I have four benders now, three are homemade to do jobs that other configurations can't. One will handle up to 1/4 inch thick material, but only up to about 7 inches wide, one will handle 30 inches of width but only up to about 22 ga at that width. One bridges the gap between those, capable of bending 14 ga up to 15 inches wide, and one is open-ended so you can make bend configurations that the others can't. On the 15 incher, the jaws can open up to about 5 or 6 inches of gap, making it possible to drop in a custom die. I've made a few for various uses- nothing which I could have purchased anywhere, regardless of what it might have cost.

I think you really need to know what your bending needs are. You might find that time is well spent making your own custom forming dies. If purchasable die and punch parts will do the job, then maybe that's the way to go. Ask yourself 'what can't these punch and die parts do'

Davek0974
02-21-2015, 03:20 AM
I have checked now and the swan neck will allow the types of fold-back sizes I need and the bottom die vee is a pretty good match too, being standard tooling means I can drop in other sizes easily or make my own.

garyhlucas
02-21-2015, 10:38 AM
The tooling you show has a rather difficult to make connection to the press. In the US the common connection is simple 1/2" x 1/2" slot. So tooling just has a tang directly in line with the v point. Take a look at Swag Offroad for their simple press brake attachment.

Davek0974
02-21-2015, 11:19 AM
Yes, likely why it was cheaper. I'm confident I can work round that though, at the end of the day it would not matter if it was welded in!

There seem to be many patterns of tooling but the more popular it is the more it costs, as usual.

George Barnes
02-21-2015, 11:58 AM
This is a setup that I made for bending odd shaped flame cut parts in 3/16" and 14" plate. The die portion is a 1-1/2" cold rolled bar that has a 90 degree V milled in it. The punch portion is a 1/2" x 2-1/2" cold rolled bar with 1-1/4 square welded to it after a flat was milled on one corner. The guides are 1/4" x 1 pieces that have had a 1/2" groove milled along their length. The platens are drilled and tapped so that the locators can be positioned at critical location points on the parts that are to be bent. The long piece with the tab on the end is just a handy gauge for locating the bend line with the center of the V opening.

My press is a home brew and uses a 1 h.p. electric motor powering a 2 stage log splitter pump and 3" x 8" hydraulic cylinder. The punch has a 1"-12 thread nut welded on that screws to the cylinder rod.

http://img.photobucket.com/albums/v707/gbarnes/PressBrakeTooling.jpg (http://smg.photobucket.com/user/gbarnes/media/PressBrakeTooling.jpg.html)

Here is an example of a part that was folded on this tool.

http://img.photobucket.com/albums/v707/gbarnes/PressBrakeBentPart.jpg (http://smg.photobucket.com/user/gbarnes/media/PressBrakeBentPart.jpg.html)
This setup has bent a bunch of parts over the years. Almost forgot, the usable length on this unit is 12".

Davek0974
02-21-2015, 04:47 PM
Looks excellent, thanks for the pics.

Wayne Sippola
02-21-2015, 05:58 PM
George,

Very nice looking press brake! I've been thinking about building one, so it was nice to see a working example along with some dimensions. Thanks for the picture and details,

Wayne

Davek0974
02-25-2015, 03:53 AM
OK, progress is being made, I have the tooling and have built a frame. As it's being designed and built on-the-fly, things don't always work out.

In the picture I have my bottom plate with two 22mm uprights and a couple of springs, the Die is sitting on the bottom plate and the tool is above, sitting on the top beam.

Due to metal in stock, the top beam is a little short, so I milled in two 6mm slots along the ends, the idea was to weld in some 6mm bar to extend the beam to fit between the bushings that slide on the uprights. But as the gap is smaller than i anticipated, a fiddly welding job ensues:(

Anyway, the next question is - how to construct the beam/tool holder to fit the already mounted uprights?

I was thinking of drilling the bushes and welding it together in position, but welding is not precise and is likely to pull here and there probably leading to a jammed beam.

My next thought is to weld the beam up on the bench, then mount it in the mill and drill/bore the bushes to the known distance using the DRO on the mill. My issue with this is that it means boring two 100mm deep holes to 22mm dia - not too easy. So I thought, over-drill the holes and fit brass bushes - that means i only have to bore a small bush. Issue now is how to align the top/bottom bushes for boring :confused:

http://www.practicalmachinist.com/vb/attachments/f30/131677d1424852444-assistance-small-press-brake-build-img_0805.jpg

Fun engineering ;)

Davek0974
02-26-2015, 08:58 AM
Ok, I think I'll go with this...

Weld the beam, spacers and bushes up on the bench with the bushes nominally in the right place for the uprights to pass centrally.

Mount the assembly vertically on the mill against a large angle plate or two, then drill a clearance hole and follow that up with a 22mm drill, possibly, the drills' tendency to cut oversize will give running clearance, if not then its a simple matter to bore out the ends and fit brass bushes.

Think that'll work.

Davek0974
02-28-2015, 09:31 AM
Well, it lives...

Front...
http://www.practicalmachinist.com/vb/attachments/f30/132115d1425133099-assistance-small-press-brake-build-img_0809.jpg

Back...
http://www.practicalmachinist.com/vb/attachments/f30/132116d1425133103-assistance-small-press-brake-build-img_0810.jpg

Installed in press...
http://www.practicalmachinist.com/vb/attachments/f30/132118d1425133117-assistance-small-press-brake-build-img_0812.jpg

Tests...
http://www.practicalmachinist.com/vb/attachments/f30/132117d1425133110-assistance-small-press-brake-build-img_0811.jpg

Pretty chuffed with how it turned out, I needed to lengthen the springs by 1" so I fitted some nylon bushes that locate and extend them. The die is easily reversible, just lift out and rotate, the offset is provided by a spacer strip.

The tests were 3mm alu and 3mm steel scraps. I made a test on a real sample of what it was built for - 320mm long 3mm steel, the calculator showed 14t pressure needed and the gauge went to 13t by the time it bottomed out - a very satisfying result.

A future modification will be to add some adjustable location stops for setting the work position.