Press brake... A newbie question

TFPace · Mar 1, 2017

I'll looking for a brake to fold .120 - .187 aluminium.
These are parts for ATV's.
I have zero experience with a CNC brake.
We have a pneumatic Bantam and this isn't what we need.

There's plenty of 50-80 ton machines for sale.
The opening of the brake is important too of course

.

Tooling ???

Suggestions please.

Attached is an example of the part I'm talking about.

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gbent · Mar 1, 2017

Tooling can easily cost more than the brake. I have a Promecam with a Hurco CNC back gauge, but very little tooling. The Amada style brakes use European style tooling that is very difficult to find in the used market. American style tooling is much easier to find used.

Those parts look pretty simple for a press brake.

TFPace · Mar 1, 2017

gbent said:
Tooling can easily cost more than the brake. I have a Promecam with a Hurco CNC back gauge, but very little tooling. The Amada style brakes use European style tooling that is very difficult to find in the used market. American style tooling is much easier to find used.

Those parts look pretty simple for a press brake.

Thanks for the heads up on euro tooling versus American tooling.

dave powelson · Mar 2, 2017

Peel off the backing on those sample bend parts and look at the strain/stress cracking. Looks like there was little to no-bend radius allowed for....which is often typical.

altered · Mar 2, 2017

First you need a back gauge (you can be precise with a good one). A cnc one will open you the possibility to gauge multiple bend fast. (As in your part). Second it help to have a second axis cnc, so you can control the depth of each bend (as in your part). More axis is further more flexible to high number of part / low volume each.

For starter a promecam brake is relatively cheap this day and in good condition is a great machine. Personally a like euro tooling (amada and other brand name) due to : Harden and ground wearing zone, easy to load on the brake (32 7/8'' length) Match other section very easily. Good tooling will save you headache and last longer.

Hope it help

Jimmy_pop · Mar 2, 2017

for an aluminum part like that, would 5052 be advisable for its bending qualities? And also using a waterjet instead of a laser for a burr free edge? Pretty much able to water jet cut, bend and then sell? Maybe have to run an orbital DA sander over it prior to shipping?

adama · Mar 3, 2017

Rough safe starting point rule of thumb for bendable materials is a top tool radius of at least material thickness, a V opening of 8x material thickness. The more of both the less tonnage less risk of cracking. Sharper the top tool greater cracking risk, smaller the bottom V the greater the tonnage. About 4x material thickness is the minimum limit for most materials but tonnage needs go up a lot.

Worth remembering in alu - polished stainless and similar bending the less tonnage needed the less the marking during bending. Get a V with a decent radius edge (alu wants a large edge radius on the V use some cardboard or polyurethane non marking tape and you can easily bend those parts and not need to touch them with anything. Done with care - the right tools and the laser peal off film won't even get cut through!

That part wants sectional tooling too.

dana gear · Mar 4, 2017

For what's its worth,Some times it depends on the amount of parts you are forming. if a shop is only forming 30 parts then the answer most likely will be different then if they were forming 2000 of the same bends at a time.
Years ago on short runs we would use box and pan/apron brakes and press brakes with homemade adjustable back stops, not a lot of high dollar kind of stuff and we took our time to form it right.
That said there are presses here that we purchased used for 2500.00 and have done tons of great work with.
There is also presses here that cost a small fortune, so it really boils down to how many parts are you going to form and how much you want to spend.

TFPace · Mar 4, 2017

dana gear said:
For what's its worth,Some times it depends on the amount of parts you are forming. if a shop is only forming 30 parts then the answer most likely will be different then if they were forming 2000 of the same bends at a time.
Years ago on short runs we would use box and pan/apron brakes and press brakes with homemade adjustable back stops, not a lot of high dollar kind of stuff and we took our time to form it right.
That said there are presses here that we purchased used for 2500.00 and have done tons of great work with.
There is also presses here that cost a small fortune, so it really boils down to how many parts are you going to form and how much you want to spend.

Dana,

We're more like the 30 part versus the 2000.

The tooling looks like it can be as challenging to buy as the press itself too [emoji6]

Thank you for your reply.

Tom

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brianweldor · Mar 5, 2017

I'm curious, how does your Atek press brake come up short? Not enough tonnage? Poor accuracy?

TFPace · Mar 5, 2017

brianweldor said:
I'm curious, how does your Atek press brake come up short? Not enough tonnage? Poor accuracy?

Pneumatic brakes and stroke control don't work well together.
Plenty of tonnage but the accuracy isn't there at all.

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gbent · Mar 5, 2017

I don't know anything about your pneumatic brake, but would it be possible to make depth blocks that could be placed on either side of the workpiece to set the maximum intrusion of the punch into the die? This should give a dead nuts same bend every time.

I'm guessing the machine was originally intended to spank the part.

TFPace · Mar 5, 2017

gbent said:
I don't know anything about your pneumatic brake, but would it be possible to make depth blocks that could be placed on either side of the workpiece to set the maximum intrusion of the punch into the die? This should give a dead nuts same bend every time.

I'm guessing the machine was originally intended to spank the part.

gbent,

I'm certain a hard stop would be perfect to "dial-in" my brake. There is a knob/lever on the rear of this machine the let's you increase or decrease cylinder travel.

Scruffy887 · Mar 5, 2017

You can get a nice CNC press brake with repeatable ram stroke in the .0004 range. European tooling made to the same .0004 spec. Expect to pay at least 100k. Tooling $35-45 per inch for punch OR die. Then it comes down to raw material thickness spec. Went nuts a few weeks ago trying to dial in some 10 gauge stock. Part had 4 90 degree bends and 4 45/135 degree bends. All air bending of course. New Trumpf 3100. Could not get same angle across 35 inches so I adjusted left and right ram stroke to compensate. Even worse mess. Then I miked the sheet and found .002 difference in thickness side to side. That makes a big difference with air bending.
And the last bit is aluminum bending. Sometimes it just does what it wants.

So exactly what is it your current press cannot do well that you need done well? Are you doing one angle first for all parts and changing setup to the smaller angle?

TFPace · Mar 5, 2017

Scruffy887 said:
You can get a nice CNC press brake with repeatable ram stroke in the .0004 range. European tooling made to the same .0004 spec. Expect to pay at least 100k. Tooling $35-45 per inch for punch OR die. Then it comes down to raw material thickness spec. Went nuts a few weeks ago trying to dial in some 10 gauge stock. Part had 4 90 degree bends and 4 45/135 degree bends. All air bending of course. New Trumpf 3100. Could not get same angle across 35 inches so I adjusted left and right ram stroke to compensate. Even worse mess. Then I miked the sheet and found .002 difference in thickness side to side. That makes a big difference with air bending.
And the last bit is aluminum bending. Sometimes it just does what it wants.

So exactly what is it your current press cannot do well that you need done well? Are you doing one angle first for all parts and changing setup to the smaller angle?

Scruffy,

There are several issues with the press.
1. The jaw opening is small. I form several shapes that have long legs and this press limits me.
2. The back cage is manual and a pain to adjust. It's a two man job.
3. My tooling stinks... I know... go buy some

To answer your question on the the fold steps. The part in my initial post was the part I'm considering making in house. My customer is wanting us to cut these and then form.

If I had some smaller with dies I could possibly make this work. As Gbent mentioned about making some hard stops, etc.

Bondo · Mar 5, 2017

I built a small press brake for my 50 ton air press. I have a 230 ton brake already, but it's great for the random bracket or 2.

I have it set up with a 4 way die so it can bend 24 ga through 3/8". It can bend 24" wide between frame rails. It is also very simple to put in different size dies for different applications such as yours.

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TFPace · Mar 5, 2017

Bondo said:
I built a small press brake for my 50 ton air press. I have a 230 ton brake already, but it's great for the random bracket or 2.

I have it set up with a 4 way die so it can bend 24 ga through 3/8". It can bend 24" wide between frame rails. It is also very simple to put in different size dies for different applications such as yours.

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Bondo,

Nice name. [emoji6]

My tooling or lack there of and quite honestly lack of working around a seasoned brake operator are not helping me either.

I don't know if my Bantam has enough space to accommodate a four way die.
That would make life much easier with this machine.

I'll take some pictures tomorrow and post.

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TFPace · Mar 6, 2017

TFPace said:
Bondo,

Nice name. [emoji6]

My tooling or lack there of and quite honestly lack of working around a seasoned brake operator are not helping me either.

I don't know if my Bantam has enough space to accommodate a four way die.
That would make life much easier with this machine.

I'll take some pictures tomorrow and post.

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Here's my brake.

https://uploads.tapatalk-cdn.com/20170306/de06c718cb4633d982c64542a3a746ed.jpg[/IMG

Is there a standard dimension American tooling?

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kb0thn · Mar 6, 2017

Do you really want to do that bending in house? For 30 pcs type orders, I would guess you would pay about $2 to $4 to have those pieces bent. Around $100 for the lot charge is what our laser / waterjet shops would charge. And they would be delivering good pieces for that price and using $250k of equipment to get there.

I have a 17 ton Diacro hydraulic press brake and we make stuff like that. I buy cheap tooling from Power Brake Dies in Chicago (see their in stock special ... essentially just drops). Maybe $10 per inch for punch and the same for die, on average. So I've already spent more on tooling than the $1250 for the brake itself. And I have a manual back gauge. So in doing a part like yours, if I had my good guy on it ... would probably scrap two or three blanks. If I was doing it, I would probably scrap 5 blanks before I got it good enough. But then I would keep going try to make it perfect, and scrap a few more. The reason I have the press brake isn't that we can do it cheaper, but we can do it on our schedule with no lead time. If you can live with the lead-time, I would think you would be better off having the parts supplied to you cut and formed.

-Jim

TFPace · Mar 6, 2017

kb0thn said:
Do you really want to do that bending in house? For 30 pcs type orders, I would guess you would pay about $2 to $4 to have those pieces bent. Around $100 for the lot charge is what our laser / waterjet shops would charge. And they would be delivering good pieces for that price and using $250k of equipment to get there.

I have a 17 ton Diacro hydraulic press brake and we make stuff like that. I buy cheap tooling from Power Brake Dies in Chicago (see their in stock special ... essentially just drops). Maybe $10 per inch for punch and the same for die, on average. So I've already spent more on tooling than the $1250 for the brake itself. And I have a manual back gauge. So in doing a part like yours, if I had my good guy on it ... would probably scrap two or three blanks. If I was doing it, I would probably scrap 5 blanks before I got it good enough. But then I would keep going try to make it perfect, and scrap a few more. The reason I have the press brake isn't that we can do it cheaper, but we can do it on our schedule with no lead time. If you can live with the lead-time, I would think you would be better off having the parts supplied to you cut and formed.

-Jim

Jim,

You make a valid point on jobbing the forming out.

I'm a used machine buyer too. Getting shops around here for small orders is challenging to say the least.

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