Finger/Box Brakes -

[jeepxj]

Got a small production run to do and have no experience with box brakes.

090 aluminum
this is the end state of the part.


The long bend there has a total of 4" of material to bend. I can adjust the slot dimensions a bit if needed.




looking at units like:

Grizzly G0556 - 12" 20-Gauge Benchtop Pan and Box Brake - Grizzly Industrial, Inc.

<h1>G0556 12" Pan and Box Brake</h1> <h2>The best 12" pan and box brake on the market.</h2> <p>This G0556 12" Benchtop Pan and Box Brake is built to take on any serious bending work.</p> <p>It can handle setting an angle in 20-gauge mild steel up to 135°.</p> <p>The G0556 comes with six...

www.grizzly.com

They gona laugh at this kinda thickness?

 

[GeoBruin]

Got a small production run to do and have no experience with box brakes.

090 aluminum
this is the end state of the part.


The long bend there has a total of 4" of material to bend. I can adjust the slot dimensions a bit if needed.




looking at units like:

Grizzly G0556 - 12" 20-Gauge Benchtop Pan and Box Brake - Grizzly Industrial, Inc.

<h1>G0556 12" Pan and Box Brake</h1> <h2>The best 12" pan and box brake on the market.</h2> <p>This G0556 12" Benchtop Pan and Box Brake is built to take on any serious bending work.</p> <p>It can handle setting an angle in 20-gauge mild steel up to 135°.</p> <p>The G0556 comes with six...

www.grizzly.com

They gona laugh at this kinda thickness?

The slots you have at the bend will minimize the effective width of the material to be bent, but that's almost 11 gauge material.

If you have access to a hydraulic press, I might recommend something like the SWAG finger brake kit for that kind of money.

Alternatively, you may be able to get away with something like a vise mounted finger brake. They make them in 4", 6" and 8" depending on how big your part is (and how big your vise is).

 

[JradM]

Pre-made press brake attachments are available too.



You could use that with a inexpensive manual hydraulic press - but you did say "production run" so I'm guessing speed is a factor. A manual hydraulic press would be SLOW.

I can see both why you would want to use a brake instead and why you'd be concerned about it's ability to handle material that thick. They're not made for that type of bending... but the slots remove a lot of material and I'm guessing this part isn't that big? I think it seems plausible.

If you have a good vise, like GeoBruin's suggestion of a vise-mounted finger brake. They're not as robust as using a press, but that would be faster (and cheaper).

 

[cmandp]

I have just a little experience with sheet metal and mostly aluminum. But I don't think that grizzly brake will have too much issue with 090 aluminum at 4" (without you're relief cuts even). A press brake attachment for a hydraulic press isn't going to be as precise as a nice bench mounted finger brake and won't give you the clearance needed to bend the part back on itself I don't believe.

BTW do not buy 6061 sheet for this (I would avoid 6000 series altogether). It will likely be T6 temper and will crack at the bends. 3003, 5052 or 2024 alloys are going to be what's commonly available that will bend nicely.

Also I would eliminate the fold back over on the part if possible (or do it a different way like welding after bending). You might be able to do it depending on clearance with the brake but it will be a lot easier if you don't have to.

 

[Snip's]

What grade of aluminum? I wouldn't use 6061, as it will start splitting on the outside bend radius...
I would use 3003 or 5052...

 

[Snip's]

You might want to center the bending slot on the short tab so it doesn't pull to one side...

 

[Sumboodie]

Pre-made press brake attachments are available too.



You could use that with a inexpensive manual hydraulic press - but you did say "production run" so I'm guessing speed is a factor. A manual hydraulic press would be SLOW.

I can see both why you would want to use a brake instead and why you'd be concerned about it's ability to handle material that thick. They're not made for that type of bending... but the slots remove a lot of material and I'm guessing this part isn't that big? I think it seems plausible.

If you have a good vise, like GeoBruin's suggestion of a vise-mounted finger brake. They're not as robust as using a press, but that would be faster (and cheaper).

I have one of those. I'd imagine someone that has experience can make great use of it. I can handle single bends and sorta be near the actual bend area I want... ish haha.

Got it off Amazon for around $175 I think.

 

[jeepxj]

going with 5052 AL.

You might want to center the bending slot on the short tab so it doesn't pull to one side...

Ahh yea sure do.

 

[jeepxj]

I have just a little experience with sheet metal and mostly aluminum. But I don't think that grizzly brake will have too much issue with 090 aluminum at 4" (without you're relief cuts even). A press brake attachment for a hydraulic press isn't going to be as precise as a nice bench mounted finger brake and won't give you the clearance needed to bend the part back on itself I don't believe.

BTW do not buy 6061 sheet for this (I would avoid 6000 series altogether). It will likely be T6 temper and will crack at the bends. 3003, 5052 or 2024 alloys are going to be what's commonly available that will bend nicely.

Also I would eliminate the fold back over on the part if possible (or do it a different way like welding after bending). You might be able to do it depending on clearance with the brake but it will be a lot easier if you don't have to.

4" is factoring on the slots. so for the brake there is 4" of 090 to bend. the part length is about 9.5" overall but the brake wont see it that way.

looking to avoid welding on the part. using the bolt to control 2 planes for stiffness.

 

[cmandp]

4" is factoring on the slots. so for the brake there is 4" of 090 to bend. the part length is about 9.5" overall but the brake wont see it that way.

looking to avoid welding on the part. using the bolt to control 2 planes for stiffness.

Ok, in that case for that little brake I'd keep the relief slots. I think it might have some trouble at 9.5".

I get why you have it but it is going to be difficult to line up precisely if it's bendable. Bend order will be important.

 

[jeepxj]

Ok, in that case for that little brake I'd keep the relief slots. I think it might have some trouble at 9.5".

I get why you have it but it is going to be difficult to line up precisely if it's bendable. Bend order will be important.

yes absolutely keeping the reliefs. keeps the bendable material to 4" overall. which I think I can reduce by another 25-30% if needed.

it doesnt need to be bang on accurate. I'm going to slot out one of the tab holes slightly to have an allowance from 88 to 92" on the main long bend.

 

[jeepxj]

like so:

 

[JSGAuto]

Adding a small flat to that radii would be useful for "production" Easier to bank off a backgage/stop.

 

[jeepxj]

Adding a small flat to that radii would be useful for "production" Easier to bank off a backgage/stop.

good call

 

[david3921]

You could form this with two passes...provided that the second form is a plunge. First form would be the tabs. Second would be a plunge that would bend the two sides up. Yep, it's expensive. The other way it to use goose neck dies for the two remaining forms. The Grizzly shown won't be able to do it as it only allows 7/8" height. The straight die shown won't be able to to it either. Not enough clearance. The issue you have is the inside is very narrow.

 

[isb cornbinder]

I have wanted a box and pan bake for decades. Finally there was what I wanted on Craigslist. The price was more than right at $1300.
I would like some kind of counterbalance to help with the lower bar. Suggestions??

 

[jeepxj]

You could form this with two passes...provided that the send form is a plunge. First form would be the tabs. Second would be a plunge that would bend the two sides up. Yep, it's expensive. The other way it to use goose neck dies for the two remaining forms. The Grizzly shown won't be able to do it as it only allows 7/8" height. The straight die shown won't be able to to it either. Not enough clearance. The issue you have is the inside is very narrow.

ahh I see what you're saying. if I drop off the back flange im not sure on structure.

could do a unit like this with more vertical fingers:


or an old chicago



if this is working in reality like it is in my head.

bend sequence:

tab - tab - short long side, tall long side.

 

[RichieP_MechE]

Do you want/have to do this yourself? OshCut or sendcutsend should be able to do this pretty easily and cheaply. I like to use OshCut when checking "is it bendable", their 3D bend simulation is top notch. https://app.oshcut.com/cart

 

[Steve_P]

All I'll say is to look at Ryerson, or whatever your source, and see what the minimum recommended bend radii is for your material.

 

[jeepxj]

Do you want/have to do this yourself? OshCut or sendcutsend should be able to do this pretty easily and cheaply. I like to use OshCut when checking "is it bendable", their 3D bend simulation is top notch. https://app.oshcut.com/cart

I can get them cut all day long for 5x less than the finished bent part from osh, sendcutsend,etc. For what amounts to 4 bends I can cover my tooling cost pretty quickly.

 

[jeepxj]

All I'll say is to look at Ryerson, or whatever your source, and see what the minimum recommended bend radii is for your material.

k value? fusion calculated it. no idea if its accurate.

5052 H32 is what im going with.

 

[cannuck]

the 5052 would work just fine, but you need a real box and pan brake, not some Chinese toy. You also need one that can be supported with new fingers, as my suggestion is you need to grind the radius into the finger. Normally you get the radius by setting the top (clamp) back, but if you do that your bend will have a varying radius and a dent (stress riser). with a radius on the finger tip the leaf just wipes around making a constant radius. As you have no doubt figured out you can work with one finger, but what you REALLY need to do is make templates out of slightly thinner material so you can set up (backstop) each bend and then do 100 of the first, re-jig and test than 98 with second bend and to on to the end. There is no way you can meet the accuracy requirement to get you double tab holes to line up by marking and eyeballing the bends.

 

[jeepxj]

the 5052 would work just fine, but you need a real box and pan brake, not some Chinese toy. You also need one that can be supported with new fingers, as my suggestion is you need to grind the radius into the finger. Normally you get the radius by setting the top (clamp) back, but if you do that your bend will have a varying radius and a dent (stress riser). with a radius on the finger tip the leaf just wipes around making a constant radius. As you have no doubt figured out you can work with one finger, but what you REALLY need to do is make templates out of slightly thinner material so you can set up (backstop) each bend and then do 100 of the first, re-jig and test than 98 with second bend and to on to the end. There is no way you can meet the accuracy requirement to get you double tab holes to line up by marking and eyeballing the bends.

yup i planned to make 4 stations on a 4' brake if I end up with one that large. each station with a backstop jig.



I happened upon these. kinda curious how they would hold up. I can print my own.

Pardon Our Interruption...

also wondering if i dont just use a marketplace H frame, new cylinder and power pack to make a hydro brake with decent cycle times.

 

[cannuck]

yup i planned to make 4 stations on a 4' brake if I end up with one that large. each station with a backstop jig.



I happened upon these. kinda curious how they would hold up. I can print my own.

Pardon Our Interruption...

also wondering if i dont just use a marketplace H frame, new cylinder and power pack to make a hydro brake with decent cycle times.

The vice mount tool can make nice bends, BUT: would be a proper ***** to set up backstop tooling and with any press brake you need punches with radius and angle to allow sufficient overbend to end up at 90 degrees. Easy with a box and pan (you make up adjustable travel stops for the leaf)

 

[jeepxj]

The vice mount tool can make nice bends, BUT: would be a proper ***** to set up backstop tooling and with any press brake you need punches with radius and angle to allow sufficient overbend to end up at 90 degrees. Easy with a box and pan (you make up adjustable travel stops for the leaf)

I got some slotting in the holes to allow for not perfect 90s on the long bends. but trying to think about how to knock them out effectively without eating up hours upon hours.

all i'm learning is to negotiate harder on getting them bent by the shop.

 

[cannuck]

I got some slotting in the holes to allow for not perfect 90s on the long bends. but trying to think about how to knock them out effectively without eating up hours upon hours.

all i'm learning is to negotiate harder on getting them bent by the shop.

Sorry to be so far away. You would be welcome to come and set up on my WWII vintage 48" stuff (for which I can still buy parts from OEM = Brown Boggs). how are you duplicating what was originally a bespoke punch and die to cut blank?

 

[jeepxj]

Sorry to be so far away. You would be welcome to come and set up on my WWII vintage 48" stuff (for which I can still buy parts from OEM = Brown Boggs). how are you duplicating what was originally a punch and die to cut blank?

thanks for the offer. but you live in america's hat.
what do you mean duplicating cut blank? if you mean how am i getting the flats; laser cutter

 

[cannuck]

thanks for the offer. but you live in america's hat.
what do you mean duplicating cut blank? if you mean how am i getting the flats; laser cutter

That is what I wondered about - laser or plasma.

 

[jeepxj]

That is what I wondered about - laser or plasma.

yea laser. cleaner edges and less heat distortion on these smaller cuts. like the zip tie slots.

 

[cannuck]

yea laser. cleaner edges and less heat distortion on these smaller cuts. like the zip tie slots.

The nice part about 5052 is that some of the hardening you might lose in cutting you will make back when forming. I would still want to know load path and orient loaded little bridges down rolling grain and least loaded axis going cross grain.

 

[Steve_P]

k value? fusion calculated it. no idea if its accurate.

5052 H32 is what im going with.

I recommend that you do some more research and verify your design. I am NOT a "sheetmetal" expert, but minimum bend radii depends on material, temper, grain direction orientation when you form it... The reason I say this is because your radii look small for aluminum to me, and this throws up red flags. Radii is a factor in K value, but I have no idea what you're assuming.

You'll never get that hole and slot to line up in the real world like it does in CAD if they're the same diameter. Unless there's a reason, the slot should be wider/bigger diameter.

 

[cannuck]

I recommend that you do some more research and verify your design. I am NOT a "sheetmetal" expert, but minimum bend radii depends on material, temper, grain direction orientation when you form it... The reason I say this is because your radii look small for aluminum to me, and this throws up red flags. Radii is a factor in K value, but I have no idea what you're assuming.

You'll never get that hole and slot to line up in the real world like it does in CAD if they're the same diameter. Unless there's a reason, the slot should be wider/bigger diameter.

Recommended minimum bend radius for 5052 is 1.5T (i.e. sheet thickness) but personally I like 2.0T (mostly because in my boat building days it was me paying for any warranty claims. But, you will note for 90 pcs I recommend making at least 100 since there is a steep learning curve as you add each bend...ESPECIALLY where 2 holes must line up.

 

[jeepxj]

The nice part about 5052 is that some of the hardening you might lose in cutting you will make back when forming. I would still want to know load path and orient loaded little bridges down rolling grain and least loaded axis going cross grain.

we're holding popcans and maybe 40oz yetis here on top end of weight.

at 50kg we're getting movement lol

 

[jeepxj]

I recommend that you do some more research and verify your design. I am NOT a "sheetmetal" expert, but minimum bend radii depends on material, temper, grain direction orientation when you form it... The reason I say this is because your radii look small for aluminum to me, and this throws up red flags. Radii is a factor in K value, but I have no idea what you're assuming.

You'll never get that hole and slot to line up in the real world like it does in CAD if they're the same diameter. Unless there's a reason, the slot should be wider/bigger diameter.

fusion did the calcs in its sheetmetal functions. I told it the material and thickness.

the hole and slot are already over sized for the bolt. ton of wiggle room here already.

one of my example parts I got done up a bit ago shows that. also of note: that cut file had the material at .100 instead of 0.090 that they had on hand causing the slight offset of the tabs.





tons of bolt room even before I slotted the inner hole a bit.

 

[david3921]

Swag has goose neck dies that would probably work.

SWAG Gooseneck Dies, Fit The 12 Ton, 20 Ton & Compact Finger Brakes Only

Gooseneck Dies For 12 Ton, 20 Ton & Compact Finger Brakes Only Are you looking to increase the bending capabilities of your SWAG finger press brake kit? The SWAG Gooseneck dies are laser cut at 90° to allow for air bending. These punches are used for forming right angle bends, channels, or other...

www.swagoffroad.com

Do you have to produce it in aluminum? Looks like steel would be a lot easier to form and wouldn't have to be so thick for the same strength.

 

[whateg01]

Not sure what you ended up with but a gooseneck punch isn't required if the bends are done in the right order, which you may have already figured out. I'm curious how you did the offset bends on the end though.

 

[jeepxj]

Swag has goose neck dies that would probably work.

SWAG Gooseneck Dies, Fit The 12 Ton, 20 Ton & Compact Finger Brakes Only

Gooseneck Dies For 12 Ton, 20 Ton & Compact Finger Brakes Only Are you looking to increase the bending capabilities of your SWAG finger press brake kit? The SWAG Gooseneck dies are laser cut at 90° to allow for air bending. These punches are used for forming right angle bends, channels, or other...

www.swagoffroad.com

Do you have to produce it in aluminum? Looks like steel would be a lot easier to form and wouldn't have to be so thick for the same strength.

want to sell them raw finish to reduce cost. either AL or stainless.

 

[jeepxj]

Not sure what you ended up with but a gooseneck punch isn't required if the bends are done in the right order, which you may have already figured out. I'm curious how you did the offset bends on the end though.

you mean order of bends?

 

[whateg01]

you mean order of bends?

No, in a regular apron brake, the apron is solid so it would want to bend both flanges at the same time, but on your part the bend is offset by the material thickness

 

[cannuck]

No, in a regular apron brake, the apron is solid so it would want to bend both flanges at the same time, but on your part the bend is offset by the material thickness

On many regular box and pans the leaf (apron) has a removable angle top edge. You use a short one to allow clearance (essentially a lower mate to the finger) to clear things beside each other. Main body of blank goes under clamping finger and you bend one tab up then move it over and do the second.

I was so distracted by panic jobs yesterday I neglected to mention the simple way of getting a nice radius on aluminum bends. If you are doing 0.090 and you need a 1.5T centerline radius you set back the top clamp 0.090 and bend a 5000 (pure Al) shim of same thickness tight around the finger. Set back clamp another 1T and your centerline radius is 1.5T (and you don't have to make a custom finger. Need 2t? Use 1/8 shim and you will be close