Sheet Metal Forming Question

[ImperialAlex]

Ok, so this is a pretty common bend to see, where we have a flange that is flush with the edge:

side profile:

My question: How the heck are these actually manufactured? I understand the basic principle of a box and pan brake but what I'm wondering about is how a sheet would be clamped down for this. The bend line is "inside" the main sheet so how do they prevent bending the non-flange parts?

 

[EdZ]

The bend line is "inside" the main sheet so how do they prevent bending the non-flange parts?

The 'edge' that presses into the sheet to bend it is not a single solid piece, but a series of modular replaceable 'fingers':

The 'fingers' fit into matching grooves that are also modular. By leaving a 'gap' between the fingers, you can leave parts of a sheet unbent.

 

[ricochet]

Wow, I learned a lot from that one photo... thank you for sharing it!

 

[jeshikat]

​

 

[ImperialAlex]

Thanks, the images are super helpful! Looks like you need a press brake to do those kind of bends (rather than just a box&pan brake)

 

[Josh | NFC]

@Aibohphobia
@ImperialAlex

So I literally have been researching this because I am trying to bring manufacturing into my home for a chassis project I am entertaining, so thanks for the ask and the answer.

@Aibohphobia
@EdZ

Are you aware of a die that could fit in a small format press that is affordable? Or is it something I need to have machined?

On another note I have been looking at electrobrakes which are pretty cool and quite versatile, but embedded flanges I still can't think of away around a press.

 

[ImperialAlex]

@Josh | NFC I think the cheapest way to get a press brake into your home might be this: http://www.swagoffroad.com/SWAG-Press-Brake-Kits_c_53.html which is a DIY kit of dies+holder that you put into a hand-cranked 20ton Harbour Freight shop press.

It's pretty ghetto and probably not a lot of fun to use, but it does look like making a case just with a box&pan brake would be pretty difficult (unless you could somehow find a way to not need any of these bends - and that's not even counting "internal" bends like most PCI slot bracket thingies are)

 

[Josh | NFC]

@Josh | NFC I think the cheapest way to get a press brake into your home might be this: http://www.swagoffroad.com/SWAG-Press-Brake-Kits_c_53.html which is a DIY kit of dies+holder that you put into a hand-cranked 20ton Harbour Freight shop press.

It's pretty ghetto and probably not a lot of fun to use, but it does look like making a case just with a box&pan brake would be pretty difficult (unless you could somehow find a way to not need any of these bends - and that's not even counting "internal" bends like most PCI slot bracket thingies are)

Yeah, I'm a redneck so I have a 20 ton press kitted out for making 4x4 parts and that is kinda what I was talking about. I think @EdZ and @Aibohphobia are prolly reading my post and asking themselves why I didn't read page 134 of the epic sheet metal tutorial Aibohphobia has put together. But I did. I just am trying to figure out how to live without a fancy computer controlled press with built in dial indicators and other black magic for this project...

 

[EdZ]

I'm not sure if such an adapter exists unfortunately. You've got small hobby brakes for doing straight bends by hand for basic boxwork, industrial brakes for production with a wide selection of special purpose dies, and not much in-between because there's not really much call for a hobby brake able to take punches & dies that cost more than the press itself does. That SWAG press kit @ImperialAlex linked looks like the closest to a professional punch&die set at non-industrial prices, but you're limited to the smaller selection of tooling they have available. If you've already acquired a set of punches & dies, then an adapter for your existing press should be possible, the mounting profiles are standard and published (for a slow press not experiencing a lot of cycles, precision milling is probably overkill).

 

[Josh | NFC]

Thanks, EdZ.

I'm actually going for a decent brake, but was thinking about adapting a small punch press for Louvers or something to that effect for the PCIE key tab. Problem is punches tend not to have enough room for that operation.

Im sure an arbor press could be modded but was hoping someone saw one designed for accepting new dies. I sure haven't.

Peace

 

[TunnelVision]

At the low end price-wise, I've wondered about the vice mounted sheet metal benders - pretty limited I'd imagine but they are segmented:

Or: