Sheet metal folding

[BensPlasmaAu]

I was wondering if anyone could explain how to plan out a fold in CAD. For instance if I have a 1.6mm thick sheet and I wanted to put a 90 degree fold, how much do I need to allow when planning it out in CAD?

Hard to explain really. Does anyone follow my line of questioning?

Next part of the question. Is there a program that allows you to build a box and then "unfold" it and export to a dxf so it can be sent to the plasma?

[Jaime Branco]

If you need the exterior size be like 50 mm by 50 mm you need to draw one rectangle with 96.8 and fold at 48.4.

Let me try explain you always need to subtract the material thickness . If you make 3 folds to make like a U and use sheet of 1 mm and you need that the exterior to be like 40 50 40 the interior is going to be 39 48 39 you make a rectangle with 126 mm

Jaime

[icmplasma85]

If you can post a picture or dxf of what you need as a finished product (bent) along with material thickness but not in metric I'd be glad to sketch that up for you and even send you a drawing of how to bend it (if you have a brake). I've bent quite a few stair pans for commercial stairs, and Jaime Branco is exactly right about material thickness. If you have a .25" plate vs a 12ga plate and trying to make the same part in regards to dimensions, you will bend it @ different measurements to produce the same final product. confused yet? Stand in front of a brake for 4 hrs straight bending the same part, you will learn quickly.

[Gamelord]

Not only do you need to allow for the thickness of the metal, but you also need to allow for the radius of the bend. Metal is not like wood where your angles are perfectly 90 degrees. You have some material loss that happens when the metal bends and the radius can vary depending on how your brake is set up. Thinner metals are easier to get sharp bends but thicker metal will require larger radius bends.

[little blue choo]

Glad I saw this post. I just purchased a 48 inch pan and box break from Grizzly several weeks ago. I have been busy with the birth of my new grandbaby and the very near loss of my daughter so I haven't even unbolted it from the shipping crate. Now that Mom and Baby are home I plan on getting started with it soon. I know its not the quality break a lot of you have but it should do what I want to do with it. I plan on making a lot of LED lit signs and need it to bend the box.

Rick

[Gamelord]

I wrote on the top of my brake with sharpie the bend radius width for each guage metal. I just had to go through trial and error to get the measurements. Now the bends come out spot on. Even so, if I am working on something with very close tolerances I usually use a piece of scrap to double check the bend first.

[BensPlasmaAu]

If you need the exterior size be like 50 mm by 50 mm you need to draw one rectangle with 96.8 and fold at 48.4.

Let me try explain you always need to subtract the material thickness . If you make 3 folds to make like a U and use sheet of 1 mm and you need that the exterior to be like 40 50 40 the interior is going to be 39 48 39 you make a rectangle with 126 mm

Jaime

Brilliant, this is exactly what i was looking for to add to the CAD drawings.

If you can post a picture or dxf of what you need as a finished product (bent) along with material thickness but not in metric I'd be glad to sketch that up for you and even send you a drawing of how to bend it (if you have a brake). I've bent quite a few stair pans for commercial stairs, and Jaime Branco is exactly right about material thickness. If you have a .25" plate vs a 12ga plate and trying to make the same part in regards to dimensions, you will bend it @ different measurements to produce the same final product. confused yet? Stand in front of a brake for 4 hrs straight bending the same part, you will learn quickly.

No picture or drawings yet that make any sense. I have many ideas and plans for some stuff so when i get something, i'll have a go using the measurements and rules above and post it. It will probably be atrocious to start with, but as with everything, you've got to try and fail before you do and succeed. Just like everything to do with building your own plasma cutter and business.

Not only do you need to allow for the thickness of the metal, but you also need to allow for the radius of the bend. Metal is not like wood where your angles are perfectly 90 degrees. You have some material loss that happens when the metal bends and the radius can vary depending on how your brake is set up. Thinner metals are easier to get sharp bends but thicker metal will require larger radius bends.

I unfortunately don't have a brake yet. Hopefully i will be taking delivery of a finger break soon if all goes well. Defeinately need to practice and do the trial and error method.

Glad I saw this post. I just purchased a 48 inch pan and box break from Grizzly several weeks ago. I have been busy with the birth of my new grandbaby and the very near loss of my daughter so I haven't even unbolted it from the shipping crate. Now that Mom and Baby are home I plan on getting started with it soon. I know its not the quality break a lot of you have but it should do what I want to do with it. I plan on making a lot of LED lit signs and need it to bend the box.

Rick

Rick, best wishes go to your family in this time. You actually have a break, which is 90% of the way to actually bending and making stuff. Keep going, i'm sure we would all like to see the end results.

[Jaime Branco]

Not only do you need to allow for the thickness of the metal, but you also need to allow for the radius of the bend. Metal is not like wood where your angles are perfectly 90 degrees. You have some material loss that happens when the metal bends and the radius can vary depending on how your brake is set up. Thinner metals are easier to get sharp bends but thicker metal will require larger radius bends.

this is true but i'm using a 3meters 130T digital PRESS BRAKE(a olter model of this one https://www.youtube.com/watch?v=1LVJ3BO6uBo) and if you use a small die like a 8 ou 10 mm for sheet of 1 or 2 mm you get only the sheet thickness plus the inside measurement.
If you need to bend sheet of 3 4 5 ou 6 mm this is not true you need to use a big die like 20 40 ou 60 mm and you get some offset.

Jaime

[Thor]

Solidworks will draw in sheetmetal mode and unfold for dxf files to be cut and a print to show bend lines and locations etc. (once you know the correct bend radius you'll be using and enter it in that is)
Fusion 360 is supposed to have sheet metal out now, I havent played with it all as still havent learned the basic stuff in featurecam. I want to but its just so different from solidworks that I was taught on back in school its hard to get used to for me, guess I need to find some online courses and sit down and work at it.

[steel 35]

Next part of the question. Is there a program that allows you to build a box and then "unfold" it and export to a dxf so it can be sent to the plasma?

May look at Sheet lightning Pro. (Software) Arc light has some videos using it. I often wonder about it!

[RAD]

I was wondering if anyone could explain how to plan out a fold in CAD. For instance if I have a 1.6mm thick sheet and I wanted to put a 90 degree fold, how much do I need to allow when planning it out in CAD?

Hard to explain really. Does anyone follow my line of questioning?

Next part of the question. Is there a program that allows you to build a box and then "unfold" it and export to a dxf so it can be sent to the plasma?

Normally you would minus 2x the thickness for each bend, for example if you would like to bend an 'L' of 50mm x 50mm and using 1.6mm thk. mat'l. your flat layout would be 96.8mm wide with your bend line down the middle, or simply draw your shape in CAD and offset your thickness and use all internal dimensions for your flat layout, example: you want to bend a channel section of 50mm wide (for both flanges) x 100mm deep using 3mm thk. mat'l. your internal dimensions for you flat layout would be 47mm x 94mm x 47mm.

Sheet lightning pro is wonderful for transitions and elbows it is a great software

[whiskeymike]

Solid works is very good. Autodesk inventor also does sheet metal and folding. They both have a decent learning curve, but it's worth it if you are doing a lot of work with these types of things. It takes into account the material, bend method, thickness, etc..

You can get a free year or two of inventor to try it and use it as a student.

[Nacs Fab]

Bend Tech has a sheetmetal program.

http://www.bend-tech.com/products.html

[kaharshs]

Just do an internet search for bend allowance or bend savings. You need to know material thickness, bend angle, and the radius of bending die you will be using. I have been doing aircraft sheet metal for 13 years and there is no substitute for accurate flat pattern layout. You will need to add or subtract material thickness depending on wether you are going for the inside or outside dimension of your part. Also the bend line placement changes on wether you are using a power brake or a leaf brake.