Tabs for retaining lasercut workpiece

[Chri541r]

Hi,

I'm looking for information about general design rules/guides for lasercutting, more specifically design of "retaining tabs" (not sure what the proper term is). I need to cut multiple identical parts in a single row and subsequently cold-roll the entire steel plate to create a tube from which i can cut the now cylindrical parts.
So I need to know how to design tabs.

The plate to be cut will be a 1500 x 3000 x 10 mm stainless steel sheet AISI304.

I have attached a sketch to help explain.

 

[hendersdc]

That is going to be tricky and probably involve some trial and error. I haven't done exactly what you are looking for but I would make the tabs as small as possible while still making it through the rolling process, have as many as are needed to ensure that the part actually gets rolled instead of just getting a few bends, and make sure that the size of the tabs and slot between parts allow easy access for whatever your cutout method is. You would potentially need a lot more clearance to get a pair of cutters in vs a cutoff wheel.

I am assuming you are rolling this with the axis of the resulting cylinder oriented vertically in the sketch, if this is true then it looks like you are planning to leave the entire end face of each part attached in the rolled direction which I think is probably a good idea too.

If parts were coming out of the sheet prior to rolling I could give you much more specific numbers.

 

[dvd]

Why aren't you using a laser tube cutter?

https://www.youtube.com/watch?v=QoF1nxKW0vw

 

[Chri541r]

hendersdc:

Thanks for your answer. You are correct about rolling orientation, the final diameter of the tube is approx. 800mm. I plan to use an anglegrinder to cut free the parts. The tabs and slots in the current drawing are 5mm wide, so that would leave 5 x 10mm tabs which I hope will be enough.
If the parts were to come out of the sheet prior to rolling, what would be the right dimensions for tabs etc.?

dvd:

Unfortunately I don't have access to such machinery, also finding stainless steel tube in 10mm gauge with an 800mm dia. would be hard.

 

[3DDave]

If you can roll the flat into a tube you have a source of tube.

 

[hendersdc]

If you were removing the parts from flat sheet the tabs would be as small as possible, just big enough to hold the part on the sheet while still being lasered. Ideally they fall loose from the sheet with a light shaking by hand. With 10mm thick material this isn't really possible. I would make the tabs 0.010" thick and they would still need to be popped out using a flat head screwdriver or twisted out by hand but that is much easier than cutting.

That laser tube cutter sure would make things easier!

 

[Chri541r]

3DDave:

Thats true, but I am situated in Denmark, so it will be hard if not impossible to find someone who can handle the size of the tube.
On a sidenote, I actually tried to look up some cnc/turn/laser tube cutter, and found one very close to me. Unfortunately they were not able to cut my size of tube.

hendersdc:

Laser tube cutter would be the best answer no doubt, too bad it won't be an option for me. Thanks for the advice on the tabs. I guess things will be different with subsequent rolling though, as you mentioned.

 

[dvd]

Might be able to find water jet or plasma cutter for larger tube diameters. Don't know what surface quality you require.