Design of laser cut sheet aluminum tabs?

[KirbyWan]

Howdy all,

I have a series of parts that I would like to have laser cut out of sheet aluminum, but still be connected to the parent sheet for PAA processing. Here are the details:

Sheet 1, .010 aluminum with 34 parts fit on a 4' X 12' sheet. I want the parts laser cut, but still connected to the parent sheet so that they can be run through our FPL etch/phosphoric acid anodize line then bond primed and the bond primer cured in an oven. Then the individual parts seperated to be used in a bonded panel assembly.

Sheet 2, .025 aluminum chem milled down to .012/.014 in areas with 8 parts on a 4' X 10' sheet. Same processing as above.

What are best practices for desinging connections. I need them thin enough to break out easily, but thick enough that the parts will not fall out during processing and handling. The anodize also will need to run current through the tabs of course. I tried to do a search on this, but I'm not sure what the correct terms for these tabs are.

Thanks for your help.

-Kirby

Kirby Wilkerson

Remember, first define the problem, then solve it.

 

[MikeHalloran]

I don't know what to call them either, but I know what you're asking for.

You have to ask your laser cutter how wide a kerf the laser leaves in the sheet.

If, for instance, the laser removes a line .007" wide, then you would modify the DXF file you supply to leave gaps of say .010", which would produce tabs .003" wide, which break easily.

Actually, they may be a little too narrow: .003" tabs will allow a CNC punch press operator to just shake the sheet to remove all the product. You want your tabs a little sturdier than that.





Mike Halloran
Pembroke Pines, FL, USA

 

[ckeen]

The correct term is a "micro-joint." Most CAM packages include this feature.

 

[ProgressiveRacing]

Any way you can run an experimental piece before going to full sheet?

Tabbing parts is somewhat commonplace but at this thickness it might be a little tricky; never tried to tab a material this thin so I'd go about it with a test, compensate and go from there till I had a process nailed down.

.004-.005 wide tabs seem fine to me but then, this is awful thin. You certainly don't want to ruin the work getting it loose from the sheet.

Good luck.

The Manufacturing Reliquary

http://cmailco.wordpress.com/

 

[KirbyWan]

We ran a test on a scrap sheet and it sort of worked. We used .100 wide tabs, but not very many of them. They were easy to snip through with a flush cutting nipper. But with too few it was a part handeling nightmare. For now we are going to have them just cut the parts out and we may revisit tabs at a later date.

By the way, if anyone can give me a clue as to how deep the heat affected zone would be for laser cut parts with the thickensses described above I would appreciate it. I asked the question on the metal and metallurgy forum thread330-277812 but only got one answer and that was for steel up to 1/8" thick. If someone could post an answer there for that question then someone else might be able to find it later with a search.

Thanks,

-Kirby

Kirby Wilkerson

Remember, first define the problem, then solve it.

 

[looslib]

Try a tab width of .03-.05 and space them about every 3-5 inches, depending on the edge length of the pieces.

Enough to keep the parts in, yet small enough to allow the parts to be broken out.

"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli