cutting super thin stuff (.032 aluminum) on a fiber laser, fixturing?

[Parkerbender]

Hi guys,
We have a part that we are making that is .032 6061 sheet, and the parts are about 6"x60" with lots of features. Currently we have a pretty bad scrap rate and the cut quality is trash because even down at 100psi or so and a 1.0 nozzle that sheet shakes so bad it's all tip touches and the head dances and it's really like a war going on in there... Has anyone ever cut super thin stuff before? I have tried weighting it down and it still shakes in the middle and sometimes then pulls the material in and puckers and the weights don't let it flatten back out. I can't think of a way to suck it down with vacuum since it's a laser... Maybe clamps on the corners and pulling it tight like a drum? If a guy uses strong magnets do you think that will mess up the head height sensor?
Anyway, it's been a battle... I actually bought a timesaver to sand the backsides to help a little, but that thing is a battle of its own (the tracking doesn't want to work all the time so it smokes a $40 belt basically every time you use it)

Thanks for any ideas or insight!

-Parker

 

[TKassoc]

Buy a piece of 2" or thicker aluminum honeycomb core material to set your sheet on. The extra support from a 3/8" or 1/4" inch cell spacing helps everything stay put.

 

[Parkerbender]

ooch, looks like $500+ freight for 1" thick, have you tried this? Seems like it would blast through it, but if it works it works... Spendy to just try, though! Is there a good place to find 2" thick stuff?

 

[Strostkovy]

Are your slats in good shape?

 

[Parkerbender]

Pretty decent, could make new ones I guess but I think it's mainly just because it is so thin and light and getting blown by high pressure n2... I think something needs to hold it, I just don't know what/how.

 

[Strostkovy]

How diverse is the outer profile? Can you blank them first and place the parts in a fixture for the rest of the cutouts?

 

[Parkerbender]

Pretty weird, curves and things. And currently there are 10 different outer profiles

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There has to be a way, just gonna be trickier than I thought!

In the meantime we still can make them there is just a lot of hand work and scrap which there shouldn't need to be...

 

[kb0thn]

How about vacuum pods in safe areas of the sheet? You may have to nest around them. My fiber laser has pneumatic plate clamp and plate lifter. I could see teeing in with plate clamp to run vacuum generator to a few strategically placed vacuum pods. The wood working / homemade CNC router people have little vacuum pod setups.

 

[mattthemuppet]

this is probably a dumb idea as I've never seen a laser cutter in action, but could you mount a spring loaded wheel/ ball to the cutting head? So that when the head lowers down to cut, there's something applying down force to the sheet to dampen any movement.

 

[Strostkovy]

Have you tried far more aggressive and frequent microtabs?

 

[TKassoc]

Pretty weird, curves and things. And currently there are 10 different outer profiles

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There has to be a way, just gonna be trickier than I thought!

I use honeycomb on my laser when I cut thin (0.005"-0.015" SS) material. It burns away a bit but retains enough structure to hold the material. I bought some surplus sheet on eBay years ago so I don't have a current source for you.

Honestly, that's a turret punch part. The hole flares can happen in the machine and the perimeter cut with a Wilson wheel--> https://wilsontool.com/en-us/products/punching/thick-turret/special/wilson-wheel-rolling-shear

 

[604Pook]

Can you stack the sheets? Cut multiples at a time with a thicker/heavier sacrificial sheet on top? If need be pre drill holes through the sandwich in a cut out and bolt it together?

 

[Garwood]

That's a turret punch part if there ever was one.

 

[Strostkovy]

I'm trying to think of what I did differently because I've cut a bunch of 1/32" aluminum on our CO2 laser by doing absolutely nothing special.

 

[kb0thn]

I'm trying to think of what I did differently because I've cut a bunch of 1/32" aluminum on our CO2 laser by doing absolutely nothing special.

I guess it depends on what type of laser he has. My laser (Mazak Super Turbo X) moves the table in the x-axis. So stuff is shaking more than a stationary table machine. But the torch height tracking seems pretty fast. The machine sign off parts are specified as 20 ga steel and the sheet that we got in was complete trash. The height tracking followed around that sheet far better than I expected it would.

 

[Scruffy887]

I cut a bunch of thin aluminum with no issues. Flashing thickness. Maybe your support slats are trashed or too far apart?

 

[Parkerbender]

Have you tried far more aggressive and frequent microtabs?

I am new and dumb to laser things, I am not using any microtabs. Gonna do that and maybe it solves all the problems...

 

[kb0thn]

I am new and dumb to laser things, I am not using any microtabs. Gonna do that and maybe it solves all the problems...

I was just at Bystronic's flat laser factory in Switzerland and learned about nanotabs. If I understand correctly, you just reduce power for a segment of a line and don't burn all the way through. Parts break off like chocolate squares from a chocolate bar.