SPOTS on ZNSE Lens L3030

[CLT-Tech]

On my 4000 Watt Trumpf 3030, Cutting with a 5" head, 1/8" SS with Nitrogen assist, My cutting head lense gets destroyed after no more than 10 minutes of cutting. Every Time!

This only seems to happen with .125 stainless steel. (304b) . Even with Trumpfs technology table unmodified, I am still losing lenses to spots, then focus goes out the window.

Does anyone else experience this problem? And what can be done? I've tried many things over the years (nozzle standoff, wattage, focus, speed, gas pressure, nozzles, boron nitrate on the sheet. Nothing helps, and this only happens with 1/8 ss and 1/8 galv.

[MacGyver]

You say "only with SS and...", but does that include aluminum, as well? Could be flashback. if you haven't done aluminum yet (since that would do the same). At that kind of power, a melted pool of metal makes a really nice reflector. Also, make sure your beam is aligned correctly. If it's off by the time it gets to the focusing lens, it could be heating the lens carrier and causing more havoc. Are you sure the air assist is getting to the focusing lens?

[CLT-Tech]

You say "only with SS and...", but does that include aluminum, as well? Could be flashback. if you haven't done aluminum yet (since that would do the same). At that kind of power, a melted pool of metal makes a really nice reflector. Also, make sure your beam is aligned correctly. If it's off by the time it gets to the focusing lens, it could be heating the lens carrier and causing more havoc. Are you sure the air assist is getting to the focusing lens?

Only .125 Stainless. cutting aluminiums has never hurt my lense. Thinner or thicker stainless has never been a problem. Only 1/8 stainless causes permenant damage to my lense. Makes no sense to me or the service guys at trumpf. I thought reflectivity was the problem, but even with a coat of boron nitrate on the material, the effect is the same.
As for the air assist at the lense. . . . i have no clue

[westland]

That is weird. Has it always done this?

I don't know what the default tech table settings on that machine are, but looking at the defaults on my 3050, I find it really bizarre.

What size nozzle are you using? What are the pierce settings? Are you cutting with reduced lead in? What is the assist gas pressure? What is the stand off? Are the parts a mainly large contours or a blend?

Jamie

[CLT-Tech]

Trumpf tech table on l3030 L contour
-2.5 autolas +
4000 watts
10,000 htz
185 in/min
.0300 standoff
11 bar
2.3 nozzle

I have tried other parameters (nozzle size, standoff, lower speed, lower watage, acceleration, gas pressure), and still have the same problem. Machine cuts beautiful Large medium and small contours for a couple minutes and then SHAZAMM!! Cut lost, blows snots across top of sheet, blows spatter onto my lense.

[westland]

The settings look comparable to mine. I've changed most of the thinner materials like this to a 0.060 standoff. It helps take care of sheet bounce issues. The nozzle size seems big to me, I usually run a 1.7 nozzle for this material with a bit more pressure. What's the smallest you've tried?

Is this the thickest stainless you cut with this head? Is power ramping on?(Not sure if this is the same on the 3030 as the 3050.)

What else has trumpf had you do? Have they blamed the material yet?

Jamie

[CLT-Tech]

I have tried with and without power ramping.

Trumpf did tell me i had a bad batch of material, but this has been going on for 2 years with many diffirent material lots.

I have tried up to a .0520 standoff, and have tried a 2.2 , 2.0 , 1.7, 1.4 nozzle with various pressures.

I think im just going to have to create a tech table to cut this material with a 7.5 cutting head, and just hope i can focus the beam exactly where i need it. I have done this before, and the reason is simply that the lense on the 7.5 cutting head is much further from the material than the 5 inch cutting head.

[westland]

Trumpf did tell me i had a bad batch of material, but this has been going on for 2 years with many diffirent material lots.

I've heard the same thing, I know that as soon as I hear this, that the person I'm talking to has no more ideas and it's simplely a catchall.

Sounds like you've done just about everything I'd have tried.

The really "off the wall" schtuff is all that's really left. Maybe delete the entire tech table, copy a different one and try it. I was having a strange problem with 0.090 aluminum that was fixed that way.

You should be able to setup the 7.5 to do it. You might lose a bit of speed, but I think that would be preferable to lenses.

What's the standoff for the pierce?

Jamie

[ImanCarrot]

What about sticking a sacrificial Zinc Selenide window in front of the lens- it'll catch the spatter and will be cheaper to replace than the lens. Order in bulk and it'll be cheaper even still. Just a thought?

[Acedart]

I also operate a Trumpf 3030, and the first time I tried to cut 10 guage stainless, it just sprayed sparks, and only cut about half way through(of course we didn't have any spare material to practice on). I ended up changing the tech table to 7 guage stainless and it cut, I have since changed all of the 10 SS guage parameters to match those of the 7 guage SS.

[westland]

What about sticking a sacrificial Zinc Selenide window in front of the lens- it'll catch the spatter and will be cheaper to replace than the lens. Order in bulk and it'll be cheaper even still. Just a thought?

I've never used them, thought I've been warned repeatedly by one tech not to. YMMV. It still doesn't take care of the problem that shouldn't be occurring.

Jamie