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Pete Ganz
05-09-2007, 12:15 PM
Hi,

I have a 35Watt ULS VL-300 which i've been advised will cut 1/8" acrylic ok but that 1/4 or thicker probably not.

I was wondering if I could cut thicker material by doing multiple passes, maybe changing focus between passes.

I'm not looking to do this alot but once in a while to do wider instrument panels where the thinner material ins't rigid enough.

Thanks for any advice.

Pete

Mike Mackenzie
05-09-2007, 12:23 PM
Pete,

You should be able to cut 1/4 inch with that system. I would recommend not to walk away and leave it while it is cutting and if you have air assist you should use it.

Anything thicker you could do multiple passes but the edge quality will suffer. I would not recommend it.

Dave Jones
05-09-2007, 12:24 PM
You probably could but the quality of the cut won't be as nice as if you did it in a single pass. If you planned to sand the edges it would be fine. If you were doing intricate cuts then they probably wouldn't look so good.

Keith Outten
05-09-2007, 12:33 PM
Pete,

My 35 watt Epilog will vector cut 1/4" acrylic at 100% power and 6% speed in a single pass. Your machine settings will be a bit different but should be somewhere in the neighborhood I expect.
.

Mike Null
05-09-2007, 12:36 PM
That's exactly what I do. I make 3 passes on 1/4". Could probably do it it two. There's some debate as to refocusing. I haven't decided myself as I feel that refocusing increases kerf.

Jim Huston
05-09-2007, 2:30 PM
Don;\'t know if others do this but I have done it on delrin by focusing to the middle of the thickness I was cutting. Allowed me to cut in one pass where as it took 2 passes when focused normally. Any comments on this??
Jim

Rob Bosworth
05-09-2007, 3:13 PM
Jim, a good rule of thumb to use when vector cutting thicker materials would be to set your focus 1/3 of the way down into the material. This will usually give you a more perpendicular edge on your cut. It moves the focus down into the material, and keeps the energy density up in the cutting area. Smaller beam size, less material being removed, and smaller kerf. It is much more effecient.

Nigel Morgan
05-10-2007, 1:31 AM
Hi,

You are lucky Keith, my Epilog 45W is down on 8% speed and 100% power cutting 3mm acrylic, I really think I have a tube problem.

Cheers

Nigel

Mike Trenshaw
05-10-2007, 1:42 AM
I have a ULS-M300 an have done just that. Three passes at 3% speed. I could do it with a faster setting, but I like the smooth finish I get this way.

-Mike


Hi,

I have a 35Watt ULS VL-300 which i've been advised will cut 1/8" acrylic ok but that 1/4 or thicker probably not.

I was wondering if I could cut thicker material by doing multiple passes, maybe changing focus between passes.

I'm not looking to do this alot but once in a while to do wider instrument panels where the thinner material ins't rigid enough.

Thanks for any advice.

Pete

Rodne Gold
05-10-2007, 2:56 AM
35W should easily cut 6mm pex.
In terms of focussing into the material , pex is a waveguide type material and will not allow the beam to diverge that much so albeit its "safer" to focus into the material , it's not needed.
Air assist is the key to cutting pex , not so much that it cools the edges and enough to eject melt and stop flaming.
Multipass is bad , firstly the first pass melt has nowhere to go and resoldifies in the groove or spills out onto surfaces and pex expands when hot so its highly unlikely your 2nd or 3rd pass will be in register with the first.
Nigel , a tube problem would manifest itself as most likely a 1/2ing of power or intermittent operation , the first thing I would check if you find a gradual increase in power needed to cut is the alignment of the beam.

Peck Sidara
05-10-2007, 1:16 PM
Hi,

You are lucky Keith, my Epilog 45W is down on 8% speed and 100% power cutting 3mm acrylic, I really think I have a tube problem.

Cheers

Nigel

Nigel,

I'd recommend the following for what appears to be a loss of power.



Double-check, triple check all of the optics you could possibly see, this means removing the lens assembly on the engraving head. Once the assembly is off, remove the lens (making sure you note how it came off, it's polarized) and remove the mirror. The other mirror you can check is the one on the far left. Remove the side panel if you have to but take your time to inspect. What you're looking for is discoloration, delamination, pits, cracks etc. I've seen one too many times where a loss of power is caused by a $100 optic and only after the customer replaced the laser tube did they take a 2nd look at the optics.
Your air-assist nozzle that hangs below the lens assembly, turn on your red dot pointer, focus on something (ne-thing) and see if the air-assist nozzle is possibly in the path (in the way) of the laser beam (red-dot pointer). Not likely to happen but it's happened before.
If neither of the two above works, consult with technical support and determine whether we should inspect the #1 and #2 mirror. Removing these mirrors for inspection will result in your alignment being off. Consult with tech support so you'll know what to do next if you decide to check these mirrors.It's possibly not the tube but something else.
Regards,

Larry Bratton
05-10-2007, 4:26 PM
What frequency settings do you use? Most plastics I have cut need at least 2500.

Peck Sidara
05-10-2007, 5:51 PM
Larry,

For the Epilog lasers, the general rule of thumb is a lower frequency of 500-1000 for woods, leather and materials which you don't like having much of a "char-grilled" edge look. For acrylics and most plastics, a higher frequency of 2500-5000 is great because it gives the edge a more flame polished look.

Hope that helps.

Larry Bratton
05-10-2007, 7:55 PM
That's me Peck. I think I learned about the frequency in here. 2500 cuts very nice for me. Thanks

Nigel Morgan
05-15-2007, 1:31 AM
Thanks Peck,

I am talking with the reseller here, though an optic here is more like $200 US, $270 NZ. How often would you say the optics and mirror should be changed.

Cheers

Nigel

Peck Sidara
05-15-2007, 10:08 AM
Nigel,

Replacement of the lens or mirror(s) is dependent on three variables:

Maintenance
Maintenance
ApplicationI always recommend cleaning the optics daily and when cleaning, if there's not much dirt/dust, go to once every other day. If the optics are really dirty when cleaning it on the daily basis, clean it twice a day. You get the idea.

If the optics are maintained regularly, I don't expect having to replace any of the optics for years.

If you're doing normal stuff, the above applies. I threw in the application because if you're cutting some really cruddy stuff then it's likely the lens and the mirror are getting debris build up, causing the coating to delaminate or heat build up where the optic may crack.

Kind regards,