Upgrading a 40w laser tube?

[Craig_Johnson]

I recently converted an FSL MLE-40 to use the AWC 608 controller. The manual on the old laser says that operating the laser above 15miliwatts will shorten its life. It was able to cut thru 1/16 acrylic in a single pass but I never checked the wattage. Now I have the wattage set to 23% and it runs 15.7 miliwatts, but takes 5 passes at 50mm/sec to cut. Making a page take 20+ minutes to cut for .060 acrylic with two layers of lamination on each side. I'm thinking I could replace the 40w tube with a 60w tube since I have already bought the 20w/40w/60w powersupply. Any thoughts on that?
Thanks

[swamidog]

i have no problems cutting 1/16th acrylic with my 60W tube at 18mA power with a single pass at 10mm/s.

http://youtu.be/kl05Yo-VGhA

I recently converted an FSL MLE-40 to use the AWC 608 controller. The manual on the old laser says that operating the laser above 15miliwatts will shorten its life. It was able to cut thru 1/16 acrylic in a single pass but I never checked the wattage. Now I have the wattage set to 23% and it runs 15.7 miliwatts, but takes 5 passes at 50mm/sec to cut. Making a page take 20+ minutes to cut for .060 acrylic with two layers of lamination on each side. I'm thinking I could replace the 40w tube with a 60w tube since I have already bought the 20w/40w/60w powersupply. Any thoughts on that?
Thanks

[NickWL]

I have no trouble cutting acrylic a good deal thicker than that on my K40 (35 watt) at around 13ma and 15mm/sec

[brian257]

Do you have PPI turned on? My 60W power supply and 40W tube runs about 34 o0r 38% to get 18mA. You should be cutting much better than you are.

[Craig_Johnson]

It was a busy weekend, but I do have some results that seem to give me what I want:

20% power yeilds 14.7 miliamps (within the range FSL specified for the tube)
15mm/sec
2 passes

This takes 24 minutes, which is not accecptable.

I have 2 questions - what is PPI? and can I simply swap out the 40w tube for a 60w tube with the 20/40/60w power supply I purchased here?
Thanks

[NickWL]

I have 18mA marked on my cabinet as the maximum for my K40-supplied laser tube. I try to max out at 17mA.

The upside of burning out the tube? I get to build a BIGGER laser cutter!!!

[Craig_Johnson]

OK, so I set the PPI setting to 600 and with the power set at 20% I get 8.5 miliamps on the tube. I am able to push the power percentage to 50% and get just under 15 miliamps but I have not done enough testing to see if it will cut any faster. One thing I noticed is that because I have two layers of lamination film on each side of the .060 acrylic, the back side gets a slightly postage stamp effect. The beam thickness on the back side is at least half the width of the front. More testing will tell.

[Craig_Johnson]

Looks like all the 60w tubes are 1200mm long and simply won't fit into my 40w case which uses the 700mm tube. Beam diameter is also bigger, I suppose focusing would tune that somewhat.
Might as well plan on moving to the 4x8 sheet of plywood version. I guess I'll be making due with what I have for a while.

[Tech_Marco]

OK, so I set the PPI setting to 600 and with the power set at 20% I get 8.5 miliamps on the tube. I am able to push the power percentage to 50% and get just under 15 miliamps but I have not done enough testing to see if it will cut any faster. One thing I noticed is that because I have two layers of lamination film on each side of the .060 acrylic, the back side gets a slightly postage stamp effect. The beam thickness on the back side is at least half the width of the front. More testing will tell.

When you enable the "PPI", the cutting power will be dropped by a lot, 50% to 75% depends on the frequency. If you couldn't cut well without PPI, you will get worst if you enable it!


Marco