What is wrong with this 150W?

[Dave Sheldrake]

30.6mA is fine on a 150 watt F series,

% controls are worthless without knowing CURRENT...never trust percentages without knowing current.the 95% figure is right,and is for a properly adjusted PSU, it gives a 5% buffer for current spikes

The speeds are about right for an average 150 or a good 80, the 150 watt tube will do it for a lot longer than an 80 will (like running a 300hp engine at 2,500 revs or at the red line) to get the same speed in a lower gear

If you go to thinner materials you will get more speed, you will also need fast air (from a dry air supply on a shop compressor)

Engraving is a different animal, once you start generating carbon (why the engraving looks brown etc) you are trying to engrave a substance that sucks up lasers like a sponge does water.

For a demonstration of the above...try running 4mm plywood at 95% on an 80 watt tube at 50mm per second

nothing so far about any of your comments or figures is a surprise (remember, bigger tubes give smaller spot sizes are the incident beam is bigger hence higher power density)

[Mike Lysov]

I've cut through 1/2" ply at 80W with no problem, even 3/4" oak. Recently I cut through 6mm marine ply, charred edge, but it worked. I can absolutely cut 12mm regular ply on my 130W machine.

Sure you can do it but not at 100mm/s. That was my initial question if time unit is correct on the specified speed. It should be 100mm/m
I have also Synrad 100W machine, never tried to do thick plywood on it but have done a lot of 9mm MDF signs. The speed required for it is 1%. I cannot say exactly how much it in mm/m but I can guess that it is about 400mm/m top. So it is close to 1300mm/m speed on my 280W machine for the same material.

Not being able to cut, and not being able to cut at "any reasonable speed" are very different. A reasonable speed for one person may not be for another. I consider the speed to be "reasonable" if it is faster than cutting with a jigsaw. For example, I recently cut parts for a 20ft boat out of 6mm marine ply. For the long strakes (8ft each) the cutting was too slow. Instead I just used the laser to mark the lines then I cut by hand. However for the frames it was faster to let the laser do the cutting - I just had to sand the charr off the edges.

it is true, but I am talking about doing someone's order, not something for internal use. For me even at the speed where only knots a problem there is much bigger issue with edges. Not because they are charred but because the glue between timber sheets is so bad that when you look at edges you can see holes in a glue layer. I have had only one client who wanted a plywood sign for outdoor so bad that he said they would not care about quality of an edge as their priority to have a sign outdoor mounted. For all the rest who asks me to do thick plywood I have to explain that they will get a shape very bad edges and they usually do not want it to be made of plywood anymore.

[Joseph Shawa]

Crazy but I spent most of the wee hours this morning chewing on the same problem with my 150 W laser.
I am using LaserCut software.
I wanted to cut a bunch of small 1 mm x 5 mm square holes IN POLYESTER. I kept getting chads and wanted the cleanest cut with no debris left.
BIGGER pieces seemed to cut out cleanly but I thought that maybe it was melt keeping them from falling through.
So, I adjusted the settings on the squares and found that for the small squares the best setting on my machine was speed/power/corner power was 100/40/25.
I stretched the pieces to be 15 mm long and the best cuts came at at 100/60/25. 100/100/5 did NOT cut through nor 90 or 80 or 70 power. With longer cuts on bigger pieces I can run at 100% power and speed and for whatever reason there is NO issue.
I cannot figure out why. I just have to assume that it is the software or power supply but I'm not sure how to find out.
I did finally get rid of the chad problem, though. Rather than cutting just squares I used the entry path tool to start the cut in the middle of the cut piece and exit there as well. The cut was much smoother; almost unnoticeable at the beginning and end points.
So now I just slow the speed to a bit an all my cuts are clean.

[Kev Williams]

Lasers are funny animals. No two are alike, and many times what works once on one machine never happens again--

My 80w Triumph, with a 2" lens was able to cut thru this 20mm+ thick piece of cherry in one pass-- Slow, but one pass--
The burn is consistent. All was right with the world that day.
ch1.jpg

So I put in the 3" lens, assuming (wrongly) that with the longer focal length, it should make it thru in one pass also, maybe even faster....
ch2.jpg
--You can see the multiple burn depths, I think it took me 4 passes, and even then I had to snap off the corner. It just fell off after the 2" pass.

I've tried to cut thru other, less thick wood in one pass, pine and maple I think, wouldn't do it. Haven't tried this piece of cherry again, maybe it will, maybe not...
I'm thinking probably not...

So many variables involved with these machines. And they're finicky. And some stuff- like certain plywood glues- are like Kryptonite to lasers.
A few days ago I finally changed the X belt on my LS900. To do this required removing the mirror over the lens, which a few years ago I made 'adjustable' ...
After getting it all back together, I found the beam spot was hitting a full mm off it's old position in both axis's. Easy to fix--
And now the laser seems to work better. Checking the mirrors, my laser's hitting the mirror and lens more centered than it was before. Good!
But for some reason, my red light is now so dim I can barely see it.. not good! Not sure why, as it's hitting the mirror good, and seem to be hitting the lens near the center...
So why is it half as bright? (FWIW this LED is normally not all that bright, on purpose, attenuated by the factory so the dot is smaller and easier to actually see where it is)
Even though it doesn't look like it, maybe it's hitting part of the mirror housing or the lens barrel..?

--changed the belt, and the whole machine's normal 'attitude' changed.

speaking of beams hitting things, you guys having trouble cutting thru things USING A LENS CONE, try removing the cone to see if that helps.
I found out my cone blocks some of my 3" lens's beam (partly why the cherry wouldn't cut) and it blocks a ton of my 4" lens's beam.
I haven't used my cone since about week 2. I firmly believe they're counterproductive. The 3 metal laser's I've owned never had one. Must be a reason...

[Joseph Shawa]

"I haven't used my cone since about week 2"

How do you keep your lens clean? Seems backblasts of smoke would soil it quickly.

[Kev Williams]

The air hose normally connected to the cone I have wide open, running down the side of the lens tube to blow the smoke away from the lens when I'm cutting or engraving smoky stuff like leather, works okay. Lens still gets dirty but not all that fast, and cleaning it's a piece o'cake since I don't have to take the cone off!

I'm always changing lenses too, I engrave leather with a 3" lens, most else with a 2", so it just works well for me with no cone.

[Rich Harman]

How do you keep your lens clean? Seems backblasts of smoke would soil it quickly.

I still have my cone on (it is part of the lens holder) but I have rerouted the air assist to outside the cone similar to what Epilog does. My lens remains much cleaner than when I had air blowing through the cone.

[Bert Kemp]

How does it keep it cleaner blowing on the outside rather then thru to cone, don't get how that works??

I still have my cone on (it is part of the lens holder) but I have rerouted the air assist to outside the cone similar to what Epilog does. My lens remains much cleaner than when I had air blowing through the cone.

[Rich Harman]

How does it keep it cleaner blowing on the outside rather then thru to cone, don't get how that works??

I think when blowing through the cone some sort of vortex is created which can suck things up into it.

[Dave Sheldrake]

I think when blowing through the cone some sort of vortex is created which can suck things up into it.

True, if the air enters at the side into the cone it works a little like one of those cyclone vac cleaners and stuff gets sucked up into the lens chanber

[Kev Williams]

My cone just screws to my lens holder, I assume most are the same way. I had Triumph make me several different (longer) lens holders,
one is 8" long, so I can 'reach' stuff I need to engrave with the table removed.
tr2.jpg
I can put the cone on all of 'em if I want
Another reason I don't use a cone, OR the auto-focus's on my other machines, is they're in the way-- I do a lot of engraving on things that are stepped, or otherwise have high places and low places, and I can't engrave the low places if the cone or focus plunger hits the high places!

...counterproductive...


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[Joseph Shawa]

Seems that an air "ring" around the lens would keep clean air only at the lens but a cone tip would jet the air out and would disallow smoke entry into the cone/lens.

I have thought about running a small air line to each of my mirrors to keep them cleaner. Anyone do anything like that?

[Dave Sheldrake]

I have thought about running a small air line to each of my mirrors to keep them cleaner. Anyone do anything like that?

Yup, all of mine have it, it also helps to keep them cool on the more powerful machines. Especially if you tap off some air above the lens, it stops dust floating down through the beam entry hole in the head and settling on the upper side of the lens

[Bert Kemp]

ok Maybe I'll move my air to the outside and see if its better

I think when blowing through the cone some sort of vortex is created which can suck things up into it.