PDA

View Full Version : ULS owners - help ? advice on wood over-burn ?



Mike vonBuelow
09-11-2019, 3:42 PM
I belong to a makerspace here in Sacramento, and using a 60w laser. I'm getting wood burn, which I think is an air assist problem, and slow exhaust, but the owner says 'it's normal'

Anyone have similar experience? Fixes?

The air assist is a ULS, and I was told that the software controlls the air input - is there a way to trick it into providing more air ?

I would like to avoid having to mask, or do clean-up afterwards

T.I.A.

Kev Williams
09-11-2019, 3:52 PM
Turn the air assist OFF, it's causing the problem by forcing the soot onto the wood. Air assist should only be used for cutting, not raster engraving :)

Mike Null
09-11-2019, 3:55 PM
In my opinion the owner is correct. All three of the machines I've owned produce a similar effect. In your first example you might try lowering the power or speeding up the machine as it looks somewhat charred but, even so, you'll still get the residue. If the machine has "engrave from the bottom up" that will help some.

I just read Kev's post and I agree with that but you will still have a residue issue due to the exhaust drawing the air over the engraving to the back of the machine.

Mike vonBuelow
09-11-2019, 3:57 PM
Kev, where/how can I turn off? Settings menu ?

Kev Williams
09-12-2019, 12:09 AM
Well- the only ULS I ever owned didn't come with air assist (ahem ;) ) - But my other 4 machines do-
My Gravograph machines, air can be turned on both in the settings menu,
415925

and manually on the keypads-
LS900 left, LS100 right, and they also have air flow knobs-
415926415927

My GCC explorer, which I bought from Gary 4 years ago, has air but I've never used it- it MIGHT be controllable on the keypad, but to be honest I'm not sure, but it IS controllable in the software:
415928
--and I just looked, I can't see an air control valve, but one could easily be added to the air line connection...

My Chinese Triumph's air is 'turn on the pump' for air and the nose cone has a flow control knob...

so check around :) -- For your problem, the air is coming from either a pump or air compressor tank, any way to just disable the air source?

Anthony Rowley
09-12-2019, 5:25 AM
Hi Mike, Just use some polish before engraving, put quite a lot on to coat the wood. The smoke then gets traped in the polish and you can just wipe it off.

Bill George
09-12-2019, 8:48 AM
If its not your machine, its a makerspace I don't think you should mess with machine settings. Get some blue masking tape and apply as needed.

Nick Cicala
09-12-2019, 10:32 AM
You should be able to turn it off in the print driver menues. The only way to increase air flow is to direct line it and bypass the internal pump (might be external). Masking will almost always get rid of burn, and yes it's a "normal" thing natural to the process.

Kev Williams
09-12-2019, 12:11 PM
would any of YOU want to pull the residual masking off that wolf's head? ;)

Nick Cicala
09-12-2019, 12:45 PM
would any of YOU want to pull the residual masking off that wolf's head? ;)


If I'm getting paid to then of course! I see it as a necessary part of the job even though the laser is done firing. The other option would be to hit it with an orbital sander but that also risks damaging the engraving.

Kev Williams
09-12-2019, 2:46 PM
Suggestion for those of you who mask stuff on a fairly regular basis, and use transfer tape rather than blue tape--

I found a transfer tape that works great for laser masking, the reason is, it sticks well, and the best part, when you dampen the top-side of the tape, it immediately loses about half of its adhesion, making it much easier to remove. Using the sheared edge of any laserable acrylic scrap will usually squeegee it off easily.

Name/model: TransferRite Ultra 582U, it's a medium tack tape.

When masking Rowmark for cutting, when I'm done I just spray the pieces with a very light soapy water mix (about 10 drops-ish dawn dishsoap to a pint of water) and the masking loosens up immediately, comes off much easier than if left dry. When I do scads of small parts, I'll throw them in a bucket and cover them with hot water with a little dish soap mixed in. After 20 minutes or so most of the masks will have come off.

Plain water works too... and I usually wet the masking and remove it immediately, only takes a couple of seconds. The one catch with this tape is that if left wet for like more than 20 seconds, the adhesive can get real stretchy like cheese which is a bit counter productive. Nothing's perfect ;) -- if that happens, just let it dry out a bit. :)

I've never used it on wood but I'm thinking dabbing the mask with a plain-water damp sponge would work without messing up the wood...

Mike vonBuelow
09-12-2019, 5:06 PM
Thanks all for the replies & advice :) !!!

David Takes
09-16-2019, 10:20 AM
I can tell by the shine in one area that is not an overburn, it is wood resin bonding to the surface. Wipe it away with denatured alcohol. Let us know how it goes.