Dust issue when engraving lamacoid signs

[Mohammed Issa]

I hope everyone is doing great!

I'm trying to get some lamacoid (aka lamicoid or engraving stock) to properly engrave. I have bought some trotec engraving stock (almost $100 a sheet) but I am not getting any good results. I have a 90W Chinese laser. I'm trying with approx. 300mm/s speed and 15-20% power.

The problem I am having is that the dust that is being produced from the engraving is contaminating what has already been engraved and cannot be easily wiped or cleaned. Here are some of the things I have tried:

1. I have tried engraving from bottom to top (as apposed to from top to bottom) so that the suction takes the dust away from the already-engraved surface, but that did not help much.

2. I have tried doing a couple of passes of lower power (as apposed to one pass) to take care of the contamination. That seemed to help a little but I still need to scrub the sign afterwards.

3. I have tried a lot of different cleaning materials to scrub the contamination off, but that doesn't bring out the crisp back color. It is also not feasible to clean each sign made.


P.S. I have tried a few different color combinations and the problem is persistent (I have tried silver on black, black on white and blue on white).

P.S. This engraving stock is made to be lasered (not the CNC stuff).

What do you guys think of this problem? has anyone faced the same issue?

Thanks in advance!!

[Bert Kemp]

try masking the whole engraving

[David Somers]

Bert....if he is getting contamination of what has already been engraved a mask may not help much. It would protect the material that is not engraved, but not the areas that are engraved.

Mohammed, Have you talked to Trotec about this? Since this is a material they are selling they may have run into this and have some suggestions.

Other than that, how about attaching some kind of small brush to the lens tube? You would want it on the side you have already engraved, and close enough to the area being lased without actually getting into the beam as it engraves. It would need to be set low enough that the bristles get down into the engraved area. The idea isnt to brush out that area as you go, but rather to have the bristles prevent the dust from settling on the freshly engraved surface? Alternatively, could you put a second air hose on the tube so that you are aggresively blowing the dust away from the already engraved area? My thinking with this again is to keep the dust away from the already engraved area in the first place; not letting the dust settle in there at all if possible.

[Mark Sipes]

I use Mr Clean Erasers and Naphta Pulls the dust right out. Like Red's Host sauce.. I use it on everything!

[Mohammed Issa]

Bert, I think David is right in that regard. The clean (un-engraved) materials can easily wipe off after engraving, but it's the engraved letters/numbers that are getting contaminated.

David, thank you for that suggestion, I will have to think about that brush technique, but I'm just a little hesitant to have any physical contact between the head and the material, because the material is not 100% secured in place (like CNC's) and if one of the bristles gets snagged on the material, it wouldn't be pretty.

Mark, what settings do you use on your laser, and what wattage is it?

Is my machine too strong for this stuff? (90W Chinese laser).

[Tony Lenkic]

Mohammed,

I use same material as you but I have a Speedy 300 60 watts and there is no issue with what you described.
One thing I would ask how is your blower/extractor working. You may need better evacuation of smoke / residue.
Another question is how deep are you engraving. Remember this is micro surface cap and it requires to just engrave through to expose core material.
On red and blue cap I typically got out of focus 30 - 40 thous for cleaner one pass engraving.

[David Somers]

Mohammed....how about the second air line to blow it off before it settles? I engrave on a clay coated material and it leaves an insane amount of dust, but almost all in one direction. Air applied in the right direction might keep it from settling. I havent bothered because it washes off under water very easily, but in your case perhaps that would help.

Or, as Tony suggested, play more with your settings until you are JUST cleaning off the top layer. You might need to sacrifice a small section of the material to run a test series to get the right settings. But it would be a one time test to give you a good setting for later uses. There are a number of threads that discuss patterns for doing this on the forum if you dont already have a method you use.

[Bert Kemp]

General speaking a 90 watt is a little high for engraving but you should be able to increase your speed and lower your power enough to do what you want. I've done that same material on my 60 watt also with no issues .