Help Engraving Glass

[Keith Winter]

Long time reader first time poster!

First thanks to everyone who posts, I've learned a lot from reading the forum! I'm hoping someone can help me with the inconsitant results I'm trying on glass. I've read every thread on glass I can find on the forum and google. I've tried various DPIs, 500 and 333, tried different speeds, and power, and different shades of grey. Reading the forums here and experimenting on about 40 test glasses, what I've found works the best on my Trotec Speedy 300, 75 watt is 333dpi, 70% grey (4c4c4c), 80 power, 50 speed.

However even with those settings I can laser one glass and then laser the next and about 80% it looks nearly perfect 20% of the time it appears to "skip" over part of a letter or a design, leaving it un-filled in looking. It's really frustrating. Seems to not matter the glass, although I have found some glasses laser better than others. No matter the glass, about 10%-20% of the glasses have the skips in them.

It's somewhat inconsistent where the skips occur, but I have found the "skipping" becomes worse the more complex the design or smaller/thinner the text though. Is this isn't normal is it? I'm starting to wonder if my new laser is messed up (6mo old)? Any of you pros have ideas on why it this is happening and how to fix it? (See attached photo. NOTE it actually looks a bit better in the photo than in person.)

[Scott Shepherd]

Nothing wrong with your laser, that's why so many of us are against lasering glasses. The skipping is caused by not enough power to chip the glass uniformly in that area. It various because the glass varies. Bump the power up 20% and see if they go away.

[Dan Hintz]

what I've found works the best on my Trotec Speedy 300, 75 watt is 333dpi, 70% grey (4c4c4c), 80 power, 50 speed.

Keith,

That sounds too powerful, and pieces of the design falling off is proof of that. Bump your speed up to 100 (or lower your power to 40-50) and see what you get...

[Dan Hintz]

Nothing wrong with your laser, that's why so many of us are against lasering glasses. The skipping is caused by not enough power to chip the glass uniformly in that area. It various because the glass varies. Bump the power up 20% and see if they go away.

LOL, we're giving him complete opposite advice ;)

On my 60W ULS, I'm at 100S/60P at 333dpi and get nice engravings. Since the Trotec is double in speed, that's the same as 50S/60P on a 60W Trotec. He has 25% more power in the cartridge and is lasering at 30% power above my setting. That's a lot of power.

[Kev Williams]

per Dan: "and pieces of the design falling off is proof of that"... If you look thru a 10x or so magnifier at those "skipped" areas, you'll find your skips are missing pieces of glass that have popped off ("exploded" off?) the surface. I bought a pack of cheap mirror tiles from HD to practice on for a job, and there's more pop-offs than "good" area when I laser the stuff! From small chips to 1/4" and longer thin shards, it's horrible glass to laser etch! BUT, since it IS so horrible, should I ever succeed in getting a good etch on the stuff, those settings may just render near perfect etching on decent glass! (If I can ever find time to do some practice runs!)

[Scott Shepherd]

Too funny Dan! I don't give that advice from the Trotec side of things, but rather my Universal. I had a serious problem getting glass to engrave. It was skipping entire letters. Only way I ever got it resolved was to slow down and crank up the power. When I did, it worked really well. I know you have done a lot of research engraving glass. So have I, that's why I use a sand blaster now ;) Seriously, I'd try it both ways. Give it more power on one, rotate the glass and do less power. See which one works.

Just a word to the wise, once you get it set and working great, 2 glasses into it, it's going to do the same thing again. You're chasing the end of a rainbow :)

[Keith Winter]

LOL, we're giving him complete opposite advice ;)

On my 60W ULS, I'm at 100S/60P at 333dpi and get nice engravings. Since the Trotec is double in speed, that's the same as 50S/60P on a 60W Trotec. He has 25% more power in the cartridge and is lasering at 30% power above my setting. That's a lot of power.

Thanks Scott and Dan, my second best setting is 95p 100s. Pretty similar to 80p 50s in the results. Dan can you elaborate a bit more? Since the Trotec is double your speed is that part of the issue? Do you experience these issues when you engrave?

[Keith Winter]

Too funny Dan! I don't give that advice from the Trotec side of things, but rather my Universal. I had a serious problem getting glass to engrave. It was skipping entire letters. Only way I ever got it resolved was to slow down and crank up the power. When I did, it worked really well. I know you have done a lot of research engraving glass. So have I, that's why I use a sand blaster now ;) Seriously, I'd try it both ways. Give it more power on one, rotate the glass and do less power. See which one works.

Just a word to the wise, once you get it set and working great, 2 glasses into it, it's going to do the same thing again. You're chasing the end of a rainbow :)


A bit discouraging to hear that. I do feel like it's chasing the rainbow though at times. That is one of the main reasons we bought the laser. Hundreds of glasses a week, each personalized with a different person's name and design as you can see (we have about 20 templates we work off of). I tried 100% power 50 speed as you suggested, even worse results. I've tried everything I can think of, I've even tried the dishsoap/windex/etc some people suggest, but it's never consistently the same. Surely there has to be a way to get consistent results on a laser? That's one of the main selling features at every show, how much faster it is than using a rotary on glasses (which is what we used to do)....

[Keith Winter]

Keith,

That sounds too powerful, and pieces of the design falling off is proof of that. Bump your speed up to 100 (or lower your power to 40-50) and see what you get...

Just ran it at 100 speed 50 power. I came up blank. It literally engraved nothing you can see, same Z as my last runs I posted a picture of earlier. Bumped it to 70 power 100 speed, I can see it although it is much lighter than before and even more of the letters are missing.

[Keith Winter]

Just ran it at 100 speed 50 power. I came up blank. It literally engraved nothing you can see, same Z as my last runs I posted a picture of earlier. Bumped it to 70 power 100 speed, I can see it although it is much lighter than before and even more of the letters are missing.

70p 100s attached. Note: I don't use a rotary attachment, we have to do such qty in a day it's impractical to do them one at a time. I measure my Z off 1/2 in between the end point and and middle of the glass as the Trotec rep advised. Since the power was so low on this one it did not go all the way around the edges.


Dan photo #1 70p 100s tops of most all the home brews letters missing, inside part of C A H of michaels missing
Scott photo #2 95p 50s tops of most all the home brews letters missing, inside part of C A H S of michaels missing

[Scott Shepherd]

What? You are doing that without a rotary attachment? If so, there's your problem, without question. You can't have the beam going that far out of focus. You see what happened with Dan's setting? You didn't see any image, right? Because it wasn't enough power. When you go so far out of focus, you'd essentially doing the same thing. You're reducing the power when the beam goes out of focus, which is why you are having this problem. You can't engrave a glass like that flat and expect consistent, good results. It's just not going to happen.

A rotary attachment would slow you a lot from your current method. I could probably sandblast a glass a minute or 90 seconds once set up, but it takes some time setting it all up.

[Gary Hair]

Note: I don't use a rotary attachment

You have about 1/8" of focal range on a 2" lens so there is no way to get an image that size without a rotary attachment. That said, sandblasting is the only way to do glass and even more so when you have any quantity greater than 1 or 2. You could use a photo-resist and have about 2 minutes total per glass between applying the resist, blasting and cleanup. No question that a laser is the WRONG way to go with this project.

[Dan Hintz]

Keith, reduce your dpi to 250 and see if it's acceptable for your application. If memory serves, 70% black was a good compromise for me, but I still did it at 333 dpi. When I initially tried with 100% black, I was getting chipped pieces, like you have... that's a sign of too much power in one area, hence my suggestion to back off the power and speed things up. 100S/70P is not too far outside my ULS settings, so if that's what works for you, go with it. You really should be running a power grid, though, to dial in the perfect setting. Try 100S with a range of powers from 40-80 in increments of 5, and try several different black levels from 70-90 in increments of 5. That should give you 5 power grids of 9 squares each, which should easily fit on one or two glasses.

[Keith Winter]

What? You are doing that without a rotary attachment? If so, there's your problem, without question. You can't have the beam going that far out of focus. You see what happened with Dan's setting? You didn't see any image, right? Because it wasn't enough power. When you go so far out of focus, you'd essentially doing the same thing. You're reducing the power when the beam goes out of focus, which is why you are having this problem. You can't engrave a glass like that flat and expect consistent, good results. It's just not going to happen.

A rotary attachment would slow you a lot from your current method. I could probably sandblast a glass a minute or 90 seconds once set up, but it takes some time setting it all up.


Thanks for the reply Scott.

Yes we're doing it all without a rotary, speed is the issue with a rotary, I can only do one at a time. We need to do about 100-200 glasses a day, each with a different design and each with a different name. We have both a 4" and a 2.5" lens. We normally use the 4" lens because it allows for a larger focal variance. NOTE: I've tried the 2.5" and the 4" the same issue exists with each. I understand your concern about not using a rotary, but to be honest even the points that are 100% in focus still do this. it's been some time since we last did a piece of flat glass, but when we setup the machine initially we were doing completely flat glass and had a similar issue if I recall. We did about 30 mason jar glasses last week with different designs and initials (they virtually completely flat surfaced) and initials worked fine 95% of the time, but when I did a design on them the same issue happened. Which makes me think the roundness of the glass is not the issue. Engraving other materials seem to be fine, but do you think it could be something wrong with the machine itself?

[Keith Winter]

You have about 1/8" of focal range on a 2" lens so there is no way to get an image that size without a rotary attachment. That said, sandblasting is the only way to do glass and even more so when you have any quantity greater than 1 or 2. You could use a photo-resist and have about 2 minutes total per glass between applying the resist, blasting and cleanup. No question that a laser is the WRONG way to go with this project.

Hi Gary,
We have a 2.5" and a 4" lens. We have the same issue with both, but the 4" allows a larger tolerance as you said. Does this method work on hundreds of singles a day? Meaning each has a different name and/or design on them? What is the time it takes to do 100-200 one offs a day?

[Keith Winter]

Keith, reduce your dpi to 250 and see if it's acceptable for your application. If memory serves, 70% black was a good compromise for me, but I still did it at 333 dpi. When I initially tried with 100% black, I was getting chipped pieces, like you have... that's a sign of too much power in one area, hence my suggestion to back off the power and speed things up. 100S/70P is not too far outside my ULS settings, so if that's what works for you, go with it. You really should be running a power grid, though, to dial in the perfect setting. Try 100S with a range of powers from 40-80 in increments of 5, and try several different black levels from 70-90 in increments of 5. That should give you 5 power grids of 9 squares each, which should easily fit on one or two glasses.

Thanks for the reply Dan,

I'll try 250 dpi again, I initially ruled it out because the lines started looking jagged at that DPI, but it's worth a shot! I am using 70% black as you said, I actually got that tidbit from another post you did on the forum ;) and it has helped quite a bit, it was worse before I tried the 70% you suggested a couple months back. It's what I'm using on the results we're currently getting. I also tried black, 90%, 80%, and 60%, but found 70% to be the best.

Can you explain what the power grid is and how to make it? Could this be an issue with the machine itself, what do you think? It's new, and trotec will come service it but we have to pay for the hotel and the flight to get them here they said. Either glass is the hardest thing ever to dial in, or something else is going on. I burned through another 10 glasses today testing settings in addition to the 40 or so I've already used for testing trying to dial it in with no luck :(

[Scott Shepherd]

Keith, it's nothing wrong with your machine. It's a lot wrong with your technique. Trust me when I say this, you cannot successfully, repeatedly do what you are trying to do. It's not going to work. You cannot take a lens that far out of focus and expect the power density to be equal across the entire surface. It's simply not going to happen. You can try things and you'll have some random success, but that's not what you're after, you're after consistent results. You will never get consistent results with an engraving surface as tricky as glass, engraving it where parts come in and out of focus.

You could easily do 100's of glasses a day with a sandblaster, each one different. It's not the cheapest method, but it's the best method in my opinion.

[Dan Hintz]

We normally use the 4" lens...

Well, this explains the extra power needed compared to my settings to get a mark... larger dot size on the 4" means a lower power density compared to the 2" (what I use, with a rotary).

These are the questions we forget to ask sometimes...

[Keith Winter]

Ahh. I didn't know that either. Wondered why nothing below 60 worked... ever.

[Keith Winter]

Keith, it's nothing wrong with your machine. It's a lot wrong with your technique. Trust me when I say this, you cannot successfully, repeatedly do what you are trying to do. It's not going to work. You cannot take a lens that far out of focus and expect the power density to be equal across the entire surface. It's simply not going to happen. You can try things and you'll have some random success, but that's not what you're after, you're after consistent results. You will never get consistent results with an engraving surface as tricky as glass, engraving it where parts come in and out of focus.

You could easily do 100's of glasses a day with a sandblaster, each one different. It's not the cheapest method, but it's the best method in my opinion.

Cost is not really the man concern, those Trotec lasers cost an arm and a leg LOL! It's the time it takes. I have my doubts a rotary would make a difference. As I said it does the same thing on a completely flat mason jar glass like this: http://www.homewetbar.com/old-south-personalized-mason-jars-set-p-1961.html so it must be something else if flat objects don't work either. I'm glad to know this happens, as I was seriously starting to think something was wrong with the machine. As the to sandblasting I appreciate the thoughts on that, I could buy 5 of those booths for the same price as 1 laser so that's an option if it's fast. I might take that offline with you for more questions. Thanks for that!

As far as lasering glass, I'm open to trying anything to get this working better, any ideas?

[Scott Shepherd]

Keith, those glasses aren't "completely flat" by any means. I've engraved them myself on our Trotec. The larger spot size of the 4" lens is going to work against you when doing glasses in my opinion. You are micro fracturing the glass. In that case, I believe the smaller the spot size, the better chances of a good result. But a 2" lens has a very small focal length (about 1/8" max).

What PPI are you running? What's the Hz on that setting you are using? Try moving that around. Try it at 1000 Hz and see if that helps. If not, try it at 500 and see if that's better. You're just trying to find some combination that works, and I don't know what that might be, but at this point, I'd go higher power, higher PPI, and maybe even hitting the glass with a scotchbrite pad after engraving, just lightly. Sometimes that can make it look more uniform.

[Gary Hair]

but do you think it could be something wrong with the machine itself?

Yes, absolutely... it's the wrong tool for the job. Just because all you have is a hammer that doesn't make everything a nail.

[Gary Hair]

Meaning each has a different name and/or design on them?
Yes, it's ideal for that.

What is the time it takes to do 100-200 one offs a day?
It would be less time than lasering, I guarantee it! Unless you have multiple people working on this project you won't be able to use either method for 200 a day - at just 2 minutes each that's over 7 hours of continuous work, is that realistic? Even though the laser isn't really suited for glass, it would only really work on a rotary attachment - that's not going to allow you to produce 100 a day let alone 200 or more.

[Keith Winter]

Keith, those glasses aren't "completely flat" by any means. I've engraved them myself on our Trotec. The larger spot size of the 4" lens is going to work against you when doing glasses in my opinion. You are micro fracturing the glass. In that case, I believe the smaller the spot size, the better chances of a good result. But a 2" lens has a very small focal length (about 1/8" max).

What PPI are you running? What's the Hz on that setting you are using? Try moving that around. Try it at 1000 Hz and see if that helps. If not, try it at 500 and see if that's better. You're just trying to find some combination that works, and I don't know what that might be, but at this point, I'd go higher power, higher PPI, and maybe even hitting the glass with a scotchbrite pad after engraving, just lightly. Sometimes that can make it look more uniform.

Hi Scott,

We're running 333 dpi and 666 hz. We tried 500 dpi and 500 hz but we found it did not work as well over dozens of tests. Additionally the 500 dpi glasses tended to flake when someone scrubbed them when washing, something we found out from real world customer testing, the 333 dpi doesn't do that most of the time. Can I run 333dpi image and 500hz 1000hz? Is that what you are suggesting? I thought the hz had to be a multiple of the dpi 333x2=666 500dpi = 500hz or 1000hz but maybe I misunderstand that? Is there some common reference for trotec HZ on materials out there? Thanks for your help!

[Kevin Cederquist]

Not saying you're going to have success with this, curved glass is always tricky, especially if you're going in and out of focus, but I have a suggestion. We do a TON of glass, with perfect consistent results every time. Granted it is usually tempered glass, and relatively flat, but it took a lot of testing to make it right.
You need to do two passes. What works best for us is a solid color pass (we use blue) set at low power and high speed. enough to make a consistent, if not light, mark over the entire surface.
Then immediately run a second pass with 70% gray, full power and slower speed. (around 60% speed for our Universal).
Then we take some light steel wool and lightly and quickly "scrub" the engraving to remove any loose shards. (about 3 seconds worth) There is hardly any most of the time, and we never have any bits "chip out", even after over a year of washing in the dishwasher and by hand.

Your results could vary greatly, especially since it's not tempered glass, but those work perfectly for us every time. Also, we use 270 dpi.
Might not help you, but it's a suggestion.

[Michael Gonzales]

I did 400 mugs and 200 wine glasses for a show. I had issues with about 1 for every 12 mugs and 1 for every 9 wine glasses. Out of curiosity, I went over the same "skipped" letters and adjusted the power/speed/dpi to see what would happen or change. Not much changed. It seemed like it was just bad unlaserable spots in the glass. Adjust it too much it melts it or shatters. My partner just wants to get a vision pro max engraver for glass, 10K to 15K used. Oh I used a rotary attachment and wet newspaper over the glass and other things...still skipped. They came out with some masking tape for this recently...will try it.

[Dan Hintz]

Keith,

Max out your frequency... you need to heat the glass to the melting point so it cracks as it cools. A low frequency will just annoy it.

[Scott Shepherd]

Can I run 333dpi image and 500hz 1000hz? Is that what you are suggesting? I thought the hz had to be a multiple of the dpi 333x2=666 500dpi = 500hz or 1000hz but maybe I misunderstand that? Is there some common reference for trotec HZ on materials out there? Thanks for your help!

That's exactly what I am suggesting. It doesn't have to be a multiplier at all. It has nothing to do with being in synch with anything else. Leave the resolution at 333 and then crank the Hz up to 1000 and try that. I can't say it's going to work, but it's something that will give you a little more heat in the area which might help in this case.

[Ross Moshinsky]

I run my glass at 600-800dpi, 30speed 100pwr on a 30 watt. We use wet newspaper. The results are acceptable (which is about what you get with laser engraved crystal/glass). I don't believe in dropping below 400dpi except on bitmap type images. I don't think the definition on letters is acceptable below 400dpi.

As for your situation, well I think you're going to have to adjust your method to do what you want. First and foremost, your cost structure is going to have to keep in mind that roughly 10% of your product will not be acceptable. The second thing you're going to have to do is shrink your engravable area significantly so that you get consistent results. Maybe you can go .25" wider on the graphic, but if your rejection rate goes from 10% to 25%, what's the point?

If your goal is to do glasses all day long, I think you need to go into sandblasting in the end. Although the cost will go up, your rejection rate will drop significantly and that could be enough to break even. You can also pick and choose which jobs you put on the laser and which you sandblast. That's the benefit of having both tools at your disposal.

[David Somers]

This is fascinating to someone like me considering a laser. All the manufacturers would have you believe that engraving glass was "Eassssssssssy!" Clearly there are a lot of issues to consider with this medium.

I am curious.....and forgive the slight pull off topic....but what other materials do the manufacturers talk up as being a "piece of cake" to work with that are actually pretty tricky?

If you folks would like me to start a separate thread for this so this conversation doesn't go too far afield let me know.

Dave

[Scott Shepherd]

This is fascinating to someone like me considering a laser. All the manufacturers would have you believe that engraving glass was "Eassssssssssy!" Clearly there are a lot of issues to consider with this medium.

I am curious.....and forgive the slight pull off topic....but what other materials do the manufacturers talk up as being a "piece of cake" to work with that are actually pretty tricky?

If you folks would like me to start a separate thread for this so this conversation doesn't go too far afield let me know.

Dave

Baby and Wedding photos on granite.

[Gary Hair]

Baby and Wedding photos on granite.

Marble is quite a different story though - I have had results that look as sharp as a b/w print on marble. The only way to get anything similar on granite is with color fill. I have used silver Rub-n-Buff to get pretty good results on granite but they are still nowhere near as nice as marble.

[Scott Shepherd]

I agree Gary, Marble is beautiful. My comment was mainly geared in the direction that the time it takes to engrave one of those tiles shown as trade show sales pitches prices them out of the market in most cases. Selling someone a 45W laser with a 2" lens and leading them to believe they can engrave 12" x 12" granite tiles with baby photos and make a living isn't exactly close to being accurate.

I know the Universal booth uses the high density optics on a lot of their samples in the booth. So engraving a 12" x 12" tile with a spot size of .001" is going to take some serious time. Sure, you can do it, but who's going to pay $250 for 1 tile? Not many people, especially not the average retail shopper looking for that stuff.

Marble is the way to go, but you don't see marble samples at the shows much.

[Keith Winter]

Not saying you're going to have success with this, curved glass is always tricky, especially if you're going in and out of focus, but I have a suggestion. We do a TON of glass, with perfect consistent results every time. Granted it is usually tempered glass, and relatively flat, but it took a lot of testing to make it right.
You need to do two passes. What works best for us is a solid color pass (we use blue) set at low power and high speed. enough to make a consistent, if not light, mark over the entire surface.
Then immediately run a second pass with 70% gray, full power and slower speed. (around 60% speed for our Universal).
Then we take some light steel wool and lightly and quickly "scrub" the engraving to remove any loose shards. (about 3 seconds worth) There is hardly any most of the time, and we never have any bits "chip out", even after over a year of washing in the dishwasher and by hand.

Your results could vary greatly, especially since it's not tempered glass, but those work perfectly for us every time. Also, we use 270 dpi.
Might not help you, but it's a suggestion.


Thanks Kevin, we've tried 2 passes. Looks great, 2nd pass works well to fill in mistakes, only issue is it flakes off for the customer later. We will try 2 passes and hit it with some light steel wool, and see if that fixes the flakes. I'll let you know. I'll also try the 270 dpi and see how it goes. Thanks!

[Keith Winter]

That's exactly what I am suggesting. It doesn't have to be a multiplier at all. It has nothing to do with being in synch with anything else. Leave the resolution at 333 and then crank the Hz up to 1000 and try that. I can't say it's going to work, but it's something that will give you a little more heat in the area which might help in this case.

Thanks Dan and Scott, I didn't know you could do that. I'll give it a shot and see how it works at a higher hz

[Keith Winter]

Yes, it's ideal for that.

It would be less time than lasering, I guarantee it! Unless you have multiple people working on this project you won't be able to use either method for 200 a day - at just 2 minutes each that's over 7 hours of continuous work, is that realistic? Even though the laser isn't really suited for glass, it would only really work on a rotary attachment - that's not going to allow you to produce 100 a day let alone 200 or more.

Thanks Gary, I'll look further into the sandblast as well then. To run the glasses it takes 1min 37 seconds for one, or if we line 6 up in a row (each with a different name) it takes around 5-6 minutes total for all 6 of them. So yes 1-2 minutes each is realistic with the laser. Although we are considering adding a second shift and/or machine to keep up with Christmas demand. If creating a mask, applying it, and sandblasting can be done in 3-4 minutes or less then we will consider a couple sandblasting booths instead of buying another laser. What's the realistic time frame do you think (and any others that want to chime in) to do the entire sandblasting procedure if each glass has a different name on it? BTW I don't want to task the laser with cutting masks, I'd rather user a cheaper tool like a cutter if that works for sandblasting too?

[Keith Winter]

I did 400 mugs and 200 wine glasses for a show. I had issues with about 1 for every 12 mugs and 1 for every 9 wine glasses. Out of curiosity, I went over the same "skipped" letters and adjusted the power/speed/dpi to see what would happen or change. Not much changed. It seemed like it was just bad unlaserable spots in the glass. Adjust it too much it melts it or shatters. My partner just wants to get a vision pro max engraver for glass, 10K to 15K used. Oh I used a rotary attachment and wet newspaper over the glass and other things...still skipped. They came out with some masking tape for this recently...will try it.

Glad to know it's not just us with the glass issue! ;) I also wondered if it had something to do with the makeup of the glass or minerals in the water they used to cure the glass at the factory.... I have two rotaries, both are signature engravers. Not sure how those compare to the vision pro max, however I can tell you it is a huge pain to do glass on the signature machines. They are much slower than the laser, you cannot fill in text which a lot of people expect, and glasses do slip from time to time. Last year before we had the laser 1 of the 2 machines spent all day doing glass, we do 3x that amount of glass on the laser every day now, and it does not run all day.... Granted we don't use a rotary on our laser, but I would say we can put out about 5 or 6 glasses on the laser for every 1 on the signature. So if 1 out of those 6 are bad we're still ahead because glass is relatively cheap, and labor is the most expensive part. Now if 3 or 4 of those 6 are bad, that's another issue all together :p On another note the learning curve is also less for new employees on the laser. Vision pro max might be faster and easier to use, I've never used it. But those are my two cents on the Signature engraver vs laser.

[Keith Winter]

I agree Gary, Marble is beautiful. My comment was mainly geared in the direction that the time it takes to engrave one of those tiles shown as trade show sales pitches prices them out of the market in most cases. Selling someone a 45W laser with a 2" lens and leading them to believe they can engrave 12" x 12" granite tiles with baby photos and make a living isn't exactly close to being accurate.

I know the Universal booth uses the high density optics on a lot of their samples in the booth. So engraving a 12" x 12" tile with a spot size of .001" is going to take some serious time. Sure, you can do it, but who's going to pay $250 for 1 tile? Not many people, especially not the average retail shopper looking for that stuff.

Marble is the way to go, but you don't see marble samples at the shows much.

Wood looks amazing on a laser, and works right every time. Arylic and slate look great too. Gary and Scott I'll have to try marble when I get a chance! David, I'm newer than a lot of the people on here (only 6 months experience) so take this with a grain of salt, but I would say if you're doing harder materials like slate and such power is important. It takes awhile to do slate with our 75w, with a 35w I don't even know if it would be possible aside from multiple passes which would kill your bottom line.

[David Somers]

Wood looks amazing on a laser, and works right every time. Arylic and slate look great too. Gary and Scott I'll have to try marble when I get a chance! David, I'm newer than a lot of the people on here (only 6 months experience) so take this with a grain of salt, but I would say if you're doing harder materials like slate and such power is important. It takes awhile to do slate with our 75w, with a 35w I don't even know if it would be possible aside from multiple passes which would kill your bottom line.

Keith,

Assuming I end up going for this I will likely end up with a 60W something. 80 would be nice, but they seem to be tied to much larger rigs than I would like. I would not be a production shop (though who knows) but more likely doing one off work. The info on the glass has been very interesting since all the dealers I have spoken with push that pretty hard. Amusing. Sort of. And glad to have that info tempered with reality from everyone's comments here!!

[Keith Winter]

A couple of other questions I have for you guys.

Here are the following additional settings for glass we use.

Halftone: Black/White
Air Assist: ON
IPC: OFF
High Quality: ON
Raster Correction: ON

Are you guys using these same setting for your glasses?

[Ruben Salcedo]

Here is another alternative... it dose take an extra step but that's how I have been able to get the best results out of a laser, I used to get similar results as you are currently getting, now I use a tape from JDS, is green and is not hard to remove... I first set my first batch of glasses send it to engrave and then while engraving I go and set another batch with the tape on and on... to remove the tape I use a plastic razor blade and clean with denatured alcohol. here is a video from JDS (http://www.youtube.com/watch?v=Za8DXYdIz3g&feature=share&list=PLiCleWhVpjohdjk4z0J38KQFfTEgd_Uk3)

Ruben

[Scott Shepherd]

I use "Color" for all my settings (not black/white) in the driver, but that's just me (unless it's a stamp, then color doesn't work). I also don't use "raster correction", but I don't think either of those settings is going to change anything for you. It's the going in and out of focus that's the problem.

Sandblasting works better the more you have, so you're actually in a better place having to do that many a day. If you have multiple people and they are all working on it, my guess is you could do a 300 a day with no problem. But, if you have to do it all yourself, then you won't get 300 a day. There are a number of steps, you have to make the negative (for lack of a better word), and then use that negative to create a mask made from a material. It takes about 2 minutes to expose the film, so as many as you can fit on a 8 1/2" x 11" piece of film will get made in 2 minutes. Applying them doesn't take long, and blasting something that big would probably take about 30 second of actually blasting time. However, you have to feed them in and out of the cabinet.

Next would be removing the masking and washing the glass off. All that stuff can be done in batches. It's a dirty process though, so it's not as sexy as the laser.

I did a bunch of wine glasses some time ago and I think they took about 10 seconds each to blast. So it's not a lot of time in the cabinet, it's more time prepping the thing than it is blasting it.

[Scott Shepherd]

Here's one from a few minutes ago, just to show the quality level of the actually etching when sandblasting.

274359274360274361

[Kev Williams]

I decided to run some tests for this discussion! (I have a garage full of goblets that have to be done in two days, so it'll help me too!)

Got out a piece of that mirror tile I spoke about and did some test runs, and took some pics. Forgive the pic quality, I can't manually focus with the camera I'm using. I chose this Marine's logo since it's solid, just etched enough to get the idea...

My machine is an 11 year old New Hermes LS900, 40 watt. The numbers represent power/speed - vertical lines per inch/horizontal dots per inch...


First up, 50/100 - 500/800, was one of the best of the bunch...

http://www.engraver1.com/erase1/mi1.jpg



Then I upped to full power and reduced the dpi's. Ended up with banded shards...

http://www.engraver1.com/erase1/mi2.jpg



Next up, full power and lower speed, and way down on the dpi's. What I got was shard city! This glass does NOT like this much power--

http://www.engraver1.com/erase1/mi3.jpg


After brushing with a copper-wire brush...that's a lotta glass!

http://www.engraver1.com/erase1/mi4.jpg


So I upped the speed to 100, pretty much just as bad...

http://www.engraver1.com/erase1/mi5.jpg


Next, 70 power 100 speed, and 300 dpi both ways...much better, but a lot of popped off small spots...

http://www.engraver1.com/erase1/mi6.jpg


So I decided to try a different tack, same speed but went up to 400 lpi and WAY down to 100 dpi-- and it came out very consistent! Only problem is the lack of small detail (like in the lettering) due to the low dpi...

http://www.engraver1.com/erase1/mi7.jpg

Same image, different angle...

http://www.engraver1.com/erase1/mi8.jpg


Here, the only change is dpi up to 200. Not bad but the banding is bad, and 3 very noticeable pop-offs...

http://www.engraver1.com/erase1/mi9.jpg


So I went to photo mode to try to eliminate the banding-- but it actually got worse! Raised the power to 80 too. Popoffs are less, but just for one test--

http://www.engraver1.com/erase1/mi10.jpg


From there I went out of photo mode, upped the power to 90, then went high lpi and low dpi. This rendered the best results yet-

http://www.engraver1.com/erase1/mi11.jpg

-----------------

-- nary a hint of missing spots or shards! Some banding but my machine is BAD with banding...And the low edge detail is still an issue, the lettering is definitely bumpy...

I'm thinking a 150 dpi would be the happy medium, except I don't have that choice, unfortunately!

So, what I've found is, lower power worked well with higher DPI and LPI levels, high power with low DPI and LPI was horrible, and good overall results were obtained from medium-high power, high LPI and low DPI.

[Scott Shepherd]

Good testing Kev- but also remember, he is engraving on things that go out of focus by more than 1/8" too.

Here's a video of the process :


https://www.youtube.com/watch?v=JXFKXaFJUZE

[Joe Hillmann]

When I do glass that will end up out of focus I run the item with two, low power high speed, passes. On my 25 watt Universal I use 100% speed and 30% power. The first pass usually leaves small un-engraved areas, and the second pass cleans it up. I also keep the out o focus area as small and close to in focus as possible by keeping the design small. Once you get to a certain point it goes way out of focus very quick.


Of course engraving two passes doubles your engraving time.

[Scott Shepherd]

Joe, that's a great idea, put the image down as two colors, select "color" on your options. On the second color, make the Z value -.100" and try that. It'll engrave the first pass where you focused it and the next pass will raise the table up .100" and it'll engrave it again. I'd certainly give that a shot for sure.

[Keith Winter]

Thanks Kev,

Good info.

Scott and Dan,

Here is the 100p 50s 1000ppi 333dpi. I had similar results with 90p 100s 1000ppi 333 dpi and 80p 50s 1000ppi as well. The results were worse than the 666 ppi.


Which made me wonder if it's actually too hot? So I tried 333dpi at 500 ppi, and also 250dpi at all 3 ppis (500, 666, & 1000) but still no dice :(

Attached is the 100p 50s 1000ppi 333dpi. 1000ppi sample as you can see it's pretty bad.

[Keith Winter]

Hi Kevin,

Ok I did the two passes 75p 50s 250dpi 666ppi. It looked AMAZING when it got done! See photo 1.

However after 3 seconds with a light brush (just a soft bristled dish scrub brush) it looks aweful. See photo #2, same glass after light brushing. This is the flaking I was describing associated with 2 passes. This might work if we can get the flaking fixed. (single pass does not do this when brushed) Can you elaborate on your engraving procedure a bit more to avoid this?

[Joe Hillmann]

For production you don't engrave the glasses with a rotary but have you at least tried engraving one with a rotary, that way once you get that to work (or work better) you will have good settings to go off of.

Also, when you are engraving them do you prop up the bottom of the glass so from top to bottom the glass is level?

[Keith Winter]

When I do glass that will end up out of focus I run the item with two, low power high speed, passes. On my 25 watt Universal I use 100% speed and 30% power. The first pass usually leaves small un-engraved areas, and the second pass cleans it up. I also keep the out o focus area as small and close to in focus as possible by keeping the design small. Once you get to a certain point it goes way out of focus very quick.


Of course engraving two passes doubles your engraving time.

Good idea. I didn't try the different levels yet, but I did try the two passes again today. Two passes looks awesome initially but flakes off easily once they wash it. How do you control the flaking when you do two passes? See my post to Kevin with a glass done in two passes, initially it looks amazing, but as soon as use a soft brush on it, it flakes to pieces.

Also on your question about if we level the piece, yes, we built an entire jig system internally for this. Each glass is measured with a level and held 100% level and stationary in the machine while engraving.

[Kev Williams]

Good testing Kev- but also remember, he is engraving on things that go out of focus by more than 1/8" too.

I realize that-- however, Keith has plenty of laser power AND a 4" lens to make up the difference.. My findings were glass likes LOW power and LOW resolution settings-- but not both at the same time. Being out of focus for 2/3 of the job means low power is out. Based on my tests, if I had a 4" lens (I wish) I set the job up at around 80 to 90% power, 500 lines per inch and 100 dots per inch. The wider dot size of the 4" lens may help tighten the resolution. Keith, if you can input any variable dot-per-inch setting, I start at 150 and work up (or down?) in 10 dpi increments. I was surprised at how the 100 dpi turned out. What I didn't try (and should) is to lower my power settings with the 200 dpi. However, my dot is about .005, and 200 dpi is exactly .005, and those settings rendered the absolute worst results! It seems my mirror wants the beam to overlap or not touch at all!


and by the way, that video was excruciating to watch--you guys honestly go thru all that to sandblast? You sandblasters never have to worry about ME taking any of your business! :)

[Keith Winter]

Here's one from a few minutes ago, just to show the quality level of the actually etching when sandblasting.

274359274360274361

Looks really sharp Scott! How long did that take you from start to finish? Masking, printing, blasting, cleaning, the whole bit?

[Keith Winter]

I realize that-- however, Keith has plenty of laser power AND a 4" lens to make up the difference.. My findings were glass likes LOW power and LOW resolution settings-- but not both at the same time. Being out of focus for 2/3 of the job means low power is out. Based on my tests, if I had a 4" lens (I wish) I set the job up at around 80 to 90% power, 500 lines per inch and 100 dots per inch. The wider dot size of the 4" lens may help tighten the resolution. Keith, if you can input any variable dot-per-inch setting, I start at 150 and work up (or down?) in 10 dpi increments. I was surprised at how the 100 dpi turned out. What I didn't try (and should) is to lower my power settings with the 200 dpi. However, my dot is about .005, and 200 dpi is exactly .005, and those settings rendered the absolute worst results! It seems my mirror wants the beam to overlap or not touch at all!

and by the way, that video was excruciating to watch--you guys honestly go thru all that to sandblast? You sandblasters never have to worry about ME taking any of your business! :)


Kev I understand DPI and PPI but what is lines per inch? Is that the same as PPI?

[Scott Shepherd]

and by the way, that video was excruciating to watch--you guys honestly go thru all that to sandblast? You sandblasters never have to worry about ME taking any of your business! :)

That's good, I hope everyone else has that opinion :) What's excruciating about 33 mugs in 20 minutes? I hope I get to constantly quote against people laser engraving glasses. I have laser engraved and sandblasted glasses in our showroom. When people walk in and tell me they want a glass laser engraved (how they know to ask that is beyond me), I hand them both glasses and they ALWAYS pick the sandblasted one. The look and feel is superior and there are no shards of glass left over for your customer to wipe off with their fingers (OUCH!).

Keith's problem is the out of focus part. It's relatively easy to get something acceptable on a flat piece.

Keith, that SEAL logo and saying took me about 15 minutes from start to finish. Maybe 20 at the most. Took about 3 minutes in the cabinet actually blasting.

You might also try a lighter power on the 2nd pass.

Also, try this- get a piece of plate glass, get the settings right on that. Then if you still have the issue, it's the out of focus issue.

[Joe Hillmann]

Two passes looks awesome initially but flakes off easily once they wash it. How do you control the flaking when you do two passes?



When using two passes I don't have flaking, to prevent flaking and have an even texture is the reason for using two passes. I would assume that if you are getting flaking you are using too much power. I am using 30% power of a 25 watt laser at full speed. I also use those settings on glass that is much less out of focus than what you are trying to do.

When the glass is sitting on its side in the jig and all leveled up how much higher is the center of the engraving compared to the edges of the engraving? If it is more than 3/16 or so I don't think you will be able to get even results using a laser with no rotary.

[Keith Winter]

That's good, I hope everyone else has that opinion :) What's excruciating about 33 mugs in 20 minutes? I hope I get to constantly quote against people laser engraving glasses. I have laser engraved and sandblasted glasses in our showroom. When people walk in and tell me they want a glass laser engraved (how they know to ask that is beyond me), I hand them both glasses and they ALWAYS pick the sandblasted one. The look and feel is superior and there are no shards of glass left over for your customer to wipe off with their fingers (OUCH!).

Keith's problem is the out of focus part. It's relatively easy to get something acceptable on a flat piece.

Keith, that SEAL logo and saying took me about 15 minutes from start to finish. Maybe 20 at the most. Took about 3 minutes in the cabinet actually blasting.

You might also try a lighter power on the 2nd pass.

Also, try this- get a piece of plate glass, get the settings right on that. Then if you still have the issue, it's the out of focus issue.


Scott I truly appreciate yours and everyone's feedback helping me get this figured out. The issue is not the roundness of the glass it does the same on a flat glass as I mentioned before. See this photo of an engraving on a flat glass, I shot even a side angle so you can see it's absolutely flat. As you can see parts of the letters and parts of the lines in the design are missing even on flat glass items. Is there another settings you guys would suggest? I'm willing to try anything you all think might help.

[Joe Hillmann]

Are those canning jar mugs from Walmart? If so I have done them before and you can get very good engraving on them.

I would suggest taking one of those mugs and start engraving at a high speed and 10% power. If that doesn't mark it step up to 15%. If that doesn't work step up to 20% power and so on until you get a good mark. The reason I suggest using one of the jar mugs is because then you don't have to take going out of focus into consideration.

[Scott Shepherd]

Keith, you keep saying those are flat, they are not flat. Flat is a sheet of glass, a drinking glass or canning jar is not what I call flat. If you did that with the 4" lens, you're okay. If you did it with the 2" lens, it's going out of focus.

[Keith Winter]

Are those canning jar mugs from Walmart? If so I have done them before and you can get very good engraving on them.

I would suggest taking one of those mugs and start engraving at a high speed and 10% power. If that doesn't mark it step up to 15%. If that doesn't work step up to 20% power and so on until you get a good mark. The reason I suggest using one of the jar mugs is because then you don't have to take going out of focus into consideration.

Hi Joe and Scott,

They aren't canning jars. They are glasses we custom order for engraving. Whereas canning jars are rounded, these are flat on 2 sides for engraving.

Scott I respect you and your work, but you're kind of derailing what was a productive conversation into a wild goose chase. If it was as simple as a flat object vs round I would never have posted this topic. Look the images I posted two posts up, it really shows how flat they are. It's not related to a flat or rounded surface, the same thing happens with these flat glasses.

[Dan Hintz]

Where on the round glasses are you focusing... at the very center, off to the sides of center a bit, or towards the back end of the engraving (the sides of the glass)? Let's see if we can dial in a good setting for a 2" lens, then we can work backwards to a 4".

You're killing a glass with each test, so let's use a grid of small 1/4" squares, with each square a different setting. Make a 3x3 grid (leave 1/16" between each square), start with 333dpi, high frequency, and engrave in power from 50-80 in increments of 5. If all of those blocks are etched, drop down to 30-60 in power and run it again. One of those squares will be etched well, the lower power ones will have sketchy etching, and the ones above will look about the same as the good one and possibly overpowered.

If you're still getting any chipping, move to 250dpi, but let's try this first.

[Scott Shepherd]

Scott I respect you and your work, but you're kind of derailing what was a productive conversation into a wild goose chase. If it was as simple as a flat object vs round I would never have posted this topic. Look the images I posted two posts up, and at the 3rd angle on the page, it really shows how flat they are. It's not related to a flat or rounded surface, the same thing happens with these flat glasses. It's something else going on that is making the engravings not come out. :(

Keith, I'm not derailing anything. I think you're confused about your expectations on how a laser works and what it can and can't do. You can't take lasers out of focus and expect consistent results. I know the glassed you post, I engraved 10 of them about 3 weeks ago. They are NOT flat. You keep saying they are flat, they are NOT FLAT.

A 2" lens doesn't like to go out of focus much more than .03" in each direction. Your interpretation of flat isn't flat.

You can get decent results with pure flat glass, but you're trying to do non flat objects without the right tools (rotary engraving). No matter what you try or what you do, it's not going to work. I'm not sure how else to tell you that. It's beyond the mechanics of how a laser works with that substrate.

It's the wrong tool for the job you are posting. 3 or 4 people have told you that now.

[Kev Williams]

Kev I understand DPI and PPI but what is lines per inch? Is that the same as PPI? DPI/DOTS per inch and PPI/PULSES per inch are the same thing: it's how many times the laser fires in an inch in the horizontal/raster plane. LINES per inch is how many horizontal lines are stacked in an inch vertically as the gantry moves slowly downward. The lower the lines per inch, the faster the engraving, but at the expense of high-detail. The gantry will move horizontally the same speed regardless of the DPI/PPI setting, so those settings have no bearing on engraving speed, only engraving QUALITY. If you look at my photos of the 100 DPI settings, you can see distinct VERTICAL lines, as if it was rastered that direction. These lines show up because at 100 DPI, the dot-firing spacing is .010", and the dot is only .005, so dot and the space between are almost equal. And since my machine is very nicely aligned (both directions of the raster pass), the lines appear straight and vertical. An out-of-alignment laser would make those lines appear zig-zagged. If I ran a pass at 100 DPI AND PPI, all dots would be equally spaced in nice tiny squares..

The whole trick to this hobby is getting those settings where things look right! :)

Now, somebody needs to explain "Hz" to me, although I'm pretty sure it's shorthand for PPI or DPI ..?

<edit>-- that all said, I do realize many machines and/or software reference 'lines per inch' as "DPI"... but honestly, I don't see how lines can be dots... ;)

[Keith Winter]

For Scott.... I went out and bought a flat piece of glass last night just for you :rolleyes: The same issue as the other glasses, so now we know it's 100% not related to the items I'm using, it's something with the settings or the laser itself on glass. Notice parts of the K & A are missing, and the B R of brew, part of the shading for the home brew part. 80p 50s 666 ppi 333 dpi (Image 1)

Kev I don't have lines per inch on my trotec that must be the PPI/HZ, Scott can you verify?

Dan on glasses I focus slightly off center to get the curve. I'm going to try that power grid like you said, I'm going to put a letter in each block, part of the issue seems to be around the letters themselves or curved designs. Solid blocks normally come out fine.

To the people using two passes, how do you eliminate the flaking the second passes causes when you use a soft dish brush on it? (2nd image) looks perfect with two passes at 75p 50s 666ppi 250dpi but then in (image 3) I scrubbed it with a soft dish brush for 2 seconds. This seems to always happen when I do two passes, how are you guys doing 2 passes eliminating that?

[Joe Hillmann]

When doing the two pass method I use the lowest power I can for both passes and end up with no flaking. On my 25watt machine I use 30% power and 100% speed. Since you are getting flaking my guess is you are using too much power.

Could you put your location in your profile and your machine and watts in your signature? It helps other people to help you out if they can easily tell what equipment you are using and it is nice to know your location.

[Scott Shepherd]

My settings for glass on our 75W Trotec are 65% power, 100% speed, 1000 Hz, 500 DPI, 2.0" lens, air assist on.

If you are using the 4" lens, I would try the 2" on flat glass and see if that changes anything. Remember, you're fracturing the glass, it's always going to be an issue. You can't control how it fractures the glass but so much.

[Dan Hintz]

I'm going to try that power grid like you said, I'm going to put a letter in each block, part of the issue seems to be around the letters themselves or curved designs. Solid blocks normally come out fine.

Use a letter 'X' or 'A', then, so the sharp corners are there.

[Keith Winter]

So I did the power grid, I actually did around 49 tests total with different settings power/speed/ppi/lens. I got some good results with the 60-80w range at 50 power 666 ppi and 1000 ppi both worked equally well. Half were with the 2.5" lens, half were with the 4" So I then applied them to the two glass designs I have been working with and burned them on additional pieces of that flat glass that I purchased last night, just to make sure the roundness issue was taken completely out of the picture. At first I was excited to see how well the 60 power setting with 50 speed was working, until my 3rd test in a row with the actual artwork when it skipped in multiple places again. I ran it a few more times with different powers that worked well on the power grid, and sure enough it skipped again.

So after 56 glasses, a 49 piece power grid, and countless hours, I have come to the conclusion that consistent results are not possible with my Trotec laser on glass. From what everyone has said this is to be expected and not likely an issue with my laser, rather a problem with glass and how it takes lasering in general. It does ok on large monograms and letters but when you add detailed designs to the glasses you're asking for trouble, 8 might come out fine but that 9th and 10th are probably going to have "skipped" areas on the glass. Also I have not yet been able to get two passes with the laser that some people said works, to pass the 3 second soft bristled scrub test. It looks great when you pull it out after the two passes, but flakes when you scrub it. So I'll avoid that unless I can get that flaking issue figured out.

I believe Scott at the beginning of the thread said it best, it's like chasing a rainbow. You think you've finally found the end of the rainbow and the perfect settings, then it skips again. As many have said, it does not appear to be the proper tool for the job no matter what the laser manufacturers try to tell you. So I'll continuing to use the laser for very basic/large letters on glass, but for the more detailed designs I'm going to look into sandblasting as Scott and others suggested. If anyone has any future tips to add, or more tips on how to properly do two passes on glass so it does not flake, I'll be happy to try any future suggestions. Just post them on this thread. I hope this thread has been helpful for everyone even though we did not get my issue fixed I've learned a lot. Thanks!

[Dan Hintz]

Keith,

It's up to you if you want to let this go, but I'd rerun that power grid at 333dpi (and possibly 250, though I don't go that low for production pieces). Anything 500dpi+ is way too high of resolution for glass as a substrate. You may also consider running the test at 60% black rather than 70%, see if that cuts down on your chips.

This is one of those problems, unfortunately, that's more easily solved in person so you can see the problem and correct on the fly...

[Mike Tavares]

Hello fellow creekers! I use for all my glassware 100% power, 25-30% Speed, 600DPI, using Standard Mode. My image is at 70% black. These settings are used for Beer Mugs, Shot Glasses, Wine Glasses etc. (Power is adjusted on thinner glassware such as flute Glasses) I use no paper towels, newspaper, soap, or water. These items are engraved using a rotary attachement on a 45watt Epilog Helix using a 2" standard lens. I can run approx. 100 Beer Mugs in an 8 hour period. The engraving is always consistant and requires no brushing or washing. They go straight into the box and are ready to be shipped to the client. I understand that settings may vary from machine to machine. Hope this info can help others. Cheers!!

[Mike Tavares]

Hello fellow creekers! I use for all my glassware 100% power, 25-30% Speed, 600DPI, using Standard Mode. My image is at 70% black. These settings are used for Beer Mugs, Shot Glasses, Wine Glasses etc. (Power is adjusted on thinner glassware such as flute Glasses) I use no paper towels, newspaper, soap, or water. These items are engraved using a rotary attachement on a 45watt Epilog Helix using a 2" standard lens. I can run approx. 100 Beer Mugs in an 8 hour period. The engraving is always consistant and requires no brushing or washing. They go straight into the box and are ready to be shipped to the client. I understand that settings may vary from machine to machine. Hope this info can help others. Cheers!!

[Bill Cunningham]

For non rotary etching, with a 2" lens you can etch reliably upto 60% of the diameter of the glass..I.E a 3" diam beer mug you can make your logo 1.8" wide. When etched it will be abt. 2" wide measured over the curve of the glass. You will get flaking on some glass unless you cushion (for lack of a better word) the impact of the beam on the surface of the glass. When you have enough time to pre-coat the glassware, try this: Go to the grocery store and buy some envelopes of gelatin..(not jello..ha..) Mix it with a little hot water, and make it thick(thicker the better as long as it's not lumpy). Paint this on the surface of the glass, and leave it till it drys like a soft coating (usually overnight does it). then hit it a little harder with the laser than you normally would, and use at 600 dpi (or what ever your lasers equiv. is..) Now your etching the glass through a soft coating that keeps the micro fracturing under control and etches without flaking in 99% of the cases. This coating mix also works well on artist canvas. Coating it and letting it dry, surface treats the canvas to allow a ordinary inkjet printer to print sharp photos on ordinary painting canvas.. If you inkjet print on inkjet canvas the canvas your buying (at very high prices) is treated like this..

[Keith Winter]

Well we found part of the issue! We had a bad tube and the alignment was slightly off. Tube was only 6 months old so it was likely imperfect from the start. Tube finally went out last week, we had complete failure on everything, glass, wood, etc. Trotec replaced it the next day (thanks Trotec!) and the tech ran some sort of pattern to test laser alignment. It was off as well. The pattern is similar to a nozzle check on a printer, makes super tiny lines that are horizontal and vertical. The lines were a bit squiggly when he started, he tuned it while on the phone with support, and when he was done the lines were all straight. Never seen anything like it in the manual, so I'm unsure what it's really called. They also added a new feature for substrates in the newer job control called correction. They turned that up for some materials. Laser is now burning a lot hotter, and everything is coming out significantly better.

With the new tube, woods are much darker. Glasses are much better too. Not all perfect, but I'd say before with the old tube 2 or 3 out of 10 were bad and had to be redone. Now maybe 2 or 3 out of 50 have to be redone. Still not perfect, but a big improvement!

[Kevin L. Waldron]

Just curious....... anyone tried running with an inert gas, where oxygen/air is not so great a part of the equation? ( we have and thought the improvements where worth the effort.... our lasers are set-up for gas and/or air)

Blessings,

Kevin

[Dan Hintz]

Just curious....... anyone tried running with an inert gas, where oxygen/air is not so great a part of the equation? ( we have and thought the improvements where worth the effort.... our lasers are set-up for gas and/or air)

Blessings,

Kevin

Air (or lack thereof) should have no effect on glass engraving in any setup most of us are likely to have.

[Joe Hillmann]

Have you tried engraving the glass when it is cold? I recently found out that some glass produces much more consistent results when cold.