glass engraving sample

[Kevin Clark2227]

I am working on a different type of sample for a client. It appears to be regular glass. I have used the settings of 100S and 45P for the images attached. They don't seem to be frosted like glass mugs that I have done in the past. Not sure what settings to use from here. Because the one photo of the words did not show up very well IMO, I did a second side of the item trying to do color fill to help it stand out. But the color fill did not turn out well either I think. I tried using both liquid detergent and wet paper towel and using tape. Any suggestions? Sorry can't get my second image uploaded. We'll keep trying.

[Dan Hintz]

What resolution are you running it at, and what black setting are the letters at? I see some serious chipout on the edges of letters, which is usually a sign of too high dpi or too hot... your power looks reasonable, soooooo....

[Mark Sipes]

Just finished a 12 trophy package for a golf event , all glass. I used setting of 95% power 15 speed 500 DPI, 200 PPI and 80% Black. No wet newspaper, soap, etc. Also no chipping, all frost.

Note that is for a 25W system, so a speed of 30-40 would probably be about right for you. The ppi setting is the most important..

[Kevin Clark2227]

I used a DPI of 600. As far as the black setting not sure how to look that one up. Still a noobie

[Mark Sipes]

Are you using Corel to prepare file. In color bar there are a series of black to white shades... 80% is 3 less than 100%. fill

[Kevin Clark2227]

K: 100 in Corel Draw

[Mark Sipes]

You are set to CMYK RGB is what should be used and R-51 G-51 B-51 would be 80% Black

[Kevin Clark2227]

You are set to CMYK RGB is what should be used and R-51 G-51 B-51 would be 80% Black
So I need to convert my file from CMYK to RGB?

If so, should that fix my problem and if so, how does that fix it. Not that I am arguing, I just like to know how things work in relation to one another so that in the future I will have some knowledge to better better informed for tweaking things on my own.

[Mark Sipes]

Several good discussions on the subject:

Start here http://www.sawmillcreek.org/showthread.php?182517-CorelDRAW-12-RGB-as-Default

http://www.sawmillcreek.org/showthread.php?201517-CMYK-RGB-Question

http://www.sawmillcreek.org/showthread.php?184947-coreldraw-x6-quirks

[Dan Hintz]

K: 100 in Corel Draw


I used a DPI of 600. As far as the black setting not sure how to look that one up. Still a noobie


So I need to convert my file from CMYK to RGB?

If so, should that fix my problem and if so, how does that fix it. Not that I am arguing, I just like to know how things work in relation to one another so that in the future I will have some knowledge to better better informed for tweaking things on my own.

You should always run files as RGB... CMYK does not have a 1:1 transfer to a machine that expects RGB, so you can get weird things happening, like random dots in the background of an image that was white in CMYK, but is a very light shade of gray in RGB.

600 dpi is a lot for glass. I'd drop that back to 300dpi.

You should be at 70-80% black. 100% puts the dots too close together.



The chipping you're seeing is the result of the last two items... too much power in a contained space.

[Kevin Clark2227]

Thanks of the great replies. I will be doing another sample tomorrow to see how it turns out.

[Bill Stearns]

Hey All -
'Other day, I engraved two different flag-display cases (triangular glass fronts) - one turned out fine; on the other 'couple letters were 'little "faded". (not as clear as the others.) I used a trick Bill C. taught me (pertaining to brightening up my black granite photos) - With my fingertip, I rubbed (titanium oil based white paint) across the glass, 'cross the text, then wiped it clean. This significantly brightened and cleared up the letters ... saved the day! Learned another trick 'other day - on my own: when doing lots of small metal tags - placed within my Lasermax/sheet "jig", I simply use a piece of sticky blue painters tape to pull each of 'em out! - used to have to pry 'em out with a pin. (what' a time saver!)

Bill

[Chuck Stone]

Note that is for a 25W system, so a speed of 30-40 would probably be about right for you. The ppi setting is the most important..

Does the ppi setting even come into play with raster images?
(don't think it does on my machine, but I'm not sure on others)

[Kevin Clark2227]

I think these came out better with new settings, but doesn't stand out with a photo. Not even with the color fill.

[Dan Hintz]

If you plan to use a non-solid background, colorfill is the only way to go. A photo does not provide proper contrast for the eye to separate the background from the foreground.

[Kevin Clark2227]

If you plan to use a non-solid background, colorfill is the only way to go. A photo does not provide proper contrast for the eye to separate the background from the foreground.
What is the proper fill to use?
I have Pro Color Fill & Stone Fill from Laserbits or something else?

[Bruce Clumpner]

If you use transfer tape, you can simply use rattle-can spray paint. Try to use a color that will show the highest contrast against the section of the photo your text will be in front of.

[Dan Hintz]

If you use transfer tape, you can simply use rattle-can spray paint. Try to use a color that will show the highest contrast against the section of the photo your text will be in front of.

And if you've already taken the tape off or forgot it altogether, just rub in some acrylic paint.

[Keith Colson]

One thing I want to try, also an idea for you as it looks like you would want some really permanent colour, paint will fade outside over time.

Engrave the glass. coat it with some coloured glass powder (pottery people use it) re-laser the same spot to melt the powder into the glass. Repeat if more contrast is need. This is just an idea. Anyone tried it?

Cheers
Keith

[Hilton Lister]

Just to be completely contrary, I use 1000 dpi, 100% power, 100speed, 2 passes. If it still doesn't look good, wire brush, then fill with silver Rub n Buff.
I have never been able to get a good finish with the laser using any other settings. Sandblasting is always better.

[David Rust]

You should always run files as RGB... CMYK does not have a 1:1 transfer to a machine that expects RGB, so you can get weird things happening, like random dots in the background of an image that was white in CMYK, but is a very light shade of gray in RGB.

600 dpi is a lot for glass. I'd drop that back to 300dpi.

You should be at 70-80% black. 100% puts the dots too close together.



The chipping you're seeing is the result of the last two items... too much power in a contained space.

Dan,

This is interesting... I did a big order of beer mugs at (70% gray, 70 power, 70speed, 300dpi), they came out pretty good but I wasn't happy, I tried the dish soap trick and it helped a little, probably not worth the extra time it took to hand wash every mug. A week later I ran a sample for a customer and messed up the settings (70% gray, 70 power, 70speed, 1200dpi no-soap) I let the job continue instead of stopping... I shocked at the results, it came out amazing, very frosted without any chips, I was expecting something undesirable from overheating the surface... the penalty was 4X run time. After a few more runs I settled on (70% gray, 70 power, 70speed, 600dpi, no-soap), still a remarkable improvement over the the 300 dpi however double the run time but now I don't have to use the soap/rinse/dry routine!

Maybe the type of glass (Libbey Beer Mug) made a difference... it took the 1200dpi very nicely....

[Mark Sipes]

Libbey is the most forgiving. very soft glass. move towards crystal glassware and you will see chipping to the max. Try a Riedel Wine glass. Glass will shatter.

[Dan Hintz]

Maybe the type of glass (Libbey Beer Mug) made a difference... it took the 1200dpi very nicely....


Libbey is the most forgiving. very soft glass. move towards crystal glassware and you will see chipping to the max. Try a Riedel Wine glass. Glass will shatter.

In many cases it can be a crapshoot, but generally too many fractures in the same area lead to entire sections falling away. 1200dpi is a LOT of fractures in a single area, though the 70% black helps mitigate that somewhat.

I just looked at my notes... long ago I settled on 333dpi for images, and 500 dpi for text. The 333dpi provided just the right amount of overlap without fuzzing an image's internal edges (which are rarely straight vertical/horizontal)... the extra resolution on the text gave me the edge definition needed for what amounts to a 1-bit "image" (internal to font edge is on, external to font edge is off).

A lot of my glass work is Riedel... started working with it when people here were claiming leaded glass couldn't be lasered, and what started out as a "sure it can, and I'll show them" turned into a decent money-maker.