Engraving (glass and acrylic)

[fibonacci]

We just picked up a 50W chinese laser and are having some mixed results with engraving. At the moment, I cannot decide if the problem is in the settings, the technique, or the images. I am using NewlyDraw 1.5.

I am taking an image, using photoshop to set the resolution and convert it to monochrome bitmap using random pattern dithering. I am attempting to use 250dpi, as I have heard that much higher than that causes issues on glass due to overlapping fracture patterns.

When I engrave, I do the wet paper trick where I soak a piece of paper, shake it out, lay it flat on the glass with no bubbles, and etch through it. Adding the wet paper made a significant difference, but not as much as I had hoped.

I have not had much success in finding recommended settings for speed/power on glass, and my results are quite varied.

Can anyone chime in with what settings they use?

If possible, it would be awesome if I could get an image that someone has engraved and a photo of the engraving so I have a baseline to compare it to.

[zax15uk]

Welcome fibonacci.

I use 12W @ 10cm/s with the wet paper technique, it usually produces excellent results. The scan gap setting should be 0.1 (254dpi) or 0.2 (127dpi) depending on the image (lower resolution in glass often produces a better final image at higher power, or the higher resolution if you are using a very light engraving).

Before you dither the photo in Photoshop, first scale it to the correct size. So if you want a 4"x3" design (at 127dpi), 508 pixels x 381 pixels. Then I always enhance the contrast and convert to greyscale before applying the dither filter (the filter I have allows you to preview the results and change parameters to get the look you want - not sure if you have that capability). Once dithered save it and import to Newlydraw, do not change the size or you mess up the process. Engrave at the same resolution you originally used.

I'm not sure if I have any examples in the shop that I can provide - but I will have a look.

Zax.

[zax15uk]

If you are doing a lot of photo engraving, buy Photograv.

It simplifies the process on different materials and usually has as good or better results than you can achieve manually but saves a lot of time.

Zax.

[fibonacci]

Thanks Zax. That was probably my problem. I was running at 25W at 15cm/s.

I will try the lower power and speed. When you say you increase the contrast, do you have a rule of thumb for how high to take it? Or is it just an experience thing?

As much as I would like photograv and coreldraw, neither one is going to happen. We really pushed our budget to get the larger bed laser. Also, our primary purpose for the system is vector cutting, which it does just fine, so it would be a hard sell to get money for engraving software.

One other question that might or might not be related. When you have scan selected in NewlyDraw, you have the option for 2 line, 2 line enhanced, 4 line, and 4 line enhanced. Do you have any idea what that option does? I fiddled with it, but did not see any difference.

[zax15uk]

How much I adjust the contrast depends on the original image but the best results usually require it to look slightly 'harsh' on screen.

I always select '2 line enhanced', it's been a while since I used Newlydraw but if I remember correctly it only changes the on screen view and not the output (but I could be wrong).

Zax.

[EXLASer]

We just picked up a 50W chinese laser and are having some mixed results with engraving. At the moment, I cannot decide if the problem is in the settings, the technique, or the images. I am using NewlyDraw 1.5.

I am taking an image, using photoshop to set the resolution and convert it to monochrome bitmap using random pattern dithering. I am attempting to use 250dpi, as I have heard that much higher than that causes issues on glass due to overlapping fracture patterns.

When I engrave, I do the wet paper trick where I soak a piece of paper, shake it out, lay it flat on the glass with no bubbles, and etch through it. Adding the wet paper made a significant difference, but not as much as I had hoped.

I have not had much success in finding recommended settings for speed/power on glass, and my results are quite varied.

Can anyone chime in with what settings they use?

If possible, it would be awesome if I could get an image that someone has engraved and a photo of the engraving so I have a baseline to compare it to.

Yes,just as ZAX said,you should set proper dpi -preview the results and change parameters to get the look you want,and speed set should be higher,
I atteched one sample our EXLAS 80w made(actually not very ideal,we made it in hury and laight is bad you can see the small signs are better)
Mike

[EXLASer]

More Glass etch photos we had made last time,,,I also found a nice work by jrj5x5(jim ),check link there,
http://www.cnczone.com/forums/laser_...engraving.html
B.Regards
Mike WANG
mike@xyz-tech.com

[Huahahahahaha]

if you want to make photo grafir. I already make a lot of.
Special Gift with Your Photo - Kaskus - The Largest Indonesian Community

Just using Photoshop.
then setting gravir for speed 500 power 50
just make sure all photo on correct dpi
i using 60W laser