New member in Tennessee - Marble help

[Hale Reider]

I have a small web-based business. We are making laser cut and engraved hardwood family tree. I just bought and ran some black marble for the first time. I have tried Phot-Grav manipulated images and standard Corel manipulated images. I get banding (horizontal strips) across the photo image on the marble. I have been running a number of setting, 300 DPI and about 60% power and 80 IPM provides the best, but image still has light and dark bands. It is not the marble, as the pattern repeats on blue copy paper. I am afraid it is in the laser tube. I have contacted and am sending some samples to my laser manufacturer. Machine is a 40 Watt Xenetech. Anybody have any suggestions? Thanks, Hale

[Dick Parr]

Welcome Hale to the SMC.

[Mike Mackenzie]

It sounds like laser tube to me

[Rodne Gold]

Welcome here
Banding is often a problem if your power (electrical , not laser) fluctuates. A online UPS often cures this but can be expensive. It can be a motion system problem and lubrication and retensioning belts etc can help , it can be a software thing too like a driver problem. Lasering a solid black square will eliminate a few factors that might be the problem , like the conversion software itself. If you get banding here , its a driver/power/machine problem and not to do with how you converting the photo.You can also try rotating the whole graphic (rotate the pic before using photograv) and see if the banding rotates as well , if it does its definately a software issue.
A laser actually cant really print at high dpi , a min spot size of 0.003" means that it can really only put down 300 dot per inch and on photos these dots still have to be clumped into cells to give shading. Effectively you can really only map 100-150 pixels per inch of lasering. Try running at a lower DPI , even 150-200 and dont overscan pics. IE if you were printing a scan at full size , scan at about 200-300 dpi , if you are reducing it to 1/2 size , scan at 100-150 dpi and if doubling it when printing , at 600 or so. Photograv doesnt send stuff in greyscale so its basically the same as sending any other engraving. The biggest thing with photograv is NOT to mess with the output file in your package , IE DONT resize , rotate etc.

[Shaddy Dedmore]

I have an Epilog 24TT, I had horizontal banding, usually just showed up on Marble and anodized aluminum. I could change the settings and cover some of it up (changed res, slightly out of focus...)

Talked to Epilog rep, replaced tube... problem went away.

[Hale Reider]

Thanks for the suggestions. I have already tried rotating the image in Corel Draw. Banding did not rotate. I will try running a solid square. Great idea. I saw some of the other posts from last year about material from LaserSketch. This material is from LaserBits. Anybody had any trouble with their material? Hale

[Laura Zaruba]

Hi Hale.

I normally get my marble from Lasersketch but I did try some from Laserbits as a backup. Funny thing is what I got from Laserbits was practically identical to Lasersketch so I wondered if LS is LB supplier too?

Laura DeMeyer

[Mike Mackenzie]

Yes they are Its the same stuff

[Ken Frisby]

Laura,

LaserSkectch supplies Laserbits.

[Keith Outten]

Try Color Stone International in Atlanta Georgia. They sell 12" square black marble tiles with no veins but you will need a tile saw since they don't sell marble in any other size. The cost is about 8 bucks per tile with shipping.

[Steve Spaulding]

New member, excellent exchange of information.

Lasersketch supplies Laserbits, as has been indicated, we distribute their products as well.

Just to advise there is an Photograv parameter that Lasersketch developed that works a little nicer for this specific marble then what is provided with Photograv.

Glad to send along to anyone that would like it.



Steve

[Glenn Palhof]

In regards to banding. we sometimes see this and have just slowed the speed down
which may varry from one machine to the next .
glenn palhof

[Kevin Huffman]

Hey Guys,
We have seen this issue before. It is a rare occurance but we have seen once or twice in the last 3 years. It is a combination of 3 things and how they react to each other.

1. The power going to the laser tube. Usually the power supply inside the machine isn't functioning at an optimal level. Simply replaceing the power supply sometimes fixes it.

2. The speed which the motors move at. On our GCC machines we have found that slowing your speed down will always get rid of this problem. We have tried replacing both motors and it will still do it. But when you turn the speed down it helps alot.

3. The laser tube itself. We have had instances where the laser tube and power supply had to be replaced to resolve this issue.

You may have to do 1 or all 3 to get this problem resolved.

[Barbara Sample]

Hello,
I have a LaserPro laser 30W. I experienced bands across my marble and acrylic, and being rather new to the laser, I didn't know what to do. I cleaned my lense, and tried again, and it worked. I know this sounds like a simple solution, but it worked for me. It also worked with the acrylic, but I have also found that with acrylic, if you take it out of focus, (I drop the table down one to two time) that also cleans up the acrylic.

I hope this helps. It's cheaper than replacing the tube.

Barbara
RGile Engravers
www.rgilengraver.homestead.com

[Jerry Allen]

Barbara,
Your link (www.rgilengraver.homestead.com) doesn't work.