Banding on Tile Engraving

Hello everyone!

I have an OMTech Red and Black 80w Ruida 664XG machine, with a CW-5202 Water Chiller
a 15 psi air assist.

I am using Lightburn version 9.24

I am attempting Tile engraving, running it at these settings:

Speed: 300 mm/sec
MaxPower: 15
MinPower: 15
500 DPI
Image Mode: Halftone
Cells per inch: 100
Halftone Angle: 33

I am keeping the water temp at 17-18 celsius

I am getting some banding in the end result.
I’ve attached an image that shows a successful run,
and two failed runs that I tried running the day after.

Assistance is greatly appreciated!

Did this just show up?
I’ve seen similar where they claim it’s the variance of paint layer thickness.

Probably help us more if we knew the procedure. Single layer of paint?

I try to keep the air assist down to the least amount of air, a couple of pounds, just to protect the lens and not force any particles back onto the engraving area.

However I think I can learn more from you :slight_smile:

Hello Jack,

Thank you for replying! Unfortunately this issue has been there since day one, but I’ve only started proper testing recently.

I’m using Krylon Fusion-All-In-One, doing a couple of passes, I’d say about two light coats, just enough to get a consistent cover.

I previously did some testing on Plywood and had some banding there as well. Originally thought it might have been the water chiller kicking in, so I moved the laser to its own circuit.

I will attempt another engraving with a lower PSI and come back with the results.

Are the banding always in the same place. There is some glare on the tiles, so I’m not sure of the exact area. If I see what I think I see, it’s about 1/3 off the bottom?

I’ve been doing some mirror time for a friend, but I’d like to try more time. I have some spray on bonding agent that seems to work ok but I haven’t gotten a good black yet.

I’ve found this useful it’s from Russ Sadler, two pager with good math for engraving with dots. You’ll have to tell me if it helps…:slight_smile:

What is the tooth pitch on the x-axis belt?
Does the banding occur at that pitch or even multiples of it?

If you’re thinking of what people call the ‘curtain’ effect from the belts slight movement when the teeth hook up?
If so, you can usually put it up visually next to the belt and see a pattern related to the belts teeth. I don’t see that.

Very possible I’m not seeing what you’re seeing…

Yes.

I see faint curtains sometimes when I’m doing a large area of glass. So I know it’s not related to any kind of spray on coating or whatever. The curtains usually appear to be multiples of the belt tooth pitch and is worse at some speeds than others so I’m guessing that the irregular motion of belt teeth as they go around the pulley sets up some resonance in the belt. Proper belt tension minimizes it but doesn’t make it go away entirely.

Thank you for the document Jack, looks like some good info for the engraving. I have not been able to test yet, so I don’t have any updates.

Hank, thank you for replying! I am not familiar with tooth pitch, I’ll have to do some research on it.

Hate to bring up Russ again but he has a video on ‘curtains.’ and how he fixed it. He’s very good with this stuff. I’ll probably do that fix on mine when I get me and it to a new home. :wink:

I have his lightweight head on my machine. It’s great.

Take care :slight_smile: