Poor quality photo engraving

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closeracing
Posts: 22
Joined: Sat Jul 08, 2017 1:38 am

Poor quality photo engraving

Post by closeracing »

I purchased a 60w Unich 1318 cnc laser I am having a lot of trouble with photo quality and consistency. It seems the light areas of the photo are too light and the dark areas sometimes don't show up at all, even when I run photograv files that came out beautifully on another machine. Power settings vary wildly depending on the photo (as much as 10%) I am using Corel and photograv then rdworks to run the file. Can anyone point me in the right direction?
closeracing
Posts: 22
Joined: Sat Jul 08, 2017 1:38 am

Re: Poor quality photo engraving

Post by closeracing »

Late last night my son suggested skipping photograv and using the dithering settings in RDworksv8. We ran a couple of painted tiles and they came out much better! I hope this is the fix, I don't understand it, but if it works I'm happy! :D
futrelis
Posts: 14
Joined: Sat Jul 22, 2017 12:56 am

Re: Poor quality photo engraving

Post by futrelis »

Hello!
I have the same problem.. with a chinese 50w machine.
I want to ask you what is the machine that produces good quality photo engraving with photograv ?
Is this machine an RF co2 laser (metal tube)?
closeracing
Posts: 22
Joined: Sat Jul 08, 2017 1:38 am

Re: Poor quality photo engraving

Post by closeracing »

The laser I used that always produced high-quality images was a gantry mounted RF laser. We used Corel and photograv to prepare the images and wincnc to operate the laser.
The problem is not fixed with my laser, the tech thinks I may have a bad tube. I had to make a video of RECI's troubleshooting procedure and send it to them, they are supposed to get back with me Monday.
futrelis
Posts: 14
Joined: Sat Jul 22, 2017 12:56 am

Re: Poor quality photo engraving

Post by futrelis »

closeracing wrote:The laser I used that always produced high-quality images was a gantry mounted RF laser. We used Corel and photograv to prepare the images and wincnc to operate the laser.
The problem is not fixed with my laser, the tech thinks I may have a bad tube. I had to make a video of RECI's troubleshooting procedure and send it to them, they are supposed to get back with me Monday.
The only gantry mounted rf laser i know is camtech laser master is that produced high quality images?
You must know that RF lasers are superior to laser engraving compared to cheap glass tubes.
In what material you do engraving on granite/marble ?
Unich laser machine has ruida controller with the tube mounted on the gantry or with flying mirrors ?
Last edited by futrelis on Sat Jul 22, 2017 8:12 pm, edited 1 time in total.
closeracing
Posts: 22
Joined: Sat Jul 08, 2017 1:38 am

Re: Poor quality photo engraving

Post by closeracing »

I learned on 2 gantry mounted RF laser machines. One was a Shop Sabre Laser that also had a router attachment and the other was built by the guy who owned them. We engraved wood, glass, marble, granite, and acrylic. Another nice thing about those lasers is that wincnc uses Gcode so there is no file size limitation. Doing a detailed engraving the size of a full sheet of plywood was no problem.
futrelis
Posts: 14
Joined: Sat Jul 22, 2017 12:56 am

Re: Poor quality photo engraving

Post by futrelis »

look this
http://www.sauno.ru/userfiles/XbLaser01.jpg
it was engraved with 40w glass tube and a special controller optimized for engraving.
If you find solution let me know with glass tube...

one temporary fix (but it not solves the problem) is to go to photograv interactive mode and adjust ed density to 0
histogram black to 0 white to 255 and gamma to 1.
I have glass tube and iam searching where to find an rf tube to replace glass tube if the tube is the problem or controller..
closeracing
Posts: 22
Joined: Sat Jul 08, 2017 1:38 am

Re: Poor quality photo engraving

Post by closeracing »

Yes the Unich laser uses a Ruida controller, glass tube, and flying optics.
What special controller are you talking about? I looked into changing over to wincnc controller and software, but was unable to find a solution because the Ruida has integrated motion control.

Excellent engraving! Was that on granite?
futrelis
Posts: 14
Joined: Sat Jul 22, 2017 12:56 am

Re: Poor quality photo engraving

Post by futrelis »

Yes it is on granite.
Wincnc costs about 1500eur.
Iam looking a solution with linuxcnc and a mesa card for controller...
Or another controller that can accept big files for raster engraving and produce good results similar to RF tubes.
closeracing
Posts: 22
Joined: Sat Jul 08, 2017 1:38 am

Re: Poor quality photo engraving

Post by closeracing »

Here is the quote I got from wincnc.

WinCNC Software - $850.00 (includes 30 days support to determine proper wiring and online software configuration)
PCI7200/DB37 Daughter Board - $410.00
Laser Raster/Vector Feature Activation - $300.00
CN2IO Board and 10ft DB37 M/F Cable - $300.00
DB37 Ribbon Cable extension (inside cabinet) - $25.00
Windows 10 PC Tower - $565.00
Total - $2450.00 + shipping
I don't need a computer and all the hardware can be bought online for about $400 less than the quote. The problem is that it will not work without a separate laser control, the Ruida controllers are an integrated laser + motion controller. Wincnc is generally used with synrad and coherent lasers.
Here is part of the conversation I had with the sales rep at wincnc.

" Yes, thank you. And I was able to track down a manual for the “mainboard” online. It looks like that has a built in laser controller, which would be an issue with retrofitting to WinCNC.

WinCNC uses a one wire gate signal with PWM for laser firing and power control. Generally that will require a laser controller that generates a “tickle” pulse and does a digital to analog conversion of the gate signal. In this case we would have to replace the existing “mainboard” to get WinCNC setup to control the motors and move the machine, but in doing so we would be eliminating the laser controller as well. The only solution that I could think of for that issue would be to get some sort of stand-alone laser controller that we could use to replace the one that is built into the “mainboard”. The only laser units that we really have any experience with are Synrad and Coherent lasers both of which come with a proprietary stand-alone controller. So I don’t know of anything that I could recommend. If you have any information on the laser that you have specifically I would be glad to spend a bit of time doing some research online to see if there is a feasible solution available.

Sincerely,

Kelly Davis
Microsystems World CNC, LLC.
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