Author Topic: problem with gray scale  (Read 1827 times)

philochard

  • Newbie
  • *
  • Posts: 5
    • View Profile
problem with gray scale
« on: July 31, 2019, 03:19:16 PM »
Hello,
I have baught la laser engraver 3mW on banggood.
the software sold with is benbox. But it does not handle the dimensions of the images well, that's why I took the T2laser.
However, I can not get the same image quality:
with benbox:


And with T2Laser:


Can you help me?

firmware: Grbl 1.1e Ready

Phil
« Last Edit: July 31, 2019, 03:21:02 PM by philochard »

Zax

  • T2Laser
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 7304
    • View Profile
    • T2Laser
Re: problem with gray scale
« Reply #1 on: July 31, 2019, 04:10:06 PM »
It looks like you need to adjust some settings, is it engraving backwards as it appears?

Click Reverse X-axis in the setting menu on the laser controller.

Try black and white mode and set resolution to 0.1 for testing, typically it would be 0.16~018 for most lasers.

It also looks like you have some backlash or other problem,perhaps the speed is much higher with Grbl 1.1e than the old Grbl 0.8 used by Benbox. You can select Reduced Acceleration and also slow down the feed rates to match Benbox.

philochard

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: problem with gray scale
« Reply #2 on: August 01, 2019, 03:38:54 PM »
okay,
i have decreased the speed, the best value seems to be 700, the resolution =1.
The gray scale diseapered beneath 50%..????
the result is better than yesterday, thank you for your advice

« Last Edit: August 01, 2019, 03:41:39 PM by philochard »

ggallant571

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3242
    • View Profile
Re: problem with gray scale
« Reply #3 on: August 01, 2019, 06:07:54 PM »
What type of wood are you burning? Post the image and I will test with 2.5W. 700mm/min seems quite slow for wood with a 3W laser.
SARCASM - Just one more service we offer here.

philochard

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: problem with gray scale
« Reply #4 on: August 01, 2019, 11:47:14 PM »
The wood is oak.
I had to mount the gray in photoshop to have this result
Here is the image:
« Last Edit: August 02, 2019, 03:10:38 AM by philochard »

Zax

  • T2Laser
  • Global Moderator
  • Hero Member
  • *****
  • Posts: 7304
    • View Profile
    • T2Laser
Re: problem with gray scale
« Reply #5 on: August 02, 2019, 06:28:16 AM »
I don't really understand your results, you are getting vertical lines when engraving horizontal (wood grain?) and some have severe backlash (the offset shadow image).

Have you verified the machine with vector shapes, circles are best to eliminate mechanical problems?

If you are using my default firmware and parameters (0-255 for laser power) you should be getting much better results without much trouble.

ggallant571

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3242
    • View Profile
Re: problem with gray scale
« Reply #6 on: August 02, 2019, 07:33:38 AM »
I think you picked a very difficult to engrave image.
SARCASM - Just one more service we offer here.

philochard

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: problem with gray scale
« Reply #7 on: August 02, 2019, 02:36:01 PM »
I think it's the type of wood.
I have tried on chestnut and the result is perfect

ggallant571

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 3242
    • View Profile
Re: problem with gray scale
« Reply #8 on: August 03, 2019, 08:59:57 AM »
I etched you pattern twice, once on maple and again on mahogany. The maple (lighter) had
more distinction between the shades. My fixture is a 2.5W and the speeds were about 2500mm/min
with a 0.1mm resolution.

I did cleanup the white and changed the background from transparent to white (my software treats
transparent as black).

This image is a really poor candidate to evaluate laser etching performance. There are
a multiple of better test patters that are intended for calibrating speed, intensity, & backlash.
SARCASM - Just one more service we offer here.

philochard

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: problem with gray scale
« Reply #9 on: August 04, 2019, 11:49:02 AM »
Hello,
I partially solved the problem by sanding the wood with a grain of 240.
 The chosen image is representative of the final work, I want to build a brone acade style "bobble bubble".