EDIT YOUR PROFILE HERE

Please or Register to create posts and topics.

Noise burns in white areas

So, been having some great experiences with the board so far!

I have ran into a small issue though when running a raster engraving.  On the light areas, it appears the laser is slowly building up then discharging in those areas.  (see images)

Any idea what could be causing this?

Uploaded files:
  • 29497314_10214918304093768_8161019216288284672_n.jpg
  • 29468684_10214918302613731_3907270974831067136_n.jpg

Hi this is noise from the picture. Make sure that the resolution of the picture matches that of the engraving selection. When you import pictures into inkscape, it sets it by default to 96 so change that to 380dpi in the preferences.

also you can try to run the engrave a bit slower to see if that makes a difference. I notice that there are very few grey shades in the picture which can indicate that you are running it too fast. Try various resolutions and speeds. 380dpi runs best at 700 or 800 while lower resolutions can be driven faster.

Cheers, Paul awesome.tech

I have exactly the same issue here. I just got my gerbil a few days ago and cannot get anything engraved without these black dots. I have made sure the default import resolution is 380 and set the engraving to 800, but they still remain. It makes the engraving of far worse quality that the standard controller driven by K40 Whisperer (also via Inkscape and the same photo, which was imported as the photo default that time). I've tried various settings (Speed, $30 etc. These affect the "darkness" of the engraving, but not the noise marks.) There is nothing on the image at all, even zoomed right in.

Even just using some fancy text from Inkscape directly to a raster does it. I've used Halftone, BW, Greyscale, all sorts of speeds and DPI but it's still there...

You can hear the laser when it does it. It's kind of "spits" and a mark appears. It occurs whether I use the raster plugin directly, or send the G-Code after it's been generated by the plugins.

Any idea's what could be causing it? It's spoiling the shine of the new controller....

Well, things get even more intereseting...

I started a brand new Inkscape (0.92.3 btw) doc, rather than one I used before with the old controller board. This was a simple B&W picture of text from the Internet and there are no random marks. Not one.... Weird....

More investigations needed here I think....

Hi FeeDeeUK, I noticed this when I copied the Aztec Calendar from Pininterest. It's a bad jpeg with some noise (grey spickles) but not too bad. When I use grey engraving then I get ugly black specks. So my hypothesis is that the png converter used in the plugin has a conversion issue when converting jpeg into grey scale png's. Jpeg converters are under licence hence we can't use them with paying for it. PNG is the free open source alternative.

The way we can get around is to take the bad jpeg into an open source graphic program such as paint.net and clean the white background (replace a white-greyish into true white). You can experiment with this because there are many options here. e.g. You can take an ink dropper and extract the colour and do a find replace. Save the enhanced file and run it again.

In the folder where the conversion file and png are saved, you can examine the converted PNG. Keep us updated on your findings.

Cheers, Paul awesome.tech

Another thing to test is the laser frequency. You can set this via $28 (0,1,2,3,etc)

PWM Laser freq Value PWM mode Remarks
244 Hz 0 fast pwm great engraving
61 Hz 1 fast pwm dither effects
1.9 kHz 2 fast pwm just b/w
15 kHz 3 fast pwm just b/w
Default 0 fast pwm Default mode
122 Hz 4 phase-freq correct great engraving
1 kHz 5 phase-freq correct just b/w
7.5 kHz 6 phase-freq correct just b/w
Cheers, Paul awesome.tech

Thanks Paul. I'll work through that. I have been having success when using non JPG source files, so you could be correct.

 

I may need to pre-process JPGs a bit first...

Forum Registration

EDIT YOUR PROFILE HERE