GF skips a line?

Last night I was doing some deep engraves (essentially solid black to engrave as deep as I could) and when watching the engrave, I noticed that sometimes the head would move and the laser didn’t fire. The head moved horizontally right to left and fired most of the time, but every once in a while it’d do a pass and the laser didn’t fire. I didn’t appear that the carriage moved up, or away from the front when these happened, and it never paused nor left a line of un-engraved material. Everything came out looking fabulous (exactly what I expected / wanted).

My design is a solid hatch of a pine tree outline Frame Tree Solid.pdf (81.4 KB) created in AutoCAD printed to scale in a PDF. That’s how I do 98.73421% of my cuts / engraves.

The only thing I could think is it took a break for 1 pass to cool, but it’s never had cooling issues, nor did it stop and tell me it was cooling.

Is this “normal”?

I guess I’m really confused as to why it was designed that way when you wanted a solid fill/solid engrave?

If I were to guess, which I guess I am doing, it’s because a lot of those hatches are actually overlaying one another, but, the beam width, power, speed, and LPI were enough to where you didn’t actually notice a gap in the engrave itself.

If you have vector fills overlaying one another, it will effectively knock the overlaid area out.

2 Likes

WOW - that makes no sense - it’s a SOLID fill from AutoCAD. In AutoCAD that doesn’t exist.

I’ve never had that issue before - that’s obviously it - should have looked at the PDF closer when I created it. Totally weird that it’d plot that way to a PDF.

1 Like

No idea. I was confused also :slight_smile: it has a lot going on in there as far as paths.

It’s not something you can tell by just looking at it - that’s the outline view in Illustrator that just removes all stroke, fill, and appearance attributes and just shows the path lines.

Totally weird. I can see the “lines” in the solid hatch when I plot to PDF. Going to try exporting it differently.

And it’s one single hatch - selecting the Pline as the boundary using a solid for the hatch pattern. Totally weird.

Bottom line - I’m making picture frames engraving this into cedar, and it’s coming out awesome, but it’s still weird.

6 Likes

Yeah, that’s crazy! It’s really weird how it was saved with an open outline and all those separate lines. Glad you got it working though and that frame is going to be stunning!

1 Like

Autocad is a print system when used that way. If your pen plotter was to do a solid area. the paper would be soaked, so it makes a Hatch. If you hand the GFUI a solid area it makes a series of lines at so many per inch. If you hand the GFUI a hatch image It will make a hatch of the hatch.

So if you want the Autocad hatch, you leave everything as vectors, then it will do the hatch as Autocad’s hatch which is a lot more capable than a series of horizontal lines, If you want to use a photo engrave then Autocad needs to have a different kind of object that is a solid and not a polyline with a hatch

2 Likes

If I were to hazard a guess… the step resolution of the carriage Y stepper motor and the LPI of your engrave do not share an integer factor in common, so over a long enough traversal range there is quantization error. The motion system has to skip a line every once in a while to compensate.

2 Likes

Sorry to hear about the trouble with running a print using a PDF generated by AutoCAD. Do you have access to Adobe Illustrator or similar design software? Depending on the software you have, there might be a fairly straightforward workflow to export a .dxf from AutoCAD, import it into a separate program and then create an SVG using the .dxf outline which will be free from any skipped lines.

1 Like

It’s been a little while since I’ve seen any replies on this thread so I’m going to close it. If you still need help with this please either start a new thread or email support@glowforge.com.