Rastering small details | in-depth trial-and-error


#1

I posted previously about etching a detailed, small design on cast acrylic. I eventually found something suitable thanks to off-focusing, but not quite the quality I had on an Epilog/Universal. I have another small-detailed design for a different material and can’t seem to meet my quality requirements.

I’ve troubleshooted raster quality for hours, it seems like the GF doesn’t have the raster quality of other machines I’ve used :confused: I hope it’s just some settings I can toggle to fix, but it is looking bleak.

Material: Rowmark Lasermax 1/8"


bottom right --> engraving from an Epilog cutter
the rest --> my attempts at achieving the same quality.

What’s wrong:

  • The border around the left logo is spotty on the vertical parts.
  • The “play” looks spotty as well.
  • The texture is not smooth.

The art is 5mm tall, created in .ai and loaded in as a .pdf.

Settings I tried to vary:

  • Speed --> kept at 1000
  • Power --> 15 was OK, 30 was deep and sometimes erased details, ~10 was too light and didn’t burn off the gold sometimes.
  • lpi --> kept at 340 (too much = overlap, is what I’ve gleamed)
  • Off-focusing --> .18", tried 0.2" and on focus but nothing seemed to improve

Other troubleshooting steps I tried:

  • Trimming down the image by adding a white inner stroke, etc. etc.
  • Scaling everything by 120%, didn’t improve it that much
  • Scoring the border, “TM”, and small details. It ended up cutting through the material! Even at 3 power and max speed!

I’m pretty tired of this, so maybe I just have to tweak the design of the whole piece and stop struggling with tiny rasters. Tomorrow I will explore some more off-focus distances, try scoring again.


#2

Don’t give up. You’ll get a response that will guide you. I haven’t focused on that area, but I have created sharp edges in plastic, so I’m a bit surprised at your trouble getting detail. Sorry that I don’t have your answer.


#3

Engraving some wooden hangers that have a curve in them, I experienced a similar look to your efforts due to the target surface being slightly below the focus of the beam.
When the surface was correctly in focus the details were razor sharp.
Got a picture of an attempt that is correctly focused?


#4

Slow your speed down. I did some tests with very tiny engraving on clear acrylic and running at 300 gave me more detail than running at 700.


#5

One of the logos in the included pic was correctly focused at 0.125". The material does feel slightly thicker than the cast acrylic, but I don’t have a caliper to check (and the manufacturer says is 1/8")


#6

I agree. I understand the desire to go to max speed but I don’t think that it’s the best idea if you’re looking for the best quality.


#7

A caliper is a must have for this work. You can get a decent one on Amazon for cheap. An accurate measurement is required for setting the focus.


#8

Thanks for all the advice. I previously could go super fast and didn’t need a caliper, but I guess the machine was just more robust/I was more lucky than today with my GF.

I will be trying at 300 speed and toying with the focus distance for now! I think I can pick up calipers when I run some errands later


#9

It will auto focus for you as long as you don’t override the default setting for each operation. For dual layer acrylic my settings are 350 power and 15 speed, no masking


#10

I had some success by scaling the original image 120%, adjusting some of the vector art, going at 300 speed (lowering the power too), and focusing at 0.22" instead of 0.125"!

I forgot to pick up some calipers, but want to see if it’s actually thicker than the cast acrylic I found de-focus settings for before.

The texture is still not great, I wonder if there’s anything that can be done about that.


#11

Here are a couple of things that might help.

When you’re working at those really small sizes, make sure you have a high resolution raster file. You can tell a lot of difference between 300, 600, and 1200 DPI. Your rasters look like 300 DPI or less.

Also, never score on the 2 tone acrylics. Score and Cut are equivalent.


#12

Here’s an example of different input resolutions vs output resolutions:


#13

If you meant DPI: my files are top-quality. I can zoom in and see everything super crisp in the .ai and .pdf formats. (For .svg it was distorted, so I stopped using that). For example this is 6400% zoom (still no pixelation, so I assume the PDF preserved the vector formatting)


super crisp

edit:
However, it looks like absolute crap when I load it into the GFUI. I thought that was normal. Remember this image is very small… like 0.25" tall and 1" across after I up-sized it.
Capture

If you mean LPI on the GFUI: I was under the impression higher lpi doesn’t equate to higher resolution because the burns start to overlap. I’ll try something at 600 and 1200 lpi just to check.


#14

Did you rotate it at all?

I recall a bug where a rotated raster graphic will go garbage in the GFUI.

But it doesn’t happen in Corel so I don’t have the details. I think it has to do with the source program maintaining the original position and modifying its attributes with a rotation value that the GFUI doesn’t handle well. I believe the solution was to copy or resample it and paste the result (& delete the original) before saving and loading into the GFUI.


#15

Nope, didn’t rotate it. This is at like maximum zoom in (1000%), the image is really tiny. There’s not really a good feel for it in the images, but if you zoomed in 1000% on your GFUI is everything crystal clear? Maybe I should try another browser (using Chrome on Windows 10)


#16

Right, those are vectors. Make that a high DPI bitmap then use the engrave setting on the GF and see how that comes out.


#17

I rastered to some insanely high dpi (1355) on Illustrator, saved as PDF, loaded in, got this. The random dots remind me of the texture that I have issues with.


#18

This makes me think there is something funky with your file. Maybe upload it here so that some of the experts can take a look at it.


#19

vector.pdf (783.9 KB)
rastered.pdf (767.9 KB)

Here we are, thanks in advance for help!


#20

I left it as a vector and just played around in AI a bit. Here is both the SVG and an AI file (latest CC format)

Pokemon Vector.zip (749.5 KB)

Pokemon%20Vector

I haven’t tried it yet, but it should engrave fine. I separated the colors just because. No real need. I think the biggest change other than grouping by colors was making a compound path out of the graphic inside the box.