I’m doing some PETG Flow Calibrations using CrealityPrint. Pass 1 looks like this. The -5, -10, -15 prints all look and feel (smoothness) about the same. The Zero is pretty good as well. How do you pick the best one?
While calibration is very important, flow rate calibration is generally far down the list of items that one needs to calibrate and your photo is a good example. Unless you’re trying to dial in perfection, zero is usually good enough. However, I will share a couple of tricks that I’ve found helpful.
-
Using the back of your finger nail, scrape across the ridges of each sample. Don’t look but listen and “feel” for roughness. That will help a lot.
-
The ballpoint pen trick. This only works with a pen that uses gel ink. It does not work with dark filaments unless you can find a white ink, very rare. Using a gel ink pen, draw a line across the grain. You will not only feel and hear the roughness but the ink itself will draw a visible line that will illustrate the roughness of the surface, smoother the better.
-
Your phone camera as a microscope. Using the macro function and at a fixed length, take a zoomed in photo of the samples in question. Then send the photos to a computer with a much larger screen and look at then side to side. It is important to take the shot directly downward so that you avoid parallax problems and it’s important to use identical distance and lighting. The variations in texture are a lot easier to see using a larger screen and macro mode which really allows much better detail than the average human eye.
2 Likes
Thanks for the detailed reply.
Have since done second pass and they nearly all look identical.
I have a pretty nice digital microscope that I will use to examine the prints,
These look too identical. Are you certain that you don’t have a static model. This doesn’t look like the flow rate was changed unlike your first example.
If you’re not seeing this gradient colors in your slicer before you send it to print, then somehow the GCODE got corrupted. It’s very easy to do.
1 Like
Yep the flow colours are identical 
will redo it.
Just checked this and while the pass 1 slice shows a clear change in colour between 20 and -10 (like your photo), the pass two sliced colours shows only a very slight change between the 0 and -9 panels
Thanks That’s a great set of tips. I have a hard time eyeballing this test too. I’ve been using the Fluidd numbers from auto calibration instead. How do you feel the automatic test compares with the manual test?
Got the digital microscope out and in the photo I show the 0, -2, -5 and -8 layers. Interesting to be able to see more and more underneath the top layer as one goes to increasingly slightly lower flows. Me thinks I need to explore the positive side of zero a bit more. Pity I chucked out the pass1 layers - must do them again and get them under the microscope.
