So often I've dialed in my extrusion multiplier and pressure advance thinking I've got it set just to find out that my printer fails a tolerance test. I'll then fiddle with my extrusion multiplier thinking that was the issue just to find out that it was because I had my pressure advance set to high or vice versa.

So, I've designed these tolerance tests to help figure out if it's an extrusion multiplier problem or a pressure advance problem. The “Open” test has a part of the outer cube that is left open, and when you set your seam alignment to “Back” it will print the inside cylinder with the seam towards the back. Betting settings this way the test will not take into account your pressure advance at the seam, it will only check for clearance between the outer cube and the inner cylinder, and this is only affected by your extrusion multiplier.

The “Closed” test encloses the whole inner cylinder, this will take into effect the pressure advance settings at the seam. So if your print passes the “Open” test, but fails the “Closed” test, then you need to look at your pressure advance settings. I found that when my tests passed the “Open” test but failed on the “Closed” test my pressure advance was too high. After lowering my pressure advance my printer would pass both tests.

So in a nutshell the procedure goes like this.

1. Set seam settings to “Back”.
2. Print the “Closed” test.
3. If “Closed” test fails, check and adjust extrusion multiplier (flow ratio). Reprint the “Closed” test and check again.
4. If “Closed” test passes, print the “Open” test. If the “Open” test fails, check and adjust pressure advance settings. Reprint the “Open” test and check again.
5. If the “Open” test, and the “Closed” test passes, your good to go.

I did include a 0.1mm tolerance test but you might find it difficult to actually get that test to pass, and this is perfectly fine. A tolerance of 0.2mm is the norm. I'm just a little OCD about trying to get my printer as tuned as possible. Honestly, I've not been able to achieve a pass on the 0.1mm yet but I love having something to strive for!

The profile that I have included with this model already has the seam set to “Back”. All you need to do is just delete the tests that you don't want to run and your set.

Also, keep in mind that having a Z offset to close to the bed can effect this test.  A Z offset that is to close can give your print an elephant foot effect, basically the filament is squished to much and can force the first few layers between the inner cylinder to merge with the outer cube.   So if after printing a test you can see a gap between the cylinder and the cube on the top but you do not see a gap on the bottom check your elephant foot compensation settings in your slicer or raise your Z offset by 0.01 to 0.05mm and start the print again.  You can also pause your print after the first layer is printed and look for a gap between the parts on your first layer, if you don't see one, again check your slicer settings or raise your Z offset a little. 

Note: I've noticed that when printing the “Closed” test the slicer will put the seam of the outer cube on the inside of the cube, this is right up next to the inner cylinder, this can still make it a little difficult to separate the two parts, but if your pressure advance is set correctly, it can still be pushed out with a little bit of force. Bambu Studio and OrcaSlicer will only allow for one seam setting when the models are grouped as parts, it's only when the models are split into separate objects can they have different seam settings.  I have added a profile that has the models separated into different objects and the outer cube of the “Closed” tests now have “Random” set for seams, this way the seams of the inside and outside parts do not line up.