How perfect does the calibration circle need to be?


I spent hours trying to dial in the circle test.

At first the circle was shifted towards the front of the printer by about 1/8".
I downloaded the cross gcode and adjusted the x and y galvo to center that on the paper.
After that I adjusted and adjusted the pots and got it as close as I can, but it will not make a perfect circle no matter what. I can hit the top, bottom, right and left dead on, but then the top left and bottom right are sucked inside the circle. If I try to adjust it out there, then it just pushes outside somewhere else.

Is there a such thing as perfectly following the line?
How far can it be off, or do I need to do something else?

I am afraid this is not going to make very accurate parts.




can you upload a picture of it?
i’m assuming that the paper is flattened



Hope this makes sense. The top left is where I cannot even get it on the line when I do have it on the line everywhere else. The bottom right I can tell is towards the inside, but I can get it pretty close. This is hours of tweaking and it just does not seem like it is going to make a better circle.
I started by adjusting the X to the center of the paper by moving the X and Y galvos. When I started the whole circle was about 1/8" off the circle towards the front of the printer.



So I got the circle close and went ahead and printed the pillars. Guess which one did not work. The side where the line was inside of the circle edge. I did get it as close as I could to the line all way around though with further adjustment. However it is not perfect.

So, I guess this means it is not close enough on that corner, or too close? There is a post portion stuck down there to the PDMS in the resin.



Here are the results from the first pillars. It seems pretty straight forward on the instructions what to adjust, except the one that did not form.
Judging by the other measurements it looks like it was the largest measurement. I am guessing it was too far away to stick?



Okay, This is about the 6th try. Almost got it where I want it. Hopefully the next print will be the one. I ran out of time tonight.
Then I should probably clean the vat and adjust to the circle again to make sure the pots are on the money.
I do think the calibration instructions should include a tolerance for the first circle check though. Maybe something like… no more than +/-1 to 1.5mm off the center of the line on any part of the circle with top, bottom, right, and left adjusted as perfect as you can get them with the advanced calibration.
If it said that, I wouldn’t have even posted this :slight_smile:
However, I think the circle should go back and be checked again after you have the level. I am guessing it will be a little off now and possibly tuned even a hair better.



I suggest you don’t touch that anymore. Your level is very good now.



that leveling is very good already. generally, as long as it is in 10.5 - 11mm you should be good
we want our users to have good print adhesion without putting too much pressure on the vat, so we recommended 10.6-10.9mm

for the circle calibration, you are also quite close. The rest of the calibration will be done via Asura



I thought the range was 10.6-10.8 according to the instructions? I was shooting for closer to 10.7. I already made one little tweek to try to bring them all down just a little more. I just ran out of time. I will try to print again tonight and see where they are at.
Then I will try to print the ring.



I couldn’t get much lower or closer to 10.7. When I tried to adjust it at all, then next print was missing two post, then when I tried to correct a little more only one post printed, so I adjusted all three back and got this.
I think this is as good as I can get. It must not be a “dial it in” to exact thing.
Maybe some vats can only go so low and that is as low as you can get them and then if you go any more you get no print?

I am printing the ring now. I can see it in there, so it must be working!