Improving print quality


#1

I’m wondering about other types of things I can look into for finer resolution prints. I have been playing with the belt tensioners a bunch, but was wondering about other tweaks that will get things looking even sharper.

So far the lowest I’ve gone is .1 mm print height, I’d also like to try lower than that. Is there a lower limit (on layer print height) for what the wilson can reliably do?


#2

I try to keep my layer heights (on wilson II) even multiples of 0.04mm. That’s because the lead screws I’m using are 4-start, 2mm pitch, and the steppers are 1.8° per step, so (math time!) —

2mm * 4 = 8mm per turn

360 degrees / 1.8 degrees = 200 steps per turn

8mm / 200 steps = 0.04mm/step

Now, you can actually move at 1/16th that resolution (.0025mm) because of the microstepping of the stepper drivers, but it’s generally considered good practice for the Z axis to keep to full steps, because that’s where the motor stator wants to sit. So for example, if you are at .1mm layer height, that’s halfway between 2 and 3 full steps, so you may get better results at 0.12 than you do at .1.


#3

Ah, good tip! I suppose using Cuda, I’m going off the suggestions of the software, hence the .1mm. Will try .12 or 0.08 at some point in the future (you know, when I have tons of time on my hands).


#4

Also, when you go to really small layer heights, calibrating the esteps of your machine becomes more critical - that’s the number of steps that the extruder stepper motor turns for each mm of extruded material.


#5

Is there a link to a tutorial on how to do that? (calibrate esteps)


#6

Here’s a short video I did to show the procedure for calibrating esteps:


#7

That was awesome! Thanks for making that video.

Do you do that on all of your production machines? Or is it ok to ignore for the larger scale parts?


#8

I will do it at least once when putting a new machine into commission, but rarely again (although I probably should from time to time). It seems like the MK7 drive gears are pretty consistent, and I always end up somewhere between 102 and 105 steps/mm.


#9

Just completed this procedure. Turns out my machine wasn’t off after all. The esteps was set to 105, I needed to adjust it down to 104. It turns out that my compression screws were WAY too loose. After tightening those down, my prints got a lot better, esp the first layer.

Are there guidelines for how tight those should be?


#10

I’m not sure how to specify that, other than “pretty tight”. I guess a guy could measure the compressed length, but if you use a different spring than I use, that wouldn’t necessarily be right either.


#11

@mjrice Wouldn’t this depend on the Z motor being on a cog point at Z print start? And unless you don’t use bed leveling, Z will (likely) vary all over the print. Am I missing something?


#12

I’m glad someone asked, I wondered the same thing!


#13

Wow – glad I saw this video. I should have thought to do this when I build my Wilson II. I’ll go back and follow this procedure. Thanks!