Print Accuracy

[bdejong11129]

So, my Voron has been showing signs of not being dimensionally correct.  You can see this in the image below where the space for the nut appears to be collapsed. It is squished, shorter than it should be.  All dimensions are smaller than what's shown in the cad drawing. 

Adding some details that I should have had.  This is from a V2.2 voron. I am going to add some more pictures and dimensions. 

Where do I start?

Edited April 15, 2023 by bdejong11129

[smirk]

I'm guessing from the layer lines that you're holding the thing in the orientation that is was printed in? Although perhaps upside down, as the top of the model looks like it was attached to the bed? It's perhaps my eye-sight, or the angle, but the whole thing looks a little more squished at one end.

I would say things to check would be (in order of getting harder/worserer/more fiddly): cooling & extrusion multiplier, extruder calibration, z-belt tensions (it's the 2.4 you're using?) to make sure it's "sufficient" but above all consistent across all of them, finally gantry and frame squareness.

[bdejong11129]

I took the part this morning and test fitted the 3mm nut and it appears to fit correctly.  Not too loose and not too tight.  It still visually looks skewed but it's very difficult to measure with the calipers given that its plastic and the calipers for inside measurement are sharp.  So, I drew up a quick flat calibration square.  30mmx30mmx5mm with a 1mm fillet.  

 

Printed this with the voron part settings, took it off the build plate and measured it. Now, this is where I made the first mistake, I didn't note the x and y dimension orientation so back to printing it again and this time I will mark it.  I did this in Prusa Slicer and used the add text and added an embossed X along the X axis. 

Second time was the charm.  Measurements came out to the following:

• Z = 4.95mm
• X = 29.9mm
• Y = 29.8mm
• Auto Z Offset  = 1.408mm

One thing I did notice is that the bottom fillet is non-existent.  It is visible on the top layer, but the bottom is flat as a pancake with nice sharp edges.  I am using the euclid probe and the protoloft Klipper_Z_Calibration routines to auto set the Z.  I also then noticed that at some point in time I enabled Elephant Foot Compensation in Prusa Slicer so back to re-printing.  I removed the value there and ran it again.  I just want a pure print at this point in time. 

Back to printing, here is what I learned.

• Removing the Elephant Foot compensation (set prior to getting the Euclid and Auto_Z working) brought the bottom fillet back.  
• Confirmed that the extrusion multiplier is actually very accurate.  If I set it to 0.95 I lost very close to 5% and when I set it back to 1.0 I gained it back.
• The Auto_Z works very well but it was here that I started to see some variation that I just couldn't explain. 
  • There was a very small but noticeable change in the readings even though the bed was hot and stable for hours while doing these test prints. 
  • I then turned my attention to the print head and its mounting. 

This is where I found that the print head had a noticeable and very tactile, shall we say "looseness" to it.  If I griped it on the top and push to the rear and back, I could watch it move, almost pivoting on the linear rail mount. When I built my Voron I followed the advice of several people that were building them and only install the single rail on the front of the x-Axis rail and did not install the bottom carriage rail.  This appears to be a mistake.  

I did several prints back to back with the same settings and got variable results. I also noticed this in the values from the Auto_Z routine.  Now I know why. 

Just so happens that I had a StealthBurner kit that I have been printing and assembling for the past month just waiting for the right day.  Today was that day. Its mounted, along with the beefier 12mm rail and after a few hours of readjusting all the stuff for Euclid, my nozzle cleaner and surprise, the gear ratio of clockwork2.(that one set me back a few hours).  We are printing our first test print.  Oh, and while I was at it, I made a few other test prints that have common 3mm, 5mm holes and a nut opening for a 3mm nut.  Both in horizontal and vertical formats. Always looking for excuses to continue my Fusion360 education. 

Now I am going to run a few bed tests specifically the bed mesh and Auto_Z to see if the repeatability of the probing improves. 

 

[bdejong11129]

Well, forgot how much "fun" tuning a printer can be.  Sarcasm X1000.    I forgot about all the towers and squares you have to print to tune things in right.  Then the bed adhesion issues while getting things running right.  Good thing I had all last night and today.  I think I am all but done. 

Other than the odd first measurement issue with the Euclid probe, I think I have it back running as it should. 

You know what will drive you mad?  Forgetting to reset all the speed settings after printing the pressure advance cube.  That cost me a few hours of WTF printing.   It did make me take another look at Super Slicer.  I love the automatic "mouse ear" brim settings.  I may have to move to SS for my Voron. 

[mvdveer]

1 hour ago, bdejong11129 said:

I may have to move to SS for my Voron. 

Used to use Simplify3D for the Enders running Marlin firmware. Started to build Vorons and switched to Superslicer - never looked back. Must admit it was a steep learning curve and I am still learning something everyday. I do not think that after 18months I even understand a tenth of the capabilities and tweaks. Luckily there are profiles you can copy as a start point and tweak from there (Ellis pif profiles as an example)

[bdejong11129]

Ran off a few prints last night after getting everything set and there is something to the slicer for sure. 

I am going to test this tonight to confirm but it appears that Super Slicer chose much different paths and the parts are nearly perfect. 

When I used Prusa Slicer, which SS is supposed to be based on it printed them differently. Printing 2 copies of the idler supports and PS printed them with different paths.  Will post pictures tonight.

[claudermilk]

SuperSlicer is indeed a fork of Prusa Slicer. It lags in adding featured from the latest Prusa Slicer, but adds a whole lot of additional levers to tweak your settings.

I remember initial tuning took forever. My latest re-do of it moved much more quickly--this time aside from experience, I went straight to the Ellis Tuning Guide and stepped through the process. I got back to a working tune very quickly.