A350 3DP cube sizes off

Snapmaker 2.0
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SM2 A350 (Mdl80012) with Quick Swap kit with firmware SM2_V1.20.2_20240617
Luban V4.14 or Cura 5.10.0

Let’s start by acknowledging @Spaced - Precision is a never ending task or goal.

That being said, I’m not trying for high precision, just reasonable print jobs. My typical print is for jigs and artifacts to use around the house. I’m fine with a few bumps and some stringing. I’ve gone through the typical calibrations (@xchrisd @Hauke and others; thanks): bed leveling, extruder E-steps, flow rate with a 20mm cube, played with retraction and acceleration but could probably dial those in a bit more. I’ve done temperature towers but really haven’t seen anything better that 200 for most PLAs I use.

My last cube was 20.02 or 100.09%; I thought close enough. Walls were on the weak side 0.78 or 98.02% but for most of my stuff, I’m getting good enough results.

I just got frustrated, again, and started looking into the performance a bit more. I made a model in Sketchup with dimensions rounded off at 0.000 mm. The model I built was basically a bottle cap, but at 60mm outside diameter, with an inside diameter at 57mm; 3mm wall thickness. Upon completion, the outside was at the 60mm, but the inside was at about 55mm, and wouldn’t fit. I’ve seen this before and got annoyed,again.

I started playing around by making a model of various size blocks (think Califlower but different); 20, 40, 80 and 140mm with centers cut out at 10, 20, 40 and 80mm; again using Sketchup where I should be getting good measures. The results were from 100.4 to 103.2% of correct sizes. The inside sizes were 96.1 to 99,7% of correct sizes. The bigger the model, the closer to being correct, probably due to measuring error (digital caliper at 2 decimal places and 3-4 measures per measurement). Inside size is consistently smaller than the outside measurement. Using both Luban and Cura to slice (fast normal parameters), just in case. For the 20mm cube, I would have just changed the M92 XYZ parameters proportionally. In this case, that should affect both inside and outside, wouldn’t it?

Currently, M92 X403.00 Y401.00 Z406.00 B888.89 Current E233.40
(BTW - what is the B value for?)

The only think I can think of, the Sketchup STL isn’t translating correctly? I’ll have to dig into this one. But does anybody have any other recommendations on how to tweak this to get inside/outside measures better? Anything in SM that I’m missing?

Thanks

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@MarkJ Wow going back in the post history for that one.

I think i have to updated it. “Precision can be a never ending task or goal. The user decides when enough is good enough.” But yes it can be a rabbit hole. A very deep one at that. With that being said. The file and instructions that got me to the point where i was “satisfied” with the snapmaker was the calibration califlower by Vector 3D Califlower Mk2 – 3D Printer Calibration & Skew Fix

Yes its a paid part, but its a really well thought out part and process. You get the current stl file, i have gotten the latest version updates for free since i bought it, and you get an excel calculator worksheet to help you define the require corrections.

The time it will help you save is worth the 14 pounds i think he is asking for it. 100% recommend.

But personally i have gotten spoiled by the $100K Stratasys system i have at work now. Snapmaker has its uses still, but i was mainly printing for my job. Which inspired them to bring Additive manufacturing in house. Which is good / Great. but at the cost of the snapmaker is not getting allot of use currently.

I found i could get square or lined shapes to be nice and accurate, never really got a true round. Enought to work for bottle cap size stuff but could always find a little off with a caliper. Again Good enough is what you define for your use and equipment. I think if i really wanted to dive back into it i could maybe half my error again, but i know im at the point of diminishing returns now that its not required to attempt to do any engineering work. My at work stratasys system, If it had even 1/5 the error that the snapmaker has i would be calling service immediately. But its a different beast.

As for your specific ending question, if it really needs to be accurate, you kind of have to pick what side you want the accuracy, inside or out side. or flip it for each piece. (an advanced option in must slicers) But take a look at the link you may find its a skew issue or something else.

Other wise i would take a second look at your extruder settings / calibration, or elephants foot. one recommendation was to make a cube off of the build plate to negate all chance of first layer or elephants foot. Think two hollow boxes, upside down on the print bed so the part you want to internal stack is the top of the print.

GL

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Its for the axis of the rotary module.

I don’t care much about dimensions but I use (s3d) slicer “inner holes” or “outer holes” compensation to get it fit.
Elephant foot could have a great bad impact, I agree with @Spaced.

I’m wondering why your steps of x and y are not the same but maybe I could better imagine with a drawing :thinking:.

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Thanks for the information on the B parameter; I couldn’t find it specifically in the SM G-code nor the Marlin G-code. I thought that was what it was based on a vague previous post but wanted to be sure.

Elephant foot should only be on the bottom based on the squeeze from the plate; correct? I thought of that but I always measure high on any cube or other print job to make sure I’m not getting that in the equations.

I downloaded Vector 3D Califlower and will try that and see where my XY parameters are at.
I’ll also look at S3D; looks like a lot in there.

Thanks @Spaced and @xchrisd.