Step 14.11 — Caliper the cube against the Prusa-printed one¶
Step 11 of 36 with a helper · Chapter 14 — Calibration and tuning
(no image — see text)
Parts:
- both cubes · already on the bench
- digital caliper · tool
Do: Measure both cubes at mid-height, not across the first layer: X, Y and Z, recorded in the table below. Same STL, same filament, same nominal settings; the only variables are the two machines.
Check
Both cubes inside tolerance: X and Y within ±0.15 mm and Z within ±0.10 mm of 30.00 mm, and within 0.15 mm of each other.
Helper Writes each caliper reading into the comparison table as the adult calls it out.
What you're looking at
A caliper on a 30 mm cube is the cheapest whole-machine test there is. Mid-height is the honest place to measure: the first layer is squashed and the top can bulge. The difference between the X and Y readings is a squareness proxy.
| Measurement | Nominal | Prusa Core One+ (B00 reference) | Voron 2.4 350 (this print) | Accept | If out |
|---|---|---|---|---|---|
| X, mid-height | 30.00 mm | ______ | ______ | ±0.15 mm | see below |
| Y, mid-height | 30.00 mm | ______ | ______ | ±0.15 mm | see below |
| Z (total height) | 30.00 mm | ______ | ______ | ±0.10 mm | over → first layer under-squished; under → over-squished |
| X at first layer | — | ______ | ______ | within 0.15 mm of mid-height X | elephant-foot compensation wrong; adjust in 0.05 mm steps |
| X − Y (squareness proxy) | 0.00 mm | ______ | ______ | ≤0.10 mm | a persistent X−Y difference on the Voron is a gantry-square problem → Ch 06b |
| Corner snap test | — | pass/fail | pass/fail | must not delaminate along a layer line | chamber too cold or fan too high |
Two honest expectations before you start chasing numbers:
- A size error is not an axis error, and not a flow number. Ellis: "don't mess with your
steps_per_mm/rotation_distance. Deviations are almost always from material shrinkage, bulging, layer inconsistencies, etc, NOT issues with your axes." The extrusion multiplier is set by eye on a top surface at 14.19–14.20, never from these readings, and Voron parts need no compensation beyond that tune. X or Y out of ±0.15: confirm the slice had shrinkage and XY size compensation at 0, finish 14.19–14.20, then measure again. Never negative XY compensation: it wrecks every bearing fit in the machine. src - A Voron-vs-Prusa difference of ~0.1 mm is chamber, not calibration. The Voron runs a hotter, more uniform chamber than the Core One+, so its parts shrink slightly differently. Both being in tolerance matters more than them matching each other.
Good stopping point · ~15 min since the last one
the Ch 13 cube is calipered against the Prusa-printed reference and the numbers are in the tuning log. No config has changed; the multiplier is set later by eye, at 14.19–14.20, not from these numbers.
Source: Ellis' Print Tuning Guide — extrusion multiplier · Voron-2 STLs/Test_Prints/