Scale
All manufacturing processes have some degree of tolerance and constraints at play. The DLS™ process is no different as it deals with the dynamics of printing. One such dynamic that affects the accuracy of parts is shrinkage.
The printer software automatically compensates for shrinkage with scale factors to suit the majority of parts. The user can both view and adjust scale factors if needed to dial in tolerance with the software's scaling features.
This lesson will show you what tools you have available inside the Printer UI to scale your part as needed.
The printer software provides two mechanisms for scaling your parts. Each serves a different purpose and behaves slightly differently.
| Scale | Correction Scale |
|---|---|---|
Primary Use | Large scale changes | Fine tuning scale changes |
Default Scale | 1:1 no automatic scaling | Pre-applied scale factor per resin and geometry* |
Amount of Scaling | Unlimited | 0.7 - 1.2 |
Axes of Scaling | Imported model axes | Current orientation axes |
Effect of Scaling | Regenerates supports and clears part labels | Leaves supports and part labels intact** |
* Only applicable resins make adjustments per geometry.
** While supports and part labels remain when adjusting Correction Scale, users should inspect your build and parts carefully to ensure you have achieved the desired results.
Scale
Correction Scale
- Resin must be selected to apply the correction scale
- Select resin - note the changes to correction scale
- Geometry-dependent resins will adjust the correction scale when the model scale is changed
All resins receive a correction scale factor to account for shrinkage due to cooling and solidification.
Some resins are also susceptible to shrinkage due to mass loss, which occurs during the thermal curing (baking) step that 2-part resins use during post-processing. Within this category of 2-part resins, some materials are particularly susceptible to the effects of mass loss. These are the resins that receive a correction scale factor based on the average wall thickness of the part geometry. 2-part resins not listed below are minimally affected by mass loss and receive a scale factor that does not change based on geometry.
- EPU 41 Black
- EPU 43
- EPU 45 Damping
- EPU 46 Black (& Soft, Extra Soft)
- EPU 46 Coloration (& Soft, Extra Soft)
- EPX 82
- EPX 86FR
- EPX 150
- FPU 50
- RPU 70
- RPU 130
- SIL 30
Note that compensation for mass loss is based on average wall thickness. Parts with variable wall thicknesses will see some variation in accuracy across the geometry.
Parts are scaled individually with correction scale.
If you use non-Carbon software to prepare a full build and import that as a single STL, Carbon will interpret your build as a single part rather than as multiple separate parts. Correction scale will therefore apply to the whole build rather than to individual parts, potentially affecting accuracy.
If you are unsure whether Carbon is interpreting an uploaded file as one part or many parts, check the Part List on the left-hand side of the UI to see if there is one or many parts listed.
Downloaded parts will be at their original model scale.
The mechanism for applying corrective scaling changed between software releases v1.38 and v1.39. Please read below for more information.
Scale factors applied automatically to your prints may be different between ≤ v1.38 and ≥ v1.39. The degree of difference will depend on the resin you are using and the part geometry, with thin-walled parts seeing the greatest difference, improving accuracy in ≥ v1.39 for applicable resins.
| ≤ v1.38 | ≥ v1.39 |
|---|---|---|
Scaling Mechanism | By Slice* | Per Part / STL Model |
Scaling Applies | Equally to all parts within the build | To each individual STL |
Scale Factor | Per resin | Per resin and geometry** |
Accounting for Mass Loss | Scale factor assumes 7.5 mm average wall thickness for all resins, except RPU 130 which assumes 2 mm wall thickness | Adjusts scale factor based on the part's average wall thickness** |
* Slice count may vary between projects on ≤ v1.38 and ≥ v1.39. **Only applicable resins make adjustments per geometry.
Scale Factors for Accuracy ≤ v1.38
Accounting for mass loss in ≤ v1.38 required users to manually apply an additional scale factor per resin for their part's average wall thickness.
For ≥ v1.39, the table below is a conversion of the old scale factors if users wish to match previous recommendations rather than use v1.39's automatic geometry-based scale factors. Note that this will provide a close approximation, but the scale factor will be applied to the part rather than per slice (as was the method in ≤ v1.38), so results may contain slight variation. If you wish to preserve an old project exactly as is, see Backwards Compatibility below.
Wall Thickness (mm) | EPU 40 | | EPU 41 | | EPX 82 | | FPU 50 | | MPU 100 | | RPU 70 | | RPU 130 | | SIL 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| XY | Z | XY | Z | XY | Z | XY | Z | XY | Z | XY | Z | XY | Z | XY | Z |
0.5 | 1.020 | 1.027 | 1.025 | 1.030 | 1.035 | 1.028 | 1.040 | 1.029 | 1.034 | 1.003 | 1.040 | 1.035 | 1.057 | 1.052 | 1.059 | 1.060 |
1.0 | 1.017 | 1.024 | 1.022 | 1.027 | 1.025 | 1.018 | 1.020 | 1.009 | 1.010 | 1.001 | 1.015 | 1.010 | 1.042 | 1.037 | 1.039 | 1.041 |
2.5 | 1.014 | 1.022 | 1.020 | 1.025 | 1.014 | 1.007 | 1.015 | 1.004 | 1.009 | 1.000 | 1.005 | 1.005 | 1.020 | 1.015 | 1.023 | 1.025 |
7.5 | 1.004 | 1.012 | 1.010 | 1.015 | 1.010 | 1.003 | 1.015 | 1.004 | 1.009 | 1.000 | 1.009 | 1.009 | 1.009 | 1.004 | 1.011 | 1.012 |
Backwards Compatibility
All projects created in ≤ v1.38 or prior will remain in their previously scaled state until actively upgraded by the user. Legacy projects will be flagged with a yellow warning dot on the Scale tab when opened in ≥ v1.39.
To Retain Old Scaling Recommended for projects with validated accuracy.
- Do nothing
To Upgrade Scaling Recommended for projects in development.
- Duplicate project to retain a copy of old scaling conditions
- Click CORRECT PROJECT SCALE button
- CTRL-Z (CMD-Z) will undo the upgrade immediately after if done by mistake This is a temporary undo condition. The upgrade cannot be reverted going forward.
Upgraded projects may yield parts slightly larger or smaller than they were previously.
- The part volume may be different (the printed part may use slightly more or less resin than it did prior to this new part scaling approach)
- Print time may be different (the project may print slightly faster or slower than it did before due to changes in the part dimensions being printed)
- Parts that are located close to the edge of the platform area may no longer fit on the platform as laid out (eg, if the newly scaled part is slightly larger); you may need to adjust the layout of your build
Projects created on ≥ v1.39 and then opened or queued to a ≤ v1.38 printer will not receive the newer correction scale factors. Projects will be scaled per the software version on that printer.
Be careful to keep all printers in your fleet updated to the latest software.