If printed parts are shorter or taller than expected, adjust your Fuse 1 generation printer settings to achieve optimal Z-axis dimensional accuracy.

If dimensional accuracy is a concern:

• Place models in the center of the build scene. Parts printed around the edges of the build volume may print taller than parts printed in the center.
• Orient parts with larger cross sections along the X/Y axis. Parts with larger cross sections may print shorter than parts with smaller cross sections.
• Place parts at the bottom of the build volume. Parts located at the bottom of the build volume are more dimensionally accurate than parts printed at the top.

To determine Z-axis dimensional inaccuracy, measure the printed part after it has been printed, cooled, and media-blasted. Use a set of calipers to measure the length of the part and compare it to the target dimensions of the model to accurately calibrate your Fuse 1 generation printer.

The following troubleshooting is for Z-axis dimensional inaccuracies. If your printed parts are showing X/Y dimensional inaccuracies, contact Formlabs Support or your authorized reseller about X/Y Scaling for your Fuse 1 generation printer.

1. Print, cool, and media blast your test print.
2. Fully close your caliper’s jaws. Zero the calipers before measuring your printed part. Check the zero point throughout your measurements to ensure no measurement error is being added into the calibration.
3. Measure the length of the part printed along the Z-axis of the printer. Write down the value.
4. Compare the measured length to the target dimension in the CAD model.
1. If the part length is greater than the target length by more than 1%: There may be a mechanical issue with the printer’s Z-drive assembly.
1. Follow the steps in Replacing the Z Motor and Drive Assembly [EN] to Step 15. Manually rotate the Z drive coupling. If the Z drive coupling is not securely attached to the motor shaft, purchase a replacement Z motor drive assembly and replace the Z motor drive assembly.
2. If the part length is smaller than the target length by more than 1%: The print bed temperature may be running higher than expected and parts may show signs of dimpling or pitting.
1. For parts printed in Nylon 12, tune the bed temperature.
2. For parts printed in other powders, contact Formlabs Support or your authorized reseller.
3. If the part length is within 1% of the target length: Place the model in the center of the build volume and print again. If there is a noticeable discrepancy between printed parts due to build locations, refer to the optimal print settings for your printer and powder.

To minimize Z-axis dimensional inaccuracies and variability between printed parts, Formlabs recommends using the Print Settings Editor in PreForm to modify your printer’s parameters.

1. Update PreForm to version 3.41.0 or later.
2. Create a custom print setting based on an existing Formlabs print setting. Check the support article Choosing the right print setting (SLS) to see if a particular print setting has better Z accuracy for your material.
3. Set the Z Correction Factor parameter based on the measured length of the part along the Z-axis and the current value of the parameter.
   • New Z Correction Factor = Current Z Correction Factor * (desired part length / measured part length)
4. When you are done editing your custom print setting, click Save. Your custom print setting is saved and the My Settings list appears.

To print with a custom print setting:

1. Import, orient, and support your models.
2. Click Edit Job Setup. The Job Setup screen appears.
3. Select a printer, material, layer thickness, and your custom print setting, as you would with a Formlabs print setting.
4. Click Apply.
5. Click the orange Upload Print button and upload your print job to your printer.

If your parts continue to be taller or shorter than expected, contact Formlabs Support or your authorized reseller.