Dimensional inaccuracy refers generally to any case where the final dimensions of printed parts do not match the dimensions of your model, within expected tolerances. Dimensional accuracy is affected by part design, material selection, part setup, post-processing, and printer maintenance, so issues can be multifaceted.

• Printed part dimensions do not match designed or model dimensions within expected tolerances

• Model design
• Material selection
• Support placement
• Part orientation
• Support touch tip size
• Layer thickness
• Dirty optical components

When initially troubleshooting dimensional accuracy issues, consider your goals:

Check the model in PreForm

Part orientation and support are critical to print success and dimensional accuracy. When troubleshooting dimensional accuracy issues, be sure to:

1. Orient your models so that supports can be placed on non-cosmetic or less-critical surfaces.
2. Place enough supports and use large enough touchpoints to hold the model steady during printing.
3. Pick lower layer thicknesses for fine details or smoother layer lines.

Follow post-processing recommendations

Proper post-processing is key for accuracy. Make sure that you are following the washing and post-curing recommendations for your resin.

• Best practices for washing prints
• Best practices for post-curing prints
• Form Wash/Form Wash L time settings
• Form Cure time and temperature settings
• Form Cure L time and temperature settings
• Fast Cure time settings

Check your printer’s optical surfaces

Contaminated optical surfaces generally lead to more severe print defects. Optical surfaces include:

• Resin tank film (Form 4, Form 3L, and Form 3 generations)
• Release texture (Form 4 generation)
• Optical window (Form 2 printers and Form 3L and Form 3 generations)
• Main mirror (Form 2)

Mild to moderate contamination on these surfaces might not cause failed prints but could still affect dimensional accuracy.

1. Check your resin tank for cured resin or other debris.
• Inspecting and cleaning resin tanks (Form 4 generation)
• Inspecting and cleaning resin tanks (Form 3L/Form 3BL)
• Inspecting and cleaning resin tanks (Form 3/Form 3B)
• Inspecting and cleaning standard resin tanks and Resin Tanks LT (Form 2)
2. Check the release texture (Form 4 generation) or optical window (Form 2 printers and Form 3L and Form 3 generations).
• Cleaning the release texture (Form 4 generation)
• Maintaining the glass optical window (Form 3L/Form 3BL)
• Cleaning the glass optical window (Form 3/Form 3B)
• Cleaning the glass optical window (Form 2)
3. Check your resin tanks for damage and replace if needed.
• Inspecting and cleaning resin tanks (Form 4 generation)
• Inspecting and cleaning resin tanks (Form 3L/Form 3BL)
• Inspecting and cleaning resin tanks (Form 3/Form 3B)
• Inspecting and cleaning standard resin tanks and Resin Tanks LT (Form 2)

Select the correct material for your application

Formlabs offers dozens of materials with different physical properties and intended applications. For the best experience, make sure your selected material is well-suited for your application. For example, stiffer resins tend to hold their shape better during printing, which may result in better dimensional accuracy.

Consult the Formlabs Materials Catalog or materials comparison tool to find the right material for your prints.

Adjust Fit Tuning (Form 3 generation only)

The Fit Tuning test was designed for dentistry applications, but it can sometimes help with specific types of dimensional accuracy issues on other models. It is best suited for adjusting the fit of vertically-printed posts into matching slots or holes. Adjusting Fit Tuning only changes aspects of your models in the XY plane (i.e., parallel to the build platform), so it cannot address dimensional issues occurring in the Z-axis. If your use case matches this, follow the instructions in this article to print the Fit Tuning test and adjust your printer.

If the troubleshooting steps above do not resolve the print failure, contact Formlabs Support or your authorized reseller.

To help us provide the fastest and most effective response to your issue, please provide the following information:

1. Upload diagnostic logs
   • On a Form 2
   • On a Form 3/Form 3B
   • On a Form 3L/Form 3BL
   • On a Form 4 generation printer
2. Serial name of the printer
   • The serial name is on the back panel of the printer in the format AdjectiveAnimal or Machine-AdjectiveAnimal, where “Machine” is the machine type.
   • On a Form 2: Tap the printer icon on the home screen. The Your Printer screen appears.
   • On other Formlabs SLA printers (Form 3 or later): Tap the printer icon on the Home screen.
3. Troubleshooting steps attempted
   • Example: “I reoriented the model in PreForm. I inspected the resin tank and did not notice any damage, clouding, or debris.”
4. Resin formulation and lot number
   • The lot number is inside the skirt of the resin cartridge.
5. Layer thickness
   • On a Form 2: Tap the queue icon on the home screen. The Jobs screen appears.
   • On other Formlabs SLA printers (Form 3 or later): Tap Queue on the Home screen. The Queue screen appears.
6. Relevant FORM files
   • If available, attach FORM files of the model to the support request.
7. Previous attempts to print the part and any successful prints
   • Example: “I printed the file part2.form three times previously. The first and second were successful. The third one failed.”