Applies to: DentalCAM & DentalCNC 7.08

Preparing STL files for good machining results

How should I prepare STL files in my CAD application? How can I improve my STL files? What are the common mistakes when preparing STL files?

You need to create the 3D data for the objects that you want to manufacture with an external CAD application. You then need to import these objects into DentalCAM and set the required parameters so that DentalCAM knows how to handle the objects. While we cannot help you with using your CAD application, we do want to help you avoid common mistakes when preparing STL files for import.

Problematic STL files can result in flawed restorations or broken tools. In the following we provide a few tips to avoid common mistakes when you prepare STL files.

Correct errors in STL files with your CAD application and/or export them with suitable settings.

If the prepline of your object is too thin, parts of the object may break off.

An STL file where the prepline is too thin

If the prepline of your object has errors, the machining result will become unusable.

An STL file with prepline errors

If the surface of your object is too rough, problems with fittings may occur.

An STL file where the object's surface is too rough

Objects in STL files are made of triangles. The higher the resolution of the STL files, the more triangles are used and the smaller the triangles become. More triangles mean more surface details.

If the resolution of the STL file is too low, triangles will become too big and there won't be enough surface details for proper machining.

An STL file with a low resolution, resulting in big triangles

If the resolution of the STL file is too high, the file size will become very large, which will result in long loading and processing times. These STL files will contain more surface details than your machine can process.

3-unit bridge with too many surface details (42 MB)

Appropriate file sizes of common indications

Indication

Typical STL file size

Abutment

3 MB

Attachments

4 MB

Bite splint

15 MB

Bridge

5 MB (5 units)

25 MB (14 units)

Coping

6 MB

Crown (single; fully anatomical)

3 MB

Implant bar

6 MB

Inlay

4 MB

Partial frame

4 MB

Screw-retained bridge

7 MB (14 units)

Telescope crown

2 MB

Veneer

2 MB

If there are incorrect surfaces between teeth, the machining result will become unusable.

An STL file with an interdental error

Acute angles will lead to the material thickness becoming infinitely small at the tip.

An STL file with an acute angle