The best measure of the performance of a particular 3D printer is the level of accuracy of the finished print that it produces. We can easily test this by scanning the printed object and making a comparison with the original STL source file.

The common dental myth is that objects with thinner layer thickness, will result in more accurate prints. To put this theory to test, we made a comparison of the accuracy of five different prints that are produced from the same STL file but with different layer thicknesses.

 

MATERIALS

• FreeShape 120 3D printer

• Meccatonicore UV Box

• STL file of a Dental Model

• Three (5) print files (i.e. IBF files) with a layer thickness of 50 µm, 70 µm, and 100 µm

• QuraModel 2.0 resin\

 

METHOD

1. Set up a print project with the STL file of the dental model.

2. Create three different print files with three different layer thicknesses, i.e. 50 µm, 70 µm, 100 µm, 125 µm and 150 µm.

3. Print each of the print files on the same FreeShape 120 3D printer, sequentially.

4. Wash and clean the printed objects

5. Cure each of the printed objects in the same UV box and for the same duration.

6. Scan each of the printed objects.  

7. Conduct an accuracy analysis of the three printed objects.

 

PRINT FILE (IBF) WITH A LAYER THICKNESS OF 150 µm

Print Scan Analysis: 94%   Layer Thickness: 150 µm   94% of the digital points on the scanned model are the same as the STL file. This is calculated by subtracting the lower limit from the upper limit.
Upper limit: 96.983%
Lower limit: 2.986%

 

PRINT FILE (IBF) WITH A LAYER THICKNESS OF 125 µm

 

Print Scan Analysis: 91.87%   Layer Thickness: 125 µm     91.87% of the digital points on the scanned model are the same as the STL file. This is calculated by subtracting the lower limit from the upper limit.
Upper limit: 97.71%
Lower limit: 5.84%

PRINT FILE (IBF) WITH A LAYER THICKNESS OF 100 µm

 

Print Scan Analysis: 96.51%   Layer Thickness: 100 µm     Print Duration: 96.51% of the digital points on the scanned model are the same as the STL file. This is calculated by subtracting the lower limit from the upper limit.
Upper limit: 97.774%
Lower limit:1.263%

PRINT FILE (IBF) WITH A LAYER THICKNESS OF 70 µm

 

Print Scan Analysis: 94.73%   Layer Thickness: 70 µm Print Duration: 94.73% of the digital points on the scanned model are the same as the STL file. This is calculated by subtracting the lower limit from the upper limit.
Upper limit 96.58%
Lower limit 1.85%

 

PRINT FILE (IBF) WITH A LAYER THICKNESS OF 50 µm

 

Print Scan Analysis: 93.382%   Layer Thickness: 50 µm Print Duration: 93.382% of the digital points on the scanned model are the same as the STL file. This is calculated by subtracting the lower limit from the upper limit.
Upper limit: 94.928%
Lower limit: 1.546%

RESULTS

The scanning and comparison process shows that the digital points of all scanned objects average 94.874% accuracy when compared to the original STL file. That is a quantifiable difference, but in a real-world situation, this is the same as what we would expect to see from print files that were created with the same layer thickness, and the difference is negligible.