A guide to STL exports for 3D Printing

In order to give the slicer a file to print with, we must first export a model from CAD. The most commonly used export option is via STL, which we shall look into within this blog post

Within an STL export you can control two main options:

• Angle Control – the maximum angular deviation between adjacent triangles.

• Chordal Tolerance/Deviation – the maximum distance between the surface of the original design and the tessellated surface of the STL model.

Changing either will control the level of faceting, from coarse to fine. The finer the quality, the larger the file size. The image above shows how you can control these options inside the SOLIDWORKS export (file -> save as -> save as type -> STL). Choosing custom allows you to manually move the sliders to control the angle to how you require.

How does the STL file correspond to 3D print quality

A limiting factor of your print quality is the quality of the file. The below images show the difference between a coarse export and a fine export from SOLIDWORKS. The coarse export took a matter of seconds, whereas the fine settings took several minutes to export. If big enough, these triangles used in the export settings will be visible in the print, making the component not look correct and could cause issues with holes turning into polygonal shapes. 

What is also worth remembering with STL exports as that it will use the orientation of your file in SOLIDWORKS and replicate this. Therefore, if you have a badly imported model in CAD, it will produce the same in the STL and therefore the same in the import- as you can see in the image below. We shall now look at how to go through the whole process of exporting, importing and then orientating a model in your slicer to obtain the best possible manner to print an item.

How to export an stl

1.Open up your CAD software (in this case we shall be using SOLIDWORKS) and open your part file. Below you can see the simple example part we shall be exploring. However the process will be similar for the part you’re using.

2. Go to the menu bar > file > save as.

3. You will then need to change the “save as type” to be STL.

4. Once STL has been selected we will confirm the options to ensure that the export will be correct. We will use the default “fine” resolution option, as this will be enough for this part due to how it doesn’t have too much curvature.

5. You may now see this message on the screen. This will appear if you have selected a body/ have multiple bodies inside the part. You can choose to only save out certain components at once. For example, if you had an assembly with off the shelf parts you can save out the stl without these being included.

And that’s your STL file saved out! If you don’t yet have a printer, but would like to see your parts 3D printed, contact us on the details below for a free sample.

01926 333 777 or check out our contact us section.