3D printing shells are more critical than you would expect. They can have a significant impact on the stability of your 3D printed model as well as how the object can be used.
What Is 3D Printing Shells Setting?
The outlines or outer perimeters of each layer in 3D printing are known as shells. You can customize your 3D printing shells according to the settings of your slicer.
Consider a 3D printed mug (like in the picture above). You should make some adjustments to your slicer before printing (explained in more detail below). Examples include the printer’s speed, layer height, and printing temperature. In theory, if you set the number of shells (i.e. shell thickness) to the maximum available for the bowl, the 3D printer will not print a bowl. Instead, you’ll receive a solid, curved block with no “hole.”
To prevent this, we’ll go through the various settings you can use and some guidelines to follow.
Shell Settings
The settings may affect 3D printing shells in many ways:
- Post-processing: If you’d like to refine or sand your 3D prints before varnishing them, for example, increasing the thickness of the 3D printing shells makes sense since refinement typically removes layers from the model. As a result of the increased shell thickness, a little more can be sanded off and finer details can be worked out without compromising the model’s structure.
- Strength: Raising the shell thickness increases the model’s resilience. As a consequence, even stronger items can be printed. Most slicers allow you to adjust this setting in the slicer’s settings.
- Cost: Increasing the number of shells will raise the cost per print because it requires more content and longer print times.
What to keep an eye out for:
You’re probably wondering how you can customize these 3D printing shells to get excellent results and maximize your 3D printing. The shells are usually printed with a thickness of 0.8 mm. This corresponds to 2-3 nozzle diameters, depending on your 3D printer. In most situations, it is important to ensure that the shells are multiple of the nozzle diameter to prevent cavities.
However, for objects with a hole, such as a cup, vase, or something else, it is best to stick to 2-3 nozzle diameters. Anything after that shifts the object so much that the cavities close up, as in the case of the bowl discussed earlier.
Cura Shell Settings
Slicers are software applications that translate CAD data into g-code, which the 3D printer can understand. Having said that, files can not only be converted but also changed and updated using various settings. We will use the Cura slicer to demonstrate how to adjust these settings.
Adjusting the Settings
The auxiliary line in blue, printed around the outside of the print, the shells in red, and the top and bottom layers in yellow are visible in the picture.
Click the “Custom” button in the upper right corner to adjust these settings in your slicer. The wall and top/bottom layer thickness are the key settings that will impact your print. The thickness to bear in mind for each of these is 1.2 mm.
Here are some recommendations for wall and top and bottom layer thicknesses:
- Less than 1.2 mm results in smaller, more compact versions at the expense of stability. Models with very thin walls and/or top/bottom layers would be fragile and brittle.
- More than 1.2 mm would result in sturdier versions with better balance. On the other hand, models with extremely thick walls and/or top/bottom layers may affect the product’s final design.
How to 3D Print a Vase
A vase is a perfect model for illustrating the use of the above settings.
A vase should be sturdy but not too thick. Set the wall thickness between 0.8 mm and 1.35 mm, and the top/bottom thickness between 1.00 mm and 1.35 mm to achieve this. The top/bottom thickness range is narrower than the wall thickness range because the bottom must have a certain layer thickness to ensure a secure stand.
To see this shift in thickness more clearly, turn to “Layer View” from the dropdown menu “Solid View” in the upper right corner. You can see the model layer by layer to see where improvements can be made and their impact. You can easily and individually configure your models using this layer view, depending on which settings fit your prints.
What is the thickest shell setting ever you 3D printed? Show your masterpiece!
Let us know in the comments below or on our Facebook page to let us know your ideas, and we would appreciate seeing pictures of your works of art!
Featured image source: duncan916 / Thingiverse
