[3D Printing Application] How to create hollow, thin-walled models to save half the material and time!
In general, Stereolithography (SLA) 3D printers can produce solid 3D printed objects. However, when creating functional parts that do not require such high strength, utilizing a hollow design can significantly save material and greatly reduce printing time.
Hollow models are recommended for the following designs:
• Art and sculpture
• Scale models
• Early concept models
• Large modules and multi-part components
Using the hollow tools in PreForm and Meshmixer (free), you can create prints in three simple steps:
Step 1: Determine the correct orientation
In SLA printing, models are built layer by layer, with the build platform rising in the Z-axis direction as it pulls the object from the resin tank. Since SLA uses a laser to cure liquid resin, hollow models can retain resin internally. Therefore, proper orientation and drain holes are crucial.
Open your model in PreForm and orient it optimally. The surface closest to the build platform should be an inconspicuous area or a surface where holes can be placed without affecting functionality. Also, avoid excessive overhangs, as these can lead to resin pooling inside.
Orienting your 3D print model optimally in PreForm will yield the best results. Consider the anticipated hole locations during this step.
Step 2: Hollow out the model
First, open your 3D model in Meshmixer. Adjust the orientation to match PreForm (Edit > Transform) to easily identify hole locations. Then, open the Hollow tool (Edit > Hollow) and adjust settings according to the layer thickness.
Meshmixer generates a shell of your model based on the specified offset. Next, create holes. Place at least one hole as close to the build platform as possible, and another on any other surface. This facilitates the drainage of resin and air during printing, and the flow of IPA (isopropyl alcohol) during cleaning. However, adding holes may compromise flat surfaces. In such cases, you can use the "Make Solid" function (Edit > Make Solid) to reconstruct the mesh, but adjust the slider to avoid potential quality degradation.
Tips for optimal printing:
• Wall thickness directly affects the strength of the printed object. Without internal structures or supports, thin, large models can be fragile.
• Thinner walls reduce material usage and weight. For higher strength or solid models, low-cost epoxy resin or plaster are also options.
Adjust settings in Meshmixer and add holes to the model (red marked areas in the image above).
Once complete, verify settings and export in .STL format.
Step 3: Print the model
Your print is now ready. Load the modified 3D model into PreForm and, as described earlier, position it so that the holes are close to the build platform. Subsequent printing and post-processing steps are the same as for regular SLA prints.
Actual time and material savings depend on the printer model and settings. As an example, for a model with a 2mm offset, 0.1mm layer thickness, and dimensions of 112mm × 85mm × 114mm, the results are as follows:
Overall Comparison
|
Solid |
Hollow |
|---|---|---|
|
Material |
246.28 ml |
77.37 ml |
|
Print Time |
15 hours 35 minutes |
7 hours 47 minutes |
Finished hollow model (using Formlabs Standard White Resin)
For more details on Formlabs resins, please visit our materials page. If you'd like to try an SLA 3D printer, please contact us here.
(Article translated from: https://formlabs.com/blog/how-to-hollow-out-3d-models/)