【3D Printing Applications】Hollow, Thin-Shelled Models: Save Half the Material and Time!
Under normal circumstances, SLA (Stereolithography) 3D printers can print 3D objects with extremely high density (solid). But when you don't need to print functional parts with such high strength, you might consider using a hollow design. Not only does it save a lot of material, but it also significantly saves time!
We recommend trying to print the following designs using a hollow method:
• Art and Sculptures
• Scale Models
• Early Concept Models
• Large Modules and Multi-part Pieces
Using the hollowing tool in PreForm and Meshmixer (free), you can print in three simple steps:
Step 1: Find the Correct Orientation
During the SLA printing process, your model is printed layer by layer, and the object is pulled out of the liquid resin as the build platform moves upwards along the Z-axis. Because SLA's forming technology involves liquid resin in a resin tank being cured by laser light, some resin may remain inside the printer when you print hollow objects. We recommend finding the correct print orientation and adding drain holes to prevent residual resin issues.
Open your object model in PreForm and orient it for optimal printing. The side closest to the build platform should be a side that will not be seen on the object or where holes can be placed without affecting the overall functionality of the part. Also, try to avoid multiple overhangs, as they can trap residual resin inside.
Orient the 3D print model optimally in PreForm; it will print best while keeping the intended hole locations in mind.
Step 2: Hollow Your Model
First, open your 3D object in Meshmixer. To easily locate the holes (Edit > Transform), you can set them the same as in PreForm. Go to the hollowing tool (Edit > Hollow) and adjust the settings based on your layer thickness.
Meshmixer will create a shell within your model based on the offset you specify. The next step is to generate holes. Place one hole as close to the build platform as possible, and at least one on your preferred surface. This will help resin and air drain during printing, and isopropyl alcohol (IPA) flow out during cleaning. However, adding holes can sometimes disrupt flat surfaces. To prevent this, use the Make Solid (Edit > Make Solid) function to generate a mesh that is easy to work with. Note that this method may reduce the quality of your mesh unless you use the slider to maintain quality.
How to print the best results:
• Wall thickness directly affects the strength of your print. Since hollow prints have no internal structure or supports, large models with thin walls will be more fragile.
• The thinner the walls, the less material your print requires, and the lighter it will be. If you need a solid or stronger part, you can also choose to print the model with inexpensive epoxy or plaster.
Make preference settings in Meshmixer and add holes to the model (marked in red in the image above).
Once complete, confirm the settings and export the object file from Meshmixer in .STL format.
Step 3: Print Your Model
Now you can start printing. Import the modified 3D model into PreForm, and following the previous steps, position the holes as close to the build platform as possible. From now on, printing and post-processing are the same as with a regular SLA printer.
Actual time and material savings depend on your machine model and settings. In our example, the results for a 112mm x 85mm x 114mm model with a 2mm offset distance and 0.1mm layer thickness are as follows:
Overall Comparison
|
| Solid | Hollow |
|---|---|---|
| Material | 246.28 ml | 77.37 ml |
| Print Time | 15 hours 35 minutes | 7 hours 47 minutes |
Completed hollow model, using Formlabs resin (Formlabs Standard White Resin)
Visit our materials page to learn more about Formlabs resin, or contact us at 3DMart if you want to test the performance of an SLA 3D printer.
(Article translated from: https://formlabs.com/blog/how-to-hollow-out-3d-models/)