Post Processing
Virtually every 3D printed part requires some post processing...
Post-processing of 3D printed parts can vary greatly. Most 3D printed parts require some degree of post-processing whether it is as simple as support or build plate adherence removal to chemical treatment. Some processes are automated and some (most) are manual.
The following are some common examples of post-processing used in the MakerSpace:
- Support removal. Supports can be removed by hand, sandpaper, filing, cutting, or a variety of mechanical techniques. Some supports are water soluble (e.g. PVA) and can be removed by immersion in water.
- Washing. Simple washing with water and/or alcohol can be very effective at cleaning 3D printed parts. The MakerSpace has a SLA automatic wash solution (FormWash by Formlabs) that is intended for use in SLA printing but can also be effective a simple cleaning of FDM parts.
- Curing. Similar to washing, the MakerSpace uses FormCure to cure SLA printed parts. Curing requirements vary by resin type and should be evaluated on a case by case basis. Curing is done to restore isotropic material properties but can also soften printed parts.
- Protective coating. There are numerous brush-on protective coatings that can be applied to 3D printed parts. Most of these are done to improve surface finish but they can also be used to seal parts.
- Chemical treatments. Similar to protective coatings, some 3D print materials are sensitive to different chemical treatments. The MakerSpace uses a system called a Polysher (https://us.polymaker.com/product/polysher/) that can be used on specific filament (Polymaker filament) to produce a smooth high-glass finish.
Many parts require supports no matter what the printing method, but often good selection of orientation can minimize or prevent the amount of supports. As shown in the image above, supports are required for all SLA printed parts.
However, this complex parts printed fine via FDM without supports since all angles were shallow enough to allow printing without supports.
FormWash: Rinses your part in isoprapnol which is very effective at washing SLA or even FDM parts.
FormCure: Uses UV light to cure SLA printed parts to improve isotropic material behavior.
Polysher: Nebulizes alcohol creating a fine mist that smooths the surface finish of specific filaments (only works on Polymaker filaments).
Post Processing of Metal Parts
Post-processing for metal printed parts is very different. Most 3D printed metal parts require significant post-processing including:
- Removal from the build plate is often much more difficult and may require mechanical machining (such as EDM).
- Surface finish preparation is often required specifically to improve fatigue performance. There is also good evidence that suggests that corrosion susceptibility is strongly dependent on surface finish.
- Hot Isostatic Pressing (HIPing) is often used to improve consolidation of printed parts.
The above stainless steel part was printed at USNA and shows the effect of mechanical polishing (left side) as opposed to the as-printed surface finish (right side).