To clean 3D resin parts, you typically use a solvent to remove uncured liquid resin from the surface after printing.
Cleaning is a crucial post-processing step for resin 3D prints, ensuring a smooth, non-tacky finish and preparing the part for final curing. The primary method involves washing the part in a suitable solvent.
According to Formlabs, a leading manufacturer of SLA printers and resins, isopropyl alcohol (IPA) or tripropylene glycol monomethyl ether (TPM) are recommended solvents for washing SLA parts. While both are effective, most users find IPA is more effective for washing parts. It's worth noting that IPA solutions can often only be bought in large quantities, so you should be prepared to store excess IPA for future use.
Recommended Solvents
Choosing the right solvent depends on the resin type and personal preference. The most common options include:
- Isopropyl Alcohol (IPA): Highly effective for most standard resins. Available in various concentrations (91% or 99% recommended).
- Tripropylene Glycol Monomethyl Ether (TPM): Another effective solvent, often used as an alternative to IPA, particularly for its lower flammability and odor.
- Specific Resin Cleaners: Some resin manufacturers offer proprietary cleaning solutions optimized for their materials.
While other substances like denatured alcohol might be used, IPA and TPM are widely regarded as safe and effective for most common resin types when handled properly.
The Cleaning Process
The typical workflow for cleaning resin parts involves immersion and agitation:
- Initial Wash: Place the printed part in a container filled with the chosen solvent (like IPA or TPM). Submerge the part completely.
- Agitation: Swirl the part around, gently brush it with a soft brush (like a toothbrush), or use a dedicated wash station to agitate the solvent. Agitation helps remove liquid resin from intricate details and surfaces.
- Second Wash (Optional but Recommended): For best results, especially with complex parts or after printing multiple models, transfer the part to a second container of clean solvent. This removes any residual resin left after the initial wash.
- Soaking (If Needed): For parts with complex geometries or internal channels, a short soak might be beneficial.
- Rinsing: While not always necessary if using IPA/TPM followed by proper drying, some prefer a quick rinse with water, especially after using certain cleaners.
Wash Station vs. Manual Washing
| Method | Description | Pros | Cons |
|---|---|---|---|
| Manual Wash | Using tubs/containers and manually agitating/brushing the part. | Low initial cost, simple setup. | Can be messy, requires manual labor, less consistent agitation. |
| Wash Station | Automated devices that use magnetic stirrers or impellers to agitate solvent. | Efficient, consistent cleaning, often includes a basket system for ease. | Higher initial cost, takes up space, requires specific containers/baskets. |
Many users find automated wash stations significantly improve workflow and cleaning consistency.
Drying the Part
After washing, it's essential to dry the part thoroughly before post-curing:
- Air Drying: Allow the part to air dry in a well-ventilated area. Be patient, as solvent can remain in crevices.
- Compressed Air: Using compressed air is highly effective for quickly removing solvent from surfaces and hard-to-reach areas.
- Fan Drying: Placing the part in front of a fan can speed up evaporation.
Ensure the part is completely dry. Any remaining solvent can interfere with the final post-curing process.
Important Considerations
- Safety: Always handle solvents like IPA and TPM in a well-ventilated area. Wear appropriate personal protective equipment (PPE), including nitrile gloves and safety glasses. Refer to the Safety Data Sheet (SDS) for the specific solvent you are using.
- Solvent Management: Solvents become saturated with resin over time and lose effectiveness. You will need to replace or reclaim the solvent. Never pour used solvent down the drain. Follow local regulations for disposal or explore methods like evaporation and filtering to reclaim some solvent. Remember that IPA solutions can often only be bought in large quantities, so responsible storage is important.
- Part Fragility: Freshly printed resin parts can be brittle before post-curing. Handle them carefully during the washing process to avoid breakage.
- Hollowing and Drain Holes: If your part is hollowed, ensure drain holes are present before printing. This allows uncured resin to escape during washing and solvent to drain out afterwards.
- Temperature: The temperature of the solvent can impact cleaning efficiency. Some wash stations offer heating features, but be cautious with flammable solvents like IPA.
By following these steps and using appropriate solvents like IPA or TPM as recommended, you can effectively clean your 3D resin parts for a successful post-curing and finishing process.
