Finishing a 3D model, particularly a 3D printed part, involves a series of post-processing steps to improve its surface quality, appearance, and functionality.
Achieving a desired final look for your 3D print often requires processes performed after printing. These steps help remove print artifacts, enhance layer adhesion visibility, and prepare the surface for paint or other coatings.
Key Post-Processing Steps for Finishing 3D Prints
Finishing a 3D printed part often involves a combination of the following processes: smoother application, sanding, polishing, cleaning and painting. The specific approach is unique to the material type used for printing. While a smooth finish with 3D printing is achievable directly from the printer, post-processing will greatly improve the smoothness of parts and overall aesthetics.
Here's a breakdown of common finishing techniques:
- Cleaning:
- Remove supports, rafts, or brims left over from the printing process.
- Wash away any residue, especially for prints made with water-soluble supports or resin prints that require cleaning before curing.
- Support Removal:
- Carefully detach support structures using pliers, cutters, or by breaking them away.
- Be cautious not to damage the model's surface.
- Smoothing:
- This can involve chemical smoothing (e.g., using acetone vapor for ABS plastic) or applying a filler/smoother product.
- Smoother application is used to fill in layer lines and imperfections, creating a more uniform surface.
- Sanding:
- Use sandpaper of progressively finer grits to remove layer lines, support marks, and smooth the surface.
- Start with a coarse grit (e.g., 150-200 grit) to tackle significant imperfections and move to finer grits (e.g., 400, 800, 1000+ grit) for a smoother finish.
- Sanding can be done manually or with power tools for larger parts.
- Polishing:
- After fine sanding, polishing can be used to achieve a very smooth, sometimes glossy surface.
- This often involves using polishing compounds and soft cloths or buffing wheels.
- Painting:
- Applying paint allows for color customization and can further hide minor surface imperfections.
- A primer coat is often recommended before painting to ensure good paint adhesion and a consistent color.
- Choose paints compatible with your 3D print material (e.g., acrylics, spray paints).
- Sealing/Clear Coating:
- A final clear coat can protect the paint, add durability, and provide a desired sheen (matte, satin, or gloss).
Example Finishing Workflow (PLA)
Here's a typical sequence for finishing a PLA print:
- Remove supports.
- Lightly sand away support marks and prominent layer lines (e.g., 220 grit).
- Apply a filler primer to fill minor gaps and layer lines.
- Sand again with a finer grit (e.g., 400-600 grit) to smooth the primer layer. Repeat primer and sanding if needed.
- Clean off all dust.
- Apply desired paint color layers.
- Apply a clear coat for protection and finish.
The exact steps and materials used will vary significantly based on the desired final outcome and the material of the 3D print (PLA, ABS, PETG, Resin, Nylon, etc.).
Material Considerations
| Material Type | Common Finishing Considerations |
|---|---|
| PLA | Sanding, filling, painting, relatively easy. |
| ABS | Sanding, painting, chemical smoothing (acetone). |
| PETG | Sanding, painting, can be trickier to smooth. |
| Resin (SLA/DLP) | Cleaning (IPA), curing (UV), sanding, priming, painting. |
| Nylon | Can be difficult to sand, dyeing is an option. |
Understanding the properties of your printed material is crucial for selecting the most effective and safe finishing techniques.
