3D printing isn’t just about design and the printing process itself – the final stage, post-processing, is just as important. Among the various finishing techniques, chemical post-processing deserves special attention, as it enables truly professional results. In this article, we’ll explore how this process works, its advantages and drawbacks, and how to apply it in practice.
What is chemical post-processing?
Chemical post-processing in 3D printing is a method of smoothing and modifying the surface of a print using specific chemical agents. Unlike sanding or heat treatment, the material is not physically abraded or melted – instead, the solvent selectively “melts away” microscopic surface irregularities. The result? A smooth, glossy finish and improved functional properties – without the need for manual labor.
Chemical Smoothing of PA12 powder prints
An increasingly important technique is the chemical smoothing of PA12 powder-based prints, especially those produced with SLS and MJF technologies. With the use of modern automated processing machines – such as pressure-controlled chemical smoothing systems – it’s possible to achieve surfaces comparable to injection-molded parts. PA12 is widely used in the automotive, medical, and functional prototyping industries due to its strength and chemical resistance. Chemical smoothing eliminates surface porosity, improves sealing and aesthetics, and reduces the tendency for dirt accumulation. Importantly, this process preserves the full geometry of the part and does not negatively affect its mechanical properties, making it ideal for demanding applications.
Most Popular Methods
- Vapor Smoothing – this is one of the most commonly used techniques. The print is placed in a chamber filled with solvent vapors – most often acetone – which gently melts the outer layer. It works especially well with materials like ABS, ASA, or HIPS.
- Solvent dipping – another option is briefly dipping the print in a liquid chemical agent. This provides fast results but requires caution – prolonged exposure can deform the part.
- Support removal and cleaning – if you’re printing with soluble materials (like PVA or HIPS), appropriate chemicals can easily remove the supports. Automated washing stations are often used here to speed up the process.
What materials are suitable for this?
Not every filament is compatible with chemical smoothing. The most effective materials include:
- ABS – reacts well with acetone
- ASA – similar to ABS but more weather-resistant
- HIPS – can be dissolved using d-limonene
- TPU, PP, PA – more demanding, require specialized agents
Before beginning any treatment, it’s important to confirm that the material is suitable – some plastics are resistant to chemicals or overly sensitive to damage.
Why is it worth it?
- Parts look injection-molded – smooth, uniform, and layer-free
- Improved sealing and mechanical resistance
- Even complex geometries can be smoothed, where sanding tools can’t reach
- The process can be partially automated – saving time and ensuring repeatability
What to watch out for
- Overexposure can deform the part
- Chemicals can be hazardous – proper ventilation and protective gear are essential
- Not all materials are compatible, and some require very precise handling
Although chemical post-processing in 3D printing requires care, it’s definitely worth considering – especially if you value aesthetics and functionality. It’s an effective way to enhance print quality without hours of manual work.
