Making Vapour Smoothing Safe with the Zortrax Apoller

When done correctly, vapour smoothing makes 3D printed models virtually indistinguishable from injection moulded models. It’s a popular post-processing technique because it eliminates layer lines, resulting in a glossy or matte final product.

However, the liquids used – acetone or MEK – are hazardous and volatile. Traditionally, vapour smoothing is performed manually with a glass bowl and liquid acetone or methyl ethyl ketone (MEK). The vapours are allowed to rise and build underneath sheet while the model is held in place by hand, or by grip.

All well and good, except the fumes are unsafe and by holding the model in places, you can’t guarantee complete penetration. Results with this method are not repeatable, surfaces are not smoothed uniformly, and you can’t realistically smooth models with small details because there is a low tolerance for overexposure. Models that are overexposed have altered definition and detail – the exact opposite of the desired result. 

So, the bright sparks at Zortrax set out to change this. The result is the Zortrax Apoller, a vapour smoothing machine designed for 3D printed parts based on ASA, ABS and HIPS.

Vapour Smoothing with the Zortrax Apoller

Zortrax Apoller

By introducing an enclosed vapour chamber with the Apoller, Zortrax solved the issues of safety when working with MEK or acetone. It vaporises these liquids in an enclosed environment that safely and thoroughly smooths off the surface of models.

The vapour travels around the chamber in an upwardly direction, ensuring even coverage. The chamber is then cooled gradually, enabling excess vapour to turn back into a liquid for reuse later (it collects in a tank for reuse).

The Apoller has an air-tight, double sealed smoothing chamber measuring 300 x 250 x 250 mm which is large enough to accommodate models printed with any Zortrax printer. Models printed in any ASA-based material are smoothed with MEK – they have a matte finish. Models printed in any ABS or HIPS-based material are smoothed with acetone – they have a glossy finish. The two solvents aren’t interchangeable.


That double-sealed air chamber is unique to the Apoller. It can actually function with one seal; the other is redundant. This is a failsafe to ensure no matter what happens, no fumes or vapours can leave the smoothing chamber.

Another feature is the power cut failsafe. In the event of a power outage, the Apoller stays closed and cannot be opened again until the power resumes. When the power is back on, the Apoller recognises what has happened and automatically decontaminates the chamber before allowing anyone to open it. Again, this ensures no matter what, no fumes or vapours leave the smoothing chamber.

Smoothing 2

Importantly, the Apoller has been granted a certificate of compliance with the ATEX 2014/34/EU Directive. This means it meets the safety standards necessary for equipment meant for explosive atmospheres. This is an important feature for commercial, industrial and engineering environments. It ensures you can meet your health and safety obligations and trust the Apoller to function safely at all times.

The Apoller smooths models made from Z-ABS, Z-ULTRAT, Z-ULTRAT Plus, Z-ASA Pro, and Z-HIPS. It also supports third-party ABS, PLA and HPA, and derivatives of these materials (such as tough PLA).

Because it superficially melts the model’s surface, the end result is a permanently smooth outer surface. It is not a temporary effect. Models show the same durability as injection moulded parts. The layer lines are only visible once again if you cut into the plastic to expose an edge.

The potential applications for vapour smoothing don’t end at creating models with the look of injection moulded models for aesthetic purposes. Properly smoothed 3D printed models can also be used as patterns for investment casting because the surface is free from any imperfections (which freshly 3D printed parts have – they’re called layer lines).

Overall, if you want to carry out vapour smoothing in a safe and controlled way, the Zortrax Apoller is what you want in your workshop. It offers repeatable results and works with a wide range of different materials.

Zortrax Apoller specifications:

– Smoothing chamber measures 300 x 250 x 250mm.
– Works with MEK and acetone.
– Intuitive touch interface.
– Has Wi-Fi and Ethernet connectivity.
– Smooths models printed with Z-ABS, Z-ULTRAT, Z-ULTRAT Plus, Z-ASA Pro, and Z-HIPS.
– Works with external materials including ABS, ASA, and HIPS.
– Advanced vapor circulation system.
– Maximal working temperature is set at 90° C (194°F).
– Minimal working temperature is as low as -20° C (-4°F).
– Minimal absolute working pressure is set at 0.4 bar.
– Safety systems meet the standard required by the EU ATEX Directive.