How Does Vapour Smoothing Compare to Other Finishing Methods?

Post-processing plays a big part in how a 3D printed component looks, feels and performs. Formero offers a wide range of finishing options, and choosing the right one depends on your material, application and what you’re trying to achieve. This article focuses on post-processing options for MJF and SLS parts, both of which use powder-based printing and come off the printer with a characteristic grainy texture and surface porosity. Here’s how vapour smoothing compares to some of the other common options.

Bead Blasting

Bead blasting is the bare minimum finishing step for MJF and SLS parts. It uses fine beads propelled at high speed to remove residual powder and clean the surface, creating a uniform matte finish. Every MJF and SLS part goes through this step before anything else is applied. It’s fast and effective at cleaning up the surface, but it doesn’t change the part’s underlying porosity or texture at a microscopic level. The surface still carries the characteristic grain of powder-based printing.

Tumbling

Tumbling takes this a step further across a full batch of parts at once. Components are placed in a barrel with abrasive media that vibrates or rotates, smoothing and polishing the surface as it moves. It’s an efficient way to finish small to medium sized parts in volume, but like bead blasting, it’s an abrasive process that works on the surface rather than sealing it.

Painting

Spray painting adds colour and a protective layer over the entire surface, with the ability to match any Pantone colour. It’s a good option when a specific colour or finish is needed, but because it adds a physical layer on top of the part, it’s worth keeping tolerances in mind. Painted coatings sit on top of the printed geometry, which can affect fit in precision applications, and can chip, wear or lift where a part experiences regular handling, contact or friction.

Dyeing

Dyeing works differently to painting. Rather than coating the surface, parts are immersed in a dye solution that colours the material throughout, so there’s no added layer and no coating to wear off. Dyeing is a good option when colour is needed without the tolerance or durability trade-offs that come with a surface coating, though it adds little in the way of protecting the part.

Z-Bonding

Z-bonding involves applying a bonding agent to the surface of SLS and MJF parts to improve water resistance. It’s a useful option when waterproofing is the priority, rather than a way to add strength to the part. As with painting, the bonding agent sits on the surface, which adds a small amount of thickness that can matter for tightly toleranced parts, and the bonded layer can be affected by repeated contact or abrasion over time.

Vapour Smoothing

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Before smoothing

After smoothing

Vapour smoothing works differently to all of the above. Rather than adding or removing material, it uses a controlled vapour environment to soften and reflow the exterior of the part at a microscopic level. As the surface re-solidifies, it seals porosity and removes the grainy texture typical of powder-based printing, without changing the part’s composition or adding any foreign material and because nothing is added to the surface, there’s no coating to wear off.

The performance gains go beyond appearance, and they come down to what’s physically happening to the material:

• Sealed micro-porosity. Powder-based printing leaves microscopic gaps between fused particles. Vapour smoothing melts and reflows this outer layer, closing those gaps. This is what makes the part more resistant to moisture ingress and easier to clean, since there’s no longer a porous surface for liquids or contaminants to sit in or work into.
• Reduced surface friction and wear. A smoother, consolidated surface reduces the microscopic roughness that causes drag and wear in parts that slide, rotate or make repeated contact with other components. This translates to more consistent behaviour over the life of the part, rather than performance that degrades as the powder texture roughens further with use.
• More consistent mechanical behaviour. Surface porosity can act as a starting point for cracks or fatigue under repeated stress. By sealing that surface, vapour smoothing supports more predictable performance under load and handling, which matters for parts intended for functional testing or genuine end use rather than visual prototypes.
• Improved hygiene and cleanability. A sealed, non-porous surface doesn’t trap residue the way an untreated powder surface can, making vapour smoothed parts a better fit for applications involving handling, fluids or skin contact.

This combination of benefits is what makes vapour smoothing useful well beyond cosmetics. It’s a functional upgrade that can remove one of the practical barriers to using additive manufacturing for end-use components.

Which Should You Choose?

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Before smoothing

After smoothing

If you need a quick, economical clean-up, bead blasting and tumbling are often enough. If colour is the goal, dyeing avoids the tolerance and wear trade-offs of a coating, while painting suits projects needing a specific finish or Pantone match. If waterproofing is the priority, z-bonding is worth considering. If your priority is a refined, production-like finish with genuine functional gains such as sealing, durability and dimensional consistency, vapour smoothing is the strongest option.

Formero’s vapour smoothing service is available for MJF and SLS parts, giving you a practical way to bridge the gap between 3D printing and traditional moulded finishes.

Still unsure which finish is right for your part? Every project has different requirements, whether that’s tolerances, colour, durability or budget, and the best option isn’t always obvious. Contact our team and we’ll help you work out which post-processing option, including vapour smoothing, is the right fit for your next project.

3D Printing, Knowledge Hub