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Pair of SLS PA12 nylon covers after vapor smoothing showing sealed semigloss surface finish

Vapor Smoothing of SLS Parts

Vapor smoothing is the highest level of surface refinement for SLS 3D printed parts. The process uses a controlled vapor chamber to gently melt the outer surface of dyed black PA12 nylon, changing the natural powdery texture into a smooth, semigloss finish. This creates an appearance close to injection molded plastic and delivers a professional look for production parts and end use applications.

Sealing the surface improves more than appearance. Vapor smoothing lowers porosity, enhances chemical and water resistance, and reduces friction for a better fit between mating parts. It is ideal for housings, enclosures, and assemblies where smooth surfaces, tight tolerances, and durability are critical.

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Unique Process of Vapor Smoothing for SLS Parts

What is Vapor Smoothing?

Vapor smoothing is our premium finishing option for SLS PA12 nylon. Through a controlled vapor process, the rough powdery surface is melted and reformed into a uniform, satin gloss finish. This produces parts that look and feel more like molded components, with enhanced durability, lower friction, and improved chemical resistance.

How the Process Works

Parts are prepared with temporary hang points and loaded into a sealed chamber. Inside, an environmentally friendly vapor is released under heat and pressure. As the vapor condenses onto the surface, it briefly softens the nylon, allowing the texture to flow and seal. Once cycled and dried, the parts emerge with a smooth, sealed surface. Because this step involves specialized equipment, we partner with DyeMansion in Austin, TX, to ensure consistent, production quality results.

Appearance and Finish

  • Premium Look: Surfaces are transformed into a sleek, semigloss finish with reduced grain.
  • Smooth to Touch: Parts feel softer and more refined compared to shot peening or natural finishes.
  • Reflective Sheen: The finish creates a subtle sheen that enhances the professional look of each part.
  • Black Dye Only: Vapor smoothing currently requires black dyed PA12 nylon; white nylon will discolor under smoothing.
  • Witness Marks: Each part will carry a small, discreet mark where the hang point was removed.

Benefits of Vapor Smoothing

  • End Use Ready: Best choice for customer facing or consumer applications.
  • Performance Boost: Lower friction surfaces improve wear and ease of cleaning.
  • Chemical Resistance: Smoothed parts stand up better to oils, greases, and solvents.
  • Durable Finish: The sealed surface reduces porosity, enhancing long term strength and stability.
  • Consistency: Dyed black parts show richer color and more uniform tone after smoothing.
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Vapor Smoothing Expectations

Warping Risk

Thin walls or broad flat areas can shift slightly during vapor smoothing. We recommend designs with walls thicker than 1.5 mm to reduce the chance of distortion.

Blistering in Recesses

Narrow grooves or deep recesses may trap vapor, creating small surface bubbles. Avoid very tight channels if a flawless cosmetic finish is required.

Gap Closure

Gaps smaller than 1 mm can fuse together when vapor bridges the surfaces. Larger clearances ensure features remain open after finishing.

Material Consistency

Different nylons or composites respond differently to vapor smoothing. To achieve a consistent look, keep parts in the same material and finish when possible.

Surface Reflection

The glossy finish makes parts look premium, but it can also highlight layer lines or blemishes that are less visible in matte finishes. This is cosmetic only and does not affect function.

Witness Marks

Every vapor smoothed part requires a hang point during processing. A small witness mark will remain where the hook is removed, always placed as discreetly as possible.