Additive Post-Processing Services

Yes, certain post-processing methods can affect part tolerances and dimensions — sometimes subtly, other times more significantly. At KingStar Mold, we carefully account for these effects during the design-for-manufacturing (DfM) phase to ensure your finished part performs as expected.

Here’s how specific methods may impact your part:

• Sanding and polishing
These remove surface material to eliminate layer lines or support marks, which can reduce part dimensions by a few tenths of a millimeter depending on surface complexity and how aggressively it’s sanded.

• Vapor smoothing
This chemically melts the outermost layer of plastic to create a glossy finish. While it doesn’t remove material in the traditional sense, it can slightly round edges and reduce sharp features, particularly on small or highly detailed parts.

• Post-machining
Machining is often used to tighten tolerances beyond what additive processes can achieve. However, it must be planned in advance — parts are typically printed with extra stock material in specific areas so that machining can bring them down to final specs.

• Coating and painting
These processes add a thin layer to the surface, which can increase dimensions slightly, typically in the range of 0.01–0.1 mm depending on the type and number of coats applied.

• Heat treatment (for metal parts)
Processes like stress relief, annealing, or HIP (Hot Isostatic Pressing) can cause minimal shrinkage or warping, especially in large or thin-walled DMLS components.

Because these dimensional changes vary depending on material, geometry, and finishing method, KingStar Mold integrates tolerance compensation into your part design early on. This proactive approach ensures your final part meets tight dimensional requirements — even after post-processing.

The right post-processing method depends on your part’s material, geometry, performance needs, and surface finish requirements. At KingStar Mold, we evaluate these factors and recommend the most efficient and cost-effective solution for your project.

Here are a few examples for reference:

• SLA part with fine detail, intended for display
→ Recommended: Light sanding + polishing or clear coating
→ Why: Enhances transparency and smoothness without damaging delicate features

• FDM part used for mechanical testing
→ Recommended: Vapor smoothing + post-machining
→ Why: Improves strength, surface finish, and dimensional accuracy for functional tests

• MJF nylon component with complex geometry for end use
→ Recommended: Dyeing + media blasting
→ Why: Dye reaches internal areas, while blasting improves uniform appearance

• SLS part with rough surface, going into a consumer product
→ Recommended: Tumble polishing + painting
→ Why: Smoothing followed by color matching for aesthetic and branding needs

• DMLS stainless steel part requiring tight tolerances
→ Recommended: Post-machining + heat treatment + passivation
→ Why: Achieves precise dimensions and corrosion resistance for functional applications

• PolyJet prototype with multiple colors, for presentation
→ Recommended: Light sanding + decals or pad printing
→ Why: Enhances appearance while preserving vivid color patterns

If you’re unsure what your part needs, KingStar Mold’s engineers can help you determine the right balance between performance, cost, and aesthetics. Just share your design specs—we’ll take care of the rest.

Additive manufacturing (AM), commonly known as 3D printing, has revolutionized how prototypes and end-use parts are made. But printing the part is only part of the process. Post-processing is the critical next step that transforms raw printed parts into final, usable components. It ensures the part meets the required standards of appearance, performance, and functionality.

This article explores what post-processing involves, why it matters, and how it’s tailored to various additive technologies.

Why Post-Processing Is Essential

While 3D printing builds parts layer by layer, the surface finish, mechanical properties, and dimensional tolerances often fall short of final application needs. Post-processing bridges that gap by:

• Improving surface quality and removing support marks or layer lines

• Enhancing mechanical strength and durability

• Meeting tight dimensional tolerances

• Preparing parts for assembly or cosmetic applications

• Ensuring part cleanliness, stability, and compliance for regulated industries

Common Post-Processing Methods

Different materials and print technologies require different finishing methods. Below are some of the most widely used:

• Sanding and Polishing

These mechanical processes smooth surfaces and remove print artifacts. Manual or automated sanding is often used on FDM, SLA, or PolyJet parts, followed by polishing for a refined finish.

• Vapor Smoothing

Used primarily on thermoplastics, this process melts the outer layer of the part using controlled chemical vapor exposure, creating a glossy, sealed surface ideal for painting or sealing.

• Media Blasting and Tumbling

These abrasive techniques remove loose particles, improve uniformity, and polish complex surfaces. Suitable for SLS, MJF, and metal parts.

• Dyeing and Painting

Dyeing is common for porous plastic parts where painting is impractical. Painting, on the other hand, is used for cosmetic appeal or brand matching and can include EMI shielding coatings or custom color specs.

• Plating and Coating

Electroplating can dramatically increase the strength and conductivity of plastic or metal parts. Specialty coatings also improve corrosion resistance or aesthetic properties.

• Machining and Inserts

Post-machining is used to achieve tight tolerances not possible during printing. Threaded inserts may also be added for assembly purposes.

• Assembly

When a printed part is part of a larger system, final assembly is often performed in-house as part of post-processing.

Tailoring Post-Processing to the Technology

Each 3D printing method—FDM, SLA, SLS, MJF, PolyJet, DMLS, and STEP—has unique material behaviors and surface characteristics. Post-processing strategies must be adapted accordingly. For instance:

• SLA and PolyJet parts often need support removal and polishing

• SLS and MJF parts benefit from media blasting and dyeing

• DMLS (metal printing) may require heat treatment, machining, and passivation

Streamlining with In-House Post-Processing

Outsourcing finishing steps can introduce delays and inconsistencies. Companies like KingStar Mold offer integrated, in-house post-processing services. This helps shorten lead times, maintain quality control, and reduce supply chain complexity—all while delivering high-performance, production-ready parts.

Final Thoughts

Post-processing is not just an optional add-on—it’s a vital phase in additive manufacturing that ensures your 3D printed parts look better, perform better, and last longer. Whether your goal is aesthetic appeal, functional integration, or compliance with strict specifications, the right post-processing strategy can make all the difference.

Need help optimizing your 3D-printed parts? KingStar Mold offers turnkey additive manufacturing and finishing services to help you get the job done—fast, efficiently, and to your exact standards.