Additive Post-Processing Services

Yes, certain post-processing methods can affect part tolerances and dimensions(but 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, so 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.

Choosing the right post-processing starts with understanding your part’s “job”—and as a manufacturer handling thousands of projects, we’ve learned that context matters more than any one-size-fits-all rule. Here’s how we break it down in our shop:​

If your part is an SLA prototype with fine details (like a medical device model for a client presentation), we’ll likely recommend light sanding followed by a clear coat. Why? We’ve found this preserves tiny features (think 0.5mm text or intricate grooves) while boosting transparency which may be a bonus for impressing stakeholders.​

For an FDM part heading into mechanical testing (say, a custom bracket for industrial machinery), vapor smoothing + precision machining is our go-to. In our experience, the chemical smoothing seals layer lines to prevent stress cracks during load tests, and a quick CNC pass ensures it mates perfectly with existing components. We’ve saved clients weeks of rework by catching tolerance gaps here.​

Complex MJF nylon parts (like a drone housing with internal channels) often need dyeing + glass bead blasting. The dye penetrates those hard-to-reach areas evenly (we test with UV light to check coverage), and blasting removes any stray powder without dulling the color—key for end-use parts that need both function and brand consistency.​

And when it comes to DMLS stainless steel components (aerospace fasteners, for example), our team swears by post-machining + heat treatment + passivation. We’ve seen firsthand how heat treating eliminates print-induced stress (critical for high-vibration environments), while passivation forms a protective layer that withstands 500+ hours of salt spray testing—non-negotiable for our aviation clients.​

Unsure where your part fits? Share its purpose, material, and pain points (e.g., “it needs to survive engine oil” or “the surface looks too rough for our brand”). And our engineers will walk you through options we’ve proven to work in similar scenarios.

To us, post-processing is where 3D printing stops being a “prototyping tool” and becomes a production solution. It’s the hands-on work we do after the printer finishes that turns a “rough draft” part into something that performs, lasts, and fits into your workflow.​

Printing lays down the foundation, but even the best 3D prints have limitations: FDM parts have visible layer lines, SLS nylon is porous, and metal prints from DMLS can hide tiny stresses. Post-processing fixes these, and not as an afterthought, but as a planned step in our in-house workflow.​

Take our process for SLA resin parts: After printing, we don’t just yank off supports. Our technicians use precision tools to trim supports flush, then wet-sand with progressively finer grits (we start at 400, end at 2000) to preserve details while eliminating marks. It’s tedious, but we’ve learned that rushing this step leads to parts that look unprofessional in client presentations.​

For metal parts, post-processing is about reliability. We once had a client with a DMLS titanium bracket that kept failing load tests. It turns out, the print’s rapid cooling left internal stresses. Our fix? A custom heat treatment cycle (1,200°F for 4 hours, then slow-cool) that relieved stress without warping the part. Now it’s used in their industrial robots, holding up to daily use for over a year.​

The best part? Doing this all in-house lets us adapt on the fly. If a PolyJet prototype needs a last-minute logo added, our pad printing team can tweak the design the same day with no need to wait for an external vendor. That’s the difference between post-processing as a “step” and post-processing as a partnership: we’re invested in making your part work, from the first layer to the final inspection.​