3D Printing Post-processing
Surfaces, finishes, and post-processing—a crucial aspect of additive manufacturing. They influence the appearance, feel, function, and durability of 3D-printed components.
Why Post-Processing Is Crucial in 3D Printing
3D printing produces parts layer by layer. Depending on the process, this results in characteristic surface patterns (e.g., faint layer lines or a matte powder texture). With the right post-processing, the surface can be specifically tailored to meet specific requirements—for example, to improve appearance, enhance tactile feel, or create defined functional surfaces.
Common goals of 3D printing post-processing:
- Smooth or even out surfaces
- Enhance the appearance of components (color, paint, finish)
- Improve functionality (e.g., handling, mating surfaces, assembly)
- Protect the surface (depending on the environment/wear and tear)
3D Printing Post-Processing Methods
Mechanical & Thermal Post-Processing
Removing powder, support structures, and residue:
- Depending on the 3D printing process, support structures must be removed or powder residue must be cleared from the part. This is often the first step in ensuring that geometries, channels, and functional areas are clearly accessible.
- Typically used for: SLS, MJF, FDM, SLA/PolyJet
- Result: a clean blank as the basis for further steps
Blasting (e.g., glass beads / media blasting):
- Blasting makes the surface more uniform and visually smoother. This is particularly effective in powder-based processes for homogenizing the typical matte texture.
- Typically used for: SLS, MJF
- Result: a smooth, matte finish
Tumble finishing / Trowalizing:
- Mechanical smoothing reduces visible layer lines or roughness and is particularly suitable for defined visible surfaces. Depending on the component’s geometry, the process is applied either to specific areas or across the entire surface.
- Typically used for: FDM, SLA, and in some cases SLS/MJF (surfaces visible to the eye)
- Result: a noticeably smoother surface; depending on the effort involved, up to "very fine"
Milling & Turning
Light and heat treatment for curing
Chemical Post-Treatment & Surface Smoothing
Chemical smoothing can homogenize surfaces, particularly in certain types of plastic. The goal is to achieve a more uniform feel and appearance.
- Typical for: depending on the material/requirements (material-dependent)
- Result: visibly more uniform, less "layered appearance"
To produce uniform, seamless surfaces with a reduced layered appearance—particularly for components with high aesthetic requirements and results similar to those achieved in injection molding.
Coating, Dyeing & Varnishing
Dyeing
- creates a uniform appearance and often strikes a good balance between “technical” and “presentable.” This can make the surface appear significantly smoother, especially on powder-coated components.
- Typically used for: SLS, MJF
- Result: uniform color effect (depending on the material and geometry)
Painting / Coating
- improves visual quality and allows for specific color values or effects. Depending on the design, it can also protect the surface.
- Available in RAL colors, matte/glossy, UV protection
- Typically used for: SLA, FDM, SLS/MJF (when a high-quality finish is required)
- Result: high-quality appearance, defined look
- You can find all the information you need about coating types, surface finishes, and selecting RAL colors on our page on 3D printing coatings.
Sealing / Waterproofing:
- Coatings can make surfaces more durable and, depending on the requirements, stabilize the component surface for future use. This is important when components are frequently touched or subjected to stress.
- Epoxy resin coating (waterproofing, chemical resistance)
- NanoSeal Infiltration (Water- and Oil-Tightness)
- Copper-clad laminate for ESD-compliant components
- Typically used for: SLS/MJF (depending on the application), FDM
- Result: a more durable surface and, depending on the application, better protection
Classification
Post-processing by material
Plastic
3D-printed plastic components offer a wide range of post-processing options. Depending on the process and material used, mechanical, thermal, or chemical steps can be combined to specifically improve the surface, feel, and function.
Typical post-processing steps for plastics:
- Vibratory finishing and trowalizing for smoother surfaces
- Sandblasting – all SLS / MJF / SLM components are sandblasted as standard
- Milling, Turning
- Light and heat treatment for curing
- Chemical polishing for injection-molded-like surfaces
- Dyeing, Varnishing and coating
- Sealing to protect against environmental factors
Objective: To optimize the appearance, handling, and protection of the components.
Metal
For additively manufactured metal components , the focus is on functional suitability. Post-processing here serves primarily to achieve defined mechanical properties, dimensional accuracy, and surface quality for technical applications.
Typical finishing processes for metal components:
- Milling
- Rotate
- Grinding for smooth surfaces & improved dimensional accuracy
- Sandblasting: All SLS / MJF / SLM components are sandblasted as standard
- Painting: for RAL colors with a finish (matte, glossy)
- Heat treatment (thermal) for excellent strength and hardness
Objective: To ensure the mechanical performance and functionality of metal components in real-world applications.
3D Printing Post-Processing - Frequently Asked Questions
What does post-processing mean in 3D printing?
Post-processing refers to all the steps that take place after the actual 3D printing process. The goal is to specifically improve printed components in terms of surface finish, appearance, or function. This includes, among other things, cleaning and removing powder or support structures, blasting, smoothing, or sanding, as well as cosmetic finishes such as dyeing or painting. Post-processing is thus a crucial step in adapting components to their intended end use.
How can the surfaces of 3D-printed parts be smoothed?
The appropriate method for surface finishing depends on the 3D printing process and the material used. Mechanical methods such as grinding or polishing are frequently used. In powder-based processes, blasting is also often employed to achieve a more uniform surface. In certain cases, chemical smoothing may also be appropriate to significantly reduce the typical layered appearance. The appropriate method is always determined on a case-by-case basis.
What kind of post-processing is typically required for SLS or MJF parts?
For parts manufactured using SLS or MJF processes, post-processing typically begins with debinding and cleaning. The parts are then often sandblasted to create a uniform surface. Depending on the requirements and desired appearance, additional steps such as dyeing, sealing, or applying functional coatings may follow. The extent of the post-processing depends on the intended use of the component.
Does post-processing affect a component's dimensional accuracy?
What kind of post-processing is recommended?
To ensure that the post-processing is appropriate for the objective, it is helpful to clearly categorize tasks based on requirements:
When aesthetics are the top priority:
- Sanding/Polishing → for visible surfaces
- Painting/Coating → "Showroom" Look
- Dyeing → a calm, uniform appearance
When function is the priority:
- Dust removal/support removal → clean starting point
- Blasting → a smoother surface
- Minor rework → Define fits/surfaces
When durability and protection are the top priorities:
- Sealing/Waterproofing → Stabilizing the surface
- Coating → Combining protection and aesthetics
We provide application-specific advice and recommend only those steps that make technical sense.
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