Whether from additive or conventional manufacturing, there is hardly a part that we produce that does not require one or more finishing steps. They include support removal, material and surface enhancements, and refining techniques. You receive these services in addition to having your products manufactured in-house with us. As you can see already from the overview, you have access to a rich spectrum of professional finishing techniques for optimal results at FIT – and with us, you get everything from a single source!
Metal coating is a professional post-processing technique for the durable metal coating of additively manufactured plastic and metal parts by electroplating. Components can be partially or completely coated. Electroplating refers to the permanent coating of an object with a metal layer. First, the component is made conductive. It is then suspended in an electrolyte bath and connected to the power supply. Metal ions detach from a copper or nickel anode (positive pole), which is also suspended, and deposit on the workpiece (the cathode) in an electrochemical process. The longer the object is in the bath and the higher the electric current, the stronger the deposited metal layer becomes.
Metal properties for plastic parts
Metal coating is used to electroplate 3D-printed plastic components with a target geometry of ± 20 µm, ensuring a homogeneous layer thickness all over the part’s surface, provided the component geometry permits. Metal coating is ideal for both the optical and functional improvement of components, as it results in an appealing metal look as well as real mechanical and electrical part properties. If e.g., a stereolithography component is coated with a nickel layer (150 µm), the part will gain properties comparable to carbon. Moreover, plastic components can also be easily and quickly transformed into a shaped metal substitute, at a fraction of the manufacturing cost of a sheet metal part.
Hot isostatic pressing (HIP) is an HPHT (high-pressure heat treatment) process used for the compression and densification of metal and ceramic parts. The exposure to pressure and high temperature allows process-related defects such as pores and cracks to be closed, thereby increasing component density. At a pressure of up to 2,070 bar and temperatures of up to 1,400 °C as well as cooling rates of 4 °C/sec, HIP treatment can improve the mechanical properties of the part and produce a part density of 99.99 %.
When used with aluminum parts from laser melting (LM or PBF-LB/M), HIP serves to improve the part quality by closing frequently occurring process-related pores and cracks. When used with titanium components such as medical implants from electron beam melting (EBM or PBF-EB/M), HIP serves to increase product safety. The compression chamber has a size of Ø 270 mm x 240 mm and can be subdivided into several levels to process components of different sizes.
99.99 % part density
HIP is fully validated by FIT and integrates seamlessly into our in-house process chains. With HIP and other post-processing techniques available in-house at FIT, transfer from production to post-processing happens seamlessly and without any logistical delay or loss of information. This makes it possible to provide optimal lead times while avoiding any obstacles incurring when involving outsourced, third-party services. The entire process is completely monitored to ensure stability, traceability, and reliability. All process data is tracked and can be documented and handed out in a quality report with evidence of measured values and photos if required.
There are two different approaches to infiltrating, both of which produce greater stability and moisture resistance in plastic components. Infiltration can be used to create airtight and watertight components.
1) Brushing technique
The 2K epoxy resin penetrates the surface, closes the pores, and creates an airtight and watertight impregnation. This technique is particularly apt for large components from selective laser sintering (SLS or PBF-LB/P). For binder jetting components, infiltration serves to increase part strength.
2) Dipping technique
Dipping is mainly used for smaller parts as well as components with complex outer and inner geometries because the impregnating agent can reach difficult areas that would otherwise be inaccessible. A colorless Dichtol is used for this purpose. By using black Dichtol, the component can be colored black in just one step and without further post-processing steps.
Vibration grinding, also known as barrel finishing, is an automatic wet grinding technique for smoothing the surfaces of plastic and metal parts. The easy-to-use equipment is suitable for processing very different shapes and sizes of the workpiece. The components are placed in a container together with abrasives and a liquid additive which will remove rough particles from the surface, by rotation and oscillation. The surface of the components, the remaining roughness, and the amount of removed material can be controlled depending on the duration of the process. For instance, particularly smooth surfaces are required by the food industry for reasons of better cleaning. However, small holes, gaps, or internal structures remain untreated. Vibration grinding is recommended for components up to a size of 200 x 100 x 100 mm, but not for delicate, fragile parts.
The coloring of the components takes place semi-automatically in an immersion tank. During dipping, the color penetrates up to 300 μm into the surface, resulting in uniform and shape-independent dyeing. This penetration of the color makes the components also scratch-resistant. Dipping is recommended for components up to a size of 300 x 300 x 300 mm. 10 standard colors are available. If requested, individual customer-specific colors can be realized. By dipping, it is possible to color geometries that are difficult or impossible to paint. Dipping will not apply an additional layer to the component and will not change the properties of the component.
In thermal vaporing, an extremely thin metal layer is applied in a gaseous state to the substrate. Like this, components with a sophisticated finish gain a metallic appearance. Vaporing is recommended to achieve surfaces with a shiny chrome appearance such as reflectors for headlights and decorative inlays. After vaporing, a hard layer of varnish or SiO2 is applied by plasma polymerization to achieve greater resistance to damage, however, vaporing is distinctly less durable than metal coating by electroplating.
Depending on the project definition, single components (either manufactured by FIT, purchased, or provided by the customer) are mounted to accomplish the entire assembly. This can be done by a catalog of options available in FIT‘s model building department, e.g. by screwing, gluing, or welding metal or plastic parts.
During chemical smoothing, the top layer of the plastic part is liquified and restructured so that the part gains a smooth surface. The stronger the treatment, the greater the associated loss of detail on the component will be. Smoothing can be applied to both outer and inner surfaces (depending on the geometry). Sealed like this, surfaces become glossy (depending on the degree of smoothing), dirt-repellent, hygienic, and easy to clean. The smoothing reduces the layer traces and the notch impact so that the smoothed parts have higher mechanical stability than the original component. The smoothing also allows for higher color brilliance in colored materials. Treated parts are free of loose particles. Particularly suitable for smoothening are, for example, components made of PA and TPU with a wall thickness of at least 1 mm.
Blasting is a mechanical process for finishing surfaces, e.g. for cleaning and homogenization. At FIT, manual and fully automated blasting techniques are an integral part of the post-processing of plastic or metal parts, either from additive or conventional manufacturing. For transparent components from stereolithography or vacuum casting, blasting is used for matting effects of the surfaces (frosted glass effect) as well as to prepare painting.
1) Blast compacting of SLS components
Blast compacting of laser-sintered plastic components uses compressed air to shoot ceramic blasting beads in a blasting system to level out unevenness at the component surface and to close open pores. This procedure results in a very homogeneous and smooth surface. Blast compacting is recommended for components up to Ø 150 mm.
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2) Centrifugal “Twister” blasting for components from laser melting and EBM
In fully automated centrifugal blasting, the blasting material, e.g. small stainless steel balls, is shot onto the metal components via a centrifugal wheel, thus producing homogeneous and reproducible surfaces at a minimum force. Depending on the size and shape of the workpieces, it is possible to attach up to 10 components to one carrier (max. diameter 140 mm). This makes it possible to process up to 100 components simultaneously in just one blasting operation.
In order to achieve the desired result by painting, various preparatory steps are necessary, e.g. to eliminate a corrugated structure or other surface defects. Before paint or clear-coat is applied, the component is initially cleaned of loose material residues by blasting, followed by priming and/or filling as well as sanding. This process can be repeated, if necessary until the required surface quality is achieved. After completion of the preparatory steps, the component can be painted. At FIT, a professional paint booth (6.0 x 6.8 m) with a drying room as well as a professional color mixing system are available. Textured, matte, gloss, or high-gloss paint can be mixed in almost all RAL and Pantone colors, to be applied in one or more color layers.
3D-printed components sometimes do not have the accuracy required for their intended use. If so, defined areas have to be treated to achieve the required tolerances, surface quality, and functions. This can be achieved by a catalog of options available at FIT, such as milling, turning, eroding, grinding, and drilling.
By polishing, we increase the surface quality of metal and plastic parts. Depending on customer requirements, various finishing techniques are available. We offer both manual and machine polishing with different polishing pastes and discs. Polishing can be used as an intermediate step for further post-processing techniques or as a closing step.
Mirror finish high polish
For titanium components, we also offer a special mirror finish. This means the surface of the titanium blank is processed in several pre-polishing and polishing steps after a rough pregrinding. This produces a mirror-finish, high-gloss surface with extremely low roughness.
Heat treatment is a controlled thermal process to reduce tensions and improve material properties in the manufactured component. Material properties such as elongation at break, hardness, and temperature resistance can thus be positively influenced. At FIT, a catalog of techniques is available depending on material, requirement, and size.
1) Heat treatment of plastic parts
Using a tempering process, plastic components, e.g. SLA components made of Accura® HPC or vacuum-cast parts made of PU, are heated in special furnaces to improve their mechanical and thermal properties.
2) Heat treatment of metal parts
Various processes are available for metal parts depending on the material:
Tolerances can be reliably checked with tactile 3D measurement using precise measuring calipers.Learn more >
You need certainty regarding the material properties of your components? With the static universal testing machine, various testing methods on test specimens are possible.Learn more >
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