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Metal AM Finishes

Following production, parts will typically go through a series of post-build processing steps including support removal, abrasive blasting, machining, and sometimes polishing.  Parts are usually greater than 99% dense and require no further sintering or other infiltration process to be considered fully dense.

Dependent upon the material used and the complexity of the parts built 3T can offer a range of in-house finishing or, through our select supplier network, we can support most of our customers’ requirements including materials treatments, machining, coatings and independent measurement verification.

Abrasive blasting

Abrasive blasting is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface, or remove surface contamination. A pressurised fluid, typically air or water, is used to propel the blasting material (often called the media). There are several variants of the process, such as bead blasting, sand blasting, wet blasting, and shot blasting.

At 3T the type of abrasive blasting that is selected will be depend on the material and the exact requirements of each individual customer.  Please talk to a member of the team for specific advice on the appropriate finish to meet your needs.

Here are some examples of different finishes on parts produced in Cobalt Chrome:

Metal AM part using DMLS

As sintered
(Ra = 10 µm)

Metal AM part shot-peened with metal

Bead-blasted with Metal
(Ra = 5 µm)

Metal AM part shot-peened with Metal and Ceramics

Bead-blasted with Metal & Ceramics (Ra = 4 µm)


Metal polishing to smooth the surface of the metals can be achieved to the full range of requirements, including to a mirror-like finish. Polishing is often required prior to other surface treatments to prevent corrosion, surface contamination, and not just simply to enhance the aesthetic appearance of parts. It is a common requirement for components used in automotive and aerospace sectors. Medical instruments are frequently highly polished to help maintain hygienic conditions and prevent contamination of surface marks in the metals.

Polishing can be achieved via manual, mechanical or electrochemical techniques. 3T can provide a service via it’s supplier network that use sophisticated computer-controlled machines to polish intricately shaped articles, or have dedicated experts for hand finishing to specific industry requirements.

Metal AM part with polished finish

Metal AM parts unfinished and polished

Parts unfinished and polished

Example parts showing difference between ‘as sintered’ and polished finish