3D print finishing, internal channels

3D printing is without doubt a real gamechanger when it comes to manufacturing internal channels and cavities. The shape of the internal channels can be almost as complex as the designer likes to design them. Sounds wonderfull, BUT: How to finish these internal cavities of 3D metal printed components?

Reducing surface roughness

In cooperation with students from the University of Ghent, Raytech conducted further research to optimize the finishing process of internal channels and shapes in additively manufactured parts.

Up to 80% reduced roughness on Ti64 alloy (!)

Through research and especially by a lot of testing (trial and error), the process of blasting + chemical polishing, succesfully reduced the surface roughness of DMLS-parts. By a combination of blasting and chemical polishing it’s possible to achieve an internal surface roughness reduction of +/- 80%.
Although nice and surprising results can be achieved with this post-processing technique, several requirements need to be taken into account:

Terms & conditions;

• Design guidelines for 3D metal printing should be followed.
  • Avoid unnecessary support structures. Less support = less post-processing. Designing self supporting structures is key.
  • Lower 3D print layer thickness results in better surface quality (stairstep effect)
  • …
• To obtain smooth surfaces, it’s necessary to start the finishing process with quality 3D printed parts. Poorly manufactured 3D prints would ask much more processing time and chemical usage.
• Sufficient wall thickness of internal cavatities is required. Walls must be able to withstand pressure generated by post-treatment process
• Best results are achieved when flow can be circulating through the cavities.
• Process is mainly tested on titanium alloys. By adjusting parameters and settings, other materials could also benefit from the finishing process.

Suitable applications for this finishing technology

• Nozzles
• Hydraulic manifolds
• Fluid transportation
• Internal cooling systems

For detailed info concerning this topic, please feel free to take contact with us. We will enthusiastically answer your questions about this innovative way of finishing 3D metal prints.