UNTOUCHED by Human Hands…almost. High-Speed Surface Finishing Metal Alloy 3D Printed Parts

For additional information contact the Contributing Editor: David A. Davidson Deburring/Finishing Technologist | +1.509-563.9859 Cell and WhatsApp ddavidson@deburring-tech-group.com | dryfinish.wixsite.com/iso-finish

Original Post by Olaf Diegel, Professor of Additive Manufacturing at University of Auckland, New Zealand.

UNTOUCHED by human hands… almost. Here is a batch of our little Creative Design and Additive Manufacturing Lab bottle openers after effortless polishing. The top picture is straight off the machine, and the bottom picture is after centrifugal isotropic finishing. Other than breaking them off the build platform, and transferring them from one barrel of media to another, there was almost no other handling involved.

They were printed in AlSi10Mg, on an EOS M290, and polished on an MFI HZ-40 system (Thank you Dave Davidson for supplying the system, and all the other folk at Mass Finishing (Cole & Marci) for the excellent service!). The polishing was done by Arno Ferreira. Total polishing time, with 3 different media grades, was probably around 2.5 hours (will eventually be less, but we are still figuring out how long to run with each particular media), and total handling time was around 30 minutes.

Contributed by Cole Mathisen, Sales manager: MFI

Improve Surface Finish and achieve a High-Polish on Additive parts in minutes with Centrifugal Iso-Finishing Technology
Additive manufacturing is quickly becoming a feasible option for full-scale manufacturing.

The combination of modern software, new materials and printer technology is allowing additive manufacturing or AM to bring efficiency and flexibility to manufacturing operations. The parts created using these processes are often left with very rough surfaces and scale and other imperfections. Companies using additive manufacturing need to come up with a quick solution for smoothing and polishing their parts.3D Printing of models is often referred to as “Rapid Prototyping. Using traditional hand polishing methods to improve the extremely rough surfaces of these parts is anything but “Rapid.” An operator can spend days to get all of the surfaces smoothed out by hand. Centrifugal Iso-Finishing processes can achieve a polish on several parts at once (Like the ones featured above) in just two hours.

The Process: Achieving a polish on a 3D Printed part depends greatly on the material and the initial roughness and scale left over from the printing process. On relatively clean (no heavy heat scale or atmospheric discoloration) titanium or stainless steel 3D printed parts with an initial surface roughness of 300-400 micro-inch Ra here is a typical example process that is used with Centrifugal Iso-Finishing Machines:

Step One: Heavy grinding with aggressive plastic or ceramic media for 60 – 90 Minutes

Step Two: Pre-Polish with lighter plastic for 30 Minutes

Step Three: High Polish with dry corn cob polishing media for 30 minutes or wet porcelain m for 15 Minutes

Total process time: Two Hours (Not including loading)

Equipment Recommendation: 3D printed parts that have a high production volume to justify tumbling equipment tend to be smaller in size. For this reason the HZ-40 is a popular option. Its small footprint (roughly 3′ x 4′) makes it ideal for fitting into tight lab operations. See photos and videos of an HZ-40 machines in operation below:

For parts that are too large to fit in the HZ-40 barrel (longer than 10 inches and wider than 5 inches) a larger machine like the HZ-60, HZ-120 or HZ-160 with a bigger processing chamber is required. See a smoothing and polishing operation being performed in an HZ-60 Centrifugal machine below: