Summary for surface improvement of rapid-manufactured parts Discussion
surface improvement of rapid-manufactured parts is the central question here: Nathan Race of Clemson University asks how to smooth rough 3-D printed parts made from sintered 420 stainless steel powder infiltrated with bronze, while preserving dimensional control on complex shapes and curved surfaces. He notes the bronze wicks into the part and leaves stainless powder protruding, creating a very rough finish, and asks whether a treatment can bring the surface to as-machined or better. The replies are brief but practical. AF Kenton suggests electropolishing as a process worth trying, implying it may help on stainless surfaces with good control. Bud Graybill recommends drag polishing, another finishing method that can follow complex geometry. No one claims a guaranteed best solution, and the thread does not compare the methods in detail, but both answers point toward polishing-based finishing rather than coating or peening.
Q. Hello,
I’m working with a Clemson University research lab to improve the surface finish of parts made in our 3-D Printer. The parts have a sintered 420 stainless steel powder (30um) base structure infiltrated with molten bronze to achieve full density. The resulting surface is very rough due to the capillary forces that draw the bronze into the part and leave the stainless powder protruding. We’d like to be able to get the finish to as-machined or better using a process that can accommodate complex 3-D geometries and curvature. We’ve considered many avenues from PVC coating to shot peening. Is there a treatment option out there that can be applied with good dimensional control and yield a good quality surface finish? Any information would be greatly appreciated.
Nathan Race
Researcher – Clemson, SC, United States
2005
A. Electropolishing is worth a try.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
A. You used the words rough and protruding. To me, that means surface modification before any secondary coating and the best way to achieve those results is via mechanical finishing or more specifically mass finishing equip. Size and volume will determine proper equip.
AF Kenton
retired business owner – Hatboro, Pennsylvania
A. Look into drag polishing.
BUD GRAYBILL
polishing shop – California