Summary for non-round diamond polishing Discussion
Polishing the interior surface of a non-round polycrystalline diamond is the challenge John Rumpz describes: round or hourglass-shaped bores can be finished fairly easily by moving the part in a circular and up-and-down motion with diamond powder in an ultrasonic drilling process, but square or rectangular interiors prevent that motion because the drill needle must match the profile. The opening is also very small, about 0.250 inch, which limits processing options. No solution is given in the excerpt, so the thread mainly frames the problem as a search for a cost-effective way to achieve a mirror finish in a confined non-round cavity. The key practical takeaway is that the geometry, not just the material, is the main obstacle, and any workable method would need to accommodate the small, non-circular interior profile.
Q. Our company routinely polishes the interior surface of a polycrystalline diamond form. When this interior profile is round (or more accurately similar to an hourglass) it is quite simple as we can move the piece in a circular motion as well as up and down. Diamond powder is used in conjunction with an ultrasonic drilling process to achieve mirror finish. However, when the interior profile is square or rectangular, we can no longer spin the piece in the desired circular fashion as the drill needle must take the same shape as the profile. Looking for cost effective ways to polish this interior surface in non-round shapes. Note that the inside of the piece is small 0.250″ approx. so this does restrict processing options.
John Rumpz
– Woodburn, Indiana USA
February 10, 2016