The two most popular for this would be the high energy Centrifugal Barrel Finisher, or CBF, and the disk finishing machine. The CBF Machine can produce highest speeds and energy requisite for the removal of surface metal, burs and parting lines. This is achieved by the barrels turning in one direction while the tuffet holding the barrels turns in the opposite direction creating the high energy and speeds. It is also important that a hex-shaped barrel be used to give additional action during the process.
NOTE: Results from round barrels are not as favourable.

The machines can be run for both wet as well as dry processing to include wet cutting, dry smoothing and dry polishing. Fixtures to hold parts in place to keep from colliding can also be installed inside of the barrel (dry processing only).

Disc-Finishing machines, (also regarded as high-energy machines) are now becoming another popular means of mass-finishing platinum. The action of the disc - finisher is not as rigorous as with the CBF machine, but it does a good job on platinum and has the advantage of having an open bowl to view parts. It is ergo­nomically superior to CBF machines, thus, making the switchover and separation of parts far less cumbersome. Many people prefer this convenience over time. The toroidal action taking place in the machine bowl produces a quality surface finish for both cutting and smoothing. Results from polishing platinum in these machines have not been as favourable as with the CBF or the drag-finishing machines.

The drag-finishing machine is ideal for parts needing fixturing to avoid collision and scratching. Its principle is simple. The fixtured parts lower into a processing bowl with dry (smoothing or polishing) media and then rotate for a desired time. Once the process is complete the fixtures rise out of the media and can be removed. One of the important points about the drag-finisher is its ability to finish the inside of the parts as well as the out­ side.

We also recommend that you use a drag-finisher with the planetary type centrifugal motion. By this it is meant that, like with the CBF machine, the fixtures rotate in one direction while the turret moves in the opposite thus creating an optimal processing movement of the parts through the media. A bi-directional motion is also favourable. This is a setting on the drag-finisher which when activated will tum at first in a clockwise motion for a set amount of time, and then stop and go in the opposite direction for, also, a set time. I would recommend 30 minutes in each direction.

Vibratory bowls can also be used with good success for burnishing platinum parts. The size and shape of the steel media should be considered when using this method depending on the shape, size, and how intricate the design of the parts is. With a vibratory bowl it is important to find the right toroidal action so the 3-dimensional movement of the media can achieve its maximum function. Basically, the steel media will press or flatten the surface thus tightening the metal. Depending on the parts, I have found vibratory bowls a very good secondary process (tightening and giving shine to the surface) before putting the parts into a drag finisher to give the part a high lustre. In some cases, the process has even given parts a final polish.

In the cut down process, or first step, it is important to find a media which is aggressive enough to remove the surface layer in a relative timely fashion. Always make sure the media size does not present any lodging problems and can reach all of the necessary areas of the part. The compound used with this media should assist in cutting and / or cleaning the parts. For dry media, it is also important to find a size (i.e. of walnut shell) which will be suitable to perform its primary function but not lodge in the parts. A good rule to remember is that the larger the media the more aggressive it is. There are a variety of cutting or polishing pastes, powders and liquids available for dry media, which are used to enhance the media performance and to keep the life span of the media longer. Combinations or media sizes, when processing either wet or dry, is also a consideration. An example of this would be using larger plastic cones along with smaller pyramid shaped plastic or ceramic media which can reach areas the cones which can reach areas the cones cannot reach but also allowing the cones to work the larger, flat or rounded surface areas.