Titanium Stents

Finishing medical parts requires very stringent testing and results to ensure that the parts are deburred properly. Titanium stents are inserted into arteries to keep them open. A properly deburred edge and smooth surface finish is absolutely necessary to ensure that the medical part works exactly as expected.

Titanium is a hard metal and is often deburred in a vibratory tumbler with Ceramic Media. The size and shape will depend on the geometry of the part and size of the openings. Adding a medium size grit such as Aluminum Oxide will increase the abrasiveness of the tumbling process and provide a smooth, rounded edge. If embedding of the grit is of concern, using a Ceramic Media that is aluminum oxide free (i.e., KDF Bond) with an addition of Silicon Carbide will also produce excellent results.

Finishing Pewter

Pewter is a soft, malleable metal consisting primarily of tin. Decorative plates, jewelry, figurines and even keys (see picture below) can be made with pewter. Since pewter is so soft, it is difficult to maintain a polished finish on the surface. It is common to treat the pewter design with a black coating that is then polished away from the high spots to produce an exaggerated 3-dimensional effect.

Key Art Co.

The black oxide coated parts are vibratory tumbled with Precision Ceramic Spheres and a mild acid cleaner such as Kramco 1030 to 'clean' the high spots. The spheres provide an excellent bright and clean finish without removing the oxide from the interior relief areas of the part. Cycle times can be as short as 10-15 minutes depending on the desired results.

If a matte finish is more desirable, a cutting/abrasive version of the Precision Ceramic Spheres can be used. To remove more of the oxide, a triangle media is ideal.

Thermoplastic Polishing

Before

This small polyamide, thermoplastic resin, hardened part had a rough surface finish as well as flashing that needed to be removed. The challenge in deflashing and polishing plastic parts is to choose a media that will be aggressive enough to remove enough material to create a smooth finish without scratching or etching the surface too much so that the part can be polished successfully.

After

A two-step process was used to first de-flash the part and then polish the surface. The first step involved vibratory tumbling with a Precision Ceramic Fast Cutting Sphere to remove the flash and smooth the surface. This shape and bond (formulation) of media provided good cutting action (deflashing and edge rounding) but not the rough, 'tumbled' finish normally associated with angular shaped media. The part was then polished with a Precision Ceramic Polishing Sphere. Again, this shape provided the best polishing action and left the part with a near-mirror surface.

Abrasive Blast Rooms

Abrasive blast rooms offer a lot of advantages when blasting large parts and when using a re-usable media such as Aluminum Oxide or Steel Shot. These rooms provide an area that can collect the media, send it to a recycling and separating system and then be re-blasted. Blast rooms can also be equipped with exhaust and dust collection systems. The major drawback is the cost typically in excess of $100,000.

An alternative to a blast room is to perform the abrasive blasting in either an outdoor area that is 'closed' in or to blast in a separate room such as a garage or shipping container. These areas can be set up to contain the media and dust but will limit the media choices to consumable, less expensive blasting media such as Crushed Glass Grit.

In order to use a re-usable media, a system such as the Blast Room Package is needed to collect, separate, clean and blast the media. Simply sweeping the used media, dust, dirt, paint chips, etc. into a feed hopper will transfer the recycled material to the abrasive separator, clean out large pieces, remove the dust and send the good media to the pressure pot for re-blasting. The Blast Room Package can simulate nearly all the benefits of a full-fledged blast room but at a fraction of the cost.

Aluminum Pre-Anodize Finish

Creating an appropriate edge and surface finish on extruded and cut aluminum parts that need to be anodized requires both deburring and a smooth surface finish. Anodizing creates a protective oxide layer which can range from a matte to a high polish finish. A major factor in the aesthetics of the final anodized part is based on the pre-anodized surface finish.

Extruded and cut

This aluminum part was extruded and cut to size. The part shows an uneven, rough surface finish, sharp edges and burrs. There are also aluminum shavings and scratches that need to be cleaned and removed.

Ceramic Media Tumbled

Vibratory tumbling the aluminum parts with a Ceramic Media will produce a beautifully rounded edge and smooth, matte surface finish. The cycle time will be short (as little as 30 minutes) but the anodized finish will typically be a smooth, matte finish.

Synthetic Media Tumbled

Tumbling the part for a slightly longer time with a less aggressive Synthetic Media will also result in a deburred, slightly rounded edge but a much smoother, more uniform surface finish. A slightly longer cycle time with a 'softer' media will significantly improve the anodized finish resulting in a bright, polished part.