What is Tumbling Process ?

Tumbling (also known as tumble polishing) is a technique of polishing or smoothing a rough surface. Different substances like stone, metal, glass etc. are used in tumbling process depending on the final requirements. We can achieve the outer edge radius on metal parts such as castings and stampings using this tumbling process. The radius may not be very exact but it is sufficient to avoid the sharp edges.

In this process, a plastic or rubber barrel is loaded with tumbling material such as stone. All these elements have similar or same hardness. They also add some abrasive grit to the barrel along with a lubricant. Silicon carbide is commonly used as grit and water as a universal lubricant. The barrel is then placed on a slowly rotating guide rails for rotation. The speed or rotation depends on various factors like geometry of parts being finished, tumbling material, degree of finish needed etc.

The parts to be finished are added to the above loaded barrel and allow the barrel to rotate. It will take out most of the sharp edges and other burrs from the parts. Time needed for tumbling also depend on several factors like degree of finish required, base material, tumbling material etc. It may range from few minutes to few days to complete the tumbling process.

Sometimes, shape of the tumbling material is changed to achieve a better control on final finish. There pre-shaped materials are called "preforms".

Tumbling is an economical process as large batches of parts can be finished with little or no supervision.

Hope you found this information useful.

Krish
Jythra Engineering Services
http://jythra.com