Finishing media is used in the method of finishing of parts. When the parts are loaded into the finishing
machines – tumbling machines and vibratory finishing machines – along with the media, they rub with
each other. The media has an coarse property which results in deburring, smoothing, polishing and
cleaning of the parts. Finishing compounds may be used all through the finishing practice to increase the
effectiveness of the finishing media. Finishing media can be mostly classified into two categories. One is
natural media like corn cob media and walnut shell media. The other category is non-natural media like
plastic deburring media and ceramic finishing media.
Corn cob media is prepared by grinding the durable wooden ring of the corn’s cob. It is prepared into an
harsh grit that can flow smoothly. Because it is natural, the corn cob media is environment friendly. This
media is fitting for use with both tumbling and vibratory machines. It has enormous absorbent
properties which makes it perfect to clean and dry parts. Corn cob grit can soak up oils, grease, dirt and
moisture without causing a score or damaging the surface of the parts in any way. It is exceptional for
use as a burnishing agent and is used for burnishing of metals in tumbling machines. Metals such as
brass and bronze which are soft in nature get the desired finish with this media.
The corn cob media grit comes from coarse variety to super fine assortment to suit an assortment of
parts, based on their mass and nature. This media is durable and does not break down easily; It can be
reused again and again and it cost effective. It reduces the cycle time of finishing operations. It is clean
and can be incinerated and poses no health or environment hazard. It has a soft abrasive action and can
be safely used on delicate components to preserve micro finishes. It is effective on both metallic and
plastic parts.
Walnut shell media is another well-liked natural finishing media. It is prepared by grinding walnut shells
that are tough and fibrous into grit – the grit sizes could be large or small based on the requirements.
The nature of the parts plus the perforation size of the screen that is used to separate the parts from the
media after the finishing process is over decide the grit size. Walnut shell media is also used in blasting
machines apart from tumbling and vibratory machines. They are ideal to de-flash plastic parts and
polishing and smoothing of metals like aluminium, bronze and brass.
Walnut shell media also comes in useful in oil drilling to prevent clogging during circulation and to
impart anti-skid properties to paint which is used around swimming pools and walk ways. This media is
angular and multi faceted. It lasts long and is reusable. Being organic, it is non toxic and environmentally
safe. It is a soft abrasive that can maintain the primer coat while removing the top coat of paint from
parts. It serves to improve the cycle time of the tumbling or vibratory finishing progression.