When you see a new piece of jewelry, you can immediately appreciate its shine and incredible smoothness of the surface. Before you see a product in this form, it goes through many different stages. Undoubtedly, each of them is important and without any of them the result could not have happened.
The appearance of only a cast product is far from perfect. The experienced hands of our craftsmen, using various tools and machines, give them the perfect look. So what happens to the workpiece after casting, how does the product get its beautiful appearance?
The first stage that follows casting is grinding. During grinding, the product is cleaned from:
• the sprue (the hole through which metal is poured into the mold);
• flash (extra material on the product remaining after casting).
Grinding is carried out first mechanically, using a machine and wheels of different abrasiveness, and removes the most noticeable flaws and irregularities. After this, small elements of the decoration are processed manually using a drill. A variety of attachments allow you to reach even the most secluded places.
Next begins a process called tumbling. This is an intermediate stage between grinding and polishing. During tumbling, smaller irregularities and scratches are removed. This process is carried out in rotating drums or special vibrating machines. In drums, the product is fixed motionless, and the tumbling bodies or liquid rotate, processing the workpiece. In vibration-type machines, abrasives or solutions are mixed in a chaotic manner, along with the decoration.
The tumbling process is divided into:
In a dry environment, this process occurs with the help of abrasive bodies, which are used as porcelain, plastic, corundum, and walnut shell crumbs. The particles used for dry tumbling are often in the shape of a cone, sphere, pyramid or cylinder. Wet processing involves the use of a buffer solution or working fluid. Reagents can be cleaning and polishing products, lime, soda or alkali solutions.
The final and decisive stage is polishing, after which the jewelry is given a magnificent mirror shine. Unlike grinding, this operation is necessary for a perfectly smooth surface finish of the product. It consists of carefully removing the thinnest, almost imperceptible, layer of coating. Jewelers often use a mechanical method using a soft polishing material:
Initially, the workpiece is degreased, then, to enhance sliding, polishing liquid is applied. After all the preparatory manipulations, the specialist, using a drill or machine with appropriate attachments, directly carries out the polishing itself.
This process can also be repeated for the product again, after securing the inserts.