De formation process

Knurling is a process of making an array of diamond-shaped indents on a smooth surface, to improve gripping. on cylindrical surfaces this can be done using a lathe machine fixed with a knurling tool.

embossing is a process of creating raisied features on a smooth surfaces, such as in coins.

but coining is a mettalurgical process. it is a process of hardening the material by applying high stress and thus reducing the grain size. the finer the grains, the more stronger a material is.

Knurling is a process of making an array of diamond-shaped indents on a smooth surface, to improve gripping. on cylindrical surfaces this can be done using a lathe machine fixed with a knurling tool.
Emobossing has same design on the both side of the sheet metal.
This process can be made by means of matched male and female roller <a href="https://en.wikipedia.org/wiki/Die_%28manufacturing%29" target="_blank" rel="nofollow noopener noreferrer">Die %28Manufacturing%29</a>, or by passing sheet or a strip of metal between rolls of the desired pattern.
Coining operation produces different shape or design on both side of the sheet metal.
Example : coin where both side have different design.