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Polishing as a Metal Fabrication Finishing Process: Part One

Metal fabrication is often discussed from the perspective of cutting or forming large amounts of material.  This shaping generally involves the subtraction of larger amounts of metal, or the use of extreme force to change the shape of the metal without breaking it.  However, there is an entire range of processes that don’t get nearly the amount of attention but are every bit as important, and those are in the category of metal finishing. Without finishing, there would be no way to achieve an acceptable end result that is deliverable to the customer.

The three types of finishing we do at EVS Metal are polishing, buffing and graining. While these sound similar, and do have things in common, they are technically different processes.  Metal graining and metal polishing are defined by the use of an abrasive that is glued to a work wheel or belt; graining is more abrasive than polishing.  Buffing, on the other hand, requires a loose abrasive that is applied (rather than adhered) to the wheel. While graining and polishing are the more aggressive forms of finishing, the end goal is similar for all three, in that all are used to achieve a smoother surface. The type of surface varies greatly, however, which is why the three different processes are all necessary; in fact, there are times when graining, polishing and buffing will be required over the course of finishing a single item.

How do graining and polishing work?  While still subtractive metalworking processes, the goal of both isn’t to remove large amounts of material.  Instead, the idea is to remove just enough to create a smoother surface, the definition of which depends on the item being finished. This doesn’t usually mean a smooth surface as defined by laymen — it has more to do with surface uniformity. The condition of the metal when it begins to undergo polishing is what determines what kind of abrasive will be necessary in order to create the desired surface.  A metal surface that has just been polished with a coarser abrasive may not look polished at all to the average eye, as these initial rounds of polishing often leave multiple shallow scratches and marks in the metal.  However, as the process continues, finer and finer abrasives are utilized until any marks are unable to be viewed without the use of a magnifying instrument.

At EVS, we have the technology and tools to achieve any desired metal finish, from #3 graining to #8 mirror. Join us next week as we continue our discussion around metal finishing and these specific finish types. Ready to discover how our precision finishing processes can add value to your manufacturing supply chain now? Simply request a quote online, or give us a call at (973) 839-4432 today.

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