The American Society of Mechanical Engineers (ASME) sets forth standards for manufacturing Bioprocessing Equipment (BPE) in their publication ASME-BPE. Included are finish guidelines (Electropolishing) for component surfaces where product can come in contact. Finishes are determined by Ra values (Roughness Average) usually expressed in microinches.

Equipment used in sanitary industrial applications must be designed and manufactured with contact finishes providing for easy cleaning and sterilization. Rough surfaces have sites where product can become embedded and contaminated with bacteria. Therefore, surface finish becomes key to sanitation. The challenge is to provide surfaces as smooth as possible.

In the metallurgy field Electropolishing is an electrochemical process for leveling the microscopic surfaces by removing unwanted metals, leaving those much less likely to corrode. Also, using this procedure to smooth the surface can eliminate sites where product can adhere. Though the process can be used on a variety of metals, it is primarily employed on stainless steel whereby the major component, iron, is removed from the surface leaving the more corrosion resistant chromium and nickel. Since the finished product is shiny and more aesthetic, the term electropolished is applied.

The BPE manufacturing process involves design, procurement, component production, assembly, testing, finishing and installation. Through the years Dragoo Metal Works (DMW) has possessed good control over key elements of the BPE manufacturing process, however, the company realized finishing outside with third parties was stretching out delivery times.

To fill the final service void, DMW has brought Electropolishing into the field of services we provide. With assemblies of your specifications, your design or ours, we offer a full range of capabilities to handle individual parts in many sizes and shapes as well as specialized, first time, new part production runs.


Stainless Steels have natural corrosion resistance due primarily to their rich chromium and nickel content. Though possessing excellent properties, sometimes stainless steel micro-surfaces can be somewhat reactive needing and extra layer of corrosion protection. Passivation is a process whereby stainless steel (other metals as well) is treated with an acid formulation, having the goal of forming a “passive” layer in the form of a more corrosion resistant metal oxide, or nitride if nitric acid is used. The process will further enrich the chromium/nickel surface, and can remove some embedded iron along with other acid soluble contaminates as well. All to the benefit of your finished product.

While passivation is a separate process, it is a natural extension of Electropolishing and we can offer each separately to fit you application.

Often the written content here can raise more questions than provide answers, so please give us a call, send us a drawing, use the contact form, and we will respond without delay.



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