Since the Technical Order 34A-2-1 specifically states the Air Force's only approved Direct Metal Additive Printing System is the EOS M290 do we still need to provide market research? If so, how do we annotate with the market research that the other commercially available Additive Printing Systems do not meet the Air Force's requirements? Or is there another FAR reference we can use to justify the Sole Source purchase?
The extent of market research depends on the nature of the acquisition and can be somewhat subjective. In fact, you already stated the basis for your market research in the background to your question. You will need to document that contract file with how "...market research indicates other companies’ similar products, or products lacking the particular feature, do not meet, or cannot be modified to meet, the agency's needs" [FAR 8.405-6(b)(1)]. A concise paragraph on how you made that determination, so that a reviewer can follow the logic, should suffice.