Mechanical Finishing Q&A: Stream Finishing to Deburr Parts While Keeping Edges Sharp
Q. We are a specialized cutting tool manufacturer. Though our tools require a sharp edge, they still need deburring. What is a consistent finishing process that you would recommend?
A. Your application requires a somewhat complex specialized system. Standard deburring systems tend to dull or radius an edge while they deburr. However, there is a solution to your problem. Compact stream finishing (drag finishing) machines are newer systems that are capable of accomplishing your objective.
Stream finishing machines have single or multiple head spindles with independently driven tool holders that hold the process parts. The spindles can be stationary, rotating or dwelled at various angles.
The turret that holds the spindles rotates and the spindles themselves also rotate or dwell through a dry or wet non-moving media within a stationary tub.
The parts being dragged through dense non-moving media create a very precise and high material removal rate. This energy enables a dry media or loose grain glass bead, aluminum oxide, silicon carbide or impregnated cob to work an edge with great precision.
The cutting tool industry uses stream finishing machines for deburring, or edge conditioning to increase tool life up to 14 times.
Stream finishing machines finish complex shape cutting tools with a glass bead/silicon carbide media mixture. The machine deburrs, keeps edges sharp and improves surface quality.
The medical bone implant, dental and general cutting tool manufacturers use this process on the taps, drills and hobs. The treated corn cob will give the parts a buffed finish. Cycle times vary, but are accomplished in a very short 1–20 minute range.
Originally published in the February 2016 issue.
Surface finish types for commercially supplied stainless steel sheet are detailed in various standards. ASTM A480-12 and EN10088-2 are two; BS 1449-2 (1983) is still available, although no longer active. These standards are very similar in that they define eight grades of surface finish for stainless steel. Grade 7 is “buff polished,” while the highest polish—the so-called mirror polish—is designated Grade 8
Metal fabricators that laser-cut with oxygen take steps to prepare parts better for powder coating.
This paper is a peer-reviewed and edited version of a presentation delivered at NASF SUR/FIN 2012 in Las Vegas, Nev., on June 12, 2012.