While optimizing the metalworking fluid selection for a stamping process that made simple round washers out of 1050 cold rolled steel, it was discovered that the grinding or turning process used to size the outside diameter of the die was leaving sub-surface stresses, creating premature die failure. Even though the stamping house is a first class operation, their experienced die makers were surprised at the observations that follow.
Until the OD grinding or turning operations used to make this die are modified to minimize the substrate stresses, the lubricant will have only minor impact on this process. The greatest improvement to this process will be related to the OD surface preparation techniques.
We suggested that the engineers evaluate surface conditioning techniques that reduce internal stresses in their tools. And by the way, the lubricant appears to be functioning properly with no welding or scoring.
Gary Rodak is the Owner of Machining Efficiencies, Inc. You can reach him at Gary.Rodak@MachiningEfficiencies.com.
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