AFTE Store - The Effect of Vibratory Finishing on Broaching Marks as a Function of Time

Previous research has focused primarily on the impact of primary machining processes (i.e. broaching, milling, grinding) on individual and subclass characteristics with speculation as to the impact of the finishing processes. As a result, research on the impact of finishing processes after machining on subclass and individual characteristics needed to be done. Based on the information gathered through research and during firearm manufacturer tours, broaching was used as the primary machining process and the effect of vibratory finishing on broaching marks as a function of time was examined. Vibratory finishing as a function of time did have a significant impact upon the individual markings caused by broaching. The finer, individual stria were removed as finishing time increased causing the grosser, individual marks to appear more pronounced. Subclass characteristics would then also appear more pronounced. An identification between different finishing times could be made; however, this research demonstrates that the firearms and toolmark examiner may need to consider the finishing method when identifications are being made.