Better Fatigue Properties
In addition to its finishing capabilities, the Harperizer imparts high compressive stresses to the parts being finished. This compressive stress, when combined with general radiusing and surface finish improvement, boosts the parts' fatigue strength and resistance to cracking by removing surface imperfections that could be the starting points for fatigue failure.
Delco engineers have found that this compressive stress is consistent from part to part and from lot to lot. There are other ways of imparting compressive stresses to parts, but many of them do it at the expense of surface finish; not so with this process.
Although the first Harperizer that Delco purchased was aimed at solving the finishing problem associated with the R-4 reed, this machine and the five purchased since then have been used to process a variety of other parts, also. Often the machines have been pressed into service to finish parts needed yesterday for final assembly operations. Some of these parts have been completely processed in as little as 15 mm.
Ultimately, the genuine value of the machines to Delco lies not so much in the solution of an immediate problem but in the expanded capability to solve any future finishing problems.