Customized Comparison Tools for Peening Coverage

Author:  Jörg Behler | Bachelor of Engineering | sentenso
Source:  The Shot Peener magazine, Vol 38, Issue 2, Spring 2024
Doc ID:  2024015
Year of Publication:  2024
Abstract:  
EVERY OPERATOR, process developer and quality manager in the shot peening industry knows about the challenges in inspecting and rating the Coverage on peened parts. The achievement of full or 100% Coverage is very essential though to determine the corresponding peening time. Knowing the peening time saves energy and wear, avoids over-peening and is the basis to comply with peening instructions that require specific multiples of 100% Coverage. Finding a reliable peening time for full Coverage usually requires a Coverage development using several sequential time-based steps producing lower Coverage rates. Estimating Coverage at lower degrees is often difficult and leads to discussions between operators, process developers and quality managers. In order to address this challenge, SAE J2277 provides patterns for comparing the inspected surface with a graded series of computer-generated pictures. These pictures are an appreciated tool for the inspector but do not claim to reflect reality. The inspection for Coverage on a real part surface after a peening process can be very challenging due to several reasons. An overview of the difficulties that prevent an easy Coverage assessment can be divided into four categories.