This post originally appeared on the Measure What You See Blog. It is posted here with permission. You can find the original post here.
Monitoring the performance of your Quality Control instruments is an important part of your quality process.
Secondary Checking Standards
For most instruments, there are secondary checking standards. These standards are not used to calibrate instrumentation. A checking standard is used to monitor the instrument’s measurement accuracy and/or repeatability. After one year, the checking standard should be returned to the instrument manufacturer for recertification. Most standard certificates are traceable to a Federal Standards organization like NIST.
For non-electronic tools like bar applicators and grind gages, visual inspection is needed. If a physical imperfection that is in contact with your product is present, the tool should be replaced. A routine replacement program is recommended for machined metal tools because general wear is difficult to visually detect.