This post originally appeared on the Measure What You See Blog.  It is posted here with permission.  You can find the original post here.

Example of gloss and haze standards for the BYK-Gardner haze-gloss.
Photo courtesy of BYK-Gardner.

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.

Checking Standards for a BYK-Gardner micro-TRI-gloss. The gloss tiles are built in an aluminum track that the glossmeter fits into to guarantee accurate and repeatable readings.
Photo courtesy of BYK-Gardner.

Example of checking standards for transmission, clarity and haze for the BYK-Gardner haze-gard i. These are designed to fit on the instrument with precision for accurate and repeatable readings.
Photo courtesy of BYK-Gardner.

Non-electronic Tools

Example of Bar Applicators.
Photo Courtesy of BYK-Gardner.

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.