Been lurking here for a while, but finally have a problem worth posting about. We manufacture rubber seals/gaskets for automotive applications, and for the longest time our QC team was using handheld Shore A durometers for batch testing. The problem was consistency: two different techs testing the same sample could get readings that varied more than I was comfortable with, especially on softer compounds.
Turns out a lot of it came down to operator pressure and how long the durometer foot was held on the sample. Manual testing just has too much “human variable” baked in when you’re trying to hold tight tolerances.
We eventually moved to an automated tabletop durometer that controls the pressure and dwell time on its own, and it made a noticeable difference in repeatability. Not going to lie, it was a bigger investment than I expected for a smaller lab, but the reduction in rejected/re-tested batches basically paid for itself within a year.
While researching options at the time, I came across a decent overview of the different hardness testing methods (Shore A/D, IRHD, etc.) that helped me understand what we actually needed vs. what we didn’t: https://www.bareiss-testing.com/material-hardness-testing-instruments/ — not affiliated with them in any way, just sharing since it helped clarify things for me when I was fairly new to this side of QC.
Anyway — for those running smaller QC labs, how are you balancing automation cost vs. manual testing? Did you go automated right away or start with manual and upgrade later?
