Our qualification tests are closely aligned with our running lab test average calculated from our very first official qualification to our latest out-the-door unit, whether it be for a repair, upgrade, analog, or new. Keeping a running lab average with detailed records of your HST’s is our way of monitoring consistent quality control in our equipment, supplies, and lab as well as keeping every HST on par with TAPPI standards.
Beginning of Our Qualification Lab Averages:
Temperature an Humidity During Qualification:
Lab Temperature, Relative Humidity, and Dew Point are logged during each qualification run to make sure that unexpected environmental changes in our lab are not affecting testing results.
Calibration Test Record:
Each qualification test run is recorded into a spreadsheet and their corresponding curve will be calculated out in the curved graphs below. One graph displays the upper and lower tolerance limits based on our updated lab average curve from prior quals. The overall qualification average is simply calculated from 5 sample runs. Each sample run comprises of a recorded time at 90, 80, 70, and 60 percent reflectance values from when the moment the test button was pushed to the buzzer trip time for each set value. The dial was just dropped down 10% after the buzzer trip and time was record until 60 percent tripped and recorded, then allowed to let the ink penetrate no further than 50 percent to allow for reverse side of paper observation. The 20 times were averaged together from all 4 reflectance values of the 5 runs to give an overall qual average that is juxtaposed to our running lab average. The curve must fall within the industry upper and lower tolerance limits of our lab averages in order to be deemed acceptable for service. The curves also need to have a similar shape to the lab average as well. Any unacceptable results and the HST will have a thorough re-cal and hardware check before a re-qual until it passes and released for shipping.
Below: illustrates and acceptable qualification for us do to it’s curve shape mimics our lab average and that is lies within its upper and lower tolerance limits.
Certificate of Calibration:
Each HST we qualify with ship with a recorded and documented certificate of calibration. It is a statement that we fully certify that your HST has been serviced, calibrated, and qualified. It reflects our master tile set readings, OCF (Official Calibration Factor – a set value during factory calibration), Customer Tile set initial reading and it’s upper and lower 2% tolerance, and a signature with qualification date reflected on certification sticker on right side of HST.
Picture of HST: