End of Line Testing - Thermostats

Traditionally the thermostats produced by the production lines were manually tested.  This involved loading 240 thermostats into one of 9 tanks which was then heated and cooled by an operator who noted the temperature at which each thermostat operated or reset. 

After investigation, the tanks were found to suffer from thermal effects which meant that different positions in the tanks were exposed to slightly different temperatures.  The system was, therefore, designed to monitor not only the states of all 240 thermostats but also 24 temperature measurements, in each tank.  It controls the heating and cooling by downloading setpoints to controllers, according to the selected recipe of ramps and dwells.

The system also automatically monitors all temperature probes for abnormal readings and indicates possible problems through an alarm beacon.  In addition, thermostats which “flash” repeatedly from one state to the other are indicated on a post test report. 

After each test, the system also automatically produces reports detailing which thermostats failed the test, the operating and resetting temperatures, and a series of SPC charts showing, for example, histograms of passes and fails at different temperatures.

If you would like advice on an end of line testing project contact us.