Complex electromechanical laboratory instruments are engineered to very tight tolerances because they are designed to operate with extremely small samples and highly accurate systems. Everything is measured on a micro scale; alignments are measured in micrometers, fluidics in microliters, and detection in microvolts. It is therefore not surprising that many common field issues are due to instruments that fail to maintain these tight tolerances.
An example of a field issue is a mechanical alignment failure. This type of failure may not be obvious, but if regular control assays are being run there will be an increased number of the control test failures as the instrument drifts away from required tolerances.
The complication with mechanical alignment failures is that the instruments may still be within the original specification, but over time the company marketing the instruments may use them for more demanding assays, and these new assays require tighter tolerances.
A good contract manufacturing company will not be content to just deliver instruments within original specification, but will look for ways to improve the alignment, and aim to deliver machines in the middle of the tolerance band, not just meeting specification. This improved instrument alignment can be achieved through carefully executed and validated design changes, production monitoring and improved manufacturing processes.