Production is outsourced but control stays in-house. Test systems developed by Hectronic are placed in the line of production and test functions, save test reports and configure computer boards and systems.
Remote access enables random sampling and updates at any time.
– I can do more or less anything from our office except of course connect things, says Lars Hägglund, one of the Development Engineers behind the test systems on all the locations where products developed by Hectronic are in production.
To fully understand the context we need to return for a moment from production to the development phase. The initial activity, among many, is verification to assure that products delivered are to the satisfaction of the customer.
– Functional testing and verification are two separate activities. Sometimes I suspect the understanding of the two and the relation between them are unclear to people, says Lars Hägglund.
Extensive testing and trials are performed on the first prototypes. Placements and soldering of components are checked and voltages are measured to make sure that limits aren’t exceeded.
– The next activity is to run the operating system to verify all the interfaces.
The prototype computer board or system is connected to the environment where it is supposed to work and is checked again. A successful verification indicates that the prototype is produced in accordance with the specification and works as intended in the application.
Working in parallel
That is the go ahead for production. A test system makes sure that production is done in accordance with the specification, the specification of the verified design. In practice activities to develop the test system and to verify the design is performed in parallel during the design phase.
– Experiences from the work to verify are input to, and support for development of the test software, says Lars Hägglund, and the other way around of course.
The functional test is less extensive than verification. Interfaces and special functions are tested. The customer influences the decision on what to test and what not to test.
– The customer has valuable knowledge in order to make sure that the computer board works in the application.
Verification in the climate chamber
The functional test lasts for half a minute up to half an hour, depending on the complexity of the design. Temperature tests take from 8 to 24 hours, sometimes up to 32 hours. Temperature tests during verification are executed in Hectronic’s own climate chamber.
– In case of strict climate requirements we normally do temperature cycling as part of the functional testing in production, says Lars Hägglund.
The climate chamber in the line of production is connected to, and controlled by the test system. Temperature curves can be adjusted remotely from Hectronic’s office in Uppsala, Sweden.
A climate chamber in the line of production is one example of an instrument that can be controlled remotely through the test system. Power supply and digital multimeters are other examples.
– Any instrument that is a part of production can be connected and controlled, says Lars Hägglund.
Extending temperature limits
Temperature testing as a part of production is a strategy to extend the temperature limit for a product outside the interval specified for on-board components. Boards from production are eliminated based on the results of functional test with the board placed in the climate chamber.
– In this case there are no guarantees the all the boards will work. Some of them might fail the test.
The majority of computer boards produced pass the test anyway and are ready for shipment.
The test system prepares to the computer boards for shipment. Another BIOS may need to be downloaded in case the BIOS required by the customer couldn’t be used during the functional test. There is a possibility to label computer boards electronically.
– The label contains information such as board model, serial number and revision for the specifications used in production.
Through the electronic label traceability is achieved which is one aspect of quality assurance, the overall goal in verification and test activities.