You not only want to know how well a box build assembly works, but you also want to know how long they will work. The last thing a customer needs is a poorly functioning electronic box build assembly and Hallmark tests the assemblies thoroughly so you are not disappointed now and in the long run. There are different methods that can be used to test the assemblies. Here is an overview of three of the ways a box build assembly can be tested.
Temperature Humidity Tests
The box-build assembly prototypes will undergo a temperature humidity test to make sure they perform properly before the device is sent into mass production. The temperature humidity test is performed by putting the box assembly into a chamber where the humidity and temperature levels can be precisely controlled. The purpose is to determine how well the box will withstand the different atmospheric conditions it will face when the box is shipped, stored, and in operation.
The duration of the test will vary depending on the relative humidity and temperature the chamber is set to produce. For the initial test, the temperature and relative humidity will be set at low levels and the electronic box assembly will sit in the chamber for about a week. The temperature and relative humidity will gradually rise until reaches about 185 degrees Fahrenheit and the relative humidity is set at about 95 percent. The entire testing period will last about two weeks.
The next step is to test the box assembly at working temperatures of about 122 degrees Fahrenheit with relative humidity levels set from 0 to 85 percent. This test takes about one working day to complete. After the box assembly has set in the chamber for the tests, it will be taken out and used to make sure all the components are functioning properly.
Thermal Shock Testing
The thermal shock test is done to see how well the box assembly handles rapid changes in temperature during shipping. This is done by simulating the box assembly getting moved from a warm manufacturing environment to a freezing cold shipping environment. The change in temperature can be rapid – as much as 80 degrees Fahrenheit per minute. Two chambers are typically used in this test.
The first chamber will be set at or below freezing and the box will be placed into the chamber for up to five minutes or so. The box assembly will then be moved into the warm chamber for up to five minutes. The process of setting and moving the box into the chambers represents one cycle. Depending on the conditions the tester is trying to replicate, the tester could perform up to 250 cycles during the test.
After the cycles have been completed, the box assembly will be tested to see how well it held up during the testing process. Several things are typically inspected to see how well the box assembly held up under the pressure of the temperature changes. The tester will check to see if the die or box cracked, if any of the wires in the box broke and if the wire bonds held up through the test. Cracks and breaks mean that there will be an electrical failure and the box assembly will need adjustments before mass production begins.
The box assembly will be shaken to simulate shipping and operational conditions. This is done to see how well the printed circuit boards, box assembly, and electrical components withstand normal and excessive motions.
The box assembly is vibrated at low, medium, and high speeds. The box assembly is physically inspected to look for cracks and/or breaks or disconnects in the wires. The box assembly is also tested to make sure all the components still work as intended.
Production of the box assemblies will start once the prototypes pass all the tests successfully. As production proceeds, other box assemblies will be tested to make sure the manufacturing process continues to meet the requirements it is designed to withstand.