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Month: October 2017

Electronic Testing Our Box Build Assemblies

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.

Vibration Testing

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.

What Membrane Switch Element Is Best For You?

At Hallmark Nameplate, we offer several different options for a membrane switch element. Each option has different characteristics that make it the right choice for different applications. To figure out which element is right for you, you need to know how you are going to use the switch. As long as you have that figured out, you can read the characteristics in detail below and come to the conclusion of which element is right for your project.

First, however, you should decide between tactile and non tactile switches. Tactile switches are made for applications where the switch needs to be held down to continue to activate the function. Non-tactile switches only need to be pressed once, but you have no control over the length of the action the button controls. Once you have decided between tactile and non-tactile switches, see below to decide on the right membrane switch element.

Conductive Silver

Conductive silver flex membrane switches are the most popular a construction for custom membrane and switches. They are very affordable, especially when compared to electromechanical switches, which can be quite expensive in some applications. Conductive silver switches can be used for both non-tactile and tactile switches. They are also often used for resistors and LEDs. Conductive silver is lead-free, so there is no danger of adverse health effects. Conductive silver is also good for extreme temperatures. Finally, these switches are very thin which makes them good for tight packaging applications. They are also quite easy to clean.

Copper Flex

Copper Flex elements, like conductive silver elements, can be used for both tactile and non-tactile switches. Copper flex element switches are often used for applications that have trace routing limitations or dense circuit patterns. Copper flex elements work well with very complex circuit boards. They are also better for hard soldering manufacturing techniques. This makes them effective in high vibration environments.

PCB-Based

PCB-based elements use a PCB as the main structure of the switch. A PCB, also known as a print circuit board, is made of copper covered fiber infused into a type of resin. The membrane switch is connected to the front of the PCB assembly. The display and any other components are on the backside of the PCB. PCB-based elements are available in non-tactile and tactile switches, as are the copper flex and conductive silver elements. However, PCB-based elements to have one main feature that sets them apart from the other elements. They can be used for capacitive switches. Another secondary advantage of PCB-based switches is that they can be multi-layered, double-sided, or single-sided. Additionally, they allow for multiple different types of connectors.

Choosing the Right Membrane Switch Element for Your Application

Ultimately, the choice of which element do you want to use for applications up to you. However, there are some general guidelines that you can follow when choosing an element to ensure that it will work for your project. If you have a tight budget, conductive silver may be the right choice for you. This is especially true if you need your device to work in extreme temperatures. Conductive silver is also good for applications that need tight packaging. If your application will subject the device to a great deal of vibration, a copper flex element may be the right choice for you. This is especially true if the device is also very complex, as copper elements work well with very complex circuit boards. Similar to conductive silver, copper flex elements are very compact.PCB-based elements are the only choice if you need capacitive switches. They are also the only choice if you need your switch is to be multi-layered, double-sided or single-sided. Finally, they are the only choice if you need to have multiple connector options.

As you can see, copper flex and conductive silver elements have many similar characteristics and can be used for many of the same projects. The main distinction of conductive silver is that it is cheaper. The main distinction of copper flex is that it is good for high vibration and for working with dense circuit boards. PCB-based elements, however, are unique and may be the only choice if you have need switches for a specialty application.