Flip the Switch

Switches and controls have always been key features of automotive design. The style and functionality achieved by automotive designers of the past are remarkable when you consider they did this with slide rules and drafting tables.  

Advances in technology, design and manufacturing capabilities have paved the way for more control, better safety and improved quality.  The evolution of how we interface with our cars is advancing quickly.   Demand for automotive switches continues to grow, with over 1 billion global unit shipments expected by 2026. 

  The evolution of how we interface with our cars is advancing quickly.

As the car gets smarter, the automotive switch has become a critical piece of nearly every circuit.  Where humans are involved, switches provide control and choice for the driver and passengers.   

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Switches can be simple or complicated and are involved in vehicle access, interior controls, powertrain options, and safety systems. Manufacturers know that switches can be frustrating to build because they typically have a small form factor and, consequently, are built in large panels.   

The SMT line can manufacture these large panels much faster than the test operation can be performed. This creates a throughput mismatch that forces manufacturers into difficult compromises.  

Testing on switches can include programming ICs, physically manipulating the switch, and checking all the permutations of complex logical rules. That can take a lot of time for each small board.  

 When manufacturing throughput greatly exceeds testing throughput, manufacturers generally operate in batch mode. The SMT line will run a certain product for 2-6 hours, building up work-in-process inventory of 4,000 to 10,000 boards, then switch to another product and so on. Meanwhile, the test operations will run continuously to keep up.  It may take 2-3 complete test cells running 3 shifts to keep up with the production of a single SMT line.  The result is an expanding and contracting pile of thousands of untested boards once or twice a day.   

 It may take 2-3 complete test cells running 3 shifts to keep up with the production of a single SMT line. 

The batch mode WIP cycle presents major risk to manufacturers when the products are not allowed to have rework – as is the case for some switches. The cost of a simple production fault that carries through an entire batch can be significant. 

Fortunately for switch manufacturers, there is a better method – parallel functional test. CheckSum’s patent-pending technology allows manufacturers to test an entire panel of boards simultaneously. So, that panel of 12 door handle switches can now be tested in the same time it previously took to test one board. Parallel testing is generally as fast as the SMT line, so it can be performed in-line, eliminating human handling and the untested Work-In-Process Inventory.

...factories look completely different when test can keep up with the SMT line...

Most importantly, factories look completely different when test can keep up with the SMT line: the entire Test Cell operation – people, systems, inventory, space – all vanishes. In-line test also provides real-time data to your Industry 4.0 system. If you are running batch mode, you may wait 4-5 hours to get the electrical test data. So much for making fast decisions.  

Is parallel test right for your operation and your products? CheckSum invites you to have a conversation about your specific needs. With just a few inputs about your products and operation, we can provide an estimate of the process and cost benefits with parallel testing. We look forward to speaking with you.