--- title: "When Automotive Switch Production Outruns Test: Use Parallel Testing to Keep Pace with SMT" description: When PCBA production test falls behind SMT, adding testers increases cost and WIP. 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[Contact Sales](https://www.checksum.com/contact-sales) - [Our Company](https://www.checksum.com/about-checksum) - [About Us](https://www.checksum.com/about-checksum) - [News and Trade Events](https://www.checksum.com/news-and-events) - [Careers](https://www.checksum.com/careers) 2 min read # When Automotive Switch Production Outruns Test: Use Parallel Testing to Keep Pace with SMT [![Picture of John VanNewkirk](https://www.checksum.com/hubfs/John%20VanNewkirk%20Photo%20Avatar.jpg) John VanNewkirk](https://www.checksum.com/checksum-blog/author/john-vannewkirk) : Oct 26, 2026, 6:27:53 PM [Parallel Testing](https://www.checksum.com/checksum-blog/tag/parallel-testing) [PCBA Testing](https://www.checksum.com/checksum-blog/tag/pcba-testing) [SMT Manufacturing](https://www.checksum.com/checksum-blog/tag/smt-manufacturing) [In-Circuit Test (ICT)](https://www.checksum.com/checksum-blog/tag/in-circuit-test-ict) [Functional Test](https://www.checksum.com/checksum-blog/tag/functional-test) [Panelized PCBAs](https://www.checksum.com/checksum-blog/tag/panelized-pcbas) ![When Automotive Switch Production Outruns Test: Use Parallel Testing to Keep Pace with SMT](https://www.checksum.com/hubfs/When%20Production%20Test%20FAlls%20Behind%20SMT%20Image.png) ##### Table of Contents [The Challenge](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#the-challenge) [Current Process vs CheckSum](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#current-process) [Test is Also a Manufacturing Feedback Loop](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#test-is) [Ask a Different Question](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#different-question) [See What Parallel Test Could Change in Your Application](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#see-what) Automotive switches have evolved dramatically, but one manufacturing challenge remains: small printed circuit board assemblies (PCBAs) are often produced in large panels, and surface-mount technology (SMT) can build those panels much faster than conventional test processes can test them. The result is more than a test-engineering problem. It can become a production-flow problem involving thousands of untested boards, delayed process feedback, multiple test cells, additional operators and fixtures, and more manufacturing floor space. **In This Article** 1. [Automotive Switches Create a Unique Production-Test Challenge](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#automotive-switch-test-challenge) 2. [What Happens When Test Cannot Keep Up With SMT?](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#test-bottleneck-smt) 3. [Parallel Functional Test Changes the Throughput Equation](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#parallel-functional-test) 4. [When Test Keeps Pace, the Factory Looks Different](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#test-keeps-pace) 5. [Is Automotive Switch Test Limiting Your Production Capacity?](https://www.checksum.com/checksum-blog/when-automotive-switch-production-outruns-test-use-parallel-testing-to-keep-pace-with-smt#production-capacity) ![Automotive switches and controls used in vehicle access, interior functions and safety systems](https://www.checksum.com/checksum-blog/REPLACE_WITH_HUBSPOT_HERO_IMAGE_URL) Automotive switches and controls continue to evolve, increasing the demands placed on production test. ## Automotive Switches Create a Unique Production-Test Challenge Switches and controls have always been key features of automotive design. The style and functionality achieved by designers of the past are remarkable, especially considering that much of the work was done with slide rules and drafting tables. Advances in technology, design, and manufacturing have enabled more control, better safety, and improved quality. Switches may be involved in vehicle access, interior controls, powertrain options, and safety systems. Some are simple; others require programming integrated circuits, physically manipulating a switch, and checking permutations of complex logical rules. Manufacturers know these products can be frustrating to build. Their small form factor means they are often assembled in large panels. SMT can produce those panels quickly, while testing each individual board can take considerably longer. ![Panelized automotive switch printed circuit board assemblies prepared for production testing](https://www.checksum.com/checksum-blog/REPLACE_WITH_HUBSPOT_AUTOMOTIVE_SWITCH_IMAGE_URL) Dense panels multiply board output from SMT and can expose a mismatch with serial test capacity. ## What Happens When Test Cannot Keep Up With SMT? When manufacturing throughput greatly exceeds test throughput, manufacturers often operate in batch mode. An SMT line may run one product for two to six hours, building up work in process (WIP) of **4,000 to 10,000 boards**, then switch to another product while test operations continue working through the backlog. It may take **two to three complete test cells running three shifts** to keep up with a single SMT line. The result is an expanding and contracting pile of thousands of untested boards once or twice a day. This WIP cycle presents significant risk when rework is not permitted, as can be the case with certain switches. A simple production fault that continues through an entire batch can become expensive. And if electrical-test results do not arrive for four or five hours, production managers lose the opportunity to make fast decisions based on immediate feedback. ## Parallel Functional Test Changes the Throughput Equation CheckSum's [Parallel Functional Test (PFT)](https://www.checksum.com/parallel-functional-test) can test compatible functions across an entire panel at the same time. For a panel of 12 door-handle switches, that means the panel can be tested concurrently instead of repeating the same serial sequence for each board. The opportunity is broader than functional test alone. CheckSum can combine parallel in-circuit test (ICT), in-system programming (ISP), selected functional circuit test (FCT), and automated panel handling to better match the manufacturing process. **One Test System. Three Test Flows.** The [ILS-X2 Dual-Panel Automated Test System](https://www.checksum.com/ils-x2-dual-panel-automated-test-system) supports single-panel, dual-panel parallel, and dual-panel sequential test flows. The right mix of tests, parallelism, and handling sequence is selected for the application. ![CheckSum ILS-X2 dual-panel automated production test system with conveyor handling](https://www.checksum.com/checksum-blog/REPLACE_WITH_HUBSPOT_APPROVED_ILS_X2_IMAGE_URL) CheckSum's ILS-X2 can coordinate parallel test technologies with flexible automated panel handling. ## When Test Keeps Pace, the Factory Looks Different The biggest benefit is not simply a faster test cycle. When test keeps pace with SMT, the manufacturing process can change. Large buffers of untested WIP can shrink, human handling can be reduced, and separate test cells, fixtures, operators, and floor-space requirements can be consolidated. In-line testing can also provide earlier data to production and manufacturing execution systems (MES). Instead of waiting hours for electrical-test feedback, the line can respond closer to the time the boards were built. As described on CheckSum's [Parallel Test Advantage](https://www.checksum.com/parallel-test-advantage) page, denser panels and faster SMT lines put increasing pressure on test. Parallel architectures create options for meeting that demand without simply multiplying test stations. 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