Philips rethinks functional test to shorten time-to-market
01 November 2020
With a long heritage in consumer electronics, particularly across lighting & audio-visual (notably as inventor of the cassette, & co-developer, with Sony, of the CD & DVD formats), multinational conglomerate, Philips is an $18B global electronics company – now primarily focused on healthcare technologies. With rising device complexity, its ultrasound test engineering team was challenged to maintain product quality, while reducing cycle time & meeting short development schedules.
This case study was originally featured in the November 2020 issue of EPDT magazine [read the digital issue]. Sign up to receive your own copy each month.
Here, Neil Evans, Senior Manager for Product Industrialization Test at Philips Healthcare tells us how his team adopted a standardised approach built on PXI and LabVIEW platforms from automated test & measurement tools provider, NI designed to abstract all coding complexity from users, without limiting the functionality required to meet stringent test coverage requirements. According to Evans, this approach successfully decreased development resources per project by 80%, improved cycle time 10x, reduced sustaining effort 10x and increased test coverage – reducing total operating expenses per project by an estimated >$2M.
Ultrasound products are crucial in a variety of healthcare applications, including cardiovascular, obstetrics, gynecology, musculoskeletal, liver and kidney imaging. To lead medical science in these areas, practitioners require higher-resolution images in more accessible form factors. Recent rapid product innovation to meet these demands has created significant and unprecedented time-to-market pressure, which is compounded by growing product complexity, higher production volumes, global manufacturing distribution, increased regulation and long station-deployment life cycles.
These factors helped create an executive-level appetite to redesign test approaches, processes and technologies, addressing the following challenges and goals:
• Complexity – Create a platform approach to address the current and future test needs of a diverse portfolio of groundbreaking Ultrasound transducers.
• Quality – Significantly improve first pass yield to increase manufacturing efficiency, while maintaining high product quality standard.
• Life cycle – Reduce sustaining costs by increasing stability over a 15+ year test-station life cycle.
• Development schedule
– Reduce test solution development effort and throughput time per new product introduction by up to 80%.
• Manufacturing volume –
• Increase manufacturing volume of some products by more than 20x, to tens of thousands of units.
• Improve manufacturing uptime across a globally distributed supply chain.
• Regulation –
• Reduce certification time, which can traditionally take up to six months per system.
• Minimise post-deployment updates that require recertification.
• Data – Maintain complete data sets for every test on every DUT (device-under-test).
Time-to-market is a key priority at Philips. In order to meet tightening development schedules, a higher-level starting point for new test solutions had to be developed that would allow engineering teams to configure an existing solution to meet their needs, rather than start from scratch. Criteria for the standard solution were:
• Provide a rapid configuration of test solutions to address new and existing product and subassembly test needs for multiple process steps.
• Scale to meet future product needs (test-step expansion, signal processing, instrument configurations and communication/data interfaces), while minimising additional code development and code recertification.
• Centre on widely available COTS (commercial off-the-shelf) elements to ease global supply-chain and sustaining challenges and significantly reduce the need for custom DUT interfaces.
A standardised platform solution was implemented, where a common set of code modules and COTS instruments could be configured to meet the test needs of each test station.
We developed a software architecture with minimal dependencies between code modules, so that each function can operate in the same fashion, independent of the context within which it runs. This allows for significant code reuse of well-written, verified code, improving time-to-market and code quality, and reducing the number of regulatory recertifications.
When a new product must be tested, the only elements to be developed are the XML configuration file and the fixture. This shortens not only development time, but also certification, as most of the code is unchanged and so existing certification documents can be referenced. This is much like when an orchestra is handed new sheet music – they can play a different tune without changing musicians, instruments or conductor.
If a product specifies a new process or measurement, the required new code can be written and added to the library without affecting existing framework. It’s similar to when a new orchestral arrangement requires a specialised instrument, such as a grand piano: It can be added without disturbing the existing configuration. Critically, the other musicians can still play all of the other pieces in their repertoire with no changes, while the pianist simply sits in silence. In our case, tests for all previous products used by the platform do not need to be redeveloped or recertified each time we add a new one.
We chose NI LabVIEW, the industry-standard test engineering tool, for its fully featured hardware-integration capabilities. The LabVIEW Actor Framework is a published software architecture that met this test solution’s extensive needs due to its well-known, tried-and-tested status – we could quickly hire and train contributing engineers for development. The common proficiency in LabVIEW across Philips also provides a straightforward path for adoption across the organisation of this standard test framework.
The primary concern in hardware selection was the measurement capability, precision timing and stability of the instrumentation. We decided to move from a solution that relied heavily on proprietary hardware to a COTS solution based on PXI because of:
• Scalability – Adding new functionality with simple modules keeps time-to-market short.
• Coverage – The wide breadth of I/O and firmware functions gives us confidence in complete test coverage, both now and in the future.
• Accuracy – PXI has best-in-class measurement accuracy, combined with tight timing/triggering across the chassis backplane, unobtainable with a ‘rack-and-stack’ box instrument approach.
• Robustness – PXI’s industry-proven hardware reliability ensures optimum overall equipment effectiveness.
We deployed the system in six globally distributed manufacturing sites and expect significant future adoption.
Results – compared to previous solution testing similar DUTs:
• Complexity – Test coverage and signal-path improvements meet the needs of a diverse portfolio of state-of-the-art xMatrix ultrasound transducers.
• Quality – Easy access to test data drives significant yield improvements through structured problem-solving.
• Life cycle –
• Significant ongoing cost savings through 10x reduction in resources required to sustain the systems.
• Almost no unplanned test downtime exists, thanks to reliable test hardware and verified error-free software.
• Absolutely no platform software changes have been required since deployment in 2018.
• Development schedule – We achieved an 80% reduction in NPI test development effort and schedule.
• Manufacturing volume –
• Product-level test cycle time reduced by 10x.
• Wafer test cycle time reduced by 5x.
• Regulation – Certification validation reduced by four months: from between five and six months to two months.
• Data – One global database system delivers complete test traceability.
Several additional factors were key to this project’s success:
• Executive sponsorship – The ability to articulate the business value that a test organisation could deliver was critical. In this case, we could forecast the exponential development and sustaining costs in-line with increased product complexity. A vision of breaking the relationship between product complexity and test-system cost provided executive buy-in.
• Engineering proficiency – Because any plan is only as good as the people executing it, critical to the creation of this initiative was our recruitment and continual engagement of two leading software architects and one hardware designer who formed our core team. We attribute this project’s success to these lead engineers’ innovation and ongoing diligence as a collaborative team effort.
• Technology Adoption – Moving to a COTS approach using PXI and LabVIEW was critical to this production test success at Philips. The combination of best-in-class modular hardware along with industry-standard software was pivotal to the millions of dollars and hundreds of hours saved in production-test engineering.
The most significant investment in standardisation comes with forming a core team to set up the initial framework. Once complete, adding updates and maintaining code bases is a lighter lift because, at this stage, teams from different organisations can participate as local contributors, leveraging existing test steps and processes, while adding to the overall code base when additional functionality is needed. Company-wide, users can utilise an ever-expanding toolset, which they can access through XML configuration files.
The process is governed in the following way:
• A core team develops and curates a general library of functions.
• Engineers on different local teams develop libraries of LabVIEW code performing new requirements.
• Each code module includes requirements and validation documentation.
• Local libraries can be contributed to the general library.
• Users create XML files that configure platforms and applications – without the need to understand the underlying LabVIEW code – using a combination of local and general library functions.
Further opportunity to optimise product and manufacturing processes exists through better utilising test data and connected test systems. The large scale of manufacturing creates a data-rich environment, so by harmonising our data approach across manufacturing sites and products, we can gain greater insights to deliver significant operational benefits.
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