Section News

Event Review: Reliability Outreach 2018

The UK and Ireland Reliability Chapter reaches out every few years to provide reliability briefings to technologists and engineers. Without such knowledge updates some engineers may be pressurised to take dangerous short-cuts, or simply not know how to address the vital delivery of reliability.

The Reliability Outreach 2018 Workshop held in May 2018 gathered experts on electronics in medical devices to address solutions on ‘Reliability Challenges for Medical Devices’. A second half-day delivered a tutorial on ‘Reliability Issues and Solutions in Engineering’.

Day 1 Presentations

Reliability & Test Engineering in MEMS Enabled Systems; An IEEE Distinguished Lecture by Nihal Sinnadurai

Nihal Sinnadurai

Chief Exec of ATTAC, Fellow IEEE, Fellow Inst.P, CEng.

Nihal Sinnadurai gave examples of MEMS trends as they impacted on quality and reliability and then dealt with solutions. Because there is not a single set of methods and standards for MEMS, professionals pick and mix from available standards for ICs, PCBs, thick-films, thin-films and packaging. Sinnadurai advised caution when adopting off-the-shelf ‘reliability standards’ that give rise to dangerous expectations with pretentions of universal applicability. Some have ceased to be relevant and outdated non-valid versions of ‘MIL’ are quoted by those who have lost touch. In developing reliable MEMS, practitioners work with their specific technologies to improve performance and longevity before attempting to ‘qualify’ the products. In-house ‘gold standards’ from over 30 years of successful implants continue to deliver good products.

While reliability assurance may add initial cost – perceived by some as a barrier to the success of integrated MEMS technology – addressing whole life cost is the intelligent approach to reliability. Sinnadurai also illustrated the practical use of Failure Modes and Effects Analyses (FMEA) using Physics of Failure diagnostics and models of degradation. He advocated development of in-house expertise of the mechanisms of failure alongside acquiring data from reliability tests in order to generate extrapolations and predict reliability probabilities. Both are needed. The trend for future MEMS is continuous monitoring to anticipate degradation.

Sustainable Manufacturing Approaches of a Mass Sensor for Portable Medical Device Applications by Zeyad Al-Shibaany

Zeyad Al-Shibaany

Project Officer and Research Associate in the Centre for Advanced Manufacturing Systems, Cardiff University.

Zeyad Al-Shibaany described the design and rapid prototyping of a resonant mass sensor for portable medical devices applications. The world nowadays faces enormous medical and healthcare challenges such as new viruses and infectious diseases, which spread out very quickly.

These challenges raise the need for having medical devices that are cheap, easy to use and easy to move from one place to another to meet the needs of hospitals and healthcare centres. The principle of the sensor is to detect small amounts of added surface mass via the measurement of a frequency shift in the resonant frequencies of the sensor’s structure.

Impressive were not only the outcome of his PhD research from Newcastle, and the developments that led to manufacture, but also his very professional presentation. It was descriptive, to the point and on time.

Prognostics and Health Management for Medical Devices by Chris Bailey

Chris Bailey

Director of Computational Mechanics and Reliability Group, Director of Enterprise, University of Greenwich, London.

Chris Bailey described techniques for estimating current and remaining useful life of a components or systems according to future operating conditions, environmental exposure and loads on the system.

He explored FMEA and detection of damage prediction of how damage may increase. He indicated that prediction based on numbers (data driven) gave more consistent results, while model driven approach required knowledge of the precise failure models. The data driven steps required specific parameters to be monitored, accelerated life testing to generate failure data, whose threshold values combined with a PHM model would be used to extrapolate to estimate remaining useful life.

During discussion, it was evident that knowledge of failure mechanisms was essential for companies to understand their product strengths and weaknesses and thereby create robust products whereas the data driven PHM was a statistical tool.

Hermeticity and Corrosion in Active Implantable Medical Devices by Anne Vanhoestenberghe

Anne Vanhoestenberghe

Implanted Devices Group, UCL Dept of Medical Physics and Biomedical Engineering.

Anne Vanhoestenberghe provided insights not only to the reliable operation of implants, but also a mini-tutorial on hermeticity requirements and non-hermetic solutions for implants.

The environment in which implants operate can be hostile to electronics – the device is in continued immersion in ionic body fluids over an expected device life exceeding 50 years. The device’s reliability therefore relies on protecting the electronics parts, which can be achieved by maintaining a very dry environment inside a cavity housing the active circuits. Implants are in contact with fragile yet crucial parts of the human body which limits even the range of biocompatible materials that can be used.

Current solutions had used sealed titanium packages, which constrain miniaturisation and multiple feed-throughs. Also, traditional (old) hermeticity test methods have significant inadequacies. She proposed solutions using conformal encapsulation (reminiscent of the BT Labs ‘Plastic Packaging is Highly Reliable’) describing new materials to prolong the corrosion free life of a device and methods to estimate lifetime and their likely translation to clinical devices.

How to protect an endoscopic capsule by Marc Desmulliez

Marc Desmulliez

Deputy Head of Research Institute of Signals, Sensors and Systems (ISSS), Director/Founder of MicroSense Technologies Ltd (MTL) and the Nature Inspired Manufacturing Centre (NIMC), Heriot-Watt University, Edinburgh.

Marc Desmulliez and his collaborators have developed modules for Ultrasound capsule endoscopy (USCE). The technique overcomes surface-only imaging and provides transmural scans of the Gastro-Intestinal (GI) tract. As the capsule is swallowed by the patient, it must withstand the harsh environment of the gut for several hours. Protection of the capsule is therefore essential.

Desmulliez described various measures taken to guarantee safe passage of the capsule as well as optimum operation of the medical digestible device. Because there is no standardised testing methodology for capsule endoscopes, they tapped into ISO 10993 (Biological evaluation of medical devices), ISO 13485 (Medical devices – quality management systems), ISO 60601, Part 2-18 (Particular requirements for the basic safety and essential performance of endoscopic equipment), FDA submission number K123666 for Pillcam 2.

The decisions required assessments whether the materials chosen harm the patient, the ageing effect and the corrosive nature of the body on the polymer package, the potential for outgassing from the polymer, the permeability of the package to water vapour and other fluids, the robustness to the range of pH values it will experience, integrity of the seal over the lifetime of the capsule. Further consideration included biting and peristalsis. All these were dealt with in delivering a usable product.

The insightful lectures concluded the first OutReach day.

Day 2 Tutorial

MEMS Failure Modes and Reliability Modelling by Marc Desmulliez

Marc Desmulliez

Deputy Head of Research Institute of Signals, Sensors and Systems (ISSS), Director/Founder of MicroSense Technologies Ltd (MTL) and the Nature Inspired Manufacturing Centre (NIMC), Heriot-Watt University, Edinburgh.

Reliability is the greatest challenge and has been a critical barrier to successful commercialization and wide acceptance of MEMS technology.

At Heriot-Watt a taxonomy targeted at practitioners has been set up to classify the various MEMS failure modes, their mechanisms, acceleration factors and possible mitigation techniques. This serves as a first-hand knowledge base for designers to develop efficient and reliable MEMS and for end-users to understand possible modes of failure.

Best practice FMEA methodology is proposed to determine MEMS failures. A case study illustration is of a micro-motor and MEMS thermal actuator. Failure analysis of MEMS thermal actuators data is shown.

Feedback Received:

Content: 9.5 /10, Technical Strength: 9.5/10, Knowledge of the Tutor: 10/10, Presentation/Communication: 10/10, Time Keeping: 10/10

Comments:

Very relevant topic area for my literature search. This tutorial brought the literature search topic into a practical context where I could easily ask questions. Speaker was very knowledgeable about EEC.

Very interesting and relevant topics for the theme of the workshop were covered. Tutorial was delivered in very engaging manner, with lots of opportunities for questions and answers. With was pleasure to have the material delivered by lecturer with clear expertise in the subject, using very well organised and illustrative set of presentation slides, and being able to address all questions form the attendees. Overall, very happy and satisfied with this tutorial.

2018-07-29T18:22:23+00:00July 29th, 2018|news, Reliability|
IEEE websites place cookies on your device to give you the best user experience. By using our websites, you agree to the placement of these cookies. To learn more, read our Privacy Policy. Accept and close