12th November 2013

Expert Advice for November- Elite Electronic Systems

Mark Mc Bride, technical manager at Elite Electronic Systems discusses the need for a comprehensive test regime for medical devices and outlines some of the testing now available in assisting manufacturers bring quality products to market.

At Elite we work on the principle that no one wants their products being returned from the market place with faults, being inconsistent or just poor quality. This is most important with safety critical devices. These returns have major implication including cost and damage to brand and reputation.
Customers have two distinct levels of expectation to meet: they must deliver to the standards expected by the general public and also to the quality standards and approvals expected by the regulators. In manufacturing medical devices Elite must adhere to ISO 13485 standards, in many instances seek FDA approval and in other cases participate in rigorous validations of manufacturing procedures.
To meet these exacting standards, in partnership with our customer we devise and implement an effective and efficient test strategies for each device.
For a medical device to achieve success with customers and regulators, this production testing must embrace a combination of compliant procedures and embrace technical excellence.
As Mark explains this doesn’t begin at production!!
In a medical device manufacture where manufacturing processes are tightly controlled and yields high design for test has to be significantly resourced from concept.
A key phase in any product lifecycle is initial design and to facilitate comprehensive test during production, designers must embrace the whole notion of “design for test”
Importance of Design for Test from Concept:
Design for test considerations need to be taken into account from the start of the design process. A successful test strategy must match test regimes to create parameters that during the actual implementation of said regime will identify the defects most likely to occur during the manufacturing process. This test strategy cannot be an after thought; it must be a vital component in the design phase. This is why it is important to have easy access to all the resources you will require in terms of the expertise and equipment required for world class design for, test and manufacturing. These resources can exist in-house at the OEM, but more often are outsourced to test houses and manufacturing houses that have this area as their core competency. Engaging with a manufacturer that has access to a test house with a good understanding of their manufacturing processes simplifies the manufacturing process substantially.

Validation Testing:
The medical device industry, particularly where FDA approval is sought, invests a lot of money in validating designs before going into production. This is best achieved through an ISO170265 approved process, where environmental stress testing (shake and bake), and EMC testing is done to strict industry standards. If good design for reliability guidelines are followed from the beginning of the design process, then validation testing is normally a seamless process where the failure modes have already been designed out and the product passes first time. This has obvious time to market advantages as well as cost savings.
NPI and Production:
Engaging with your contract manufacturing partner at the earliest stage of the design process, will ensure that the correct design for test and manufacturing considerations have been implemented in the final design. This ensures a smooth transition through NPI into full production. HASS testing then can be implemented at the early stages of production to screen out manufacturing related defects and hone the process. All this maximises product reliability and quality which will feed forward into the full life cycle.
Full Life Cycle Support:
With the long life cycle of typical medical devices, and the increasing prevalence of obsolescence issues mid-lifecycle, it is imperative to have a reliable test and manufacturing partner with the associated experience and expertise, to allow for redesign and associated validation testing to be carried out seamlessly when required through the product life.

In developing test regimes Elite utilise their own internal knowledge and experience and to provide a complete test solution for any customer and will partner with outside agencies to compliment the skill base that already exists. With testing of medical devices, Elite recommend Anecto a test house with a significant European presence.
Anecto offer Elite and their customers unrivalled flexibility combined with excellent industry specific knowledge and experience of the medical device industry.
The full range of testing offered by this powerful partnership includes:
Test at sub assembly or board level:
• Dedicated Full Functional Testing (Board Level)
• Combined ATE (bed of nails) with functional Test
• IC Programming and Verification Facility
• Analogue and Digital Network Terminal Equipment Approval Testing
• Board Level ATE
• Voltage Signature Diagnostic Capability to Component Level
• Boundary scanning facility (Debug or Full Functional Test capability)

Test For Complete Systems:
• Complete System Full Functional Test
• Analogue and Digital Network Terminal Equipment Approval Testing
• Reliability (Soak) Testing with our on-site Environmental Chamber
• Earth Bond and Electrical Strength Safety

Further testing for reliability etc:
• Exposure Testing: IP Testing, including IPX6K, IPX9K, Salt Spray (Corrosion), Dust (IP5X, IP6X)
o Standards include, EN60529 Water/Dust Ingress, EN60068-2-52 Salt Mist Cyclic, EN60068-2-11 Salt Mist
• Accelerated Stress Testing: Vibration testing (With Temperature), Various Climatic Tests including Controlled Temperature and humidity cycling
• Environmental Performance Testing: Humidity, and Altitude Simulation Testing, as well as Thermal Aging, Thermal Shock Testing and Thermal Cycling.
o Standards include EN60068-2-1 Cold, EN60068-2-2 Hot, EN60068-2-14 Temperature Cycle/Shock, EN60068-2-78 Damp Heat Steady State, EN60068-2-30 Damp Heat Cycle, EN60068-2-38 Humidity Composite Cycle
• Altitude Testing (Standard EN60068-2-13 Low Pressure)
• Accelerated Stress Testing : HALT, HASS, HAST
• Mechanical tests including Tensile testing, Drop/Impact testing and Shock Testing,
• Vibration Multi-axis Vibration testing, including vibration with temperature superimposed
o EN60068-2-6 Sine Vibration, EN60068-2-64 Random Vibration, EN60068-2-27 Shock, EN60068-2-31 Drop/Topple, EN60068-2-32 Free Fall
• Transportation testing as per ISTA and ASTM Standards.
• EMC Emissions testing 18m x 13m ALSE, UN ECE-R10, 72/245/ECC, 2009/19/EC – Transient

This extensive range of test provision offers every customer the opportunity to develop a bespoke test regime particular to their product.

Testing in Practise
Elite are the supplier of Electronics for The Magstim Company who are based in Wales. This relationship provides an excellent example of how a test regime is developed and works.
As Magstim developed their products and moved towards scale manufacture, a series of collaborations between Magstim and Elite set out the parameters for the testing required.
As Elite provide a sub assembly i.e. populated PCB’s, for Magstim they are required to provide testing at board level only. Even at this level Elite and Magstim were involved in extensive discussions in developing suitable test procedures and rigs.
In the first instance Elite recommended a series of board level tests, developed suitable test rigs to facilitate these tests and sent all of this to Magstim for validation and approval.
Once validated and approved, Elite set about training core staff in operation these specific test rigs and recording procedures required by Magstim.
Elite now have a bespoke test regime for Magstim delivered on a production scale.
All test results are uploaded to Magstim giving them full test coverage on every board Elite produce.
This level of test gives Magstim a high degree of confidence in every PCB they use in their system.

 

For more information contact Shaun Mc Bride  – smcbride@elitees.com