Why a PCB-standard in the universe for Medical Device Applications is a hard nut to crack!

Medical Device Applications, the ones that you for sure will be certain are made by the book and after correct standards, when you first need them. Applications that scale in variety when it comes to size and technology. Advanced, large x-ray machines, robotic arms, and microscopic hearing devices or sensors. Applications for both the exterior and the interior of the human body.

When you think of the variety of environment these applications must tolerate, it is not hard to understand that finding one standard to embrace them all, is a challenge.

Two years ago Elmatica initiated a task group for Medical Device Applications. IPC accepted the challenge and founded IPC-6012 and 6013 Medical Addendum with me as chair. With experience from similarities in the Automotive addendum, the task group quickly discovered the need for a different approach to this addendum.

The purpose of the IPC 6012 Medical Addendum Working Group is to determine an enhanced IPC Standard (6012 and 6013) for PCB fabrication beyond IPC Class III to demonstrate suitability for medical devices and provide a high degree of assurance of the reliability and durability of the PCB.

Let’s find the consensus in the jungle! Possible? Yes!
The task group, consisting of several members from the entire PCB industry, first met at Electronica in 2016 and has since then continuously developed the standardized PCB Requirements for Medical Device Applications. Is the work exciting – yes for sure! Is the work challenging – yes, absolutely!

As I said in the beginning, in an industry where failures can be fatal, the development of rigid standards is necessary.

My thoughts the entire way, and the idea behind the addendum, was to find a consensus in the jungle of corporate specifications – a common document describing basic PCB requirements for Medical Device Applications. We collected all learnings from developing the addendum for the Automotive Industry and tried to do the same with  Medical. When developing a new standard, experiences from the complete production chain is vital, that is why it is so important to also have product owners in the task group.

The task group has met on a regular basis, discussing, solving challenges, discoveríng new ones, arguing, disagreeing and finally agreeing. Working with standards like this often provides the feeling of one step forward, then two steps back. It’s hard work, but it’s important.

When the new standards are approved, the manufacturers of PCB can rely on specific standards for production. The requirements and parameters for building and supplying printed circuit boards for the Medical Device Applications will then increase in reliability and transparency.

In the development of these two standards, we have today come to a point where we have agreed on most of the requirements and are ready to write a draft document for each of the two standards for industry review. We have recently been working in two subgroups focusing on two important segments, that soon will be presented for the larger group and will hopefully agree on a consensus.

“Rome was not built in a day”
They say that “Rome was not built in a day”, developing advanced addendums with several parameters to fulfill is not completed by just snapping your fingers either.

We have after several webinars and meetings in the task group, experienced that addendums in the industry for Medical Device Applications, require a quite different approach than in the Automotive Industry. The demands and specifications that need to be taken into account are quite different. The challenge is to define what specifications that can apply and work for PCBs in both small sensors under the skin, to larger medical equipment.

We have identified PCBs used in several applications such as implants and hearing-aid that have line widths, thickness, hole sizes and other features below current tolerances and limits in today’s “Design, performance and acceptability standard”.
Imperfections in the material that in a normal PCB would be acceptable, may cause application failures in these products. Where volume manufacturing of a standard PCB accepts a waiver of IPC´s test frequency requirements, suppliers of these Micro PCB exceeds the standard!

Micro PCB – a term to be discussed
A “Micro PCB” is a new term we recently had a discussion with members of the IPC TAEC (Technical Activities Executive Committee) around and ended up with a completely new terminology for it. We call it Design Producibility level D, which in reality means we push IPC design standards (IPC-2220 series) to be more up to date. This will take time to implement globally within IPC, but thanks to the miniaturization in some Medical Device Applications these standards will be the first ones to use the new term.

So what are the IPC Design Producibility levels?

In the IPC-2220 series, IPC refers to Design Producibility levels of features, tolerances, measurements, assembly, testing of completion or verification of the manufacturing process, that reflect progressive increases in the sophistication of tooling, materials or processing, and, therefore progressive increases in fabrication cost. These levels are:

Level A General Design Producibility – Preferred

Level B Moderate Design Producibility – Standard

Level C Least Design Producibility – Reduced

The new proposed level suggested due to the complexity in the PCBs for Medical device Applications is called:

Level D: Advanced Design Producibility – Exceedingly Reduced

The producibility levels shall not to be interpreted as a design requirement, but rather as a method of communicating the degree of difficulty.

Today these PCBs are made to customer requirements rather than following the IPC standard, this is not the path we want to continue on. We are today 44 members in the task group, representing the PCB Industry, Electronic manufacturing and Medical Device Applications industry. The task group is still open to new members, and above all, we need more people from product owners or Electronic production for Medical Device Applications.

With digitalization, AI and IoT, the traceability and transparency to where by whom and how a PCB is produced will be even more important. Ruling out the ones that do not follow the standards, from the ones that do! Because, that day when you might be in need of a medical device, you want to be sure it does its job, properly!

This blog post was first published in our column, The PCB Norsemen in the November edition of the PCB007 Magazine.

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