Quality Management: Key To Medical Electronics Assembly and Manufacturing

No other industry in the US is under more pressure than medical electronics, and those pressures continue mounting each year for greater innovation and products that are faster, better, at lower cost, and in total compliance with regulatory standards. Those standards are becoming more stringent and more demanding of medical electronics OEMs each year.

In short, those standards are in place and precisely monitored to assure the highest level of quality when it comes to medical electronics product assembly and manufacturing. No mistakes or excuses are allowed. There are no “ifs,” “ands,” or “buts.” Plus, in some instances, to assure the highest possible quality, 100 percent operational conditions are fitted with multiple redundancies in case something unexplained happens.

As these demands continue escalating, veteran medical electronics OEMs further embrace and work closely with their contract manufacturer (CM) or electronics manufacturing services (EMS) provider partners if they’re successfully complying with standards and regulations. If not, they search out newer, more aggressive and savvier CM or EMS provider assembly and manufacturing talent that does meet those requirements. The chart shows a listing of the top characteristics to look for. In short, the hallmarks OEMs look for are quality, reliability, and repeatability as set forth by the ISO 9001:2008 and ISO 13485:2003 Standard, which is the quality management standard for medical electronics devices.

Successful Outsourcing

Experience counts, no question about it. But even more important in this outsourcing scenario is determining if ISO 13485 is well instituted within an organization. And even as important is whether or not a quality mindset permeates throughout the entire CM or EMS provider organization. When it embodies the right culture, quality, and mindset, the CM or EMS provider is steadily and frequently analyzing the process of manufacturing under a magnifying glass. This mode of operation permits them to determine if and when improvements need to be made.

Thus, quality, culture, and that positive mindset bring to the table highly invaluable assets and eliminate complacency with manufacturing practices and policies. That same quality thinking and actions must be foremost among top echelons of management and particularly, on the assembly floor with such personnel as process engineers and technicians responsible for creating the exact thermal profiles for a medical electronics printed circuit board (PCB).

In addition, an assortment of advanced systems and equipment assure quality and reliability. Automatic optical inspection or AOI is used to ensure consistency. X-rays provide assurances that all joints are proper. (See Figure 1) First article inspection makes inspection and quality control (QC) more reliable, repeatable, and faster. The more use of automation, using precise machinery, the less human intervention is required, thus eliminating the possibility of human error.

A Disciplined Setting

ISO 13485 provides a specific and disciplined setting within the assembly and manufacturing structure. It is critical because all the manufacturing instructions are to be developed, written, and implemented according to the Standard and directly linked to it.

Moreover, ISO 13485 provides the CM or EMS partner the certification to assure medical electronics OEMs that protocols have been created and tested, correct fixtures and process improvements are in place, and incoming, operational, and process qualifications are well established. Also, as part of the failure mode and effects analysis aspects of ISO 13485, procedures and policies are put in place to assure all manufacturing and assembly equipments are properly calibrated and maintained as per manufacturers’ specifications — all under the umbrella of quality management.

Quality management systems or QMS for medical electronics manufacturing encompass a trio of certifications. Today, the ISO 9001:2008 Standard is a given, and medical electronics OEMs assume a CM or EMS provider has this Standard under their belt. But on top of that, it’s critical to have ISO 13485. Also, in some cases, US Food and Drug Administration (FDA) certifications are necessary, depending on the product being manufactured.

So, by making greater inroads and successfully progressing along from ISO 9001:2008 to ISO 13485 and then on to FDA certifications, a top notch CM or EMS provider is expected to progress from successfully producing high quality sophisticated to extremely sophisticated products, meaning tolerances continue to get tighter, quality continues dramatically growing, and the numbers of checks and balances increase to assure high quality products.

Find the Quality Mindset

The best way to determine whether or not a CM or EMS provider has that critical quality mindset or not is to investigate and question how they’re handling any and all aspects associated with ISO 13485. Some of the key ones involve both the OEM and the partnering CM or EMS provider. These are the ones that give medical electronics OEMs peace of mind:

• Are they taking a proactive or reactive approach toward quality management systems and ISO 13485?
• How well can a CM or EMS provider fully support an OEM’s risk management?
• Do quality control measures and checks and balances meet ISO 13485 requirements?
• Is the OEM keeping disciplined track of first pass yields and data matrices?
• Are the right test strategies being deployed to meet specific medical electronics sub-assemblies?

A proactive mindset is a huge asset when it comes to top quality assembly and manufacturing. Once it is clearly adopted, it pays large dividends to both the medical electronics OEM and to the partner CM or EMS provider. This means program management on the assembly floor is highly aware and on alert to anticipate potential issues when building a medical electronics product. In effect, it’s out-of-the-box thinking that opens the door to being mindful of “what ifs” and a plan for how to resolve them ahead of time. Also, that positive attitude and thinking allow a CM or EMS provider to proactively collaborate with customer OEMs to anticipate and resolve issues as well as put checks and balances into the project ahead of time.

Risk and Quality Management

On the second point, it is an understatement to say that medical electronics OEMs place considerable emphasis on risk management. These OEMs spend enormous time and money to mitigate risk, not only on product risk, but also regulatory risk. In this regard, the FDA is constantly vigilant about recalling bad products on the market. When that happens, not only are an OEM’s name and brand jeopardized, but also their competitive standing in the market. Or, in extreme cases, a devastating illness or death may occur due to a faulty product. In those instances, OEMs face the burden of considerable monetary liabilities and responsibilities. That’s why they have large and powerful risk mitigation departments.

Considering this risk management, the prudent medical electronics OEM will maintain extremely high CM or EMS provider selection criteria and place numerical rankings among suppliers. Those possible suppliers may be few, but the critical requirement of the one chosen is that it must have an established quality management system. Plus, it’s imperative for the CM or EMS provider and OEM to have a cultural fit to assure effective communications at all stages and a satisfactorily completed project.

As for the third point, addressing ISO 13485 and the quality management it requires, there can be literally thousands of quality control measures that can be put in place. The point to be made here is critical and well thought out QC measures are at the foundation of ISO 13485. Take for example an incoming QC process when fabricated printed circuit boards or PCBs arrive at the CM’s dock. QC should include checking for multiple board aspects such as hole tolerances, cutout verifications, board dimensions, and surface finishes.

Checks and Balances

Checks and balances are closely related to QC measures, but represent yet another level of quality management. So, for the medical electronics OEM, the question to ask is how many procedures, steps, and checks and balances are embedded in the CM’s or EMS provider’s manufacturing process flow chart. A successful one manufactures the product with a continual closed loop feedback system. This means that when the first article board is processed, there are changes to be made; for example, the thermal profile needs tweaking, printing speed adjustments are necessary, depth of the printing squeegee needs better control, and so on. While the manufacturing process continues, there’s feedback of this nature, and then the loop is closed with those up-to-date adjustments. These represent quality steps incorporated in the manufacturing process that lead to a highly reliable, high quality, and repeatable product.

Also, not to be overlooked, checks and balances play a big role at the design phases of medical electronics sub-assemblies. That’s because any error or miscue—even the most minor—can have devastating consequences. Those can occur either at assembly or even later on as latent defects in the field. A good rule of thumb here is to assume Murphy’s Law will prevail at some point during a design. Whatever can go wrong will go wrong. Therefore, it’s good practice to have an extra set of eyes ready and willing to check all critical aspects of a layout. For example, that extra set of eyes double checks on assuring proper component footprints and polarities, making sure a silk screen is correctly associated with a given component, and pin numbers and sequencing are accurate for complex components.

Another key design check and balance example is the proper splitting of power and ground planes, as shown in Figure 2, which is vital to reduce noise and crosstalk. Low or relatively low signal-to-noise ratios (SNR) are definitely undesirable in medical electronics designs. The reason is SNR can adversely affect signals, preventing correct medical equipment readings and subsequent patient diagnosis. PCB designers must also be aware of keeping noise-generating high frequency devices away from high-speed digital signals. Otherwise, unwanted noise has a negative impact on those high-speed digital signals.

Meanwhile, the ball is in the OEM’s court to track the fourth point, first pass yields and data matrices. Here, it’s important for the OEM to demand and have current details on first pass yields. For example, those data matrices should include quality measures, progress levels, and details at the various stages of the surface-mount technology assembly process, including testing. Those details tell the OEM what exactly is measured and how quality is being measured. Matrices like this keep the CM or EMS provider under careful scrutiny with this set of checks and balances.

Testing Criteria

The fifth and last point here is for the OEM to establish the testing criteria that a particular medical electronics project requires. The next step is to closely investigate the CM or EMS provider to determine if the right test equipment and strategies are available with that supplier. A good CM or EMS provider has an extensive range of test capabilities to include full functional, flying probe, and in-circuit testing (ICT). Having the expertise to design, develop, and implement the right testing is included in these capabilities.

If it’s a functional test that’s needed, the OEM customer generally provides a testing environment when supplying the operating system. That system includes different software tools to manufacture and test the product to simulate the environment in which the medical electronics product would operate.

On the other hand, flying probe, as shown in Figure 3, is mainly targeted at small quantity PCBs. It doesn’t require any fixtures and is slow. However, it does check manufacturing defects, as well as places an extra sense of responsibility on the CM or EMS provider to ensure that the assembled PCBs have undergone a level of testing. This particular stage, whether it’s functional, flying probe, or ICT, is an important area for the OEM to monitor.

Lastly, ICT is directed at mature products with considerable built-in and proven design confidence. There’s sufficient product volume to justify the extra costs of creating the necessary test fixture and performing the testing over a long time period. Here, the burden of responsibility falls on the CM or EMS provider to make sure their testing equipment and personnel are up to par in knowledge and capability.

Summary

Finding and maintaining a sound and effective relationship with a CM or EMS provider is challenging and often involves tradeoffs. If the right partner is selected or is even currently working with an OEM, it is basically a walk in the park. However, if the wrong partner is selected, get ready for a challenging and bumpy relationship.

This article was written by Zulki Khan, President and Founder, NexLogic Technologies, Inc., San Jose, CA, an ISO 9001:2008 Certified Company, ISO 13485 certified for medical electronics, and a RoHS compliant EMS provider. For more information, Click Here .

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