How to ensure the PCB quality in ventilators, ECG and CT scanning equipment

- Oct 20, 2020-

If life support equipment is not allowed to fail, what are the requirements for PCBs in these equipment? What should we do to ensure the quality of PCBs in ventilators, ECG and CT scanning equipment?


In FASTPCBA Group, we have received many questions about PCB applications. Where are they used? What impact will this have on the design? How to produce PCB boards to meet demand? Which factories are qualified to produce medical PCBs? In this column, we will discuss in detail the detailed information of PCBs used in medical applications, focusing on some differences in requirements and how to handle the design.


With the development of technology, we can foresee that e-medicine occupies an increasingly important position in the medical field. Advances in medical electronic technology have provided patients with more accurate diagnosis and treatment plans.


At the same time, the technological development of medical research tools has also enabled scientists to detect diseases at the molecular level and develop vaccines. According to WHO estimates, vaccines can save about 3 million lives each year. Technology in the medical electronics field will only continue to develop, and we also know that this development means that the demand for more complex PCBs will also increase.


There are many categories of medical equipment, ranging from very common standard equipment to very complex equipment. These medical applications can be divided into three different categories.


Category 1: General medical equipment. These products are generally low-risk. Although they are used in some medical treatments, they are difficult to cause personal injury, such as electronic scales, gauges and dental mirrors.


Category 2: Medical tools with certain risks. These products have higher risks than Category 1 products, but are limited to operation and maintenance risks, such as electric wheelchairs and monitoring instruments.


Category 3: Life support equipment. These products are vital and must be produced in accordance with the highest standards to ensure their high reliability. This is because once these life-sustaining devices stop or malfunction, they will have serious consequences, such as pacemakers and heart valves. We know that medical equipment must comply with certain standards while meeting certain basic standards, whether in terms of involvement, function, production, or quality system.


Table 1 lists some different key standards and examples:

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At the same time, it is necessary to focus on how these standards can be transformed into requirements or considerations that can be directly placed on PCB design (refer to Table 2).


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After evaluating the design elements, the manufacturing elements corresponding to the medical application must also be considered. These elements may directly affect the quality and reliability of the PCB. When it comes to safety, the elements in Table 3 are critical.


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In addition to the above elements, the NCAB Group has also established additional and more stringent standards:


The cleaning requirements exceed the IPC standards, use internationally well-known substrate types (we do not accept or allow the use of local or unknown brand substrates), the solder mask on the surface of the circuit board and the conductor surface needs to reach a specific thickness and a clear appearance And maintenance requirements (no open-circuit maintenance, a limited number of appearance maintenance is specified). When a VI type solder mask is required, the through-hole filling depth is more stringent and higher than the industry standard.


The certification related to these quality standards belongs to ISO 13485, which is a law/regulation in many countries/regions to ensure that the most stringent standards are adopted in the life cycle of medical equipment. ISO 13485 is largely consistent with ISO 9001. The certified level can participate in one or more stages of the medical device life cycle, including medical device design and development, manufacturing, storage, distribution, installation or maintenance And provide design and development support.


PCB design for medical applications needs to have specific elements that meet power, signal quality, crosstalk, and grounding requirements, but the most important thing is its reliability and safety.


Safety is a critical issue, including radiation, electrical performance, thermal performance and mechanical safety, and all of these safety are driven by IPC class 3 standards. Therefore, it is very critical to produce high-reliability PCBs that meet the requirements, to have a reliable manufacturer that can meet these requirements and provide reliable circuit boards for medical applications.


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