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Rigid-Flex PCBs in Medical Devices

April 25, 2023

Traditionally, rigid circuit boards were preferred for their simple design, low cost, and easy-to-cut angles, which made them less expensive to produce. However, today’s technology calls for more flexible circuitry. As devices across industries become smaller, they require more compact footprints, rendering traditional circuit boards inadequate.

Flexible circuits can bend and twist, given their form-adaptive properties. As such, they can be made smaller, allowing them to fit in places where traditional circuit boards cannot. A rigid-flex printed circuit board (PCB) is a hybrid circuit board design that incorporates elements from hardboards and flexible circuits. A rigid-flex PCB is rigid at some points and flexible at others. This article will look at the applications of rigid-flex PCBs in medical devices.

Rigid-Flex PCB Circuitry in Medical Device Applications

While rigid-flex PCBs are more expensive to manufacture, they are very versatile and can be custom-made for applications across various industries. They are highly suitable for applications across the medical field.

Medical Device Implants

Rigid-flex PCBs are a core component of implantable medical devices. In hermetically sealed containers, they are biocompatible and provide reliable, powerful computing that increases the effectiveness of the medical device. Some implantable medical devices that use medical device PCBs include:

  • Cochlear implants
  • Implanted defibrillators
  • Responsive Neurostimulator (RNS)
  • Pacemakers

Diagnostic and Medical Imaging Devices

Medical device PCBs are used in various medical imaging and diagnostic devices to treat or diagnose internal medical conditions. The following devices all rely on rigid-flex PCBs:

  • Magnetic Resonance Imaging (MRIs)
  • Ultrasound devices
  • Computerized Axial Tomography (CT) scans
  • X-rays
  • Radiation Treatment

Prosthetics

Major PCB advancements in the field of prosthetics have made it possible for users to experience a variety of sensory sensations, including pressure variations, heat fluctuations, and even texture.

Drug Delivery Systems

Rigid-flex PCBs ensure reliable, controlled distribution of medications in precise quantities in drug delivery systems such as infusion pumps.

Surgical Equipment

Rigid-flex PCBs are used in surgical tools such as electronic saws and cauterizing scissors.

Monitoring Devices

Rigid-flex PCBs facilitate the optimal operation of wearable monitoring devices, such as:

  • Blood glucose monitors
  • Body temperature monitors
  • Blood pressure monitors
  • Heart monitors

Medical Device PCB Design

PCBs are the basis of modern electronics. The medical industry relies on three types of PCBs for medical devices: rigid-flex, flex, and rigid. Rigid PCBs are very cost-effective. Flexible PCBs are the most effective choice for limited space applications since they can bend without failure. They are suitable for medical devices and wearable electronics and offer excellent packaging and connectivity options to other electronic components.

Rigid-flex PCBs integrate flexible and rigid board components. The rigid part is suitable for connecting and mounting components in densities mirroring rigid PCBs. The flexible part enables the board to fold or bend into small spaces, eliminating the need for cables and connectors between hard boards.

Medical Device Regulations for PCB Design and Assembly

The FDA’s Center for Devices and Radiological Health (CDRH) regulates corporations producing, importing, and selling medical devices in the United States. These companies must follow the following steps to comply with the FDA’s regulations.

  • Companies must register with the FDA.
  • Producers must list their devices with the FDA.
  • A company cannot sell its medical devices before receiving permission from the FDA (Premarket Notification 510(k)).
  • The device must undergo a clinical study to determine its safety to ensure Premarket Notification approval.
  • Quality Systems (QS) rules are associated with inspection of the production, design, purchasing, labeling, packaging, storing, installation, and servicing of these medical devices.
  • Manufacturers must comply with labeling requirements associated with all readable material concerning the medical devices
  • Medical Device Reporting (MDR) deals with any malfunctions and flaws that can lead to severe injuries or death. This must be reported to the FDA.

Companies that produce medical devices should be ISO: 9001 registered to ensure they strictly adhere to quality control standards and medical device PCBs should meet IPC 6013 class III requirements or beyond.