All electronic devices contain a bunch of connected wires and circuit boards. But have you ever wondered why medical devices are costlier than regular electronics? There is the aspect of providing specialized functions, such as X-ray imaging or regulating heart rates (pacemakers), but that is not it. The answer is that they provide life-critical functions, which means the circuitry must be as reliable as possible.
So it all boils down to the PCBs that run these devices, which are expensive to manufacture and assemble. Devices like ventilators and CT scanners can have tens to hundreds of these circuit boards, which adds up cost-wise. Therefore, the most appropriate question to ask is, why are medical PCBs expensive? Here’s why.
Why Are Medical PCBs Expensive?
Medical device circuit boards are costlier than ordinary PCBs because they differ in these areas.
Design
Medical PCBs must be highly stable, precise, and miniaturized in some cases. As such, the design process must pay more attention to signal integrity, wiring accuracy, and electromagnetic compatibility.
Source: OurPCB
Signal Integrity
Signal distortion or attenuation can lead to malfunctioning, which can be the difference between life and death. So factors like crosstalk and transmission line effects must be eliminated during design.
Wiring Accuracy
Wiring accuracy goes hand-in-hand with signal integrity. Since medical circuit boards have multiple traces jam-packed in a small area, signal interference, crosstalk, and other wiring issues may arise. Therefore, the design process must look at the wiring requirements for different signals, such as analog, differential, and digital.
Electromagnetic Compatibility
Careful planning of the board’s signal, power, and ground wires must be considered during design to ensure compatibility by reducing electromagnetic radiation and interference.
Materials
With materials, you have to look at the substrate, copper thickness, and solder mask.
Substrate
Ordinary PCBs use FR4 substrates, but their medical counterparts need high-performance materials, such as PTFE, Rogers, Teflon, and ceramic, to provide properties like:
- Chemical resistance
- Low dielectric losses
- High-temperature resistance
- Quick heat dissipation
These materials come at a premium.
Source: OurPCB
Copper Thickness
Copper is the standard material to use on the conductive layer in all PCBs, but the thickness can vary. In medical circuit boards, the copper layer is thicker to provide a higher current-carrying capacity, low resistance, and better heat dissipation.
The thicker copper on multiple layers adds up cost-wise.
Solder Mask
Solder masks are protective layers that prevent oxidation and shorting on circuit boards. To ensure high reliability, medical circuit boards feature high-performance solder masks that provide chemical resistance and good insulation.
Manufacturing Process
When bringing all the pieces together to make the medical PCB, the process is a bit more intricate and expensive because of the following.
Fine Processing
Due to their complex and diverse shapes, sizes, and circuits, medical PCBs often require fine drilling, cutting, and milling to ensure high precision. These fine processing techniques increase the manufacturing time and cost.
Surface Treatment
Surface treatment techniques like gold plating (ENIG and ENEPIG) are necessary in medical printed circuit boards to enhance conductivity, oxidation resistance, soldering performance, and overall PCB reliability.
Multilayering
Some medical devices have compact form factors, a feat that can only be achieved by packing large circuits in tiny spaces. This is possible through multilayering, a manufacturing process that requires multiple lamination steps, inter-alignment accuracy, and controlled pressure application.
The PCB assembly for these boards is more or less the same as that of ordinary PCBs but with more quality control procedures.
Testing and Certification
The last steps before approving medical devices are testing and certification. These steps also apply to medical PCBs, which must undergo rigorous testing that includes:
- Bio-compatibility testing
- Electrical testing
- Durability testing
- Environmental adaptability testing
Compliance certifications from regional and international organizations, such as the FDA, UL, and IPC, wrap up the process, and these cost extra for approval.
An automated PCB testing rig
Final Thoughts
There are other factors that make medical devices expensive, such as extensive R&D and strict regulatory compliance. However, their complex design, engineering, materials, technology, certifications, and approvals, which are mostly linked to the PCB, form a strong foundation for their costing. So next time you purchase a ventilator, CT scanner, or any other medical equipment, keep that in mind when negotiating the price.
