Innovations in medical device manufacturing are enabling remarkably small microsensors, enabling revolutionary advances in fields such as neurovascular surgery, ENT, oncology, and cardiac medicine. But while much of the industry conversation focuses on how sensors as small as 0.33 mm are manufactured, a critical challenge for OEMs is designing the devices these sensors must integrate with.
As sensors become smaller, they also become more difficult to handle, and careful decisions must be made to integrate sensors into devices for reliable performance, durability, and cost-effective scalability. Here’s why sensor integration is often the true bottleneck in high-stakes manufacturing, plus advice on how designers can prepare their designs for micro-sensor integration – from prototype to production scale.
Why Sensor Integration – Not Fabrication – Is Often the True Manufacturing Bottleneck
Whether you’re designing a brand-new device or redesigning a predicate device that didn’t originally feature electromagnetic navigation, micro-sensor integration presents multiple challenges that can risk the entire project if not addressed during the design phase.
An electromagnetic sensor with slanted air coils on a device.Forj Medical
Size Constraints
Cutting-edge designs demand ever-smaller micro-sensor geometries to fit in tight form factors, such as the 1.5 Fr multi-sensor catheters that Forj Medical produces. At the same time, sensors must be protected from external forces that can cause damage – but protective measures such as dielectric coatings, heat shrink jackets, and encapsulation increase the device profile.
A catheter with an electromagnetic sensor.Forj Medical
Durability
Smaller sensors are naturally more fragile, yet many sensor-enabled devices must withstand the bend forces of articulation without breaking leads. If articulation isn’t accounted for, it can lead to failures during manufacturing and clinical operations.
Thermal Management and Compression
Thermal management is critical to compensate for environmental fluctuations, manufacturing stresses, and physiological body heat. For example, if the manufacturing process involves reflowing a sensor inside of a catheter, the sensor could fail when subjected to high heat. To solve the heat issue, some designers add an outer jacket of heat shrink, but that can compress internal components and cause failures during the manufacturing process.
Signal Integrity
Designs that incorporate magnets, magnetic metals, or expose sensors to electrical fields created by other components can distort or disrupt signal integrity, making the device unreliable in critical medical settings.
Handling
Designers often focus on building for clinical applications rather than manufacturability. However, overlooking manufacturability can lead to handling issues that hinder production and scalability. Fragile micro-sensors can fail when manually fed through tight lumens, for example, so designing devices to minimize human handling can improve manufacturability and scalability.
How to Prepare Designs for Micro-Sensor Integration
Successful micro-sensor integration begins in the design phase, when critical decisions are made about sensor placement, protection, materials, and other factors that directly impact market viability. Here are five considerations that can reduce risk and influence commercial success for sensor-enabled medical devices.
1. Placement
The tip is often the best spot to place the sensor, but it’s not always the only option. In rigid devices, for example, the sensor can be placed anywhere – including the handle – as long as you know the device’s geometry. However, moving the sensor away from the tip can diminish accuracy, creating a tradeoff that must be accounted for.
Designers must also consider proximity to other components, especially magnets and those that generate electrical fields, to ensure sensors are shielded from signal distortion.
2. Protection
Sensors are exposed to multiple stressors during manufacturing and in clinical applications, including articulation and heat. Designers can implement features that protect sensors and help ensure reliable performance and durability, including:
- High-tension twisted pairs to prevent breakage under tension.
- Thick dielectric coatings or jackets on twisted pairs to withstand abrasive forces.
- High-temperature glues that won’t degrade under heat.
- Placing sensors in polyimide tubes with thick walls.
As with all protective measures, it’s important to understand tradeoffs: you might need to sacrifice some size to manufacture a durable device that performs reliably during high-stakes medical procedures.
3. Material Selection
Material selection can impact supply chain reliability and signal integrity. Materials that are difficult to source can lead to production delays, while designs that incorporate magnetic materials can disrupt sensor signals. Designers should choose readily available materials with short lead times and avoid those that could degrade sensor performance.
4. Design for Manufacturing (DFM)
As stated, designers often focus on creating designs for clinical applications, not how they’re going to scale production to thousands of units a year, fully qualified, consistently and robustly. That’s why it’s crucial to consult your manufacturer early on – even before the prototype phase – about how to ensure manufacturability at scale. A DFM-aligned manufacturer can help you:
- Create a design that leverages automation and reduces human handling.
- Design in features that make fixturing and mechanization easier.
- Design for robustness and durability during manufacturing.
- Design for repeatability, consistency, and cost efficiency.
By working directly with your manufacturer, you can ensure your device is not only clinically viable but also commercially viable.
5. Conduct Robust Testing
Testing validates your design and confirms reliable performance and manufacturability. For example, heat testing is critical for catheters that must withstand manufacturing processes and physiological environments; tensile testing ensures lead wires aren’t placed under too much stress or create resistance during articulation; and testing the device in an electromagnetic field verifies signal integrity. Robust testing throughout the design process helps identify failure points early, when they’re easier and more cost-effective to resolve.
Successful micro-sensor integration is critical to designing devices that drive revolutionary medical innovations. Applying these principles early in the design phase not only improves clinical performance, reliability, and durability, it also accelerates time to market, reduces costs, and enables scalability – directly impacting market viability and commercial success.
Dan Hanson is a product development engineer at Forj Medical. Forj Medical helps OEMs bring high-stakes medical devices to market through a Design for Manufacturing philosophy and highly scalable end-to-end production.
