Hypodermic Tubing for Medical Devices: Specifications, Challenges & Custom Fabrication
In this sponsored technical blog post, Component Supply explores the role of hypodermic tubing in medical device design and how engineers can spec and source the right solution.
Hypodermic tubing plays a critical role in the development of medical devices that require precision, miniaturization, and biocompatibility. Commonly known as hypotube or needle tubing, this small-diameter stainless steel tubing is foundational to components such as catheter assemblies, dispensing systems, and surgical instruments. For medical device engineers and R&D teams, selecting the right hypodermic tubing requires a deep understanding of specifications, materials, and customization options that can impact device performance and manufacturability.
What is Hypodermic Tubing and Why Does It Matter in Device Design?
Hypodermic tubing is a welded and drawn stainless steel tube that begins as a flat strip, rolled into a tube, and longitudinally welded. It is then drawn over a plug or mandrel to reduce the diameter and achieve precise dimensions. The drawing process gives hypodermic tubing its seamless appearance and ensures tight dimensional tolerances required for medical applications.
Materials for Hypotube: Choosing Between 304 and 316 Stainless
The two most common grades of stainless steel used in hypodermic tubing are 304 and 316:
- 304 Stainless Steel: Known for its strength, affordability, and availability. Suitable for most general-purpose medical applications.
- 316 Stainless Steel: Contains molybdenum, which enhances corrosion resistance, especially in saline or chloride-rich environments. Ideal for devices exposed to bodily fluids for extended periods.
Component Supply provides hypodermic tubing in a “full hard” temper condition, which increases column strength but reduces flexibility.
Understanding Critical Specifications
Engineers often evaluate hypodermic tubing based on the following specifications:
- Outside Diameter (OD): The primary and most consistent specification.
- Inside Diameter (ID): Varies depending on wall thickness.
- Wall Thickness: Determines the balance between flexibility and strength.
Wall classifications (e.g., extra-thin, ultra-thin) are not standardized across all manufacturers. It’s essential to refer to actual dimensional values (OD, ID, wall) instead of relying on general wall terminology.
Engineering Tip: A thinner wall allows for increased flexibility and flow rate, but may risk structural integrity in applications requiring bends.
Common Challenges for Engineers Working with Hypotubes
- Inconsistent Wall Terminology: Manufacturers may use different terms for wall thickness categories, leading to confusion. Engineers are advised to rely on dimensional data, particularly when sourcing from multiple suppliers.
- Integration into Standard Fluid Circuits: Standard compression fittings often do not align with hypodermic tubing dimensions. To address this, Component Supply offers custom-drilled polyimide ferrules, allowing hypotubes to be adapted for use with conventional fittings.
- Custom Sizes at Low Volumes: While custom hypotube specifications are possible, they often require high minimum order quantities due to production complexity and cost. Engineers looking for specific OD or ID combinations may benefit from grinding standard tubing down to required specs, particularly for prototyping or low-volume applications.
Engineering Tip: Short lengths (3″ and under) are often available in stock for testing. Custom cutting to lengths as short as 0.040″ (+/- 0.005″) is also possible.
Typical Medical Device Applications
Hypodermic tubing is foundational to many medical device assemblies. Common applications include:
- Catheter Assemblies
- Guidewire Introducer Needles
- Dispensing Needles
- Sharps and Injection Needles
- Surgical Instruments
- Needle Cannulas
The strength, dimensional precision, and biocompatibility of stainless steel hypotube make it a go-to choice for both prototype and production-scale builds.
Custom Fabrication Capabilities Available
Component Supply offers a range of fabrication options to support both standard and customized medical device needs:
- Precision, burr-free cutting to tight tolerances
- Tip Grinding
- OD Grinding
- EDM Hole-Drilling
- Flaring
- Multiple/Complex Bending Configurations
- Laser Welding
- Custom Assembly
These services are designed to help engineers move from prototyping to scalable production without compromising on precision or quality.
Choosing the Right Hypotube for Your Application
Whether you’re sourcing for prototyping or final production, selecting the right hypodermic tubing can significantly affect your device’s performance and regulatory compliance. Through Chamfr, engineers can access a curated selection of hypotubes and fabrication services from Component Supply and other verified suppliers.
Ready to find the perfect hypotube for your project? Browse Component Supply’s hypodermic tubing or reach out with your technical specs to get started.
Frequently Asked Questions For Component Supply’s Hypodermic Tubing
Can you fabricate both ends of a hypotube?
Yes, as long as the length is sufficient to accommodate tooling.
What’s the difference between 304 and 316?
316 offers enhanced corrosion resistance due to molybdenum content, making it preferable for harsh environments.
Does your hypodermic tubing meet standards?
Yes. Tubing complies with ASTM A908.
Can I request a custom gauge size?
Component Supply is not a tubing mill, but works with partners that can produce custom sizes. Note that small quantity custom runs are often cost-prohibitive. Using standard gauge sizes helps reduce cost and lead times.
About the Supplier
Component Supply bridges the gap between prototype and production by offering quality hypodermic tubing and precision fabrication services tailored to the medical device industry. They provide a comprehensive and consistent offering of hypodermic tubing, mandrels, wires, PTFE tubing, FEP & PTFE heat shrink, and more. Custom capabilities include precision cutting, taper grinding, end forming, bending, laser welding, and more.