Ultra-Small Diameter (USD) capillary tubing plays a critical role in improving the performance of liquid chromatography and related microfluidics instrumentation. Industry leaders in these fields require faster, more efficient equipment that can provide high-precision results. Thanks to USD tubing, this competitive edge is now attainable.

USD tubing used in these applications must have a clean and smooth inside diameter (ID) and be able to withstand high working pressures. Achieving these properties, however, raises some unique challenges because of the small size (less than 0.0625 inches) of the outer diameter.

In a new white paper, we explore these challenges and our manufacturing solutions, including:

ID surface roughness. USD tubing used in high-precision applications requires a smooth ID surface finish to ensure high-purity delivery of liquid and gas. Achieving proper smoothness depends on two things: how the tube is first drawn and the engineering expertise of the manufacturing supplier. We’ve developed proprietary tube-drawing processes and equipment that can draw stainless steel in coil form, resulting in more reliable flow rates and faster sampling cycles.

ID cleanliness. Impurities in USD tubing left over from the manufacturing process can result in cross-contamination and inaccurate sample readings. Our proprietary cleaning methods degrease USD coil tubing several hundred feet long—reducing the amount of cleaning time required by OEMs.

Measurement quality. The very small dimensions of USD tubing make physically gaging the size of the inside diameter (ID) problematic. As the tubing is drawn to smaller sizes, the ID takes on a starburst shape—yielding imprecise results when pinned with circular gauge pins to measure ID size. We use a variety of proprietary measuring techniques to ensure that these geometric fluctuations are accounted for.

To learn more about USD tubing, download our latest white paper.