Product Description

316L Stainless Steel Capillary Tubing with Diameter Changes, End Capping/Flaring/Necking, Sandblasting, and Marking is an advanced, integrated fabrication service that transforms fine-bore 316L tubing into complete, ready-to-install micro-fluidic or instrument components. This process combines several precision techniques: creating controlled diameter transitions (tapered, reduced, or expanded sections), forming sealed or flared ends, applying a uniform matte finish via sandblasting, and adding permanent identification via laser marking. The use of 316L stainless steel ensures superior corrosion resistance and biocompatibility, making the final product suitable for demanding applications in medical, analytical, chemical, and high-purity industries where cleanliness, precise geometry, and traceability are critical.

Product Processing

1. Material Preparation & Verification: High-purity 316L stainless steel capillary tubing is selected, verified for certification (ASTM A269), and cut to the required starting length. The material's low carbon content is crucial for corrosion resistance post-forming.

2. Precision Diameter Changing:

   • Swaging/Necking: Using precision rotary swaging machines, specific sections of the tube are radially compressed to create smooth reductions in outer and inner diameter.

   • Expanding/Flaring: The tube ends are expanded using tapered mandrels or forming tools to create flares, bell mouths, or increased diameter sections for connections.

3. End Forming & Sealing:

   • One end can be hermetically sealed by cold forming into a dome or by welding a cap (TIG or laser welding).

   • The opposite or other end is shaped as required (flared, squared, or left with a reduced neck).

4. Stress Relief Annealing: After the cold working operations (swaging, flaring), the parts undergo a controlled annealing process in an inert atmosphere to relieve internal stresses, restore ductility, and prevent stress corrosion cracking, which is vital for 316L material.

5. Sandblasting (Bead Blasting): The components are uniformly sandblasted using fine, non-contaminating media (e.g., high-purity glass beads). This process removes scale, creates a consistent satin/matte surface finish, and provides an ideal substrate for marking and further surface treatment.

6. Chemical Passivation: Following sandblasting, the parts are chemically passivated (typically per ASTM A967, Method for 316L) to remove free iron particles embedded during blasting and to maximize the chromium oxide layer, restoring the optimal corrosion resistance of the 316L surface.

7. Laser Marking: A fiber laser system applies permanent, high-contrast markings. The laser parameters are tuned for the blasted surface to create clear, durable marks without damaging the material's corrosion-resistant properties.

8. Final Cleaning & Inspection: A final ultrasonic cleaning in deionized water removes all residues. Each part undergoes 100% dimensional inspection and visual quality control. Critical parts may undergo helium leak testing for sealed ends.

Product Applications

• High-Purity Chemical & Pharmaceutical Transfer: Components for HPLC, GC systems, or process analytical technology (PAT) where diameter changes guide flow, sealed ends contain pressure, and marking ensures traceability.

• Medical Device Sub-Assemblies: Micro-cannulas, sensor sheaths, or connector interfaces for implantable or diagnostic devices requiring biocompatibility, specific end forms, and permanent lot marking.

• Semiconductor Manufacturing: Gas or chemical delivery lines within tools, where a contaminant-free, passivated surface, smooth internal transitions, and clear identification are mandatory.

• Analytical Probe Manufacturing: Sheaths for pH, conductivity, or optical sensors, featuring sealed tips, necked sections for O-rings, flared ends for connections, and a non-reflective blasted surface.

• Food & Beverage Precision Sampling: Probes or nozzles requiring sanitary design, cleanable surfaces, and identification for quality control.

Product Technical Parameters (Detailed Table)