Calibrated Polyurethane Tube Medifly PU68 Yellow (Ø 6×8 mm, 98 ShA, Yellow)

1. Purpose and Operating Principle

The bright yellow color provides clear visual identification of the line in compressed air distribution networks and multi-circuit control panels. Made from elastic thermoplastic polyurethane with a hardness of 98 ShA / 52 ShD on a polyether base (Polyether TPU), the tube combines high elasticity, hydrolysis resistance, and multi-cycle bend durability. The calibrated 8 mm outer diameter guarantees secure retention in push-in fittings per ISO/TS 11619:2014.

2. Technical Specifications

3. Design Features

Decoding the Medifly PU68 Yellow code:

Key design solutions:

• Outer wall calibration — a stable 8 mm outer diameter ensures secure retention in push-in fittings per ISO/TS 11619:2014, without air leaks.
• Polyether base — improved hydrolysis resistance compared to standard polyester-based variants, important for operation in humid environments.
• Multi-cycle bend durability — the tube retains its bore under repeated bending cycles in moving automation and robotics modules.
• Resistance to atmospheric factors — Medifly polyurethane resists ozone and has high aging resistance, allowing outdoor use.

4. Installation Recommendations

1. End preparation. Cut the tube strictly at a 90° angle, using only a dedicated guillotine-style tube cutter — an ordinary knife or pliers deform the cross-section and compromise the fitting’s seal.
2. Fitting types. Compatible with push-in and compression fittings with an 8 mm diameter from leading European and Asian brands.
3. Bend radius. Do not allow a bend radius smaller than 35 mm — a smaller radius narrows the inner bore and reduces air flow.
4. Pressure derating by temperature. As the working medium’s temperature rises, reduce the maximum working pressure: at +40°C — 4.9 bar, at +60°C — 3.6 bar.

5. Comparison within the Medifly Line

• PU68 (Ø 6×8 mm, 7 bar) — for lines with higher air flow, where high working pressure isn’t required.
• PU46 (Ø 4×6 mm, 10 bar) — a more compact tube with higher working pressure, for connecting individual pneumatic cylinders and modules.

6. Common Mistakes

• Cutting with an ordinary knife or pliers — deforms the 8 mm wall, so the fitting no longer holds a tight seal.
• Exceeding the allowable bend radius (<35 mm) — kinks the wall and reduces pneumatic system performance.
• Operating above +60°C without derating pressure — softens the polyurethane and risks rupture.

7. Applications

• Compressed air distribution networks — main lines and control manifolds.
• Industrial robotics — modules with frequent bending cycles.
• Pneumatic tools and clamping systems — air supply for power tools.
• Outdoor installations — thanks to ozone and weathering resistance.
• Color-coded control panels — visual separation of lines by color.
• Water and non-aggressive coolant supply systems.

8. Expert Opinion

Vitalii Boluchevski, lead engineer at Acvatron SRL (18 years of experience): “The Medifly PU68 tube at 8×6 mm caliber is an ideal balance between high flow capacity and elasticity.”

9. FAQ

1. Is the PU68 Yellow tube compatible with 8 mm quick-disconnect fittings from Festo and Camozzi? Yes, the calibrated 8.0 mm outer diameter with ISO/TS 11619 tolerance ensures 100% compatibility with push-in fittings from all European and Asian brands.

2. What working pressure does the PU68 tube withstand? Working pressure at room temperature (+23°C) is 7 bar, with a burst pressure of 28 bar.

3. Can this tube be used outdoors? Yes, Medifly polyurethane resists atmospheric effects and ozone, and has high aging resistance.

4. What packaging is the tube supplied in? The standard supply form is a 100-meter coil. Cut-to-length by the meter or supply in cardboard dispenser boxes is also available.