How to process the inner holes of slender tubes with an abrasive flow polishing machine to enhance smoothness? Stay tuned for a close-up look at the entire polishing process!

The abrasive flow polishing technology is designed for the complex structures of inner holes in slender tubes, achieving efficient polishing through customized process design. The following is the specific processing process and key technical points:

Polishing Process

1. ‌Specialized Workwear Fasteners‌
2. Customized fixtures for slender tube dimensions ensure secure tube clamping and no leakage in the abrasive channel. The fixture design must incorporate an inclination structure to optimize abrasive flow direction and prevent slippage.
3. ‌Abrasive Medium Selection‌
4. Select silicon carbide, diamond, or high molecular soft abrasive based on initial roughness.

• When Ra is greater than 0.6μm, first use coarse-grained abrasive to remove deep grooves.
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• When Ra ≤ 0.6μm, directly use fine abrasive polishing to achieve mirror finish.
• Abrasive viscosity must match the hole diameter to ensure balanced flow and cutting force.

1. ‌Dynamic Polishing Process‌
2. The hydraulic system drives abrasive particles to reciprocate within the pipe, removing burrs and microscopic protuberances through a squeezing and scrubbing action. The polishing duration is determined by the bore diameter, length, and target roughness, with an average single cycle time of 3-10 minutes.
3. ‌Post-processing and Inspection‌
4. Polished tubes are cleaned with a high-pressure air gun to remove residual abrasive, and the interior wall roughness is measured under a microscope (typically below Ra0.2μm). For parts with ultra-high requirements, secondary processing with electrochemical machining can be combined.

Part II: Technical Challenges and Solutions

• Abrasive Flow Control
• For slender tubes with an inner diameter less than 1mm and a depth-to-diameter ratio greater than 50, it is necessary to use a low-viscosity medium and increase the system pressure to prevent abrasive clogging.
• Uniformity Assurance
• By optimizing the fixture tilt angle and abrasive flow rate, the "bell mouth" effect at both ends is avoided, ensuring consistent wall polishing throughout the entire segment.
• Preventing Thin-Walled Tube Deformation
• Utilizing a low-pressure, high-frequency polishing mode to minimize impact stress on the tube wall4
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III. Typical Application Effects

• The inner surface roughness of the stainless steel slender tubes (diameter 1mm × length 100mm) has been reduced from Ra0.8μm to below Ra0.2μm, appearing as a mirror-like finish under a microscope.
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• The composite process (abrasive flow + electrolysis) can handle ultra-fine tubes with a depth-to-diameter ratio greater than 200, eliminating size deviations caused by traditional wire drawing and polishing.

This technology overcomes the industry challenge of internal hole polishing in slender tubes through precise control of fluid dynamics, particularly suitable for high-demand scenarios in medical devices and precision instruments.