How does an abrasive flow polishing machine handle the inner bore of a bellows to enhance smoothness?

The core process of using an abrasive flow polishing machine to enhance the surface finish of the internal bore of a bellows can be divided into the following three parts:

Fluid Penetration and Directed Abrasive Grinding

1. ‌Soft abrasive fluidityBy leveraging the high permeability of semi-solid abrasive, the abrasive is driven through the corrugated tube's inner cavity by pressure, thoroughly covering the ripple indentations that conventional polishing tools cannot reach.
2. ‌Grinding Direction ControlThe abrasive particles form定向grinding paths along the axial direction of the inner hole, effectively eliminating the cross patterns produced by traditional rotating polishing, achieving consistent patterns.
3. ‌Micro-cutting ActionThe hard particles in the abrasive (such as silicon carbide/diamond) are subjected to high-frequency wave patterns at tens of times per second, cutting the microscopic wave peaks and filling in the valleys.

Parameter Coordinated Regulation

Parameter Type, Mechanism of Action, Typical Setting Range

Abrasive Particle Size: Coarse grinding (400 mesh) to remove deep grooves → Fine grinding (2000 mesh) for precise finishing with segmented gradient adjustment

System pressure drives abrasive acceleration at 3-8 MPa, increasing complex section pressure by 30%.

Cycle Times: Single grinding volume of approximately 0.5μm, with 5-8 cycles; Increment when ripple depth is greater than 20μm.

III. Quality Enhancement Results

• ‌Roughness EnhancementThe Ra value can be reduced from the initial 0.8μm to the 0.1-0.2μm level of mirror-like finish (requires online roughness measurement).
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• ‌Shape RetentionMaterial removal is controlled within ±5μm, ensuring the wave parameters of the bellows do not deform.
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• Performance EnhancementAfter polishing, the internal flow resistance is reduced by 40%-60%, suitable for high-precision hydraulic/pneumatic systems.

‌Note:For original wave patterns with a depth greater than 50μm, it is recommended to first undergo a lapping pre-treatment (Ra≤0.6μm) before implementing abrasive fluid finishing.