Flexible Spindle Polishing for Non-Linear Channels

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Solution Overview

Problem

Conventional methods for polishing internal surfaces of complex channels, such as those found in gas turbines and aerospace components, struggle with consistency and efficiency, often requiring extreme chemicals or pressures that can compromise the workpiece.

Innovation Solution

The use of a flexible spindle with a grinding wheel that orbits the channel, controlled by rotational speed, grit size, fluid viscosity, and grinding wheel geometry, to achieve uniform surface treatment and maintain dimensional integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional polishing methods are used on internal surfaces of complex channels, then material removal occurs, but surface finish consistency deteriorates and workpiece integrity is compromised due to extreme chemicals and pressures

Engineering Contradiction:

Improvesurface finish consistencyVSAvoiddamage from extreme chemicals and pressures

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the fundamental parameters of the polishing process by using a flexible shaft-driven grinding wheel with controlled orbital motion instead of conventional rigid polishing methods. The orbital motion parameters (amplitude, frequency, trajectory) are carefully controlled to achieve consistent surface finish without requiring extreme chemicals or pressures, thereby resolving the contradiction between surface finish consistency and workpiece integrity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The flexible shaft acts as an intermediary between the drive mechanism and the grinding wheel, allowing controlled transmission of rotational motion while accommodating the complex geometry of internal channels. This intermediary enables precise control of the grinding wheel's orbital motion, achieving consistent surface treatment without the need for harmful extreme conditions

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If high rotational speed is used to increase productivity, then material removal rate improves, but orbital control precision deteriorates

Engineering Contradiction:

Improvematerial removal rateVSAvoidorbital control precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system employs dynamic control of the flexible shaft's rotational speed, allowing it to vary during the polishing process to optimize both productivity and precision. The orbital motion characteristics are dynamically adjusted based on the specific channel geometry and desired surface finish, enabling high material removal rates while maintaining precise orbital control through real-time parameter adjustment

Inventive Principle:

Principle #15Dynamics

3Productivity

If abrasive contact force is increased to improve material removal efficiency, then productivity increases, but surface uniformity deteriorates due to inconsistent abrasive contact

Engineering Contradiction:

Improvematerial removal efficiencyVSAvoidsurface uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The grinding wheel is made to follow a controlled orbital path with periodic motion characteristics. This periodic orbital action ensures that different portions of the grinding wheel contact the channel surface in a systematic, repeating pattern, distributing the abrasive contact uniformly across the surface. This achieves both high material removal efficiency and consistent surface uniformity by preventing localized over-grinding

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables consistent and efficient polishing of internal surfaces, significantly reducing surface roughness while maintaining dimensional accuracy, thereby improving the fatigue life, corrosion resistance, and efficiency of components.

Implementation Method 1

Rotational contact by the grinding wheel removes material and alters the workpiece surface, based on an abrasive wheel surface with cutting components of a grit size and distribution pattern

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

Drive logic rotates the flexible shaft for controlled rotation as the orbital movement or pattern achieves controlled contact with the interior channel surface

Methodology Applied

Scientific EffectFlexible shaft rotation:

Data Source

PatentUS20250153307A1Flexible spindle polishing

Publication Date: 2025.05.15 WORCESTER POLYTECHNIC INSTITUTE

AI summary

Precise surface treatment and finishing of an enclosed, non-linear channel through a 3-dimensional printed, additively manufactured or machined part or workpiece results from insertion of a grinding wheel on a flexible shaft and controlling an orbital movement though rotational speed, grit selection and fluid viscosity of a liquid medium in the channel. Drive logic rotates the flexible shaft for controlled rotation as the orbital movement or pattern achieves controlled contact with the interior channel surface. Rotational contact by the grinding wheel removes material based on a grit size, while the orbit is controlled through the rotation, viscosity and grit size for achieving uniform coverage of the interior surface. An internal geometry, typically circular or elliptical, is preserved while attaining a smooth surface through precise material removal resulting from the controlled orbit.