Internal Channel Cutter Head for AM Surface Roughness Removal

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Solution Overview

Problem

Additive manufacturing processes result in undesirable distortions and surface roughness on down-facing surfaces of internal channels, which can interfere with fluid flow in components like gas turbine engines.

Innovation Solution

A cutting system with a cutter head, blade, drive cable, and cutter base is used to smooth down-facing surfaces by rotating the cutter head within the channel, guided by an up-facing surface, utilizing directional cables for precise material removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If additive manufacturing is used to fabricate internal channels, then complex geometries and high-aspect ratios are achieved, but surface roughness and distortions occur on down-facing surfaces

Engineering Contradiction:

Improvechannel geometryVSAvoidsurface roughness

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The cutting system is divided into separate functional components: a cutter head for material removal, a cutter base for support and guidance, and a directional cable for positioning. This segmentation allows each component to be optimized independently for its specific function while working together to solve the surface roughness problem in additive manufactured channels.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cutter base acts as an intermediary between the directional cable and the cutter head. It provides a stable platform that contacts the up-facing surface to guide the cutter blade, while the directional cable transmits forces through the cutter base to control the cutter head's position and orientation without directly interfering with the cutting action.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If a cutting system is introduced to smooth down-facing surfaces, then surface roughness is reduced, but device complexity increases

Engineering Contradiction:

Improvesurface smoothnessVSAvoidcutting system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The directional cable functions as a flexible element that can navigate the complex three-dimensional geometry of internal channels while maintaining precise control over the cutter head's position. This flexible cable approach is simpler than rigid mechanical guidance systems and can adapt to curved and angled channel paths.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

Instead of trying to smooth down-facing surfaces directly during additive manufacturing, the invention inverts the approach by using the up-facing surface (which has acceptable surface quality) as a guide surface to indirectly control and improve the down-facing surface through the cutter base contact and directional cable guidance.

Inventive Principle:

Principle #13The other way round (Inversion)

3Manufacturing precision

If the cutter base contacts the up-facing surface for guidance, then cutting precision is improved, but the system cannot access channels with poor up-facing surfaces

Engineering Contradiction:

Improvecutting accuracyVSAvoidchannel accessibility

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The cutter base is designed to perform multiple functions: it provides structural support for the cutter head, serves as a guidance element by contacting the up-facing surface, and transmits control forces from the directional cable. This multi-functionality reduces the need for separate guidance mechanisms and enhances the system's adaptability to various channel geometries.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cutter head is positioned within or adjacent to the cutter base, with the cutting tool nested within the cutter base structure. This nested arrangement allows the compact cutting system to access tight spaces within channels while maintaining the guidance function of the cutter base.

Inventive Principle:

Principle #7Nested doll (Nesting)

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

The system effectively removes excess material from down-facing surfaces, enhancing channel smoothness and fluid flow efficiency, serving as a precursor for subsequent finishing steps.

Implementation Method 1

a cutter blade attached to the cutter head... rotating the cutter head within the channel... urging the cutter blade toward the down-facing surface to remove the excess material

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentEP4585336A1Apparatus and methods for improvement of surface geometries of internal channels of additively manufactured components

Publication Date: 2025.07.16 RTX CORP

Figure 1
Figure 2A~2C
Figure 3A~3C

AI summary

A cutting system (320; 420; 520; 620; 720) for removing an excess material (217) along a length of a channel (202) constructed using an additive manufacturing process is disclosed. In various embodiments, the cutting system (320; 420; 520; 620; 720) includes a cutter head (324; 424; 524; 624; 724); a cutter blade (326; 426; 526; 626; 726) attached to the cutter head (324; 424; 524; 624; 724); a drive cable (328; 428; 528; 628; 728) configured to rotate the cutter head (324; 424; 524; 624; 724); and a cutter base (322; 422; 522; 622; 722) attached to the cutter head (324; 424; 524; 624; 724) and having a cutter base outer surface (344; 444; 544) configured to contact an internal surface within the channel to guide the cutter blade (326; 426; 526; 626; 726) against the excess material (217).