Internal Channel Cutter Head for Smoothing AM Down-Facing Surfaces

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Solution Overview

Problem

Additive manufacturing processes result in internal surfaces of channels within components, such as those in gas turbine engines, exhibiting distortions and surface roughness, which can interfere with fluid flow and require subsequent finishing steps to achieve smoothness.

Innovation Solution

A cutting system comprising a cutter head, cutter blade, drive cable, and cutter base is used to rotate and guide the cutter blade within channels, applying a push-pull action via directional cables to remove excess material from down-facing surfaces while avoiding up-facing surfaces, thereby smoothing the internal surfaces.

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 segments the finishing operation by directing the cutter head to selectively remove material only from down-facing surfaces while preserving up-facing surfaces. The fulcrum mechanism divides the channel surface into two zones: downstream side (down-facing) requiring material removal and upstream side (up-facing) requiring no intervention.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention applies local quality by treating different surfaces differently - the down-facing surfaces receive cutting treatment to remove excess material, while the up-facing surfaces are left untouched. This localized approach ensures that material removal occurs only where needed to eliminate surface roughness and distortions.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If material is removed from down-facing surfaces, then surface smoothness is improved, but up-facing surfaces may be damaged by the cutter blade

Engineering Contradiction:

Improvesurface smoothnessVSAvoidcutter blade damage to up-facing surface

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The cutting system employs asymmetry through the fulcrum mechanism, which creates an asymmetric cutting zone where the cutter blade is positioned to contact only the downstream (down-facing) side of the channel. The fulcrum acts as a physical barrier that prevents the blade from reaching the upstream (up-facing) side, ensuring selective material removal without damage to the opposite surface.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The fulcrum serves as an intermediary element between the cutter blade and the up-facing surface. It mediates the cutting operation by allowing the blade to access and remove material from the down-facing surface while simultaneously blocking the blade from contacting and damaging the up-facing surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If conventional finishing processes are used, then surface roughness is reduced, but extensive subsequent finishing processes are required

Engineering Contradiction:

Improvesurface roughnessVSAvoidnumber of finishing processes

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The invention replaces conventional mechanical finishing processes (such as grinding, polishing, or multiple passes of material removal) with a single targeted cutting operation. By using the fulcrum-guided cutter head that selectively removes only down-facing surface material, the system achieves surface smoothness in one operation rather than requiring multiple sequential finishing processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 cutting system effectively removes excess material and smooths down-facing surfaces, enhancing the precision and uniformity of internal channels, facilitating better fluid flow and reducing the need for extensive subsequent finishing processes.

Implementation Method 1

a cutter head; a cutter blade attached to the cutter head; a drive cable configured to rotate the cutter head

Methodology Applied

Scientific EffectMechanical cutting: Abrasion

Data Source

PatentUS11471947B2Apparatus and methods for improvement of surface geometries of internal channels of additively manufactured components

Publication Date: 2022.10.18 RTX CORP

AI summary

A cutting system for removing an excess material along a length of a channel constructed using an additive manufacturing process is disclosed. In various embodiments, the cutting system includes a cutter head; a cutter blade attached to the cutter head; a drive cable configured to rotate the cutter head; and a cutter base attached to the cutter head and having a cutter base outer surface configured to contact an internal surface within the channel to guide the cutter blade against the excess material.