Plug-Located Machining of AM Parts for Precise Internal Features

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Solution Overview

Problem

Aligning tools with additively manufactured parts is challenging due to difficulties in aligning the tool centerline with the part's internal features, leading to vibrations and misalignment, especially when forming threaded surfaces or sealing bodies.

Innovation Solution

The method involves forming plug holes around a landing surface portion on the tool surface, allowing the tool to engage with the plug and cut away material to form a tooled void, which stabilizes the tool and reduces vibrations by ensuring precise alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rotating tool is directly inserted into an opening in the additively manufactured part, then the tool can engage with the part to form threaded surfaces or sealing bodies, but the intermittent contact creates large vibrations and stress in the tool

Engineering Contradiction:
Improvetool engagementVSAvoidtool stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A plug is introduced as an intermediary element between the tool and the additively manufactured part. The plug provides a stable engagement surface for the tool, eliminating intermittent contact and reducing vibrations. The plug is temporarily retained during tool engagement and then removed after machining, serving its mediating function only during the critical tool engagement phase.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The plug is pre-installed into the opening of the additively manufactured part before tool engagement. This preliminary action creates a prepared, stable engagement surface that ensures consistent tool contact from the beginning of the machining operation, preventing vibrations and misalignment that would occur with direct tool insertion.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the centerline of the tool and the centerline of the opening in the part are not perfectly aligned, then the tool may bend, thereby increasing force on the tool and misalignment of the cut surface, but achieving perfect alignment is difficult or impossible

Engineering Contradiction:
Improvealignment precisionVSAvoidalignment complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The plug serves as a mediating alignment element that provides a precise, dedicated engagement surface for the tool. This intermediary structure simplifies the alignment process by creating a clear geometric reference that guides the tool centerline, reducing the complexity of achieving precise alignment without requiring complex positioning systems or procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The plug introduces a localized feature with specific geometric properties optimized for tool engagement. By concentrating the alignment function in this localized plug structure rather than requiring overall part-feature alignment, the system achieves high manufacturing precision through a simple, focused geometric relationship between the tool and the plug's engagement surface.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If material is removed around an existing additively manufactured cavity to form a sealing surface, then the sealing body can compress against the machined surface, but the machining process creates vibrations and stress that affect cutting quality

Engineering Contradiction:
Improvecutting qualityVSAvoidvibrations and stress
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The plug acts as a mediating structure that supports the machining operation by providing a stable engagement surface. This intermediary element reduces vibrations and stress during the material removal process by ensuring consistent tool contact, thereby improving cutting quality and reducing harmful factors generated during machining of the sealing surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4094881A1A body and method for locating machining features in additively manufactured parts
Publication Date: 2022.11.30 TRANSPORTATION IP HOLDINGS LLC
  • EP4094881A1 patent drawingFigure 1
  • EP4094881A1 patent drawingFigure 2~3
  • EP4094881A1 patent drawingFigure 4~6

AI summary

A method includes forming one or more plug holes (100) into a tool surface (102) of a body. The one or more plug holes are partially formed around a landing surface portion of a plug (310) in the body. The method also includes engaging a tool with the landing surface portion of the plug in the body, and using the tool to cut away the plug from the body and at least part of the body to form a tooled void into the body.