3D Metal Printing Overlap Strategy for Joint Strength

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Solution Overview

Problem

Conventional layered manufacturing methods for three-dimensional objects, such as tire curing molds, face issues with density differences in sintered layers leading to gaps between parts and weak boundary portions, which hinder integral manufacturing and adequate joint strength.

Innovation Solution

A method involving a predetermined amount of overlap during sintering, using either laser or LED light, to ensure integral manufacturing without gaps and achieve necessary strength and thermal conductivity for different regions, by correcting positional information of part data to overlap during the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If light beam irradiation conditions (scanning speed, scanning pitch, focusing diameter) are changed according to elements to obtain different physical properties, then physical properties such as strength are improved for each element, but density differences occur in sintered layers causing gaps between parts and weak boundary portions

Engineering Contradiction:
Improvestrength for each elementVSAvoiddensity uniformity in sintered layers
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The three-dimensional object is divided into multiple elements, each requiring different physical properties. By segmenting the object into elements and assigning specific light beam irradiation conditions to each element, the patent enables differential property optimization while maintaining overall structural integrity through careful control of boundary regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different physical properties are imparted to different regions of the three-dimensional object by varying light beam irradiation conditions (scanning speed, scanning pitch, focusing diameter) for each element. This local quality approach ensures that each element has the optimal properties for its specific functional requirements while managing density transitions at boundaries.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If light beam irradiation conditions are changed according to regions to set different physical properties, then physical properties such as strength and thermal conductivity are improved for different regions, but gaps occur between parts in higher-density and lower-density regions

Engineering Contradiction:
Improvephysical properties for different regionsVSAvoidcontinuity of sintered layers
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent varies multiple irradiation parameters (scanning speed, scanning pitch, focusing diameter) simultaneously to achieve different physical properties in different regions. By coordinating changes in these parameters, the patent creates smooth transitions between regions of different densities, preventing gap formation while maintaining the desired physical property gradient.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent plans and prepares the light beam irradiation conditions in advance for each element, including pre-calculating the optimal scanning parameters and focusing diameter for each region. This preliminary planning ensures that density transitions between elements are controlled and continuous, preventing gaps before they occur during the actual sintering process.

Inventive Principle:
Principle #10Preliminary 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

Enables the production of three-dimensional objects with integral structures and enhanced joint strength, ensuring physical properties like strength and thermal conductivity are met across different regions without complex preprocessing of laser irradiation conditions.

Implementation Method 1

metallic powder deposited in correspondence to a thickness of the partial shape is irradiated by a laser based on the slice data

Methodology Applied
Scientific EffectLaser irradiation: Laser

Implementation Method 2

layers of the metallic powder sintered by laser irradiation are stacked one by one to form a three-dimensional mold

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 3

the powder is sintered by twice of light irradiation

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 4

obtain a strength required for joining one part with the other part

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3219468B1Three-dimensional object manufacturing method and three-dimensional object
Publication Date: 2020.09.02 BRIDGESTONE CORP
  • EP3219468B1 patent drawingFigure 1~2
  • EP3219468B1 patent drawingFigure 3A~4
  • EP3219468B1 patent drawingFigure 5A~6

AI summary

A method for manufacturing a three-dimensional object includes converting model data of the three-dimensional object into slice data, sintering powder based on the slice data after the conversion, and manufacturing the three-dimensional object by a layered manufacturing process of stacking a plurality of sintered layers. The method includes a part data correction process of correcting positional information of at least one of mutually adjoining part data of the model data of the three-dimensional object, and laying part data on each other by a predetermined amount of overlap, converting the model data corrected in the part data correction process into slice data, and after forming a sintered layer based on the slice data corresponding to one part, forming a sintered layer based on the slice data corresponding to the other part.