Additive Manufacturing Binder Shell Segmentation
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Solution Overview
Problem
Additive manufacturing methods using granular materials, such as metal powders, face challenges in achieving improved mechanical properties due to the interference of binder coatings during the sintering process, leading to reduced hardness and strength in the final product.
Innovation Solution
The method involves depositing successive layers of granular metal construction material with a binder forming a contiguous shell around an unbound region, followed by debinding and sintering, where the shell and enclosed material sinters together at a temperature below the melting point, allowing for improved mechanical properties without binder interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If binder is used to bind granular construction material particles together during additive manufacturing, then the object can be formed and handled, but the mechanical properties such as hardness and strength are reduced due to binder interference during sintering
Solution Approach 1:
The object is divided into two distinct regions: a bound shell region formed with binder for structural integrity and handling, and an unbound interior region without binder for optimal sintering. This segmentation allows each region to serve its specific function without compromising the other.
Solution Approach 2:
Different regions of the object are assigned different properties: the outer shell has binder for mechanical strength and handling, while the interior has no binder to enable proper sintering. This local differentiation resolves the contradiction by applying binder only where necessary for manufacturing ease.
2Stability of the object's composition
If binder is present throughout the granular construction material, then the object maintains structural integrity during manufacturing, but the sintering process is interfered with leading to reduced mechanical properties
Solution Approach 1:
The object structure is segmented into a bound shell portion and an unbound interior portion, allowing the shell to provide structural integrity while the interior remains free of binder for optimal sintering performance.
Solution Approach 2:
The binder is extracted or removed from the interior region of the object, leaving only the shell portion with binder. This extraction eliminates the harmful effect of binder interference during sintering while preserving the necessary structural integrity through the bound shell.
3Strength
If pure granular construction material without binder is used, then optimal mechanical properties are achieved after sintering, but the object cannot be properly formed and handled during manufacturing
Solution Approach 1:
The manufacturing process is segmented into two stages: first forming the object with binder to enable handling, then selectively removing binder from the interior to enable optimal sintering and achieve superior mechanical properties.
Solution Approach 2:
The binder is applied preliminarily during the forming stage to enable object creation and handling, then selectively removed from the interior before sintering to achieve optimal mechanical properties, combining the benefits of both bound and unbound approaches.
4Stability of the object's composition
If binder is used to bind all regions of each layer, then complete structural coverage is achieved, but sintering quality is reduced due to binder presence in interior regions
Solution Approach 1:
The binding process is segmented to apply binder only to the shell region where structural coverage is needed, while leaving the interior region unbound to maintain sintering quality and achieve high manufacturing precision.
Solution Approach 2:
Different binding quality is applied to different regions: complete binding in the shell region for structural stability, and no binding in the interior region for sintering quality, resolving the contradiction between structural coverage and sintering precision.
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 results in objects with enhanced mechanical properties, such as increased hardness and compressive strength, by minimizing binder presence during sintering and ensuring binder exfiltration, leading to improved microstructure and density.
Implementation Method 1
portions of each layer being bound together during or after deposition of each layer to form portions of an object, thereby forming the object in the build region from the series of layers. The binding is typically carried out by selective deposition of binder.
Implementation Method 2
objects made from metal powders as the granular construction material can be sintered, for example by heating to a temperature below the melting point of the metal, to achieve an object with substantially improved mechanical properties.
Implementation Method 3
debinding the bound regions of construction material in a debinding process conducted at a first temperature, the first temperature being below a melting point of the construction material.
Data Source
AI summary
The present disclosure provides an additive manufacturing method for manufacturing an object. The method comprises depositing successive layers of a construction material. The method comprises selectively binding first regions of each layer to form a bound shell of construction material defining an exterior of the object. The method comprises selectively binding second regions of each layer to form support portions contacting the shell and which function to internally support the shell against external forces. The present disclosure also relates to apparatuses implementing the manufacturing method, and objects manufactured by the manufacturing method.