Sacrificial Component Resists Shear Force in Binder Jetting
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Solution Overview
Problem
In binder jetting additive manufacturing, the spreading mechanism can cause defects such as layer shifting and cracking due to shear force, which existing methods fail to effectively prevent.
Innovation Solution
A sacrificial component is printed with a resistive feature that provides a counterforce to the shear force, immobilizing each printed layer of the part in the powder bed through a coupled arrangement, either via direct or indirect mechanical coupling or an anti-sintering agent, to prevent layer shifting and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a spreading mechanism is used to spread unbound powder to form layers, then the powder bed is formed efficiently, but shear force causes layer shifting and cracking
Solution Approach 1:
The sacrificial component is printed in advance with features specifically designed to provide resistive force against the shear force generated by the spreading mechanism. This preliminary structure prevents layer shifting and cracking before they occur during the powder spreading process, allowing efficient spreading while maintaining layer positioning accuracy.
Solution Approach 2:
The sacrificial component acts as an intermediary element between the spreading mechanism and the part being printed. It absorbs the shear force and mechanical stress from the spreading mechanism, protecting the part layers from shifting and cracking while allowing the spreading process to continue efficiently.
2Manufacturing precision
If the sacrificial component is mechanically coupled to the part, then layer immobilization is achieved, but additional printing steps are required
Solution Approach 1:
The sacrificial component and the part are printed together in a single continuous printing process, merged into a single coupled arrangement. The sacrificial component is mechanically coupled to the part through direct printing, eliminating the need for separate assembly steps while achieving effective layer immobilization during powder spreading.
Solution Approach 2:
The sacrificial component is self-formed during the printing process itself, with its immobilization features automatically created as part of the printing operation. The component serves its own purpose of providing mechanical coupling and resistive force without requiring external fixtures or additional processing steps.
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 method effectively immobilizes printed layers, reducing defects like shifting and cracking, thereby improving the quality of the 3D printed parts by providing a resistive force against the shear force imposed during powder spreading.
Implementation Method 1
a controlled pattern of the liquid binder may be applied to successive layers of the powder material in a powder bed such that the layers of the powder material adhere to one another
Implementation Method 2
a shear force, which may cause defects such as layer shifting and cracking of the printed part
Data Source
AI summary
An additive manufacturing system, and corresponding method, prints a sacrificial component using a 3D printing system that includes a spreading mechanism for spreading unbound powder to form layers of a powder bed and a printing mechanism for jetting binder fluid into the unbound powder to form the sacrificial component. The system forms the sacrificial component with a feature that provides a resistive force to a shear force imposed by the spreading mechanism during the spreading. The system prints a part with the 3D printing system in a coupled arrangement with the sacrificial component. The coupled arrangement in combination with the resistive force is sufficient to immobilize each printed layer of the part to resist the shear force imposed by the spreading mechanism during spreading of the unbound powder above each printed layer of the part. After printing, and before or after post-processing, the part and sacrificial component are separated.