Orthodontic Bracket Undercut Formation via Green Body Segmentation
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Solution Overview
Problem
Conventional orthodontic bracket manufacturing processes, such as metal injection molding (MIM) and ceramic injection molding (CIM), are limited by single shot molding processes, preventing the formation of complex geometries like undercuts and requiring time-consuming and costly post-formation processes to create desired features.
Innovation Solution
A method involving molding multiple green bodies in separate molds, coupling them to form an intermediate green body with undercuts, and sintering to create an orthodontic bracket with features that cannot be formed in a single shot molding process, such as a Y-shaped guiding track and retaining recess.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single shot molding process is used, then the manufacturing process is simple and fast, but complex geometries like undercuts cannot be formed
Solution Approach 1:
The molding process is divided into multiple shots where each shot forms a separate green body without undercuts. These green bodies are then coupled together to form the complete bracket assembly with undercuts. This segmentation allows each individual molding operation to remain simple while the assembled product achieves complex geometry.
Solution Approach 2:
The undercuts are formed as part of the coupling process between green bodies rather than being formed in the initial molding shots. This preliminary preparation of the coupling interface allows the final undercut features to be created during assembly, eliminating the need for complex single-shot molding.
2Shape
If post-formation processes are used to create undercuts, then complex geometries can be formed, but the process becomes time-consuming and expensive
Solution Approach 1:
The coupling process merges multiple green bodies into a single intermediate green body that contains the undercut features. By combining the molding and undercut formation steps into one integrated process, the patent eliminates separate post-formation operations and reduces overall manufacturing time.
Solution Approach 2:
The green bodies are pre-formed without undercuts during the molding process, then the undercut features are created during the coupling operation. This preliminary preparation allows the complex geometry to be formed as part of the assembly process rather than requiring time-consuming post-formation steps.
3Shape
If a movable slide is used in the mold to form features, then various bracket features can be created, but the slide geometry is limited by the need to be retractable
Solution Approach 1:
Instead of using a single complex movable slide, the patent divides the feature formation into multiple separate molding shots, each forming a simple green body. The complex geometry is achieved through the coupling of these simple bodies, eliminating the need for complex retractable slides.
Solution Approach 2:
Rather than using a movable slide to create features directly in the mold, the patent inverts the approach by forming simple green bodies and then creating the complex geometry through coupling. This inversion eliminates the slide geometry limitations entirely.
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 formation of orthodontic brackets with complex geometries like undercuts during the manufacturing process, reducing the need for post-formation processes and lowering production costs and time.
Implementation Method 1
The intermediate body is then sintered to remove the binder and form either a metal or ceramic orthodontic bracket
Data Source
AI summary
A method of manufacturing an orthodontic appliance may include molding a plurality of green bodies in plurality of molds and coupling the green bodies so as to form an intermediate green body. The orthodontic appliance may be an orthodontic bracket body. The plurality of green bodies may be molded so as to be devoid of any undercut formations. Coupling the plurality of green bodies may form the intermediate green body to include at least one undercut formation. An orthodontic bracket may include an undercut formation not capable of being formed in a single shot molding process and not formed through post-formation processes. The undercut formation may include a guiding track and/or a retaining recess configured to receive a portion of the ligating member. The ligating member may include a flexible ligating portion that overlies the archwire slot and a relatively rigid main body portion.