Orthodontic Bracket Undercut Molding
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Solution Overview
Problem
Existing orthodontic brackets face challenges in adhering well to teeth surfaces due to inadequate adhesion of cold curing cement, leading to reduced effectiveness in orthodontic corrective treatments, especially when substantial displacements are required.
Innovation Solution
The use of an injection molding process that forms orthodontic brackets with protrusions featuring altered cross-sectional regions, creating undercuts which enhance the brackets' adherence to teeth surfaces by providing a better fit for adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional injection molding is used to produce orthodontic brackets, then the manufacturing process is simple, but the adhesion of cold curing cement to the brackets is inadequate
Solution Approach 1:
The patent applies preliminary action by forming undercuts in the bracket protrusions during the initial injection molding process. This preliminary structural modification ensures that when cold curing cement is later applied, it mechanically interlocks with the undercut features, dramatically improving adhesion without requiring complex post-processing steps or specialized molding equipment.
Solution Approach 2:
The patent applies local quality by creating undercuts specifically in the protrusion regions of the bracket where adhesion is most critical. Rather than modifying the entire bracket structure, the undercut features are localized to the contact areas with the tooth surface, improving cement bonding where needed while maintaining the simplicity of the overall molding process.
2Force
If brackets are designed with simple protrusions for adhesive bonding, then the manufacturing is easier, but the tensile forces required for substantial tooth displacement cannot be maintained
Solution Approach 1:
The injection molding process preliminarily forms undercuts in the bracket protrusions during manufacturing. This preliminary structural feature enables the bracket to maintain high tensile forces during orthodontic treatment, as the undercut geometry provides mechanical interlocking that prevents bracket detachment under substantial displacement forces.
3Reliability
If undercuts are formed in bracket protrusions, then adhesive adhesion is significantly improved, but the molding process becomes more complex
Solution Approach 1:
The molding apparatus is configured to preliminarily form undercuts in the bracket protrusions during the injection molding process itself. This integrated approach achieves reliable adhesive bonding without requiring separate post-processing steps or additional specialized equipment, as the undercut features are created inherently during standard manufacturing.
Data Source
AI summary
An apparatus usable with an injection molder for producing articles includes a first mold support including a first mold, and a second mold support including a second mold and a first die. The first mold support is movable relative to the second mold support between a first position and a second position. In the first position, the first mold and the second mold being brought together to form an injection molded article include a body having at least one protrusion extending outwardly from the body and facing the second mold. In the second position, the first mold and the first die being brought together to subsequently form the article, the first die selectively subsequently forming an altered cross sectional region in at least a portion of the protrusion, forming an undercut in the altered cross sectional region or between the altered cross sectional region of the subsequently formed protrusion and the body.