Stereo lithography protective dome for hearing aid receiver holes
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Solution Overview
Problem
In the fabrication of hearing instrument shells using stereolithography (SLA), support structures often intrude into delicate features like receiver holes, requiring extensive machining to remove and restore the original shape, which is inefficient and can damage the features.
Innovation Solution
A protective dome with a thin shell is used to shield the receiver and vent holes during the SLA process, preventing support structure intrusion and facilitating easy removal after completion, with a drain hole for excess material and designed for removal during the finishing phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If support structures are used during SLA fabrication, then the part can be properly supported and fabricated, but the support structures intrude into receiver holes requiring extensive machining
Solution Approach 1:
A removable plug is inserted into the receiver hole to act as an intermediary barrier, preventing support structure intrusion while allowing the SLA fabrication process to proceed. The plug serves as a temporary mediator that protects the receiver hole feature during manufacturing.
Solution Approach 2:
The receiver hole is pre-filled with a plug before the SLA fabrication process begins. This preliminary action ensures that when support structures are subsequently formed, they cannot intrude into the receiver hole, eliminating the need for post-fabrication machining.
2Strength
If support structures extend into receiver holes, then support coverage is improved, but extensive machining is required to remove and restore the hole structure
Solution Approach 1:
The plug is designed to be easily removable from the receiver hole after SLA fabrication completes. By extracting only the plug rather than machining away intruded support structures, the receiver hole's original structure is preserved and restoration time is eliminated.
Solution Approach 2:
The plug is a temporary, disposable component that serves its protective function only during fabrication. After use, it is simply removed and discarded, replacing the need for time-consuming machining operations with a low-cost, single-use element.
3Manufacturing precision
If a dome shield is used to protect receiver holes, then support intrusion is prevented, but the dome must be removed after completion
Solution Approach 1:
The protective plug is designed as a separate, segmented component that can be independently inserted into and removed from the receiver hole. This segmentation allows the protection function to be added without permanently modifying the hearing aid shell structure.
Solution Approach 2:
The plug is designed as a temporary protective element that is discarded after serving its purpose. Its removal restores the receiver hole to its original state, and the plug itself can be discarded or reused in other applications.
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 method prevents support structure intrusion into receiver and vent holes, reducing the need for extensive machining and ensuring the preservation of finely detailed features, thereby simplifying the manufacturing process and improving the accuracy of the finished hearing instrument shells.
Implementation Method 1
stereo lithography (SLA)...a liquid bath...The liquid photopolymer material is lowered into the bath and a laser beam is scanned across the surface of the bath
Data Source
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AI summary
To prevent stereo lithography (SLA) support structures for parts fabricated in an SLA apparatus from interfering with features in the parts, a structural shield such as a dome may be place around the feature and then discarded at the conclusion of the SLA process.