Mold Notch for Insert Tab Removal in Plastic Lens Molding
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Solution Overview
Problem
The existing injection molding methods for plastic lenses with insert members, such as polarizing films, require additional steps to position and remove positioning tabs, leading to complex post-processing procedures and potential defects from residual resin traces.
Innovation Solution
A mold design that incorporates a notch on one parting surface to engage with the positioning tab of the insert member, allowing for precise alignment and simultaneous removal of the tab during the molding process, reducing post-processing labor and minimizing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a positioning tab is used to position the insert member, then positioning precision is improved, but post-processing complexity increases due to additional cutting steps
Solution Approach 1:
The positioning tab is extracted and removed from the molded product after serving its positioning function. The mold includes a positioning tab removal mechanism that automatically cuts and removes the tab during the molding cycle, eliminating manual post-processing steps while maintaining positioning precision during molding.
Solution Approach 2:
The positioning tab is pre-formed on the insert member before molding, and the mold includes pre-configured positioning structures (positioning grooves or pins) that automatically align the insert member with the correct orientation during mold closure, eliminating the need for manual positioning operations.
2Measurement precision
If the positioning tab is positioned away from the gate, then positioning accuracy is improved, but manufacturing complexity increases due to additional cutting procedures
Solution Approach 1:
The positioning tab and gate are merged into a single integrated structure. The positioning tab is positioned at the gate location, and the mold design allows the tab to be removed along with the gate during a single cutting operation, combining two previously separate operations into one step.
Solution Approach 2:
The positioning tab serves multiple functions: it positions the insert member during molding, serves as a reference for gate positioning, and is designed to be removed in conjunction with the gate. This multi-functionality eliminates the need for separate positioning and gate removal operations.
3Measurement precision
If trace portions remain after positioning tab cutting, then positioning function is maintained, but product quality deteriorates due to liquid pool formation during coating
Solution Approach 1:
The positioning tab is completely extracted and removed from the molded product, eliminating any trace portions that could cause liquid pool formation during subsequent coating operations. The mold includes automatic tab removal mechanisms that ensure complete removal without leaving residues.
Solution Approach 2:
The mold design incorporates preliminary anti-action by positioning the tab removal operation to occur before any coating processes. The tab is removed in the same cycle as molding or immediately afterward, preventing any possibility of liquid pool formation during subsequent coating operations.
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 simplifies the post-processing of molded plastic lenses by allowing for one-step tab removal and reduces the likelihood of liquid pool formation during coating, maintaining product quality and efficiency.
Implementation Method 1
filling molten resin into a cavity formed with a mold having a shape corresponding to the optical surface, and by solidifying the molten resin
Data Source
AI summary
A mold for a plastic lens that arranges an insert member inside a cavity formed between a pair of halved molds, injects and fills molten raw material resin to mold a plastic lens having a predetermined shape, integrally with the insert member. The insert member is arranged on a molding surface on one of the halved molds, a notch to be engaged with a positioning tab formed at a periphery of the insert member is engraved on one parting surface of the halved mold, overlapping with a gate position. Positioning of the insert member is performed by engaging the positioning tab with the notch. With this configuration, in molding a plastic lens having an insert member by injection molding including insert molding, positioning of the insert member is performed at the gate position without deteriorating the quality of a molded product and without increasing the load of post-processing after molding.