Contact Lens Mold Alignment via Picking Head Pins
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Solution Overview
Problem
Conventional contact lens manufacturing processes face issues with precise alignment of male and female molds, leading to lens edge damage, high prism on edge thickness, and wastage of expensive polymerizable composition, resulting in increased costs and scrapped lenses.
Innovation Solution
A method and system utilizing a picking head assembly with alignment pins to precisely align male and female mold sections without physical contact, ensuring accurate alignment and reducing optical surface damage, allowing for the efficient production of contact lenses with improved quality and reduced waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional molding processes are used without precise alignment mechanisms, then manufacturing simplicity is maintained, but lens edge damage and prism on edge thickness increase
Solution Approach 1:
Leader pins are introduced as intermediary alignment elements that fit into corresponding leader bushings on the male and female mold sections. These pins serve as mediators to establish precise alignment between the mold halves without requiring complex alignment mechanisms, thereby improving manufacturing precision while maintaining simplicity
Solution Approach 2:
The leader pins and leader bushings are pre-installed on the mold sections before the actual lens molding process. This preliminary alignment setup ensures that when the male and female mold sections are brought together, they are already precisely positioned, preventing edge damage and prism issues during the molding operation
2Manufacturing precision
If mold sections are not precisely aligned, then manufacturing process is simpler, but polymerizable composition is wasted through overflow
Solution Approach 1:
The leader pins act as intermediaries that ensure precise alignment between male and female mold sections, preventing polymerizable composition from overflowing during injection. This alignment mechanism ensures that the composition remains contained within the mold cavity, eliminating waste while maintaining process simplicity
Solution Approach 2:
Alignment is established in advance through the leader pin and bushing system before polymerizable composition is introduced. This preliminary positioning prevents overflow during the injection process, thereby preventing material waste without adding complexity to the overall manufacturing process
3Manufacturing precision
If alignment mechanisms are added to ensure precise mold alignment, then lens quality improves, but manufacturing cost increases
Solution Approach 1:
Leader pins and leader bushings are simple, inexpensive intermediary components that provide precise alignment functionality. These basic mechanical elements achieve the alignment function at minimal cost compared to complex alignment mechanisms, thereby improving lens quality without significantly increasing manufacturing costs
Solution Approach 2:
The alignment system is self-contained within the mold structure itself, with leader pins and bushings being integral parts of the mold sections. This self-service alignment mechanism eliminates the need for external alignment equipment or complex adjustment procedures, maintaining ease of manufacture while ensuring precise alignment and high lens quality
Data Source
Figure 1~1A
Figure 1B~1C
Figure 2~3
AI summary
A method and system for manufacturing a contact lens are disclosed involving aligning a male lens mold section and a female lens mold section. A picking head removes a male lens mold section from a male pallet for transfer to a female mold section on a female pallet. The picking head may move substantially freely in a plane perpendicular to the longitudinal axis of the picking head as the distance between the male and female mold sections decreases. Alignment, for example, substantially precise alignment between the male mold section, carried by the picking head, and the female mold section carried by the female pallet may be achieved before the male mold section comes in contact with the female mold section.