Contact Lens Mold Linearization for Assembly Cycle Rate

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Solution Overview

Problem

The existing injection molding processes for contact lens production face challenges in achieving high cycle rates for the removal and assembly of contact lens part molds, while ensuring traceability and efficient use of installation space, particularly in arranging and aligning circular cavity arrangements for optimal plastic distribution and molding results.

Innovation Solution

A method and device that utilize a linearization process to transfer and align contact lens part molds from circular arrangements to linear rows, allowing for simultaneous removal and assembly, with a linearization device facilitating the transformation of molds into semi-circular and then linear arrangements, enabling efficient storage and assembly, and a transfer device for perpendicular placement to optimize space usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If contact lens part molds are removed and assembled manually or using conventional sequential processes, then traceability of molded parts to their cavities is maintained, but the cycle rate of removal and assembly is too low for high-volume production

Engineering Contradiction:
Improvecycle rate of removal and assemblyVSAvoidtime for removal and assembly operations
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The invention divides the circular cavity arrangement into multiple linear rows, allowing independent handling and assembly of parts from different cavities. The linearization device separates the simultaneous removal operation into discrete linear sequences, enabling parallel processing and faster assembly cycles while maintaining cavity traceability through the structured linear arrangement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The linearization device acts as an intermediary between the circular cavity arrangement and the assembly station. It receives molded parts from the circular mold, repositions them into linear rows, and facilitates rapid assembly while preserving the relationship between parts and their source cavities, thus solving both speed and traceability requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If circular cavity arrangements are used for injection molding, then even distribution of molten plastic and good injection molding results are achieved, but the removal and assembly process becomes time-consuming and reduces cycle rate

Engineering Contradiction:
Improveinjection molding result qualityVSAvoidcycle rate of removal and assembly
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention maintains the circular cavity arrangement for injection molding to ensure quality, then segments the removed parts into linear rows for assembly. This segmentation allows the mold to retain its optimal circular geometry for manufacturing precision while the linearized output enables faster handling and assembly operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The linearization device dynamically reconfigures the spatial arrangement of molded parts from circular to linear format. This dynamic transformation occurs after molding, allowing the system to optimize for both molding quality (circular) and assembly speed (linear) at different stages of the process.

Inventive Principle:
Principle #15Dynamics

3Productivity

If all injection molded parts are transferred to the linearization device simultaneously, then the removal device is occupied for extended periods, but transferring in multiple steps with relative movement increases cycle efficiency

Engineering Contradiction:
Improvecycle rate of removal and assemblyVSAvoidcomplexity of transfer and linearization device
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The transfer process is segmented into multiple steps, with the linearization device receiving parts in discrete batches rather than all at once. This segmentation allows the removal device to be reused between transfers, increasing overall system productivity despite the added complexity of coordinated multi-step transfers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system employs periodic action by repeatedly cycling the removal device between the mold and the linearization device. The removal device performs multiple transfer cycles, each handling a portion of the parts, which optimizes utilization of the removal device while the linearization device progressively builds up the linear arrangement.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2780144B1Combined process and apparatus for removing and assembling of injection moulded parts
Publication Date: 2015.03.25 WALDORF TECHNIK GMBH & CO KG
  • EP2780144B1 patent drawingFigure 1~3
  • EP2780144B1 patent drawingFigure 4
  • EP2780144B1 patent drawingFigure 5~9

AI summary

The invention relates to a combined demoulding method and assembly method of injection moulded articles, in particular for demoulding the mould halves of contact lenses and assembly of the contact lens moulds consisting of respectively two half moulds, said method comprising several steps. The invention further relates to a device for carrying out said method.