Mold Modification for Droplet Size Consistency

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing microfluidic devices face challenges in replicating consistent droplet sizes across multiple droplet generators due to limitations in machining tolerances, leading to unacceptable variations in droplet size, which affects the reliability of emulsion-based assays.

Innovation Solution

A method is developed to tune the mold used for producing droplet generators by determining the properties of generated droplets, such as the average number of copies of a reference species, and modifying the mold to achieve consistent droplet sizes, involving iterative refinement of the mold's geometric features to ensure uniformity across successive generations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If standard molding processes are used to produce droplet generators, then manufacturing efficiency is maintained, but droplet size consistency deteriorates due to machining tolerance limitations

Engineering Contradiction:
Improvedroplet size consistencyVSAvoidmold modification process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mold is modified in advance before mass production to incorporate corrective geometric features that compensate for manufacturing variations. By performing the modification beforehand, the patent ensures that all subsequently produced droplet generators will have consistent droplet sizes without requiring complex real-time adjustments during production.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent modifies specific geometric parameters of the mold, such as channel dimensions, junction angles, or droplet formation zone characteristics, to compensate for variations that affect droplet size. By changing these parameters in the mold design, the patent achieves consistent droplet generation across multiple devices while maintaining standard molding processes.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If mold modifications are made to achieve consistent droplet sizes, then droplet size uniformity improves, but production time increases due to iterative refinement

Engineering Contradiction:
Improvedroplet size uniformityVSAvoiditerative mold refinement process
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent employs a feedback mechanism where droplet size measurements from initial production runs inform subsequent mold modifications. By systematically analyzing the relationship between mold geometry and droplet size, the patent reduces the number of iterative cycles needed to achieve target uniformity, thereby minimizing time loss while maintaining precision.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If tight size tolerances are enforced on droplet generators, then droplet size variation decreases, but manufacturing complexity increases

Engineering Contradiction:
Improvedroplet size toleranceVSAvoidmold fabrication difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Instead of requiring tight tolerances across the entire mold, the patent identifies and modifies only the specific local regions that critically affect droplet size formation. By concentrating precision requirements on key geometric features rather than the whole mold, the patent achieves tight droplet size tolerances while keeping overall manufacturing complexity manageable.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2986385B1Method of making a droplet-generating device
Publication Date: 2018.02.14 BIO RAD LABORATORIES INC
  • EP2986385B1 patent drawingFigure 1
  • EP2986385B1 patent drawingFigure 2~4
  • EP2986385B1 patent drawingFigure 5~6

AI summary

Method of making a droplet-generating device. In the method, a first-droplet generating device may be produced. The first droplet-generating device may include a molded portion created at least in part with a mold and also may include a plurality of droplet generators each formed at least in part by the molded portion. A set of droplets may be generated with each of one or more of the droplet generators. A property of at least one set of generated droplets may be determined. The mold may be modified based on the property. A second droplet-generating device may be produced that includes a molded portion created at least in part with the modified mold.