Electroform Fixation via Vacuum Adsorption for Mold Accuracy

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Solution Overview

Problem

Existing methods for manufacturing microneedle arrays with precise recessed patterns using electroforms face challenges in achieving accurate and productive injection molding, particularly due to instability in fixing the electroform and potential deformation during processing.

Innovation Solution

A production method involving an electroform with a protruding pattern, where the electroform is fixed to a mold using vacuum adsorption or magnetic forces, allowing for accurate formation of a cavity filled with resin, and subsequent curing and release, enabling the creation of a mold with recessed patterns for manufacturing pattern sheets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electroform is fixed to the mold using conventional methods, then the fixing process is simple, but the fixation is unstable and leads to deformation during processing

Engineering Contradiction:
Improvefixation stabilityVSAvoidfixing mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical fixing methods (screws, clamps, adhesives) with vacuum adsorption and magnetic forces. The vacuum system creates a pressure differential that holds the electroform firmly against the mold, while magnetic forces provide additional stabilization. This substitution of mechanical systems with physical field-based systems achieves more reliable fixation without complex mechanical components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a vacuum system as an intermediary between the electroform and the mold. The vacuum acts as a mediating force that transmits holding capability without direct mechanical contact. This intermediary approach allows for stable fixation while maintaining simplicity in the overall system design.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the electroform is fixed securely to prevent deformation, then the molding accuracy improves, but the productivity decreases due to complex fixing procedures

Engineering Contradiction:
Improvemold accuracyVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

By replacing complex mechanical fixing systems with vacuum adsorption and magnetic forces, the patent achieves secure fixation that prevents deformation during molding. These physical field-based systems provide reliable holding forces with minimal intervention, allowing for rapid setup and removal of the electroform without time-consuming mechanical assembly or disassembly operations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes changes in physical parameters (vacuum pressure, magnetic field strength) to achieve secure fixation. By adjusting these parameters, the system can provide sufficient holding force to prevent deformation while allowing for quick engagement and disengagement, thereby maintaining both high accuracy and productivity.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the electroform end portion is included in the clamping region, then the structural integrity is improved, but the cavity formation and resin filling are compromised

Engineering Contradiction:
Improveelectroform structural integrityVSAvoidcavity formation accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent segments the electroform into two functional regions: the end portion that maintains structural integrity and the main body that forms the cavity. By excluding the end portion from the clamping region, the system preserves the structural strength needed for handling while allowing the main body to be properly clamped and formed. This segmentation enables simultaneous achievement of structural integrity and precise cavity formation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different functional characteristics to different parts of the electroform. The end portion is designed with enhanced structural properties for integrity, while the main body is optimized for cavity formation. This local differentiation of properties allows each region to perform its specific function optimally without compromising the other.

Inventive Principle:
Principle #3Local quality

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 allows for the production of molds with high accuracy and excellent productivity, facilitating the manufacturing of pattern sheets with precise recessed patterns suitable for transdermal drug delivery systems.

Implementation Method 1

the electroform is fixed to the first mold by at least one of vacuum adsorption or a magnetic force

Methodology Applied
Scientific EffectVacuum adsorption: Adsorption

Implementation Method 2

the electroform is fixed to the first mold by at least one of vacuum adsorption or a magnetic force

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 3

a releasing step of curing the resin in the cavity through heating

Methodology Applied
Scientific EffectCuring through heating: Heating

Data Source

PatentEP3456505B1Method for fabricating mold having recessed pattern and method for producing patterned sheet
Publication Date: 2020.02.26 FUJIFILM CORP
  • EP3456505B1 patent drawingFigure 1
  • EP3456505B1 patent drawingFigure 2
  • EP3456505B1 patent drawingFigure 3

AI summary

Provided are a production method of a mold having a recessed pattern, and a manufacturing method of a pattern sheet having good accuracy and excellent productivity. The production method of a mold includes: a step of preparing an electroform having a protruding pattern and a mold having a first mold and a second mold forming a cavity; a step of fixing the electroform excluding an end portion of the electroform to the first mold; a clamping step of clamping the electroform excluding the end portion of the electroform and a region of the protruding pattern between the first mold and the second mold to form the cavity; and an injection step of filling the cavity with a resin.