UV Molding Tool Elastic Membrane Shrinkage Compensation
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Solution Overview
Problem
UV replication technology for producing optical and mechanical structures faces challenges due to shrinkage-induced stresses and shape deviations in curable materials, particularly in optical applications, leading to tolerance and integration issues when connecting substrates with polymer structures.
Innovation Solution
Implementing a method where the curable material is irradiated in a locally varying manner, allowing it to cure at different speeds laterally, with additional curable material compensating for shrinkage under constant pressure, applied through a molding tool with an elastic membrane and diaphragm structures for improved flow and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the curable material is irradiated with UV radiation over the entire surface simultaneously, then the curing process is efficient and fast, but shrinkage causes stresses to build up leading to shape deviations and substrate deflection
Solution Approach 1:
The UV irradiation process is segmented into multiple zones with different irradiation intensities. The irradiation is divided into a first region with higher intensity (faster curing) and a second region with lower intensity (slower curing), allowing differential curing rates that compensate for shrinkage while maintaining overall process efficiency
Solution Approach 2:
Different regions of the curable material receive different irradiation doses tailored to local requirements. The irradiation intensity is locally adjusted so that material in different positions cures at different rates, with the molding tool applying higher intensity where faster curing is needed and lower intensity where slower curing helps compensate for shrinkage
2Productivity
If the curable material cures quickly to improve productivity, then the manufacturing time is reduced, but the shrinkage-induced stresses increase causing optical property degradation
Solution Approach 1:
The curing process uses periodic or staged irradiation where different regions are cured at different rates. The irradiation is applied in a controlled sequence where the first region cures faster than the second region, creating a time-dependent curing pattern that manages shrinkage stresses while maintaining reasonable manufacturing time
Solution Approach 2:
The irradiation parameters (intensity, exposure time) are changed across different regions of the material. By varying these parameters spatially, the curing speed is optimized in different zones, allowing faster overall production while protecting optical properties through controlled differential curing
3Device complexity
If uniform irradiation is applied across the molding tool, then the process is simple to implement, but the curable material shrinks uniformly causing stress concentration and substrate deflection
Solution Approach 1:
The uniform irradiation field is segmented into multiple intensity zones. Instead of a single uniform irradiation source, the system creates distinct irradiation regions with different intensities, allowing stress distribution management while keeping the overall system relatively simple
Solution Approach 2:
The irradiation system transitions from a static uniform approach to a dynamic differential approach. The irradiation intensity becomes a variable parameter that changes across the molding tool surface, enabling active management of curing rates and stress distribution without requiring complex mechanical adjustments
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 effectively compensates for material shrinkage, reducing mechanical stress and improving the optical properties of the molded structures by controlling the curing process and flow of the curable material, resulting in more precise and accurate optical components.
Implementation Method 1
a UV-curing plastic or a UV-curing polymer, for example Ormocere, UV adhesives from Delo, Norland, Epoxy Technology, Panacol-Elosol, is brought into the desired shape with a molding tool and cured, for example, with UV radiation
Implementation Method 2
The molding tool ( 310) has an encircling elastic membrane ( 710)
Implementation Method 3
an force affecting the further settable material resulting from a surface tension of the settable material or the further settable material
Data Source
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AI summary
A method for producing a structure from a curable material by molding is described. In the first step of the method, a molding tool is positioned above a surface such that, in an area between the molding tool and the surface, the curable material borders the surface and a molding surface of the tool facing the surface, allowing further curable material to flow into this area. In the second step, the curable material is irradiated with locally varying intensity within this area, causing it to cure at different rates laterally. This allows shrinkage during curing to be compensated for by the additional curable material. In the third step of the method, constant pressure is applied to the additional curable material.Furthermore, a second method and a device for producing a structure from curable material by molding and a molding tool for an optical component are described.