Resin Viscosity Detection in Bottom-Up Additive Manufacturing
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Solution Overview
Problem
In bottom-up additive manufacturing, particularly in stereolithography and continuous liquid interface production, there is a need for real-time measurement of resin viscosity due to its variability affecting production accuracy and speed, as it depends on factors like temperature, storage conditions, and batch differences.
Innovation Solution
A method and apparatus that utilize a force sensor, such as a strain gauge, to detect the force exerted on the build platform when it contacts the resin, generating a viscosity measurement using empirical, regression, or machine learning models, allowing for real-time adjustment of production parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If resin viscosity is not monitored in real-time, then production speed can be maintained at higher rates, but manufacturing precision deteriorates due to variability in resin properties affecting polymerization control
Solution Approach 1:
The system implements real-time viscosity monitoring through force sensing during the build process, creating a feedback loop that continuously measures resin properties and adjusts production parameters accordingly. This allows the system to maintain precision by responding to actual resin conditions rather than relying on preset parameters, resolving the contradiction between speed and accuracy.
Solution Approach 2:
The invention transforms static production parameters into dynamic ones that adapt in real-time based on measured viscosity. The system adjusts exposure times, layer heights, and other processing parameters dynamically according to the actual resin state, enabling both high speed and high precision by continuously optimizing parameters to match current resin conditions.
2Measurement precision
If traditional viscosity measurement methods are used, then viscosity can be measured with sufficient precision, but the measurement process is time-consuming and disrupts production continuity
Solution Approach 1:
The build platform performs dual functions: it both constructs the object and simultaneously measures resin viscosity through integrated force sensing. The platform's inherent motion and positioning capabilities are leveraged to perform viscosity measurement without requiring separate measurement equipment or interrupting the build process, achieving precise measurement with minimal time loss.
Solution Approach 2:
The invention combines the viscosity measurement function with the existing build platform structure and motion system. By integrating force sensors into the platform and using its controlled movement to probe resin resistance, the system merges two separate functions (building and measuring) into a single unified process, eliminating the need for separate measurement steps.
3Productivity
If resin temperature is increased to reduce viscosity for faster production, then productivity improves, but manufacturing precision deteriorates due to temperature-induced viscosity variability
Solution Approach 1:
Instead of changing temperature to control viscosity, the system directly measures actual viscosity through force sensing and adjusts processing parameters (exposure time, layer thickness, scan speed) based on the measured values. This approach allows maintaining optimal viscosity for precision while compensating for any viscosity variations through parameter adjustments, rather than relying on temperature changes that affect both speed and precision.
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
Enables accurate and efficient production by providing real-time viscosity data for quality control and adjusting production speed based on measured viscosity, improving the consistency and speed of three-dimensional object creation.
Implementation Method 1
the force sensor comprises a strain gauge
Data Source
AI summary
A method of measuring the viscosity of a resin in a bottom-up additive manufacturing apparatus, includes the steps of: (a) providing an additive manufacturing apparatus including a build platform and a light transmissive window, said build platform and said window defining a build region there between, with said window carrying a resin; (b) advancing said build platform and said window towards one another until said build platform contacts said resin; (c) detecting the force exerted on said build platform by said resin; and (d) generating in a processor a viscosity measure of said resin from said detected force.