Window Cassette Optical Correction in Stereolithography

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Solution Overview

Problem

The complexity of windows in bottom-up stereolithography apparatuses has led to optical defects and variability, which can cause production failures and defects in the objects produced.

Innovation Solution

A method is introduced where a removable window cassette with variable optical properties is installed on the apparatus. The controller modifies adjustable parameters based on the window's variable properties, allowing for optical corrections to be applied, such as adjusting light intensity, image magnification, or defining exclusion regions for production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If windows are made more complex to increase versatility and speed in bottom-up stereolithography, then productivity and versatility are improved, but optical defects and variability increase causing production failures

Engineering Contradiction:

Improveproduction speedVSAvoidproduction reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary characterization of the window cassette's optical properties before using it in production. The controller measures parameters such as light transmission, distortion, and uniformity, then uses this information to pre-calculate and apply correction factors to the projection system, ensuring reliable production results without defects

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system incorporates feedback by continuously monitoring the actual optical performance of the window cassette during operation and comparing it against expected values. When deviations are detected, the controller automatically adjusts projection parameters or alerts the user to replace the window cassette, maintaining production reliability

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If interchangeable window cassettes are used to improve versatility, then adaptability is improved, but optical variations cause disruptions to the production process

Engineering Contradiction:

Improvewindow interchangeabilityVSAvoidoptical accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system changes operational parameters dynamically based on the specific window cassette being used. The controller adjusts projection intensity, exposure time, and focal plane positioning according to the measured optical characteristics of each window, maintaining manufacturing precision across different interchangeable cassettes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system creates a digital profile or 'copy' of each window cassette's optical characteristics through characterization. This digital copy is stored and used to generate corrected projection parameters, allowing the system to replicate optimal performance for each unique window without physical modifications

Inventive Principle:

Principle #26Copying

3Manufacturing precision

If optical corrections are applied to compensate for window defects, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improveobject production accuracyVSAvoidcontrol system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system performs self-characterization of the window cassette automatically when installed. The controller measures optical properties and generates correction parameters without requiring manual intervention or complex external calibration equipment, reducing the operational complexity burden on the user while maintaining high manufacturing precision

Inventive Principle:

Principle #25Self-service

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 enhances the performance of the stereolithography apparatus by reducing production failures, improving accuracy, and minimizing defects in the produced objects, by effectively addressing the issue of window optical defects and variability.

Implementation Method 1

The apparatus includes a light source... through which the light source projects... producing the object on the build surface from a light-polymerizable liquid by bottom-up stereolithography

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS12240164B2Window variability correction in additive manufacturing

Publication Date: 2025.03.04 CARBON INC

AI summary

A method of making an object on a bottom-up stereolithography apparatus is provided. The apparatus includes a light source, a drive assembly, and a controller operatively associated with the light source and the drive assembly, with the light source and/or the drive assembly having at least one adjustable parameter that is adjustable by the controller. The method includes installing a removable window cassette on the apparatus in a configuration through which the light source projects, the window cassette comprising an optically transparent member having a build surface on which an object can be produced, and with the optically transparent member having and at least one variable property therein; and then modifying the at least one adjustable parameter by the controller based on the at least one variable optical property of the window; and then producing the object on the build surface from a light-polymerizable liquid by bottom-up stereolithography.