Interdigitated Fluid Supply Bed for Stereolithography Inhibitor Distribution

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Solution Overview

Problem

Rapid operation of stereolithography processes leads to cavitation and bubble formation in polymerizable liquids due to consumption of polymerization inhibitors, resulting in defects in the three-dimensional objects produced, necessitating a new technique to manage inhibitor supply and prevent void formation.

Innovation Solution

A window cassette system for bottom-up additive manufacturing that includes an optically transparent semipermeable member with a fluid supply bed having interdigitated channel arrays to evenly distribute a polymerization inhibitor, such as oxygen, across the build surface, ensuring consistent inhibitor levels and reducing bubble formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rapid operation of stereolithography process is implemented, then productivity is improved, but cavitation and bubble formation occur due to polymerization inhibitor consumption, worsening manufacturing precision

Engineering Contradiction:

Improveprocess speedVSAvoidobject quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system pre-saturates the resin with polymerization inhibitors before the printing process begins. This preliminary action ensures that sufficient inhibitor is available from the start, preventing cavitation and bubble formation even during rapid printing operations, thus maintaining manufacturing precision while enabling high productivity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements continuous replenishment of polymerization inhibitors during the printing process through controlled release mechanisms or continuous circulation systems. This continuous action ensures consistent inhibitor levels are maintained throughout rapid printing, preventing defect formation and maintaining object quality at high production speeds

Inventive Principle:

Principle #20Continuity of useful action

2Quantity of substance

If polymerization inhibitor is continuously supplied through a single channel array, then inhibitor availability is improved, but uneven distribution occurs, worsening homogeneity

Engineering Contradiction:

Improveinhibitor supplyVSAvoidinhibitor distribution uniformity

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The fluid supply system is divided into multiple separate channel arrays that distribute polymerization inhibitors through different pathways. This segmentation allows each channel to deliver inhibitor to specific regions, ensuring uniform distribution across the entire resin volume and preventing localized depletion or excess, thus maintaining compositional homogeneity while ensuring adequate inhibitor supply

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different channel arrays are configured to deliver polymerization inhibitors to different spatial zones within the resin with tailored flow rates and concentrations. This local quality approach ensures that each region receives the appropriate amount of inhibitor for its specific requirements, achieving uniform overall distribution while accommodating local variations in resin dynamics

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

The solution effectively maintains a stable polymerization inhibitor gradient, reducing cavitation and bubble formation, thereby improving the quality and consistency of three-dimensional objects produced by stereolithography.

Implementation Method 1

an optically transparent semipermeable member with a fluid supply bed configured to feed a polymerization inhibitor through the semipermeable member

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

a fluid supply bed having interdigitated channel arrays to evenly distribute a polymerization inhibitor, such as oxygen, across the build surface

Methodology Applied

Scientific EffectFluid flow distribution:

Implementation Method 3

maintains a stable polymerization inhibitor gradient, reducing cavitation and bubble formation

Methodology Applied

Scientific EffectConcentration gradient: Density Gradient

Data Source

PatentUS11192305B2Window cassettes for reduced polymerization inhibitor irregularity during additive manufacturing

Publication Date: 2021.12.07 CARBON INC

AI summary

The present disclosure describes a window cassette for a bottom-up additive manufacturing apparatus. The window cassette includes an optically transparent semipermeable member, on which the semipermeable member a three-dimensional object can be produced, a frame surrounding and connected to the semipermeable member, and a fluid supply bed in or adjacent the semipermeable member and configured to feed a polymerization inhibitor through the semipermeable member. The fluid supply bed has at least two opposing sides and includes a first channel array having an inlet orifice and an outlet orifice and a second channel array interdigitated with but separate from the first channel array, and the second channel array having an inlet orifice and an outlet orifice. An apparatus for producing a three-dimensional object by additive manufacturing utilizing a window cassette is also described.