Belt Tensioning for Solid Imaging Layer Thickness

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Solution Overview

Problem

Existing solid imaging techniques face challenges in achieving low-cost, high accuracy, and rapid production of three-dimensional objects with uniform layer thickness and tension control, particularly in systems using solidifiable liquid resin, which often result in voids and distortions.

Innovation Solution

A solid imaging apparatus employing a radiation transparent endless belt with a belt tensioning system and fluid wedge dispenser to control the thickness of solidifiable liquid build material, combined with digital imaging projection, ensures consistent layer application and accurate three-dimensional object formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If an intermediate transfer surface is used to deliver solidifiable liquid resin layer-by-layer, then the cost of resin is reduced and excess resin removal is eliminated, but the layer thickness consistency and belt tension control become unreliable

Engineering Contradiction:
Improveresin wasteVSAvoidlayer thickness consistency
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent implements feedback control through sensors that monitor belt tension and layer thickness in real-time. The system continuously adjusts the belt tensioning mechanism based on sensor feedback to maintain consistent layer thickness, resolving the reliability issue while preserving the cost benefits of the intermediate transfer surface approach

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes the tension parameter of the endless belt during operation. By adjusting belt tension as a controllable parameter, the system maintains optimal layer thickness consistency throughout the building process, eliminating the unreliability associated with fixed tension systems

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If an endless belt is used as a transfer surface, then resin cost is reduced and vat building is eliminated, but tracking and tension control of the belt become complex

Engineering Contradiction:
Improveresin consumptionVSAvoidbelt tracking and tension system
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical tracking and tensioning mechanisms with a combination of motorized drive systems and electronic control. The belt is driven by a motorized roller with encoded position feedback, and tension is controlled through motorized adjustment mechanisms, simplifying the overall system while maintaining precision

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

Solution Approach 2:

The endless belt system is designed to be self-aligning through its continuous loop configuration and motorized drive. The system automatically maintains proper tracking and tension through integrated sensors and control algorithms, eliminating the need for complex manual adjustment mechanisms

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If layer thickness control is improved through belt tensioning, then manufacturing precision increases, but device complexity increases

Engineering Contradiction:
Improvelayer thickness controlVSAvoidtensioning system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The belt tensioning system is designed to serve multiple functions simultaneously: it controls layer thickness, maintains belt tracking, and supports the build platform. This multi-functionality reduces the need for separate dedicated mechanisms, thereby limiting the increase in device complexity while achieving improved manufacturing precision

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 provides a low-cost, high-resolution, and repeatable layer formation process, reducing voids and distortions, and enabling the creation of accurate and visually appealing three-dimensional objects with precise control over layer thickness and tension.

Implementation Method 1

selective exposure of layers of the material at a working surface to solidify and adhere successive layers of the object (i.e. laminae). In stereolithography, data representing the three-dimensional object is input as, or converted into, two-dimensional layer data representing cross-sections of the object to be formed. Layers of material are successively formed and selectively transformed or solidified (i.e. cured) most often using a computer controlled laser beam of ultraviolet (UV) radiation into successive laminae

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP1852243B1Material delivery tension and tracking system for use in solid imaging
Publication Date: 2011.10.19 3D SYSTEMS INC
  • EP1852243B1 patent drawingFigure 1
  • EP1852243B1 patent drawingFigure 2
  • EP1852243B1 patent drawingFigure 3

AI summary

A solid imaging apparatus and method employing a radiation transparent build material carrier and a build material dispensing system that accurately controls the thickness of the transferred layer of solidifiable liquid build material to the radiation transparent build material carrier to achieve high resolution imaging in three-dimensional objects built using an electro-optical radiation source.