Multi-Projector Light Homogenization for Large-Scale 3D Printing

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Solution Overview

Problem

Current 3D printing technologies, particularly DLP, face challenges with large-scale printing due to non-uniform energy distribution from multiple projectors, leading to uneven illumination and increased heat dissipation issues, limiting the size and accuracy of printed areas.

Innovation Solution

An energy homogenization method using multiple projectors where adjacent projectors project images with different pure colors, capturing and analyzing the overlapped area to segment and optimize slices, generating gray-leveled images, and applying a projection mapping function to ensure uniform energy distribution across the printing area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple projectors are used to increase the printing area size, then the exposure area is expanded, but the energy distribution becomes non-uniform and heat dissipation problems worsen

Engineering Contradiction:
Improveprinting area sizeVSAvoidenergy distribution uniformity
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The printing area is divided into multiple projection regions, each covered by a separate projector. The slice data is correspondingly segmented and assigned to different projectors, allowing each projector to operate within its optimal energy distribution range while collectively covering a large area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the printing area are assigned different energy characteristics. The overlapping regions between adjacent projectors receive adjusted energy levels to compensate for cumulative intensity, ensuring uniform overall energy distribution across the entire large printing area.

Inventive Principle:
Principle #3Local quality

2Power

If light intensity is increased to achieve high power density for large printing area, then the curing capability is improved, but the DMD cannot withstand the high light intensity and heat dissipation becomes a serious problem

Engineering Contradiction:
Improvepower densityVSAvoidheat dissipation
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The total light power requirement is segmented across multiple projectors, each operating at lower individual power levels. This distributes the thermal load across multiple DMD chips and heat dissipation pathways, preventing any single DMD from exceeding its thermal承受能力 while maintaining sufficient total curing power.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Adjacent projectors create overlapping projection regions with partial action, where the overlapping areas receive adjusted exposure levels. This allows the system to achieve the required cumulative power density through multiple lower-intensity sources rather than relying on a single high-intensity source that would overheat the DMD.

Inventive Principle:
Principle #16Partial or excessive action

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 method enhances the scale of exposure areas, improves printability, and allows for easy transplantation of the projection mapping function, achieving high success rates in large-scale mask projection 3D printing with uniform energy distribution and reduced heat dissipation.

Implementation Method 1

using at least two projectors as a light-source for mask projection

Methodology Applied
Scientific EffectLight: Light

Implementation Method 2

using a camera to capture an image of the projection areas and the overlapped area

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP3543957B1Light homogenization method for multi-source large-scale surface exposure 3D printing
Publication Date: 2021.08.04 BEIJING UNIV OF TECH
  • EP3543957B1 patent drawingFigure 1~2
  • EP3543957B1 patent drawingFigure 3(a)~4
  • EP3543957B1 patent drawingFigure 5~6

AI summary

A light homogenization method for multi-source large-scale surface exposure 3D printing, comprising the following steps: using at least two identical projectors to respectively project pure-color images of a first color and a second color having identical attributes, an overlapping portion therebetween being a third color region, and capturing an image of the overlapping portion and calculating height and width information of the overlapping portion; splitting, according to the height and width information of the overlapping portion, a pre-processed slice and respectively recording width and height information of two slices resulting from the splitting and generating two grayscale images having identical attributes thereto; counting power values of identical positions of slices in different grayscale values, performing a further calculation, according to the counting information, to obtain a projection mapping function, using the projection mapping function as a basis for performing optimization on grayscale interpolation of the generated images; and fusing the processed grayscale images and the originally split two slices to obtain a surface exposure 3D printing slice having a uniform brightness in final shaping.