Resin-Simulating Optical Sensor for 3D Printer Calibration
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Solution Overview
Problem
Calibration of projection-based three-dimensional printing systems for photocure resins is challenging due to variations in optics and light engine performance, leading to inconsistent energy density distribution across the build plane, especially at the edges where the light path length through the resin increases significantly.
Innovation Solution
A calibration system comprising a sensor with an optical element that simulates the optical path through the resin, a positioning apparatus to cover the build plane, and a controller to adjust light engine settings based on measured light intensity, compensating for variations in the optical path length and trajectory angle, ensuring uniform energy application across the build plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the light engine projects light directly onto the build plane without resin simulation, then the calibration process is simple, but the energy density distribution is inaccurate due to ignoring light attenuation through resin
Solution Approach 1:
An optical element is introduced as an intermediary between the light engine and sensor. This optical element simulates the light attenuation properties of photocure resin, allowing the sensor to measure light intensity as if it were passing through actual resin. This resolves the contradiction by maintaining calibration simplicity while achieving accurate energy density measurements that account for resin absorption and scattering effects
Solution Approach 2:
The optical element creates an optical copy or simulation of the resin's light interaction properties. Instead of measuring through actual resin during calibration, the system uses an optical element that replicates resin's attenuation characteristics. This allows accurate calibration data to be obtained without the complexity of handling actual resin during the calibration process
2Adaptability or versatility
If the light path length through resin is increased at the edges of the build plane, then the trajectory angle coverage is improved, but the light intensity reaches the build plane unevenly with significant attenuation at edges
Solution Approach 1:
The system applies position-dependent calibration values to different regions of the build plane. Edges of the build plane receive higher energy values to compensate for the longer light path through resin and greater attenuation, while the center receives lower values. This local quality adjustment ensures uniform energy density distribution across the entire build plane despite varying trajectory angles and path lengths
Solution Approach 2:
The calibration process预先 (in advance) calculates and applies compensation values to counteract the expected light attenuation. By pre-determining the energy distribution map that compensates for edge attenuation, the system ensures uniform curing energy before the actual printing process begins, preventing the harmful effect of non-uniform illumination
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 system achieves accurate calibration by storing and applying correction values for the light engine, resulting in consistent curing of photocure resins across the build plane, reducing errors and improving the quality of three-dimensional printed objects.
Implementation Method 1
The energy density distribution reaching the build plane in resin is different than that received directly from the light source with no resin
Implementation Method 2
The optical element simulates a 'dense portion' of an optical path between the light engine and the face of the three dimensional article of manufacture
Implementation Method 3
The at least one sensor includes a photodetector overlaid by an optical element
Data Source
AI summary
A method and system for calibrating a three dimensional printing system includes a specialized sensor. The three dimensional printing system forms a three dimensional article of manufacture through a layer-by-layer process. Layers are formed by the operation of a light engine selectively curing photocure resin onto a face of the three dimensional article of manufacture. The sensor includes a photodetector overlaid by an optical element. The optical element simulates a “dense portion” of an optical path between the light engine and the face of the three dimensional article of manufacture being formed. The “dense portion” of the optical path includes a layer of photocure resin that is disposed between the light engine and the face of the three dimensional article of manufacture.