3D Printer Sensor Feedback for Layer Height Control
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Solution Overview
Problem
Existing three-dimensional printing technologies face inaccuracies in the vertical direction due to errors in the movement of printheads and platens, imprecise placement of material drops, and variations in material mass, leading to waste and incomplete parts.
Innovation Solution
A printer system that includes distance sensors to measure the height of material layers and adjust printhead operation to ensure precise material deposition, eliminating the need for a planerizer by using a controller to coordinate the movement of printheads and platens with reference to predetermined heights, thereby maintaining accurate positioning and material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a planerizer is used to remove excess material, then vertical positioning errors are corrected, but material is wasted and the planerizer operates inaccurately
Solution Approach 1:
The system performs preliminary measurement of the actual layer height using a sensor before the printhead deposits material. Based on this measurement, the system adjusts the material deposition amount in real-time to match the target height, preventing excess material deposition before it occurs. This eliminates the need for subsequent planerizer operations and avoids material waste.
Solution Approach 2:
The system implements a feedback loop where a sensor continuously measures the actual height of deposited material layers and feeds this information back to the controller. The controller compares the measured height with the target height and adjusts the printhead operation accordingly, ensuring accurate vertical positioning without requiring material removal operations.
2Manufacturing precision
If encoders are used to monitor printhead and platen movement, then positioning is controlled, but inaccurate readings are produced affecting part production
Solution Approach 1:
The system introduces an intermediary measurement sensor that directly measures the physical quantity of interest (layer height or printhead position) rather than relying on encoder readings. This sensor acts as a mediator between the movement system and the control system, providing reliable feedback that is not subject to encoder errors or interference.
3Ease of manufacture
If material drops are deposited with fixed mass, then ejection is simplified, but vertical errors occur due to mass variations over time
Solution Approach 1:
The system dynamically adjusts the material deposition parameters based on real-time feedback from height measurements. Instead of using fixed mass deposition, the system varies the deposition amount layer by layer and even position by position within a layer to compensate for variations in material properties, environmental conditions, and wear over time, maintaining vertical positioning accuracy while keeping the ejection mechanism simple.
Data Source
AI summary
A controller in a printer operates one or more printheads in the printer with reference to a predetermined height of material above a surface of a member and a height of a top layer of material above the surface of the member. The height of the top layer is identified with reference to a first sensor that generates data corresponding to a height of a face of one of the printheads above the surface of the member and a second sensor that generates data corresponding to a distance between the face of one of the printheads and the top layer of material.