Wire Detector for Melted Metal Level Sensing in 3D Printers
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Solution Overview
Problem
The existing laser and reflective sensor arrangement for determining the surface level of melted metal in 3D metal object printers is sensitive to disturbances, prone to errors due to contamination and the formation of aluminum oxide layers, and is expensive, necessitating a more robust and economical solution.
Innovation Solution
A wire detector positioned between the wire guide and the receptacle generates signals indicative of the presence or absence of solid metal wire, allowing for the determination of the melted metal surface level, using an optical or inductive sensor to replace the laser system, and employing a mechanism to reverse the wire feed direction to estimate the surface level based on wire length and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser and reflective sensor arrangement is used to measure melted metal surface level, then measurement capability is provided, but measurement precision deteriorates due to sensitivity to disturbances, contamination, and aluminum oxide layer formation
Solution Approach 1:
The invention extracts the measurement function from the problematic optical path (laser and reflective sensor) and implements it instead through electrical contact detection. A sensor detects the surface level by making direct electrical contact with the melted metal surface, eliminating sensitivity to optical disturbances, contamination, and oxide layers that plague the laser-based system.
Solution Approach 2:
The invention replaces the optical measurement system (laser beam and reflective sensor) with an electrical detection system. The sensor detects the melted metal surface level through electrical contact, substituting mechanical/electrical interaction for optical interaction, thereby avoiding the limitations of the optical approach in the harsh metallurgical environment.
2Measurement precision
If a laser and reflective sensor arrangement is used to determine surface level position, then measurement function is achieved, but device complexity increases due to sensitive optical alignment requirements
Solution Approach 1:
The invention removes the complex optical alignment requirements by extracting the measurement function from the laser-reflective sensor system. The electrical contact-based sensor eliminates the need for precise optical alignment between multiple components, significantly simplifying the device while maintaining measurement capability.
Solution Approach 2:
The invention substitutes the complex optical system with a simpler electrical detection system. By using electrical contact to detect surface level, the system eliminates multiple optical components and their alignment requirements, reducing device complexity while achieving the same measurement function.
3Measurement precision
If a laser and reflective sensor arrangement is used for melted metal measurement, then surface level detection is enabled, but cost increases due to expensive reflective sensor
Solution Approach 1:
The invention replaces the expensive reflective sensor with a more economical electrical contact-based sensor. This substitution significantly reduces the cost of the measurement system while maintaining the ability to detect melted metal surface level, making the overall system more economically viable.
Solution Approach 2:
The invention substitutes the costly optical sensor system with an electrical detection system. This replacement eliminates the need for expensive reflective sensors and laser components, reducing manufacturing costs while preserving the essential measurement function for melted metal level detection.
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 provides a more robust and economical means to determine the melted metal surface level, reducing errors and maintenance costs while maintaining accurate metal drop ejection operations.
Implementation Method 1
a wire detector positioned between a second end of a wire guide and a receptacle in a vessel that is configured for melting solid wire received from the wire guide
Implementation Method 2
a receptacle in a vessel that is configured for melting solid wire received from the wire guide
Implementation Method 3
An electrical current is passed through the coil to produce an electromagnetic field that causes the meniscus of the melted metal at a nozzle of the receptacle to separate from the melted metal within the receptacle and be propelled from the nozzle
Data Source
AI summary
A three-dimensional (3D) metal object manufacturing apparatus is equipped with a wire detector to determine a position of a top surface of melted metal contained in a receptacle of a heated vessel in the apparatus from time to time. The solid metal wire being fed into the heated vessel is retracted and the length of the retracted wire is determined using a signal generated by the wire detector. The determined length of the wire is used to identify the position of the top level of the melted metal in the receptacle so the receptacle can be replenished if the level has fallen below a predetermined capacity for the receptacle.