Powder Mass Flow Calibration for Stable Powder Cladding
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Solution Overview
Problem
Existing methods for measuring powder mass flow in powder nozzle welding lack precision and consistency, particularly due to variations in powder composition and protective gas atmospheres, which can lead to fluctuations in powder mass delivery.
Innovation Solution
A device comprising a powder doser, control unit, powder mass flow sensor, powder separator, and powder switch, which allows for precise measurement and regulation of powder mass flow by calibrating the sensor based on measured powder mass current and separating powder from gases to prevent buoyancy errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If powder mass flow is measured using a scale by collecting powder in a measuring cup, then the powder mass flow can be determined, but the measurement is time-consuming and interrupts the powder conveyance process
Solution Approach 1:
The system performs preliminary calibration of the powder mass flow sensor before actual welding operations. A calibration mode is implemented where the powder switch directs powder to a measuring cup on a scale for initial measurement, establishing a reference relationship between sensor signal and actual mass flow. This preliminary calibration enables subsequent continuous measurements without interruption.
Solution Approach 2:
A powder switch is introduced as an intermediary device that can redirect the powder flow between different destinations (measuring cup for calibration, welding area for operation). This intermediary enables the system to switch between calibration mode and operation mode, allowing non-intrusive measurement setup that doesn't interfere with the main welding process.
2Productivity
If the powder mass flow sensor is used to monitor powder mass flow during welding, then continuous monitoring is possible, but the sensor readings may be inaccurate due to changes in powder composition and protective gas atmosphere
Solution Approach 1:
The control unit continuously compares the sensor signal with the actual powder mass flow data obtained during calibration. When deviations are detected (indicating changes in powder composition or gas atmosphere), the system automatically adjusts the sensor calibration parameters to maintain measurement accuracy. This feedback mechanism ensures continuous monitoring capability while compensating for environmental variations.
Solution Approach 2:
The system dynamically adjusts calibration parameters based on detected changes in powder composition or protective gas atmosphere. By modifying the relationship between sensor signal and actual mass flow in response to parameter changes, the system maintains measurement precision despite varying welding conditions.
3Measurement precision
If the powder conveyance is interrupted to set the powder mass flow, then the powder mass flow can be calibrated, but interruptions cause fluctuations in powder mass delivery during startup
Solution Approach 1:
All powder mass flow calibration and sensor adjustment operations are performed in advance during a dedicated calibration mode before welding begins. The powder switch directs powder to the measuring cup rather than the welding area, allowing complete calibration without interrupting the welding process. This preliminary action ensures stable powder mass delivery from the start of welding operations.
Solution Approach 2:
The system implements periodic calibration checks during operation, where the control unit monitors sensor readings and triggers recalibration when deviations exceed predetermined thresholds. This periodic verification maintains calibration accuracy without requiring continuous interruptions to the welding process.
4Manufacturing precision
If protective gas atmosphere is used during powder deposition, then uniform application and consistent surface coverage can be achieved, but the gas buoyancy affects the accuracy of powder mass measurements on the scale
Solution Approach 1:
Powder mass calibration is performed in advance when the protective gas atmosphere is already established in the chamber. The control unit measures the actual powder mass delivered during calibration runs and uses this data to establish the relationship between sensor signals and actual mass flow under the specific gas atmosphere conditions. This preliminary calibration under representative conditions compensates for buoyancy effects.
Solution Approach 2:
The control unit adjusts calibration parameters to account for the buoyancy effect of the protective gas atmosphere. By modifying the calibration relationship based on the specific gas type, pressure, and flow conditions used during welding, the system maintains measurement accuracy despite the presence of gas buoyancy forces.
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 enables accurate and consistent powder mass flow measurement and regulation, ensuring uniform powder distribution and improved quality of powder nozzle welding processes by minimizing interruptions and fluctuations in powder mass delivery.
Implementation Method 1
The powder mass flow sensor can be configured to determine a powder mass flow, for example, using weight measurements, beam attenuation measurements, reflection measurements, etc.
Implementation Method 2
The powder jet conveyed into the processing area is collected in a measuring cup, and the collected powder mass is determined using a scale.
Implementation Method 3
the device comprises a centrifugal separator, a gravity separator and/or an inertial separator between the powder switch and the scale for separating the powder mass from a gas or gas mixture.
Implementation Method 4
the device comprises a centrifugal separator, a gravity separator and/or an inertial separator between the powder switch and the scale for separating the powder mass from a gas or gas mixture.
Implementation Method 5
the device comprises a centrifugal separator, a gravity separator and/or an inertial separator between the powder switch and the scale for separating the powder mass from a gas or gas mixture.
Data Source
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AI summary
The innovation relates to a device and a method for measuring a powder mass flow for powder cladding. Before the powder cladding, the powder mass flow is set by means of a powder mass determining device and a powder mass flow sensor is calibrated on the basis of the setting. Then a powder switch is used to begin the powder cladding without interrupting the delivery of the powder mass. During the powder cladding, the powder mass flow is monitored by means of the powder mass flow sensor.