Metal Powder Flow Sensing Strip for Accurate DED Feed Control
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Solution Overview
Problem
Existing direct metal deposition processes for 3D workpieces face challenges in accurately measuring and controlling the metal powder mass flow rate, especially during unattended operation and graded material manufacturing, where multiple powders are fed simultaneously with varying mass proportions, due to limitations in light-based sensing methods and interference from small powder particles.
Innovation Solution
A metal powder mass flow rate apparatus featuring a detection strip within the powder flow path, suspended at one end and fixed at the other, which deflects under gas-blown powder and is measured by sensors to determine the mass flow rate for closed-loop control, allowing for precise measurement and adjustment of powder flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If light-based sensing methods are used to detect powder material flow, then the measurement can be performed non-contact, but the measurement precision deteriorates due to interference from small powder particles
Solution Approach 1:
The patent introduces a detection strip as an intermediary element that physically contacts the powder flow. The strip acts as a mediator between the powder particles and the measurement system, converting the kinetic energy of the flowing powder into measurable deflection while being protected from direct contamination by the powder stream.
Solution Approach 2:
The patent replaces the optical detection system with a mechanical detection system. Instead of using light-based sensing that is susceptible to particle interference, the system uses a physical detection strip that deflects under the weight and impact of the powder flow, with the deflection measured by a displacement sensor.
2Productivity
If unattended operation is implemented for large 3D workpieces, then productivity increases, but measurement reliability deteriorates due to lack of real-time process monitoring
Solution Approach 1:
The patent implements a feedback mechanism where the detection strip continuously monitors the powder flow rate and provides real-time data to the control system. This allows the system to detect deviations from the desired flow rate and make automatic adjustments, ensuring reliable process monitoring during unattended operation and maintaining measurement accuracy throughout the build process.
3Adaptability or versatility
If graded material manufacturing with multiple powders is performed, then product versatility increases, but measurement complexity deteriorates due to varying mass proportions
Solution Approach 1:
The patent divides the measurement task into separate segments, with individual detection strips or measurement zones for each powder type. This allows each sensor to independently monitor its designated powder stream, simplifying the measurement of complex multi-powder blends by breaking down the overall measurement into manageable components that can be processed separately.
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 apparatus provides accurate measurement of metal powder mass flow rates between 2-80 grams/minute with high accuracy (2-5% error) across various powder sizes and densities, enabling reliable in-process control and improved quality in large 3D printing operations.
Implementation Method 1
Gas-blown metal powder causes a deflection of the free end of the detection strip
Implementation Method 2
This deflection is measured by a sensor and converted into a mass flow rate
Data Source
AI summary
An assembly for measuring metal powder material mass flow rate during direct metal deposition. A detection strip is placed in the gas-blown metal powder material flow path. The detection strip is fixed in one end and suspended at the other end. The flowing metal powder material particles induce displacement to the detection strip. A displacement measurement sensor measures the amount of displacement of the detection strip. The amount of displacement of the detection strip gives relationship to the amount of the metal powder material flowing in the metal powder material flow path. The detection strip and the sensor are connected to a housing with a metal powder material inlet port and metal powder material outlet port and includes internal features for smooth travel of metal powder material particles.