Powder Metering With Proportional Valves for Fast 3D Flow Modulation
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Solution Overview
Problem
Current powder metering devices in 3D printing have a long response time due to the distance between the metering device and the nozzle, making it difficult to stop or modulate the powder flow, change powder types, and achieve parts with graded properties.
Innovation Solution
A device with proportional valves and a control system that adjusts the flow of powder and carrier gas to achieve a given volume flow rate, allowing for precise control and recycling of powders, enabling rapid response and modulation of the powder flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the metering device is placed outside the enclosure for reasons of size, filling and maintenance, then the device structure is simplified and easier to maintain, but the response time increases to approximately ten seconds
Solution Approach 1:
The system is divided into two segments: the metering device remains outside the enclosure for easy maintenance, while a powder transfer mechanism (blower or peristaltic pump) is placed inside the enclosure near the nozzle. This segmentation allows the metering device to be easily accessible while the transfer mechanism provides rapid powder delivery with response time under one second.
Solution Approach 2:
A powder transfer mechanism acts as an intermediary between the external metering device and the internal nozzle. This intermediary component receives metered powder from the external device and rapidly transports it to the nozzle, bridging the gap between the two locations and enabling fast response times despite the external placement of the metering device.
2Ease of manufacture
If powder is transported through a flexible tube from the metering device to the nozzle, then the system is flexible and easy to install, but the response time increases due to the long distance
Solution Approach 1:
The powder transport path is segmented into two parts: a flexible tube connection from the external metering device to the enclosure, and a rapid transfer mechanism inside the enclosure that delivers powder to the nozzle. This segmentation maintains installation flexibility while reducing the effective transport distance for the critical powder flow.
Solution Approach 2:
A blower or pneumatic system is used as the powder transfer mechanism to rapidly move powder through a short internal passage to the nozzle. The pneumatic force enables fast powder delivery (response time under one second) while maintaining system flexibility through the external metering device connection.
3Productivity
If the response time is reduced to enable stopping and modulating powder flow, then the productivity and precision are improved, but the device complexity increases with proportional valves and control systems
Solution Approach 1:
The control system incorporates feedback mechanisms that monitor powder flow and adjust the proportional valve and transfer mechanism accordingly. This feedback enables precise modulation of powder flow rates and rapid stopping capability, achieving high productivity and precision while managing device complexity through intelligent control.
Solution Approach 2:
The system changes operational parameters dynamically by adjusting the proportional valve opening degree and transfer mechanism speed based on required powder flow rates. This parameter modulation enables flexible control of powder delivery (including rapid stopping) without requiring completely different hardware configurations, balancing productivity improvement with acceptable device complexity.
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 solution reduces the response time and allows for the production of parts with graded properties by precisely controlling the powder flow, enabling efficient use of materials and quick changes between powder types.
Implementation Method 1
at least a first proportional valve including an inlet connected to the first source to receive the first flow, a first outlet for selectively sending a volume percentage X1 of the first flow to the outlet junction
Implementation Method 2
The powder is generally transported in a flow of carrier gas, for example argon, to enable its movement
Implementation Method 3
the control system being configured so that the inlet of the first recycling system receives a volume flow rate substantially equal to the given volume flow rate
Data Source
AI summary
A device for metering one or more powder(s) (A, B) to produce a flow (23) of powder(s) and of a carrier gas at a given volume flow rate, comprises: ⋅at least a first source (25) suitable for supplying a first flow (27) comprising a first powder (A) and a first carrier gas (G1) substantially at the given volume flow rate, ⋅a source (33) of a carrier gas suitable for supplying an adjustment carrier gas flow (35) substantially at the given volume flow rate, ⋅an outlet junction (49) for emitting said flow of powder(s) and of carrier gas, ⋅a first proportional valve (59), ⋅an adjustment proportional valve (75), and ⋅a control system (21) suitable for controlling at least the first proportional valve and the adjustment proportional valve so that the flow of powder(s) and of carrier gas has a volume flow rate substantially equal to the given volume flow rate.