Atomized Additive Injection for NdFeB Jet Milling Without Powder Oxidation
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Solution Overview
Problem
The existing methods for adding liquid additives during the jet milling process of sintered NdFeB alloy magnet manufacturing are inefficient, leading to oxidation of the powder, aggregation, and non-uniform mixing, which affects the magnetic properties and requires lengthy mixing times, and is prone to blockages and contamination.
Innovation Solution
A device and method involving a storage barrel, weighing bucket, powder container with a blind flange, and a fluid atomization nozzle for spraying liquid additives into the powder container, minimizing oxidation and ensuring uniform mixing by separating the addition port from the powder container and using inert gas for atomization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If additives are added through opening the ball valve and pouring through a funnel, then the additives can be introduced into the powder container, but air is introduced and contacts with the powder causing oxidation
Solution Approach 1:
A connecting pipe serves as an intermediary component that allows additive introduction without direct opening of the powder container. The pipe creates a sealed pathway from the additive container through the blind flange opening, preventing air contact with powder while enabling additive delivery.
Solution Approach 2:
The system maintains an inert or controlled atmosphere within the powder container by keeping it sealed except through the controlled connecting pipe pathway. This prevents oxidation by excluding air from contacting the powder during the additive addition process.
2Ease of operation
If additives are poured through a funnel into the powder container, then additives can be added, but additives aggregate together and mixing time increases
Solution Approach 1:
The system uses gas pressure (pneumatics) to atomize and spray the liquid additive through the connecting pipe into the powder container. This creates a fine mist distribution of additives throughout the powder, eliminating aggregation and significantly reducing mixing time compared to pouring methods.
Solution Approach 2:
The additive is transformed from a liquid state that would pour and aggregate into a atomized spray state. By changing the physical state through atomization, the additive distributes uniformly as fine droplets, preventing aggregation and enabling rapid mixing.
3Productivity
If additives are added before jet milling to improve efficiency, then particle fluidity improves and grindability increases, but the ball valve and funnel become blocked by agglomerated powder and additives
Solution Approach 1:
The connecting pipe acts as a removable intermediary that facilitates additive addition without becoming part of the permanent powder container structure. It can be easily detached and cleaned separately, preventing contamination and blockage issues from transferring to the main powder handling system.
Solution Approach 2:
The additive addition system is segmented into separate components: additive container, connecting pipe, and spray nozzle. This segmentation allows the adding mechanism to be independently cleaned and maintained without affecting the powder container or jet milling equipment.
4Manufacturing precision
If holes are opened on the side wall of the powder tank for additive addition, then mixing uniformity improves, but the holes contact with powder and are blocked by the mixture, making cleaning inconvenient
Solution Approach 1:
The connecting pipe serves as a removable intermediary that provides a controlled pathway for additive delivery. It can be detached and cleaned separately from the powder container, eliminating the cleaning problems associated with permanent holes in the tank wall.
5Ease of operation
If the opening hole is used for additive addition, then additives can be introduced, but the opening increases the risk of oxidation of the powder in the powder tank
Solution Approach 1:
The connecting pipe serves as a sealed intermediary pathway that allows additive introduction without creating an open hole in the powder container wall. The pipe maintains the sealed environment, preventing air ingress and oxidation while enabling controlled additive delivery.
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 approach reduces oxidation, improves mixing homogeneity, shortens the mixing cycle, and increases the yield of high-quality magnets with consistent C element content, making it easier to maintain and clean the device.
Implementation Method 1
a fluid atomization nozzle (19) located at the end of the connection pipe (4)
Data Source
AI summary
The present disclosure refers to a device and a method for the addition of liquid additives in the form of a spray during a jet milling step in a process for the manufacture of sintered NdFeB alloy magnets. The device includes: a storage barrel for the liquid additive; a weighing bucket which is in fluid communication with the storage barrel and is adapted for weighing a predetermined amount of the liquid additive; a powder container to accommodate NdFeB alloy material prior to or after jet milling, wherein the powder container includes an opening that is plugged with a blind flange; a connecting pipe, which is in fluid communication with the weighing bucket and passes through an opening of the blind flange into the interior of the powder container; and a fluid atomization nozzle located at the end of the connection pipe.