Magnet-Polymer Pellets for Additive Manufacturing
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Solution Overview
Problem
Current methods for producing bonded permanent magnets face challenges in creating intricate shapes and sizes with high mechanical and magnetic field strengths, often resulting in sub-standard hard magnetic properties and variability in magnetic strength throughout the part.
Innovation Solution
A method involving the production of uniformly sized magnet-polymer pellets through blending thermoplastic polymer with hard magnetic material, followed by extrusion and cutting to create hardened pellets, which are then used in additive manufacturing processes like BAAM to produce bonded permanent magnets with improved uniformity and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional molding methods (injection molding, compression molding) are used to produce bonded permanent magnets, then production efficiency is improved, but the ability to create intricate shapes and maintain uniform magnetic properties throughout the part deteriorates
Solution Approach 1:
The magnet is produced through segmentation of the manufacturing process into pellet preparation and additive manufacturing stages. Uniform magnet-polymer pellets are first prepared with consistent composition and size, then deposited layer-by-layer through additive manufacturing. This segmentation allows each stage to be optimized independently, achieving both production efficiency and uniform magnetic properties throughout the intricate shape.
Solution Approach 2:
Preliminary action is applied by pre-preparing uniformly sized magnet-polymer pellets with controlled composition and magnetic particle distribution before the additive manufacturing process. This preliminary preparation ensures that when material is deposited and cured, the magnetic properties are uniform throughout the final part, even in intricate geometries that would be difficult to achieve with conventional molding.
2Shape
If binder jetting additive manufacturing is used to produce bonded permanent magnets, then intricate shapes can be created, but hard magnetic properties deteriorate due to insufficient density
Solution Approach 1:
Parameter changes are applied by controlling the composition, size, and distribution of magnetic particles within the magnet-polymer pellets, and by optimizing the extrusion and curing parameters during additive manufacturing. These parameter optimizations enable achieving sufficient density (improving hard magnetic properties) while maintaining the ability to create intricate shapes through additive manufacturing layer-by-layer deposition.
3Weight of moving object
If magnetic powder blending with polymer binder is performed to create bonded permanent magnets, then low weight and cost are achieved, but mechanical strength and magnetic field strength deteriorate
Solution Approach 1:
Composite materials are used by creating magnet-polymer composite pellets with optimized composition, where magnetic particles are uniformly distributed within the polymer matrix. This composite structure maintains the low weight advantage of bonded magnets while improving mechanical strength through proper particle-matrix bonding and magnetic field strength through optimized magnetic particle concentration and orientation during extrusion and curing.
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
Enables the creation of bonded permanent magnets with exceptional mechanical and magnetic field strengths, and uniform properties throughout, allowing for the production of complex shapes and sizes with retained magnetic properties.
Implementation Method 1
subjecting the blended magnet-polymer mixture to an increasing temperature gradient from the inlet to the outlet of the temperature-controlled barrel extruder
Implementation Method 2
wherein the temperature at the outlet is at least to no more than 10° C. above a glass transition temperature of the blended magnet-polymer mixture
Implementation Method 3
feeding the blended magnet-polymer mixture at the outlet of the barrel extruder directly into an extruding die, wherein the extruding die is set at a temperature below the temperature of the outlet of the barrel extruder and below the glass transition temperature of the blended magnet-polymer mixture, to cool and harden the blended magnet-polymer mixture
Implementation Method 4
blending thermoplastic polymer and particles having a hard magnetic material composition to produce a blended magnet-polymer mixture
Data Source
AI summary
A method for producing magnet-polymer pellets useful as a feedstock in an additive manufacturing process, comprising: (i) blending thermoplastic polymer and hard magnetic particles; (ii) feeding the blended magnet-polymer mixture into a pre-feed hopper that feeds directly into an inlet of a temperature-controlled barrel extruder; (iii) feeding the blended magnet-polymer mixture into the barrel extruder at a fixed feed rate of 5-20 kg/hour, wherein the temperature at the outlet is at least to no more than 10° C. above a glass transition temperature of the blended magnet-polymer mixture; (iv) feeding the blended magnet-polymer mixture directly into an extruding die; (v) passing the blended magnet-polymer mixture through the extruding die at a fixed speed; and (vi) cutting the magnet-polymer mixture at regular intervals as the mixture exits the extruding die at the fixed speed. The use of the pellets as feed material in an additive manufacturing process is also described.