Low-Pressure Molded Inductive Component for Coil Insulation
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Solution Overview
Problem
One-piece compression molding inductors face challenges such as high DC impedance, deformation, and poor insulation due to high pressure during the molding process, making it difficult to achieve mass production, especially for small-sized products, and requiring compromise in material strength and density.
Innovation Solution
A low-pressure forming process is adopted, where the coil and powder are subjected to low pressure (≤0.5 T/cm2), with a magnetic central core formed by cold press molding followed by low-temperature sintering, and an insulation layer is applied to reduce internal stress and DC impedance, improving the product's magnetic properties and working current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-pressure compression molding is used to form one-piece inductors, then the density and strength of the T-core improve, but the coil deforms and DC impedance increases significantly
Solution Approach 1:
The inductor manufacturing process is divided into separate stages: first forming the T-core, then separately forming the coil, and finally assembling them. This segmentation allows each component to be optimized independently, avoiding the coil deformation that occurs when both are molded together under high pressure.
Solution Approach 2:
The T-core is pre-formed and cured before the coil is added. This preliminary action creates a stable base structure that can withstand subsequent processing steps without causing coil deformation, while still achieving the required density and strength.
2Manufacturing precision
If high-pressure compression molding is applied to the powder, then the pressing density improves, but the insulation layers on powder particles are damaged causing poor insulation
Solution Approach 1:
The patent changes the pressure parameter from high-pressure compression molding to low-pressure forming (≤0.5 T/cm2). This parameter change maintains sufficient pressing density while preserving the insulation layers on powder particles, eliminating interlayer short circuits.
3Reliability
If spot welding is used to connect the coil to the terminal wire frame, then the electrical connection is achieved, but the DC impedance increases and manufacturing difficulty increases for small sizes
Solution Approach 1:
The patent replaces the mechanical spot welding process with a low-pressure forming process that creates electrical connections through direct contact and bonding during the forming stage. This substitution eliminates the need for separate welding operations, reducing DC impedance and simplifying manufacturing, especially for small-sized inductors.
4Ease of manufacture
If the cold pressed T-core is made with high strength for wire wrapping, then the wire wrapping process improves, but the secondary pressing effect cannot be achieved and interface cracks occur
Solution Approach 1:
The patent separates the T-core formation and coil formation into independent processes. The T-core is formed first with optimized density, then the coil is separately formed and assembled. This eliminates the conflicting requirements between wire wrapping strength and secondary pressing effectiveness, as the coil is not wrapped under tension but formed in place.
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 low-pressure forming process reduces DC impedance and internal stress, enhancing the product's reliability and yield, achieving an impedance value of less than 32.18 mΩ and an interlayer defect rate of less than 50 ppm, while improving the working current and reducing the difficulty in producing small-sized inductive components.
Implementation Method 1
inductive component, which comprises a coil and a magnetic central core, wherein the magnetic central core is formed by cold press molding followed by low-temperature sintering
Implementation Method 2
the magnetic central core is formed by cold press molding followed by low-temperature sintering
Implementation Method 3
cold press molding followed by low-temperature sintering
Implementation Method 4
low-temperature sintering has a stress relieving effect
Data Source
AI summary
Disclosed are an inductive component and a preparation method therefor and an application thereof. The preparation method comprises the following steps: (1) mixing and granulating a first magnetic alloy powder, a second magnetic alloy powder, and a binder, and then performing pressing, and baking and curing the pressed blank to obtain a magnetic central core; (2) combining the magnetic central core obtained in step (1) with a coil and placing into a mold cavity, injecting a cladding powder slurry, and then baking to obtain a semi-finished component; and (3) coating an insulation layer on the surface of the semi-finished component obtained in step (2), performing paint stripping, and then performing electroplating to form an electrode layer to obtain the inductive component. By performing the low-pressure forming process, the inductive component provided by the present application has the advantages of low basic pressure between the coil and the powder, small change of the DC impedance of the coil and small internal stress of the powder, solving the problems of high interlayer defect rate and interlayer short circuit of the products caused by serious insulation damage of the powder under high pressure in the existing process.