Ultra-Thin Power Inductor Casting to Protect Coil Integrity

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Solution Overview

Problem

Conventional dry pressing integral molding of small-size and ultra-thin power inductors leads to deformation of the coil, damage to the insulating paint, high production costs, and low production efficiency, making it difficult to manufacture products with high performance and reliability.

Innovation Solution

A method involving integral pouring followed by cutting, combined with warm-water pressing and curing treatment, is used to prepare small-size and ultra-thin power inductors, reducing molding pressure and improving production efficiency, suitable for mass production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If dry pressing integral molding is used to manufacture small-size power inductors, then the inductor structure can be formed, but the molding pressure causes deformation of the internal coil and damage to the insulating paint

Engineering Contradiction:
Improveinductor structure formationVSAvoidcoil integrity and insulating paint protection
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The manufacturing process is divided into two independent stages: first forming the magnetic powder core structure, then separately arranging the coil and pouring encapsulant. This segmentation eliminates the need for high-pressure molding that damages coils, while still achieving integrated inductor formation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The magnetic powder core is pre-formed into a box structure before coil placement. This preliminary action allows the coil to be arranged in a pre-formed structure without requiring high-pressure molding, thus preventing coil deformation and insulating paint damage.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If dry pressing integral molding is used, then the inductor can be manufactured, but the high molding pressure and equipment requirements limit production efficiency and increase production cost

Engineering Contradiction:
Improveinductor productionVSAvoidproduction efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The process separates core formation from coil assembly and encapsulation, allowing each step to be optimized independently. The pouring process replaces high-pressure molding, enabling faster production cycles and higher efficiency without compromising product quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The high-pressure mechanical molding process is replaced with a pouring process that uses fluid encapsulant to fill the magnetic powder core structure. This substitution eliminates the need for high-tonnage pressing equipment, reducing capital investment and increasing production speed.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If conventional dry pressing integral molding is used, then production can proceed, but ultra-thin inductors with height less than or equal to 0.6 mm are difficult to manufacture

Engineering Contradiction:
Improvemanufacturability of ultra-thin inductorsVSAvoidultra-thin inductor production
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The manufacturing process is segmented to form the magnetic powder core first, then arrange the coil, and finally pour the encapsulant. This allows precise control of each layer's thickness, making it possible to manufacture ultra-thin inductors with heights ≤0.6mm without the distortion caused by high-pressure molding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The process changes from high-pressure mechanical compression to low-pressure pouring and curing. This parameter change enables precise control of ultra-thin dimensions while maintaining structural integrity, as the pouring process applies uniform pressure without the localized stress concentration that plagues thin-component molding.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the pouring method of first pressing a magnetic powder to mold a box and then arranging a coil separately is used, then coil deformation is avoided, but the process is complicated and production efficiency is low

Engineering Contradiction:
Improvecoil integrityVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The magnetic powder core formation and coil arrangement are merged into a single integrated process where the coil is placed in the pre-formed magnetic powder box and the encapsulant is poured in one continuous operation. This merging eliminates the complicated separate steps of the conventional pouring method while maintaining coil integrity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The magnetic powder core is pre-formed into a box structure with precise dimensions before coil placement. This preliminary action simplifies the subsequent steps, allowing the coil to be easily arranged and the encapsulant to be poured without complex tooling or multiple operations, thereby improving production efficiency.

Inventive Principle:
Principle #10Preliminary action

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 method effectively prevents coil damage, reduces molding pressure, and enhances production efficiency, enabling the production of high-performance inductors with uniform pressure application and suitable for mass production.

Implementation Method 1

sticking hollow coils onto a thermosensitive adhesive film

Methodology Applied
Scientific EffectThermal activation of adhesive: Adhesive

Implementation Method 2

injecting a magnetic slurry and drying to obtain a pouring body

Methodology Applied
Scientific EffectSlurry pouring and curing:

Implementation Method 3

subjecting the first structure to warm-water pressing and curing treatment

Methodology Applied
Scientific EffectThermal curing: Heat Treatment

Data Source

PatentEP4336525B1Power inductor and preparation method therefor
Publication Date: 2026.03.25 HENGDIAN GRP DMEGC MAGNETICS CO LTD
  • EP4336525B1 patent drawingFigure 1~3
  • EP4336525B1 patent drawingFigure 4~6
  • EP4336525B1 patent drawingFigure 7~8

AI summary

Provided in the present application are a power inductor and a preparation method therefor. The preparation method comprises the process steps of slurry preparation, slurry casting, coil winding, coil arrangement, slurry pouring, warm-water pressing, curing treatment, UV adhesive film lamination, cutting, etc. A small-size power inductor can be simply and efficiently prepared, the preparation method is particularly suitable for ultrathin inductors, the phenomena of a short circuit, an open circuit, etc., appearing due to the damage to copper wires that is caused by using dry-pressing integral forming technology are avoided, and the problem of a single box body being easily damaged during casting is solved, thereby facilitating industrial applications.