What causes cracking in monolithic inductor cores?

2022-06-10 14:21

What causes cracking in the magnetic core of a monolithic inductor? Inductors are used in most electronic devices today. Only with an inductor can electronic equipment avoid being easily damaged by current‑related issues. As the inductor industry continues to evolve, driven by advances in manufacturing technology and product R&D, inductor products are constantly being upgraded. Monolithic inductors represent a newer generation of these upgraded components, with applications that are quite widespread. Many people have likely encountered the problem of cracking in monolithic inductors. Such cracking is influenced by factors related to the powder material and the manufacturing process, as well as by the outer diameter of the coil. So, what exactly causes cracking in the magnetic core of a monolithic inductor?

Inductors are used in most electronic devices today. Only with inductors can electronic equipment avoid being easily damaged by current‑related issues. As the inductor industry evolves, driven by advances in manufacturing technologies and ongoing product R&D, inductor products continue to be upgraded. Integrated molded inductor It’s a new product launched after an upgrade, with a wide range of applications. I’m sure many of you have encountered it before. Integrated molded inductor Cracking issues. Inductor cracking is related to the powder material and the manufacturing equipment, as well as to the outer diameter of the coil inductor. So, what causes cracking in the magnetic cores of monolithic molded inductors?

Integrated molded inductor What causes core cracking?

1. Excessive pressure from the molding machine can cause cracks in the inductor; such cracks may compromise the product’s electrical performance and pose a risk of degradation over prolonged operation. Products exhibiting this defect should be classified as nonconforming.

2. Cracks caused by improper powder formulation leading to poor bonding appear only on the surface, with all electrical properties identical to those of a normal product. Following reliability verification, such products can be classified as substandard. If internal cracks are detected—whether through grinding or X-ray inspection—the item is deemed defective.

3. Cracks on the product’s side caused by stress on the copper wire shall be identified as nonconforming items through surface grinding and X-ray inspection.

To determine the cause of inductor cracking, first examine the fracture surface to distinguish whether the crack occurred before or after furnace processing. Then, by considering other known factors, identify the root cause, enabling targeted corrective measures to resolve the cracking issue.

What are the common methods for troubleshooting inductors?

1. Troubleshooting Short Circuits and Open Circuits in Electromagnetic Coils To detect short circuits or open circuits in electromagnetic coils, use the ohmmeter setting on a multimeter. A resistance reading of zero indicates that the coil is completely shorted; a finite resistance value lower than the normal range suggests a short between turns; and an infinite resistance reading indicates that the coil is defective.

2. Locating core faults: Electromagnetic coils exhibit impedance, which comprises inductance and resistance—both the coil’s inductance and its winding resistance. For electromagnetic coils, inductance typically exceeds resistance; inductance is primarily determined by the number of coil turns and the magnetic circuit of the core. A fully closed magnetic circuit yields high inductance, whereas a magnetic circuit with air gaps results in lower inductance. Under a given voltage, measuring the magnitude of the current (i.e., the excitation current) allows one to assess whether the core has a fault. If this current is significantly higher than that of similar electromagnetic coils, it indicates either a reduction in the number of coil turns or an inter-turn short circuit. If the coil itself is functioning normally, the issue may stem from poor core lamination or insufficient core cross-sectional area, or from short circuits between core laminations.

3. Locate faults causing changes in inductance. Since malfunctions of the electromagnetic coil and the iron core can lead to variations in inductance—typically a decrease—measuring the coil’s inductance is sometimes necessary. Inductance can be measured using an AC inductance bridge or a multimeter.

What is the difference between a monolithic inductor and a conventional inductor?

What is a monolithic inductor? What are its advantages and applications?

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In the current trend toward product miniaturization, inductor sizes continue to shrink to meet the demands of consumer electronics, automotive applications, fast‑charging systems, and AI devices for slimmer form factors and higher integration. Meanwhile, advances in high‑permeability, low‑loss magnetic powders and high‑performance coil materials enable small‑size components to satisfy requirements for high current handling and low losses.

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