How are capacitors manufactured from HONGDA Capacitors

2024-05-12

Capacitors play an important role in the electronic components, these components are ubiquitous, found in nearly every electronic device, from the simplest household gadgets to the most complex industrial machinery, but how are capacitors manufactured? How many types of capacitors available, what’s their functions in the circuit? Do you know?

How are capacitors produced? We will take chip multilayer ceramic capacitors as an examples to introduce the details. Firstly, let’s have a brief introduction of capacitors.

1.1 What is a Capacitor?

A capacitor is a passive electronic component that stores electrical energy in an electric field. It consists of two conductive plates separated by an insulating material known as the dielectric. When a voltage is applied across these plates, an electric field develops, allowing the capacitor to store charge.

1.2 Function

The primary function of a capacitor is to hold and release electrical energy. However, this simplistic description belies the component's versatility across various applications. Capacitors are used for energy storage, such as in the flash units of cameras where a large amount of energy is released in a short burst. They also play a crucial role in filtering, helping smooth out fluctuations in power supply in power circuits. In signal processing, capacitors work to block direct current (DC) while allowing alternating current (AC) to pass, enabling the separation of signals with different frequencies.

Capacitors are integral to the timing and waveform shaping circuits, where they are used in conjunction with resistors or inductors to create oscillators or filter circuits. This capability is essential in electronics, including computing devices, audio equipment, and telecommunication systems.

1.3 Classification

Capacitors can be classified based on their dielectric material. Each type offers different properties, making them suitable for various applications:

1.1.1 Ceramic Capacitors are made with ceramic dielectric material. They offer excellent frequency characteristics and stability, making them ideal for high-frequency applications such as signal processing.

HONGDA Capacitor’s ceramic capacitors: HLC series, pls see pic 1,

from 0201, 0402, 0603, ..., 2225 size available;

Capacitance up to 330uF, voltage up to 7200V

We keep regular stock for the common items, lead time: 2week only.

Pic 1

1.1.2 Electrolytic Capacitors use an electrolyte as the dielectric. They can store a large amount of charge but have limitations in terms of frequency performance and stability. These are often used in power supply circuits.

SMD and Radial aluminum electrolytic capacitors available from HONGDA Capacitors, lead time: 4weeks only. Pls see pic 2.

pic 2

1.1.3 Tantalum Capacitors are similar to electrolytic capacitors but offer better performance, reliability, and size efficiency. They're commonly used in space-sensitive electronics like laptops and mobile phones.

HONGDA Capacitors, as the leading tantalum capacitors factory in China, not only offer standard tantalum capacitors CA45 series, we also have radial epoxy dipped tantalum capacitors CA42 series, low ESR tantalum capacitors CA45 series, polymer tantalum capacitors CA55 series. We also desgin in Niobium Oxide capacitors, pls see pic 3.

Pic 3

1.1.4 Film Capacitors use plastic film as the dielectric. Known for their reliability and stability, they are used in circuits that require high precision, such as timing circuits.

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How to manufacturing ceramic capacitors?

Producing chip multilayer ceramic capacitors (MLCCs) involves a sophisticated manufacturing process that integrates advanced material science with precise engineering. These capacitors are widely used in electronic devices for their high capacitance in a small package, reliability, and cost-effectiveness. Here’s an overview of the production process:

1. Preparing the Ceramic Powder

The process begins with the preparation of the ceramic powder. This involves mixing various raw materials, including barium titanate for the dielectric material, alongside other oxides to modify the dielectric properties. The mixture is then ball-milled with solvents and binders to create a finely dispersed slurry.

2. Casting the Ceramic Layers

The slurry is cast into thin sheets through a process known as tape casting. A doctor blade spreads the slurry onto a moving carrier film, resulting in a thin, flexible ceramic tape after drying. The thickness of this tape can be adjusted to control the final capacitor's voltage rating and capacitance.

3. Printing the Internal Electrodes

Next, a metallic ink, typically made of palladium-silver or nickel, is screen-printed onto the ceramic tape to form the internal electrode layers. This step requires precise control to ensure the correct alignment and thickness of the electrodes.

4. Layering and Laminating

After printing, the ceramic tapes are stacked in layers, alternating between ceramic and electrode layers. The number of layers depends on the desired capacitance value. This stack is then laminated under heat and pressure to bond the layers into a cohesive block.

5. Cutting and Burring

The laminated block is then cut into individual capacitor units. A burring process removes any sharp edges, preparing the units for further processing.

6. Termination and Plating

The next step involves applying a conductive material to the exposed edges of the capacitors. This creates the external electrodes that will connect the capacitor to the rest of the circuit. The terminations are typically plated with nickel and then tin to allow for easy soldering onto circuit boards.

7. Firing

The units are fired in a kiln at high temperatures. This process, known as sintering, fuses the ceramic particles and internal electrodes together, creating a solid, monolithic structure. The firing conditions are carefully controlled to achieve the desired electrical and mechanical properties.

8. Testing and Inspection

After firing, each capacitor undergoes rigorous electrical testing to ensure it meets the specified capacitance, voltage, and performance criteria. Visual and mechanical inspections are also performed to detect any defects.

9. Packaging

Finally, the capacitors are packaged, often in tape and reel format for automated assembly, and shipped to customers.

The production of chip multilayer ceramic capacitors is a complex process requiring precision and control at each step. Advances in materials science and manufacturing technology continue to improve the performance, reliability, and cost-effectiveness of MLCCs, expanding their application in the electronics industry.

HONGDA Capacitors’ MLCC is packed in reel and tape, with our own label, date code, you can trace our parts well.