PCBA Tech - What are the process requirements for PCBA processing

With the rapid development of the electronics industry, the quality of PCBA processing has an important impact on the quality of the finished product. Therefore, PCBA processing has received the attention of enterprises. There are many electronic components used in PCBA processing, so what are the common components used in chip processing? What about electronic components? Let's take a closer look at "What are the technological requirements for PCBA processing".

[Which electronic components will be used in PCBA patch processing]

PCBA patch processing mainly includes two major processes: PCB circuit board production and SMT patch processing. Electronic components are inevitably used in the middle. Electronic components are the basic part of PCBA patch processing and also affect the performance and quality of PCBA finished products. Key factor. So what are the commonly used electronic components for PCBA patch processing?

1. Resistance

Resistors are electronic components with resistance characteristics and are one of the most widely used components in PCBA. Resistors are divided into fixed resistors and variable resistors (potentiometers), which play the role of voltage division, current shunting and current limiting in the circuit.

2. Capacitance

Capacitor is also one of the basic components in PCBA processing. It is a component that stores electrical energy and plays the role of coupling, filtering, DC blocking and tuning in electronic circuits.

3. Inductance coil

Inductance coil is abbreviated as inductance, which has the function of storing magnetic energy. Inductance coils are usually composed of bobbin, winding, shield, magnetic core and so on.

4. Potentiometer

A resistor whose resistance value can be changed, that is, a resistor that can be continuously adjusted within a specified range, is called a potentiometer. The potentiometer is composed of a shell, a sliding end, a rotating shaft, a ring resistance body and 3 lead-out ends.

5. Transformer

The transformer is composed of an iron core (or magnetic core) and a coil. The coil has two or more windings. The winding connected to the power supply is called the primary winding, and the remaining windings are called the secondary winding.

A transformer is a device that transforms voltage, current, and impedance. When an alternating current is passed through the primary coil, an alternating magnetic flux is generated in the iron core (or magnetic core), causing a voltage (or current) to be induced in the secondary coil. Transformers are mainly used for AC voltage conversion, current conversion, power transmission, impedance conversion and buffer isolation, etc., and are one of the indispensable important components in the PCBA machine.

6. Crystal diode

Crystal diodes (ie semiconductor diodes, hereinafter referred to as diodes) are made of a PN junction, electrode leads, and an externally sealed tube case. It has unidirectional conductivity.

7. Transistor

Transistor (hereinafter referred to as triode) is the core device for signal amplification and processing, and is widely used in PCBA complete machines.

8. Field effect tube

The field effect transistor (referred to as the field effect tube) is also a kind of semiconductor device with a PN junction. Unlike the triode, it does not use the conductivity characteristics of the PN junction, but uses its insulation characteristics.

9. Electroacoustic devices

The devices used in the circuit to complete the conversion between electrical signals and sound signals are called electro-acoustic devices. It has a wide variety of speakers, microphones, earphones (or earplugs), microphones, receivers, etc.

10. Optoelectronic devices

Photoconductive devices that use semiconductor photosensitivity to work, photovoltaic cells and semiconductor light-emitting devices that use semiconductor photovoltaics to work are collectively referred to as optoelectronic devices.

11. Display device

Electronic display devices refer to photoelectric conversion devices that convert electrical signals into optical signals, that is, devices used to display numbers, symbols, text or images. It is a key component of an electronic display device and has a great impact on the performance of the display device.

12. Sensor

A sensor can sense a device or device that is measured and converted into a usable signal according to a certain rule. It is usually composed of sensitive components and conversion components.

13. Surface mount components

Surface mount components (SMC and SMD) are also called chip components or chip components, which include resistors, capacitors, inductors and semiconductor devices, etc., have small size, light weight, no leads or very short leads, High installation density, high reliability, good anti-vibration performance, easy to realize automation and so on.

[Analysis of PCBA patch processing technology requirements]

PCB circuit boards that provide power generation are almost all called circuit board processing, and circuit board processing is a board that mainly processes power initiation functions. The smt patch processing process of circuit board processing is basically divided into three major processes: automatic placement of SMT patch components, wave soldering plug-ins, and manual operation. So what are the technological requirements for circuit board processing in the process of SMT processing?

1. First of all, the temperature resistance requirements of the circuit board processing PCB, whether it meets the level required by the customer; whether it is in line with the lead-free process; whether the source board is blistering, the abnormality is the process requirement of the plastic cardboard.

2. The temperature resistance value of the PCBA chip processing device can fully meet the requirements of the melting temperature of the parts on the board (satisfying 40-90 seconds above 222 degrees; withstand temperature above 245 degrees). If customers have special requirements, they must notify and provide information in advance.

3. The distance between the parts in the circuit board processing during the patch processing, the large and small materials of the material cannot be less than 1mm, and the distance between the materials below 0805 is greater than 0.3mm.

4. The pad design requirements for PCBA patch processing, the pad cannot have wire holes, and the component pads must not have tin leakage holes. The circuit design of the circuit board processing must meet the packaging requirements of the device.

5. The half of the circuit board is required to be processed, and there should be no gaps on the transmission side.

Some customers' products require the process requirements of double-sided mounting. The general reference selection is the reference of the production capacity of the patch manufacturer and the accuracy of the placement machine.

In order to achieve high accuracy in the PCBA production process of the circuit board processing, the PCBA processing double-sided surface assembly process of the circuit board processing: A side printed solder paste-patch-reflow soldering-flip board-B side printed solder paste-patch -Reflow soldering.