Requirements for Vacuum SMT Nozzles During Installation

（1）No component throwing (throwing rate within the allowable range);

（2）No slipping (insufficient vacuum suction will cause component position slipping after inspection);

（3）No material adhesion (components should be reliably separated from the nozzle after being placed in position).

2.Basic Principle of Vacuum SMT Nozzles

The principle of vacuum suction relies on the force generated by the pressure difference between the vacuum system and atmospheric pressure to grasp and move objects. This method of fixing or moving objects using pressure difference has numerous daily applications, such as vacuum cleaners, vacuum suction hooks, and traditional Chinese medicine cupping. Vacuum technology is widely used in industrial production.

（1） Atmospheric Pressure

According to fluid mechanics principles, all objects in Earth’s atmosphere are affected by the gravity of air. This force is the effect of atmospheric pressure, defined as the pressure exerted by the atmosphere per unit area. The standard atmospheric pressure at ground level (1 ATM) is approximately equal to the pressure generated by a 760 mm tall mercury column (mmHg). Different pressure units are used across various fields, countries, and regions, with specific units commonly applied in this technology.

（2）Vacuum and Vacuum Level

Generally, vacuum refers to a state where gas pressure is lower than atmospheric pressure, rather than an "absolute vacuum" with no air at all. In other words, gas under vacuum conditions is thinner than that under atmospheric pressure. The degree of thinness of gas in a vacuum is measured by the "vacuum level". Traditionally, a high vacuum level indicates that the gas pressure is much lower than atmospheric pressure, while a low vacuum level means the gas pressure is slightly lower than atmospheric pressure.