Static elimination device of pcb automatic testing machine and static elimination method thereof

Abstract

The invention discloses a static elimination device for an automatic testing machine for a printed circuit board (PCB) and a static elimination method of the static elimination device. The static elimination device for the automatic testing machine for the PCB comprises two arm main body supports, cross arms, vacuum nozzles and electric conduction cones, wherein the cross arms are arranged on the arm main body supports; the vacuum nozzles are arranged on the cross arms; and the electric conduction cones are arranged near the vacuum nozzles. The static elimination method of the static elimination device comprises the following steps of: (a) measuring the distance from a position at which a lead passes through a tank drag chain from the vacuum nozzles to a grounding end to determine the length of the lead, and respectively installing two wiring terminals on both ends of the lead; (b) installing the electric conduction cones at the side of the vacuum nozzles of the cross arms; (c) installing the lead; (d) releasing static charges on the PCB to the ground by the electric conduction cones and the lead after the PCB is sucked by the vacuum nozzles; and (e) ending a static elimination process. The static elimination device for the automatic testing machine for the PCB and the static elimination method of the static elimination device disclosed by the invention are remarkable in static elimination effect, and therefore, on one hand, the using smoothness of the testing machine is ensured, and on the other hand, the PCB testing efficiency is also greatly improved.

Description

【Technical field】 [0001] The invention relates to the technical field of PCB testing, in particular to a static elimination device for a PCB automatic testing machine and a static elimination method thereof. 【Background technique】 [0002] With the rapid development of the electronics industry, there are more and more types of PCBs, and the pre-processes of the tested PCBs are also different: most of them are directly tested for cleaning, drying, transmission, and lamination; some need to add a Process: PCB hole inspection machine; some of them also added a withstand voltage test in the early stage of the on-off test; , for scanning cards without electrostatic discharge, the static electricity will be released to the ground through the test channel, the sensitive chip on the card is easily impacted by the energy release, and the severe one will have a permanent breakdown; and for a special electrostatic discharge area, these high Both static electricity and high energy stor...

AI Technical Summary

Problems solved by technology

The principle of ion fan and wind rod to eliminate static electricity is: load different polarity (positive and negative) high voltages on the discharge probe, and then ionize the surrounding air to generate a certain amount of positive and negative ions, which are blown by the fan or wind rod to the tested PCB The surface is neutralized with the static charge on the surface of the PCB. Since it is neutralized, the time to completely eliminate the static charge is related to the concentration of ions. This is related to the airflow of the blowing probe, which will have side effects: ①. Airflow If the airflow is large, it will generate a lot of noise, which is difficult for the operator to accept; ②. The airflow is large, which will generate a large load on the air compressor, which will increase the power consumption of the customer, and the customer is not easy to accept; and the ion fan, The principle of the wind rod is the positive and negative ions generated by the air around the high-voltage ionization probe. Since it is high-voltage ionization, the probe needs frequent maintenance: the tip cannot be oxidized, and the life cycle of the probe is so short. If you don’t pay attention It will lose its effect soon; in the actual test, the testing speed of the testing machine is relatively fast, and the PCB with a material number of about 20,000 points can be tested in only 4 seconds, while it takes about 10 seconds for the static elimination equipment to completely eliminate static electricity. The rate of static elimination equipment can not meet the needs of testing.

[0004] According to the actual problems encountered in the test of the testing machine, two special types of PCB boards were found: ①. The large copper panel that has just been cleaned and dried (the area of ​​the copper skin on the PCB is relatively large). The area is large, the heat absorbed is relatively large, the board surface is relatively dry, and the static charge accumulated on the board during the transmission process is relatively high, and the rate of static electricity elimination will be very slow; ②.The embedded inductance coil that has just undergone a withstand voltage test The characteristics of this board: the power board with embedded inductance coil that has just undergone a withstand voltage test, when the high voltage test is performed, a certain amount of charge energy will be stored in the inductance coil, and this energy cannot be used by the static eliminator Eliminated, when conducting the on-off test, it will give a huge impact to the switching device of the scanning card. The severe one will cause the damage of the ASIC chip, and the light one will cause the ASIC to continue to perform power-off recovery operations, which will greatly reduce the test efficiency; for For the test of this special type of PCB board, it is necessary to adopt an effective method for pre-processing

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