What are the anti-static products commonly used in factory workshops?
There are quite a variety of antistatic materials, but they can be classified into the following categories:
1. Anti-static clothing and wristbands
Anti-static clothing and wristbands are an important part of eliminating the anti-static system of the human body, which can eliminate or control the generation of static electricity in the human body, thereby reducing the most important source of static electricity in the manufacturing process.
Anti-static clothing includes anti-static suits, big shackles, shoes, caps, anti-static gloves, anti-static finger cots, anti-static toes, etc. Anti-static clothing is made of anti-static cloth of different colors. The cloth yarn contains a certain proportion of conductive yarn, and the conductive yarn is made of a certain proportion of stainless steel fiber or other conductive fiber and ordinary fiber. Static electricity on the garment is eliminated by corona discharge and leakage of the conductive fibers. Since the stainless steel fiber is a metal fiber, the antistatic fabric woven therefrom has stable electrical conductivity and does not vary with the number of washings of the garment.
The anti-static wrist strap is the most important static protection product for the operator when it comes into contact with electronic components. Through the grounding path, the static charge carried by the human body can be safely released. It consists of anti-static elastic band, movable snap button, spring cord. Protective resistor and plug or collet. The inner layer of the elastic band is woven with an antistatic yarn, and the outer layer is woven with ordinary yarn. It is an anti-static coverall, an anti-static wrist strap and an ankle strap.
2. Anti-static packaging and transportation products.
There are many anti-static packaging products, such as anti-static shielding bags, anti-static packaging bags, anti-static sponges, anti-static IC packaging tubes, anti-static component boxes (boxes), anti-static bubble film and anti-static trolleys. In addition to the electrostatic conductors for electrostatic shielding, these packaging products are mostly made of static dissipative materials, and some are made of antistatic materials. The purpose is to protect the installed circuit or device and the printed circuit from static electricity.
3. Anti-static floor and table mat
Anti-static floor and table mats are also indispensable in electrostatic protection engineering. There are also a variety of anti-static floors, according to the time-sensitive nature, permanent and temporary; conductive rubber, PVC, conductive ceramics, etc. according to the material; according to the laying method, there are ground directly laid and overhead activities floor. It can be determined according to actual needs and costs. If you need to walk a variety of cables and pipelines on the ground, such as computer anti-selection overhead raised floor is better.
Anti-static mats are mainly anti-static composite rubber sheets, which are mainly used for trapping table tops, pipeline anti-static work surfaces, anti-static racks and making floor mats. The surface layer of the material is divided into grass green, the conductive material is an antistatic agent; the bottom layer is black, and the conductive material is carbon black. In addition to the above three categories of products, there are other anti-static products, such as anti-static soldering iron, anti-static seats, chair covers, anti-static maintenance kits. Among them, anti-static soldering iron is very commonly used in post-processing and maintenance. The general soldering iron needs to unplug the power supply when soldering the static sensitive components, and the antistatic soldering iron adopts the DC temperature and voltage power supply. The heating elements are mostly made of materials with constant temperature characteristics and small electrostatic capacitance, which can greatly reduce various interference signals. . In addition, the soldering iron can also be grounded electrostatically to further eliminate various signals on the soldering iron tip. Therefore, it is not necessary to unplug the power supply when soldering.
Second, electrostatic discharge meter (electricalizer, electric neutralizer or ion balancer)
Static eliminator is another large class of anti-static equipment outside the anti-static material. Its main principle is to use the action of high-voltage electric field or radioactive ray to locally ionize the air, resulting in a large number of ion and electron pairs, which are opposite to the polarity of the charged body. Ions (or electrons) approach and neutralize the charged body to achieve the purpose of eliminating static electricity. The main parameters are:
Effective de-energizing current IC; (>1.0×10-7A/cm); -- the amount of charge generated by the de-energizer per unit length that can be neutralized during unit time;
Ion flow extraction efficiency h (ion wind); - the ratio of the total number of ion extractions per unit time to the total number of ions generated by the discharge needle per unit time;
Electrostatic neutralization ability N (ion wind); (>250V / s) - the voltage value of static electricity can be eliminated per unit time.
The main types of electrostatic discharge meters are:
Inductive electrostatic discharge meter:
Composition: grounding pin electrode; principle: local high pressure; form: single needle, multi needle, brush, wire; material: conductive fiber cloth, serrated conductive film or rubber, brush carbon fiber or metal fiber; Features: simple, no The source and the power-dissipating ability are small, and the object with a large charge density is applied, and the working distance is short, 10 to 20 mm.
High voltage consumer:
Composition: high voltage source + discharge needle (multiple) or discharge rod; classification: DC and power frequency;
The characteristics of DC consumer: strong power consumption, large range of action (150mm ~ 600mm); but short circuit current is large, easy to spark discharge.
The characteristics of power frequency consumer: the power supply is driven, convenient, low power consumption, the working distance is 25mm~35mm, and the application range is the widest; however, it is necessary to maintain the ash as soon as possible and replace the passivated needle.
Radioisotope Consumers:
Composition: isotope source + shield frame + protection net;
Features: no power supply, simple structure installation, easy maintenance, no heat and fire, but the power consumption is poor, the working distance is 20~30mm.
Ion wind consumer:
Composition: DC high voltage power supply (or radioactive source) + corona discharger + air supply system;
Features: most applications, long working distance, wide range (up to 1m), low power consumption of electrical appliances; but complex structure, requiring gas distribution system; environment (clean, dry 70%,) and maintenance (daily, regular and temporary) High standard.