Introduction to anti-static workbench
The anti-static workbench refers to a workbench that can limit the electrostatic potential and is suitable for electrostatic protection operation. The workbench has many styles, but according to the structure, it basically consists of anti-static countertops, supports and accessories.
Countertop: Anti-static countertop refers to a plane that can limit the electrostatic potential and is suitable for electrostatic protection operation, with a certain degree of strength and flatness.
The countertop is the key to the anti-static workbench. The mesa is in direct contact with the electronic device, so it is necessary to effectively limit the electrostatic potential and quickly discharge the electrostatic charge. In addition, the countertop should also provide a flat operating surface that is resistant to abrasion, scratching, impact and contamination, so as to complete various operations.
The current general work surface is made of anti-static melamine high-pressure decorative laminate (commonly known as anti-static fireproof board, hereinafter referred to as anti-static fireproof board) made of surface material and wood material. The wood material is generally a particle board, and the conductive effect is achieved by embedding an electric conductor such as a steel column. The surface resistance and system resistance of a general antistatic table are about 108 Ω.
The problem with the current anti-static countertop is that the anti-static performance is not too stable, and the resistance value is too high to release the static charge quickly and effectively. Second, the comprehensive physical and chemical properties are relatively low and cannot be effectively adapted to different work intensity and environment. As a work surface that directly contacts various types of electronic devices, the ideal surface resistance and system resistance should be between 106 and 108 Ω, and the starting voltage should be lower than 100V. At the same time, the countertop should have comprehensive physical and chemical properties, including wear resistance, scratch resistance, impact resistance, pollution resistance, anti-aging, environmental protection and other properties. As we all know, advanced manufacturing has high requirements on the production environment, and the requirements are clean and non-polluting. The anti-static work surface is made up of anti-static fireproof board and other materials, usually particle board, and adhesive must be used. Adhesives and particleboards release harmful substances such as formaldehyde, so the antistatic table must also consider the formaldehyde emission index. Formaldehyde emission should be less than 0.5mg / l (equivalent to European E1 standard), wear resistance should be greater than 1000 rpm, resistance to scratch, impact, pollution, anti-aging and other properties should meet GB/T7911-1999 "thermosetting resin Provisions for impregnated paper high pressure decorative laminates (HPL).
The above problems are mainly caused by the performance of the anti-static fireproof board directly limiting the performance of the anti-static work surface. There is another article on the quality of anti-static fireproof panels, which will not be discussed in this paper. It is recommended to use imported anti-static fireproof board. For example, the Aibo company's anti-static fireproof board can meet the requirements of the anti-static workbench. At the same time, the composite substrate should be changed to environmental protection and safety compared with antistatic inorganic materials. The invention has an antistatic electrostatic material with a volume resistance of about 104 Ω and a formaldehyde emission of less than 0.1 mg/l. The impact resistance is superior to the particle board, and the system resistance and the electrification voltage can be stably controlled, which is an ideal substrate.
support
Support refers to the member used to support the table top, which is divided into steel support and composite wooden support according to the material. The steel support is made of steel pipe of not less than 1.5mm, and the external anti-static powder coating is divided into C type and H type according to the structure; the composite wooden support is made of double-layer anti-static fireproof board composite wooden substrate;
The H-shaped steel support is mainly used for the heavy-duty workbench, and the wooden composite support is mainly a simple workbench. Because of its beautiful appearance, the steel support can also play a grounding role, the height can be adjusted, and the accessories can be prepared at will, so it is accepted by more and more users and becomes the mainstream product of anti-static workbench. .
The C-shaped steel support is composed of adjustable height support legs and support surfaces. The support foot is made of steel once stamped. The support surface is generally welded by steel pipe. Considering the bearing requirements, the thickness of the steel is generally not less than 1.5mm, and the surface is covered with anti-static powder coating. The surface of the steel support is flat and brilliance. It is not allowed to peel off the bubbling, dents, indentations and surface scratches, pitting and cutting edges of the sprayed layer. Deburring should be performed for cutting, drilling and chamfering.
The surface of the steel support must cover the powder coating, mainly to increase the corrosion resistance of the steel, while increasing the appearance. The main component of the powder coating is epoxy resin or polyester material. It is an insulating material. It is electrostatically charged with a certain high-voltage static electricity. It is uniformly adsorbed on the surface of the workpiece by air spraying. After heating, it is heated. The solid particles deposited on the surface can be melted and solidified into a uniform, continuous, smooth, smooth coating film. Generally speaking, electrostatic spraying refers to a powder coating using the above processing method. This "electrostatic" describes the processing method, not the antistatic meaning in the true sense. It is precisely because the electrostatic coating process requires the powder coating to be charged, and adding any antistatic material will inevitably affect the chargeability of the powder, so the antistatic powder coating is difficult to process. The Japanese side has introduced such products, but has not seen the products, and has not heard of sales in the domestic market.
Is the steel support of the anti-static workbench required to be anti-static? I think we have to treat it differently. The area of the steel support is generally small, and does not directly contact the product, and the film thickness of the general powder coating is about 50 to 70 μm, and the voltage of 500 V is broken down. Tests have shown that for steel supports with a film thickness of 50 μm, the test instruments specified in ASTM F150-1998 "Testing methods for conductive and static dissipative elastic floor resistance" are used. Under the same test environment, 10 V and 100 V cannot be used. Measure the resistance. However, when the voltage is greater than 500V, the surface resistance can be measured to be 106Ω, and the surface resistance will decrease as the voltage rises. Therefore, I believe that the steel support of the anti-static workbench in the general environment can be used as a protective coating by using ordinary powder coating. However, for the required anti-static workbench, anti-static powder coatings must be used, but the recommended voltage should be less than 100V.
annex
Attachments are all kinds of non-essential components for extended use. There are many types of accessories, which can be flexibly adjusted according to the needs of users. They are mainly divided into wood and steel types. The system resistance value should also meet the requirements of the user.