1, Commonly used materials for sheet metal chassis
1). An ordinary cold-rolled sheet – SPCC. SPCC refers to the continuous rolling of steel ingots into steel coils or steel plates of required thickness by cold rolling mills.
An SPCC is ostensibly unprotected. When exposed to the air, it is easily oxidized. In a humid environment, its oxidation speed is accelerated, and dark red rust appears. During processing, the surface of the precision metal plate chassis shell should be painted, plated or protected.
2). Stainless steel SUS304. One of the widely used stainless steels has better corrosion and heat resistance than chromium-containing steels due to its nickel content. It has good mechanical properties, no hardening after heat treatment, and no elasticity.
3). Hot dip placed steel sheet – SGCC. Hot dip placed steel coil refers to the semi-finished product after hot rolling, pickling or cold rolling. After cleaning, annealing, immersed in a molten zinc bath at a temperature of about 460 ° C, and coating on the steel plate, the zinc layer is then quenched, tempered, leveled and chemically treated.
The SGCC material is harder than Innoscience materials, has poor ductility (avoid deep drawing design), a thicker zinc layer and poor weldability.
4). Stainless steel SUS301. The chromium content is lower than SUS304, and its resistance to corrosion is low. However, after cold processing, obtaining good tension and hardness in the stamping process, there would be good elasticity. It is mainly used for spring leaf springs and electromagnetic interference protection.
5). Galvanized steel. After degreasing, pickling, electroplating and various post-processing processes on the continuous electro-galvanizing production line, the precision sheet metal chassis shell becomes an electro-galvanized product.
Not only does SECC have the mechanical properties and similar processing properties of ordinary cold-rolled steel sheets, but it also has excellent corrosion resistance and decorative appearance. Sheet metal chassis processing is highly competitive and substitutable in the electronics, home appliances and furniture markets.
2. Causes of deformation of sheet metal parts
1). Raw material deformation. If the raw materials of sheet metal processing parts are stacked in the wrong way or subjected to impact during transportation, deformation of the sheet would be caused.
2). Uneven heating. Uneven heating of sheet metal parts can also cause deformation of the sheet when it is compressed and extended.
3). Cooling does not happen at the right place. If the heated sheet metal parts are placed in a wet or watery place during the cooling process, they could also be deformed.
4). Hole deformation occurs when there is When the sheet metal processing parts are bent, the holes on the workpiece are easilydeformed. At this time, pitting grids should be added to the top sheet to increase friction and prevent the workpiece from slipping during bending.
3. Precautions for chassis assembly
In the process of sheet metal shell processing, assembly is required after painting. Although this is a simple assembly process, there are also some damages to the processed parts of the sheet metal shell that would cause problems.
As a result, the quality of the processed parts of the sheet metal shell might not meet the product quality standards. Therefore, how should we assemble the sheet metal shell?
The assembly process of sheet metal enclosure:
1. Before assembling the processed parts of the sheet metal chassis, be sure to carefully read the relevant materials such as the assembly and packing list.
2. Relevant materials such as accessories, semi-finished products, and purchased parts are taken out according to requirements. Full-time personnel are allowed to control and inventory them into the warehouse to prevent consumption and loss.
3. When assembling sheet metal shell processing parts, semi-finished products, tools, etc. cannot be placed at a relatively high position, so as to prevent objects from slipping down accidentally, hurting people or products.
3. When assembling the processed parts of the sheet metal shell, it is necessary to operate reasonably and effectively according to the sequence of the flow, and pay attention to the left and right sides.
It is also very important for the operators to cooperate with each other. The product workpiece must not be scratched. After passing through the relevant departments, it can only be changed after permission.
5. During the processing and assembly of sheet metal shells, semi-finished products should not be placed in positions with safety risks. These should be placed in a stable area without risk of displacement.
The purpose is to prevent workers from being injured by falling objects. When the product workpiece is erected, displaced or laid down, it must be guided by full-time personnel to prevent accidents.
The above is the assembly process of sheet metal shell processing. In the processing and assembly of sheet metal shells, the technological process should be reasonable and effective, the order of assembly must be paid attention to. The surroundings must be observed during actual operation. Pay attention to the safety of the surrounding staff to avoid accidents.
4. Factors affecting the normal operation of sheet metal chassis
1). Anti-seismic factor. When the sheet metal chassis is working, the hard disk, optical drive, and multiple fans in the sheet metal chassis would vibrate when they run at high speed. Shock resistance is also a key structural design of the chassis.
2). Thermal factor. In order to ensure the normal operation of the sheet metal case and increase the heat dissipation effect, there would be holes of the necessary parts of the sheet metal case, including the side plate holes of the box body, the air inlet holes of the exhaust fan and the exhaust holes of the exhaust fan, etc.
Therefore, the shape of the holes must meet the technical requirements of blocking radiation. The thermal conductivity of the sheet metal chassis is thus one of the factors affecting the normal operation of the sheet metal chassis.
3). Electromagnetic shielding. When the sheet metal chassis is working, some of its components generate a large amount of electromagnetic radiation. If it is not prevented, it will cause certain harm to the human body. Therefore, the sheet metal chassis has become an important line of defense for shielding electromagnetic radiation and protecting health.
A well-shielded case can also effectively block external radiation interference and ensure that the internal components of the computer are not affected by external radiation.
The openings on the sheet metal chassis should be as small as possible, and round holes with strong radiation blocking ability should be used as much as possible. Secondly, attention should be paid to the electromagnetic shielding of various indicator lights and switch wiring.