What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the process of electronic accessories such as mobile phones and computers, especially multi-layer circuit boards, there are generally fixed connections between multi-layer circuit boards or other components. At present, there are two main connection methods. One is to use laser welding. However, the laser welding equipment is expensive and has very high requirements on the position of the weldment. Therefore, during welding, it must be ensured that the final position of the weldment needs to be the same as the laser beam will impact. Solder joint alignment. The other is to use a metal rivet to pass through the positioning hole, and then impact the rivet with a punching needle, so that the open end of the rivet is deformed and opened and pressed on the fixed piece to form a rivet fixed state. However, in actual operation, when the open end of the rivet tube is opened and deformed by the impact, strong cracking often occurs, resulting in a small amount of conductive fracture debris, which falls on the circuit board or other devices to be connected, causing Short circuit, in view of this shortcoming, some manufacturers have changed the metal rivets to plastic materials, but the plastic rivets have poor ductility and often break when impacted with a punching needle, resulting in the failure to achieve the riveting fixing force of the original metal rivets. In addition, the above two fixing methods are complicated in operation and low in installation efficiency.
Traditionally used for plastic fastening screws, most of the thread designs are self-tapping threads, but for different plastic types, the self-tapping threads also have many different classifications, such as PT profile, Plastite series, Remform profile, etc. The structural parameters and manufacturing process of these threads are inconsistent, or require different main molds and wires. Therefore, to find a plastic screw that is universally applicable to various plastic types, has a single pressing structure, low-cost and simple manufacturing process, especially its special self-tapping thread, is an important issue that needs to be solved urgently at present. question. The purpose of Yueluo Yueluo Guangdong Yueluo Hardware Industry Co., Ltd. is to propose a plastic screw to solve the screw fastening problem that is generally applicable to different plastics. The purpose of Yueluo Guangdong Yueluo Hardware Industry Co., Ltd. is to realize a kind of plastic screw through the following technical scheme, it is characterized in that, the thread of the screw is composed of asymmetric threads with a profile angle of 30°, and the threads are The bottom surface of the connection between them is an arc surface. Yueluo preferably, the asymmetrical thread has a forward thread angle greater than the reverse thread angle, and the sum of the two-direction thread angles is 30°. Yueluo further preferred that the tooth profile angle of the asymmetrical screw thread in the forward mounting direction is 20 degrees, and the tooth profile angle in the reverse mounting direction is 14 degrees. Yueluo Guangdong Yueluo Hardware Industry Co., Ltd.'s application of plastic screws, through the improvement of special thread structure, reduces the radial pressure and installation torque when the screw is installed, reduces the damage to the plastic hole; and increases the pull-out resistance of the screw force, it is not easy to appear loose assembly. At the same time, the design of the bottom surface of the connection between the threads of the arc optimizes the flow of the material of the installation object, which improves the integrity of the installation connection.
Traditional rivet nuts are usually cylindrical, and special tools are required to complete the riveting operation between the workpiece and the sheet, and tools are completely required for locking. And in the actual production process, it is often encountered that there are square holes on the workpiece, and bolts need to be installed in the square holes, especially in the power cabinet and the control cabinet when the workpiece with prefabricated square holes is used as the main frame, due to Due to the special structure of the workpiece, the installation nut can only be inserted from the side, and the installation cannot be completed when the side installation space is limited, which brings inconvenience to the installation.
At present, many manufacturers do not want the product to be disassembled by the user, so they set the anti-disassembly mark on the product. The common method is to apply red or blue anti-disassembly paint on the fastener, such as the nut, once the user disassembles it by himself. , the paint at the connection will fall off, and it can no longer be aligned, so that the manufacturer can judge and identify it and provide a basis for warranty. However, it is inconvenient to paint some joints, and the use of tamper-evident paint is not healthy and environmentally friendly.
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