What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
With the advancement of technology in various industries, the current structural design of screws has evolved from just simple locking to focusing on work efficiency during the locking process and not destroying the integrity of the objects to be locked. New cases such as No. 556784 screw improvement and No. 289415 screw that integrates locking, stability, labor-saving, fast and multi-function which were previously designed and approved and published in the Central Taiwan Bulletin are the main representatives of screws. It is clear that It is learned that the two cases not only fully improve the shortcomings of the traditional simple locking screws, but also achieve the purpose of substantial improvement of the screws designed in each case in actual use.
The main part of the pin screw is an ordinary screw, and the pin can be arranged in the melting section of the screw or the drop groove of the metering section or the smooth cylindrical surface without screw grooves at the end of the metering section. The pins are arranged in a certain arrangement, with varying degrees of density and quantity. Cylindrical pins are formed by fitting the pins into the holes of the threaded rod; square or diamond-shaped pins are formed by milling directly on the threaded rod. If these pins are set in the melting zone, the pins can break up the solid bed, destroy the two-phase flow, stir the solid and liquid phases together, increase the contact area between the undissolved solid phase fragments and the contained material, and promote molten. If the pin is set in the melt conveying area, its main function is to divide the material flow, increase the interface, change the direction of the material flow, and rearrange the flow beam. Divide and merge multiple times, change the flow direction, and homogenize the melt composition and temperature. The mixing section is an inwardly slotted structure arranged at the end of the common screw homogenizing section, and its outer diameter is equal to the outer diameter of the screw. The grooves are divided into several groups, and each group is the confluence area of the material. The materials are divided by grooves, meet in the confluence area, and then divide and confluence. The principle is similar to the pin type. The characteristic of the separate screw is that in addition to the original screw thread (called the main screw) on the melting section, there is also an additional thread (called an additional thread) whose outer diameter is slightly smaller than the outer diameter of the main thread, and the main and auxiliary threads are With different leads, the secondary thread starts from the end of the feeding section (and connects with the feeding section here), and after several threads, gradually intersects the main thread of the homogenizing section. The screw groove depth and thread lead of this kind of screw change gradually from the beginning of the feeding section to the end of the homogenization, that is, the thread lead gradually narrows from the width, and the groove depth gradually becomes shallower from the depth, which can maximize the compression of the material.
1. First remove the sludge on the surface of the broken head of the broken screw, use the center gun to kill the center gun of the section, and then use an electric drill to install a drill bit with a diameter of 6-8 mm to drill the hole in the center of the section, pay attention to the hole must be drilled through. After the hole is drilled through, remove the small drill bit and replace it with a drill bit with a diameter of 16 mm, and continue to expand and drill through the hole of the broken bolt. 2. Take a welding rod with a diameter of less than 3.2 mm and use a medium and small current to carry out surfacing welding from the inside to the outside in the hole of the broken bolt. Take half of the entire length of the broken bolt at the beginning of the surfacing welding. When starting the surfacing welding, the arc should not be too long. In order to avoid burning through the outer wall of the broken bolt, surfacing to the upper end face of the broken bolt, and then continue surfacing to weld a cylinder with a diameter of 14-16 mm and a height of 8-10 mm. 3. After the surfacing is completed, hammer the end face with a hammer to make the broken bolt vibrate along its axial direction. Due to the heat generated by the previous arc and the subsequent cooling plus the vibration at this time, the broken bolt and the thread of the body will be loose in between. 4. Carefully observe, when it is found that a small amount of rust leaks from the fracture after the knock, take the M18 nut and put it on the surfacing column head and weld the two together. 5. After welding, use a torx wrench to cover the nut while it is still hot, and twist it back and forth, or tap the end face of the nut with a small hand hammer while twisting back and forth, so that the broken bolt can be taken out. 6. After taking out the broken bolt, use a suitable tap to process the thread in the frame to remove rust and other debris in the hole.
The purpose of Yueluo is to provide a brake pad rivet with shrinkage that can not only solve the problem of normal feeding during assembly, but also save the processing cost of the original machining chamfering and reduce the quality risk of the rivet in use. its production method.
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