What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In CN203807560, nails and bolts are used to connect the plates, but the heads of the nails and the bolts are enlarged ends that are wider than the rods, and the heads of the nails and the bolts cannot penetrate into the interior of the door body, so in terms of appearance, the more More nails and bolts will leave more spots on the surface of the door that are not suitable for the door itself. In the prior art, the treatment method for these spots is generally to paint with paint, which can only make the door panel consistent with the head of the nail and the bolt in color, but cannot change the shape of the head of the nail and the bolt, and the appearance is still good. Obvious spots were noticed, which made the door panels connected by nails and bolts to the panels, which could not be used as door panels for household doors.
GB bolts are generally divided into two types: GB30 bolts and GB21 bolts. The difference is that the hexagonal head of GB30 is larger than that of GB21. The materials are all used: Q235. The grade is 4.8, the hardness is weak, and it is used for parts with low hardness requirements and infrequent activities, which are called ordinary bolts. The most typical use: machinery, construction, fixing, fastening.
Procurement and sales in the testing process know that the quality of screws is manufactured, not detected, but in manufacturing, we must try our best to make them as good as possible. But it is unlikely to be completely error-free and error-free. We all know that errors are unavoidable and can only be approached infinitely. Therefore, at this time, the quality inspection of the screw is required to improve the quality of the screw. At the beginning of ordering from screw wire material into the production of screw industry manufacturers, you must first check the wire diameter of the screw wire and the material of the screw. Generally, the wire diameter of the screw is measured with a caliper to measure the size of the wire diameter, whether it is suitable for self-ordering. Same size. After testing these, it is the testing in the production process, starting from the head of the screw, to determine the size of the head, the opposite side of the head, the diagonal angle, the depth of the cross groove, the tolerance range of the screw, and so on. These are checked with calipers. In the inspection of all aspects when rolling teeth, the main thing is whether the thread can pass the pass and stop gauge, and whether the screw thread can pass the gauge and stop. Next is the electroplating measurement problem. After electroplating, whether it meets the requirements of environmental protection and whether it can pass the time required by the salt spray. Tools include environmental testing machines and salt spray testing machines. In short, in the process of screw production and sales, there must be necessary tools to detect the quality of screws. The summary should be summarized as follows: calipers, hardness testers, salt spray machines, environmental testing machines, pass and stop gauges, etc. When producing and selling screws, there will be a screw specification and screw model. With the screw specification and screw model, we can understand what specification screw and what size screw the customer needs. Many screw specifications and screw models are based on national standard specifications and models. Generally, such screws are called ordinary screws, which are generally available on the market. There are some non-standard screws, which are not based on the national standard specifications, models and sizes, but are customized according to the standards required by the product materials. There is no stock in the general market at all. In this way, it is necessary to make drawings and samples.
Make further details to make the technical scheme of Guangdong Yueluo Hardware Industry Co., Ltd. easier to understand and master. As shown in Figure 1, Yueluo is a schematic diagram of the thread design structure of the plastic screw of Guangdong Yueluo Hardware Industry Co., Ltd. It can be seen from the figure that this creation mainly controls the tooth angle of the thread. Compared with the normal tooth angle of many self-tapping screws, which are 48 degrees, 60 degrees and 34.5 degrees, the tooth angle of Guangdong Yueluo Hardware Industry Co., Ltd. The profile angle is formed by a 30-degree asymmetrical thread I. In particular, the asymmetrical thread I has a forward thread angle greater than the reverse thread angle. A more preferred embodiment is an asymmetric thread. The tooth profile angle α of the in-line installation is 20 degrees, and the tooth profile angle β of the reverse installation is 10 degrees. With this narrower non-stacked thread, the radial pressure on the plastic material is effectively reduced. In addition, the connecting bottom surface 11 between the screw teeth is designed as a circular arc surface. In the process of forming the self-tapping thread, it is more conducive to the flow of the material and the formation of the thread, and at the same time, the material can be more closely matched with the screw. Moreover, the radial pressure of the casing is relatively uniform, and the formed threads are not easily damaged. Yueluo has been tested by a series of professional parameters. Compared with other traditional screws, the plastic screws designed by Guangdong Yueluo Hardware Industry Co., Ltd. have better radial pressure, shell deformation after installation, load distribution, installation torque, drawing The force distribution, the strength of the pull-out force and the mounting torque range all show advantages. In particular, it can be installed with less torque to achieve the same clamping force and pulling force. Compared with a specific parameter, the thread strength of Delta-PT is 387N, while the thread strength of Guangdong Yueluo Hardware Industry Co., Ltd. reaches 444N. Yueluo can understand the plastic screw structure and implementation of Guangdong Yueluo Hardware Industry Co., Ltd. detailed above. It can be understood that through the improvement of the special thread structure, the radial pressure and installation torque during screw installation are reduced, and the damage to the plastic hole is reduced; And the pull-out resistance of the screw is increased, and it is not easy to appear loose in the 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.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
