What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
met a customer before, and the stainless steel screws needed by the company need to be prevented from loosening. Simply put, the stainless steel screw should be used on the product material so that the stainless steel screw will not fall off lightly. The screws are required to be more tightly connected with the product material. For the solution of stainless steel screw anti-loosening, there are two solutions. Next, the following two solutions to prevent loosening of stainless steel standard parts are presented. The first is to use the resilience of special materials, such as engineering resin materials, which have good resilience. Attach it to the stainless steel screw thread. Make it mechanically rub against the nut, or material product. Generate vibration and absolute resistance. Completely solve the problem of loose screws. The second, simply put, is to apply a layer of glue on the thread of the stainless steel screw, the so-called dispensing. This glue is called drop-resistant glue. This glue has good properties such as high stickiness and non-toxicity. This glue is applied to stainless steel screws, and when dry, it adheres extremely well. The stainless steel screw thread can be combined with the nut thread, or after the product threaded hole is joined, resulting in a super tightening effect. Play a super good anti-loosening effect.
The main purpose of the screw is to make the industrial product form a fixed one. In use, it often happens that the teeth cannot be closely attached, the screw head will be broken if the screw is locked too hard, or the tooth pattern is not properly locked, etc., and the use conditions are not met, all of which are quality. the problem of accuracy. Screws are mass products, not handmade works of art. In mass production, the purpose is to achieve high-precision and stable quality and popular prices to supply consumers. The accuracy of screws is usually 6g, and the rough screws used in construction projects are 14g. The value of screws is very important. In the world, there are examples of automobile factories going bankrupt because of poor screw quality; there are also examples of planes falling and vehicles being overturned because of poor screw quality.
Due to the high demand for electronic products and the reduction of assembly line workers, in order to cope with the problem of labor shortage, manufacturing factories need to use automatic screw locking equipment to replace manual labor. In the existing automatic locking and paying equipment, most of them use a screw arranging machine to arrange the screws, and an electric screwdriver (electric batch) takes the screws back and forth, or the special equipment blows the screws into the electric batch to send the screws to the electric batch, and back and forth. The method of taking is too time-consuming, and the method of blowing air is not suitable for screws with small aspect ratios.
According to the force of the connection, it is divided into ordinary and hinged holes. According to the shape of the head: there are hexagonal head, round head, square head, countersunk head and so on. Among them, the hexagonal head is the most commonly used. Generally, countersunk heads are used where connections are required. [1] The English name of the riding bolt is U-bolt. It is a non-standard part. The shape is U-shaped, so it is also called a U-bolt. There are threads on both ends that can be combined with nuts. It is mainly used to fix tubular objects such as water pipes or sheets such as The leaf spring of a car is called a horse-riding bolt because it fixes the object in the same way that a person rides on a horse. According to the length of the thread, it is divided into two categories: full thread and non-full thread. [2] According to the thread type, it is divided into two types: coarse thread and fine thread. The coarse thread is not displayed in the bolt mark. The bolts are divided into eight grades: 3.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, and 12.9 according to their performance grades. Among them, the bolts above grade 8.8 (including grade 8.8) are made of low-carbon alloy steel or medium-carbon steel and are heat-treated (quenched). + Tempering), commonly known as high-strength bolts, and below grade 8.8 (excluding 8.8) are commonly known as ordinary bolts. [2] Ordinary bolts can be divided into three grades: A, B, and C according to the production accuracy. Grades A and B are refined bolts, and grade C is rough bolts. For connecting bolts for steel structures, unless otherwise specified, they are generally ordinary rough grade C bolts. There are differences in the processing methods of different grades. Usually the corresponding processing methods are as follows: ① The bolts of grade A and B bolts are processed by lathes, with smooth surfaces and accurate dimensions. High, rarely used; ②C-grade bolts are made of unmachined round steel, the size is not accurate enough, and its material property grade is 4.6 or 4.8. The deformation is large during shear connection, but the installation is convenient and the production cost is low. It is mostly used for tensile connection or temporary fixation during installation. [2]
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