What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In the existing joint replacement, self-tapping screws are mostly used, and their triangular thread structure has a certain self-locking ability. After a long period of service, it is prone to loosening. The surrounding bone may not be tight enough after implantation, resulting in a sharp decline in its self-locking ability, and there may be a risk of regression, causing certain damage to the human body.
Although there are many types of self-tapping screws, they all have the following common points: (1) They are generally made of carburized steel (accounting for 99% of the total output). Also available in stainless steel or non-ferrous metals. (2) The product must be heat treated. Carbon steel self-tapping screws must be carburized, and stainless steel self-tapping screws must be solution hardened. In order to make the self-tapping screw meet the mechanical properties and performance required by the standard. (3) The product has high surface hardness and good core toughness. That is, inner softness and outer rigidity. This is a major feature of the performance requirements of self-tapping screws. If the surface hardness is low, it cannot be screwed into the matrix; if the toughness of the core is poor, it will break as soon as it is screwed, and it cannot be used. Therefore, inner soft outer steel is a very important requirement for self-tapping screws to meet the performance requirements. (4) The surface of the product needs surface protection treatment, generally electroplating treatment. The surface of some products must be treated with phosphate (phosphating), such as wallboard self-tapping screws are mostly phosphated. (5) Produced by cold heading process. It is recommended to use high-speed cold heading machine and high-speed thread rolling machine or high-speed planetary thread rolling machine for production. The emphasis here is on high speed to ensure product quality. Only self-tapping screws produced by high-speed machines have well-formed heads and high-quality threads.
shaft retaining ring installation tool and an installation method thereof relate to an assembly tool and an installation method thereof, comprising a pressing cylinder and a taper sleeve. The maximum diameter of the tapered end is slightly smaller than the inner diameter of the circular straight hole of the pressing cylinder, and the lower end of the tapered sleeve has a positioning structure matched with the shaft of the shaft retaining ring to be installed. The method includes the following: place the taper sleeve on one end of the shaft where the shaft retaining ring is to be installed and position it well, then place the shaft retaining ring on the tapered end of the taper sleeve, and finally press down the pressure cylinder to make the shaft Use the retaining ring to slide down the conical surface of the taper sleeve to the shaft to be installed with the retaining ring for the shaft, and finally get stuck in the groove of the shaft. Yueluo does not need to open the retaining ring for the shaft, which reduces the operation force and labor intensity. The operation method is simple, the structure is simple and reliable, the cost is low, and it is easy to popularize and use.
Stainless steel usually refers to steel that has the ability to resist corrosion by air, water, acid, alkali salt or other medium. Depending on the alloy composition, the focus is on rust resistance and acid resistance. Although some steels are rust-resistant, they are not necessarily acid-resistant, and acid-resistant steels are usually rust-resistant. Austenitic stainless steel is mainly used in the production of fasteners. In people's daily life, the stainless steel often referred to is also austenitic stainless steel. The stainless steel fasteners we use are mainly made of austenitic 302, 304, 316 and low nickel 201 as raw materials.
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