What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Knurled copper nuts are widely used in the following fields: notebook computer plastic casing, desktop computer plastic casing, GPS plastic casing, router plastic casing, mobile phone plastic casing, infinite communication facility plastic casing, home appliance plastic casing, automobile, electrical appliances, medical, electronics, etc. plastic shell.
1. For low strength (below 500 N/mm2 or below 60000 psi) bolts use general soft steel, generally use SAE 1008 or JIS SWRM 8 (or SWRCH 8). 2. Lower strength (600 N/mm2 or 74000 psi) ) bolts use general soft steel, but limited carbon content grade, generally use SAE 1010 - 1015 or JIS SWRM 10 - 15 (or SWRCH 10 - 15). .3. Higher strength ( 800 N/mm2 or 125000 psi ) bolts of medium carbon steel, low carbon boron steel plus quenching and tempering, generally use SAE 1035 - 1040 or SWRCH 35K - 40K. 4. High strength (900 N/mm2 or more or 150000 psi or more) bolts use medium carbon Alloy steel or low carbon boron steel, in terms of application, if the metric Class 10.9 uses low carbon boron steel, the imprint should be added under the series imprint to become 10.9, and the imprint of the inch 8.2 grade is also used with the general Grade 8 bolts The imprint is different for easy identification. High-strength bolts made of low carbon boron steel cannot be used in high temperature conditions. The design strength exceeds Class 12.9 or ASTM A574 ultra-high strength bolts are limited to medium carbon alloy steel plus quenching and tempering. The performance grades of bolts for steel structure connection are divided into more than 10 grades such as 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, etc. Among them, the bolts of grade 8.8 and above are made of low-carbon alloy steel or medium-carbon steel and are heat-treated (quenching, tempering), commonly known as high-strength bolts, the rest are commonly known as ordinary bolts. The bolt performance grade label consists of two parts of numbers, which represent the nominal tensile strength value and yield ratio of the bolt material respectively. For example, a bolt with a performance level of 4.6 means: 1. The nominal tensile strength of the bolt material is 400MPa; 2. The yield ratio of the bolt material is 0.6; 3. The nominal yield strength of the bolt material is 400×0.6=240Mpa . Performance level 10.9 high-strength bolts, after heat treatment, can achieve: 1. The nominal tensile strength of the bolt material is 1000MPa; 2. The yield ratio of the bolt material is 0.9; High-strength bolts, processing and manufacturing problems are compared Small, general fastener manufacturing companies can master the manufacturing process; but problems are prone to occur in material selection and heat treatment. Material selection is the primary link. Various alloying elements have a great influence on the properties of the material, and the material must be subjected to spectral composition analysis; secondly, the fracture problem and the choice of heat treatment process have a great influence and are very important. Dealers and traders must control the inspection and performance testing links; automotive fasteners have high requirements and must carefully control the quality.
Self-locking nuts generally rely on friction. The principle is to press the embossed teeth into the preset holes of the sheet metal. Generally, the diameter of the square preset holes is slightly smaller than that of the rivet nut. The nut is connected with the locking mechanism. When the nut is tightened, the locking mechanism locks the ruler body, and the ruler frame cannot move freely to achieve the purpose of locking; when the nut is loosened, the locking mechanism disengages the ruler body, and the ruler frame edge body movement
In order to solve the above technical problems, Yueluo provides a screw installation method. When using this method to install screws, the sensor must sense that the screws have been adjusted to the specified position before allowing the screws to be energized, which prevents the screws from being adjusted. Accidents of personal injury caused by operating errors during the process. The technical solution adopted by Yueluo to solve its technical problems is a screw installation method, which includes the following steps: a. Fix the screw hole structure that needs to be installed on the workbench, and fix the corresponding size screw to the screw mouth; b. Adjust the sensor on the track groove to the vertical position just above the screw hole structure; c. Adjust the screw position until the sensor on the screw senses the signal sent by the sensor; d. Turn on the screw power supply, and install the screw into the screw Inside the hole structure, the installation is complete. Compared with the prior art, Yueluo has the following beneficial effects. The screw installation method provided by Yueluo has the steps of preventing accidental hitting, which avoids personal injury accidents caused by operation errors during the screw adjustment process.
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