What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
An embodiment of Guangdong Yueluo Hardware Industry Co., Ltd. provides a screw slotting device, as shown in Figure 1, which includes a workbench 1, a vibrating plate 2 is arranged on the upper part of the workbench 1, and a conveying device 3 is arranged on the vibrating plate 2. Below the discharge port, the slotting device 4 is arranged on one side of the conveying device 3, and the slotting device 4 is provided with a reciprocating cutting wheel 42 that can slot the screws in the conveying device 3 when it extends out. The device 4 is also fixedly provided with a fixed wheel 48 for grinding the grooved screws. Using the screw slotting device, the screws can be automatically sorted by the vibrating plate 2, which improves the production efficiency. The reciprocating motion of the cutting wheel 42 can greatly reduce the probability of knife breakage. Sanding, fixes burrs and roughness.
GB97.1.CATPart GB97.1.SLDPRT Nominal size d d1 d2 h 1000 weight (kg) ≈ nominal diameter (NND) inner diameter (SD1) outer diameter (SD2) thickness (SD) — 5 5.3 10 1 0.443 Spring washer spring Wasket 6 6.4 12 1.6 1.0518 8.4 16 1.6 1.828 10 10.5 20 2 3.57 14 15 28 2.5 8.611 16 17 30 3 11.29 20 21 37 37.16 24 25 44 4 32.31 30 31 56 4 53.61 36 37 66 5 92.03
T-slot bolts refer to the bolts installed in the T-slot. The installation process of T-slot bolts is usually as follows. When the T-slot (generally refers to the T-slot aluminum alloy profile) is set horizontally, the bolt The bolt head is placed in the T-slot in the horizontal direction, the bolt shaft is facing outward, and then the bolt is rotated 90 degrees axially, the bolt head becomes vertical and will not come out of the T-slot, and then install the mounting hole of the object Align the bolt rod and insert it and screw the nut on the bolt rod. During the tightening process of the nut, if the thread gap is small or the thread is damaged or there is dirt, the bolt will often rotate, and the rotation angle of the bolt is uncontrollable and impossible. Observe that when the rotation angle of the bolt is in the range of about 90 degrees, the bolt is in a state of being released from the T-shaped groove at any time. Even if the nut is tightened, the installation of the installation object is invalid and unreliable, and there is a serious safety hazard. , the actual situation is that when the rotation angle of the bolt exceeds 20-30 degrees, the installation of the installation object is already unreliable.
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.
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