What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
During the daily use and operation of mechanical equipment, due to the influence of external load, internal stress, wear, corrosion and natural erosion, individual parts or the whole change size, shape, mechanical properties, etc., which reduces the production capacity of the equipment. The consumption of raw materials and power increases, the quality of products decreases, and even personal and equipment accidents are caused. Therefore, in order to make the machinery and equipment can often play the production efficiency and prolong the service life of the equipment, the equipment must be properly repaired and routinely maintained.
M4 grounding screw used to fix the grounding wire on household appliances and other equipment, the stud is cylindrical, and the thread is perpendicular to the end (section) surface. However, the screw holes on the equipment all have tapping guide grooves for sinking and guiding due to the manufacturing process requirements. When fixing the ground wire, if the screw is not positioned accurately (the screw is inclined), the screw is pressed down hard, which is easy to cause the screw and the screw. The screw hole bites the teeth, and after biting the teeth, it is easy to cause the screw to loosen or fall off, posing a safety hazard.
In the process of mechanical assembly, we often use pins to connect two parts, and the positioning pins are usually sunk into the pin installation holes on the mechanical parts. During the assembly process or after the assembly is completed, we often need to pull out the pins to assemble, revise or repair the parts. The existing method of pulling out the positioning pins is generally to use tools such as pliers, hand hammers, and blades to pull out the positioning pins, but This method is easy to damage the pin holes and pins, which will directly lead to the scrapping of the original parts. The positioning pin can be pulled out by pulling the pull rod, but in order to ensure the assembly accuracy between the parts, the matching between the positioning pin and the pin hole on the part is tight and the number of pins is large, so this method is inconvenient to operate. And time consuming.
In each maintenance, the newly replaced stud bolts and other accessories should be inspected. During the inspection, the focus should be on the head and guide part of the stud bolt. It is also necessary to strictly check that each part of the thread has No cracks or dents, also check the tooth shape of the studs for changes. Is there any abnormality in the thread pitch? If there is any abnormality, it must not be used again. A torque wrench should be used when installing the connecting rod cover. It must be tightened according to the specified standards, the torque should not be too large or too small, and attention should be paid to selecting the stud bolts and studs of the supporting manufacturer.
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