What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
At present, with the continuous improvement of microwave plasma chemical vapor deposition technology, researchers hope to obtain more excellent products by increasing the microwave power. During the use of the three screws, it is necessary to continuously adjust the length of the pins extending into the rectangular waveguide to make the reflected power of the system reach the minimum value and improve the stability of the system. Since the length of the three screws extending into the waveguide needs to be continuously adjusted with the change of the input power, and the adjustment state of the three screws cannot be recorded after the adjustment is completed, repeated adjustment is still required in the subsequent work, resulting in a time-consuming adjustment process. long and low work efficiency. Especially under high power conditions, the traditional three-screw dispenser has a high risk of microwave leakage. When manually adjusting, the human body is exposed to microwaves for a long time, which has certain potential safety hazards.
The bolt thread is generally cold worked, so that the thread blank within a certain diameter range passes through the rubbing (rolling) wire plate (die), and the thread is formed by the pressure of the wire plate (rolling die). The plastic streamline of the threaded part is not cut off, the strength is increased, the precision is high, and the quality is uniform, so it is widely used. In order to make the outer diameter of the thread of the final product, the required thread blank diameter is different, because it is limited by factors such as thread accuracy and whether the material is coated or not. Rolling (rubbing) thread is a processing method that uses plastic deformation to form thread teeth. It uses a rolling (screwing plate) die with the same pitch and tooth shape as the thread to be processed, while extruding the cylindrical screw blank, while rotating the screw blank, and finally transferring the tooth shape on the rolling die to the On the screw blank, the thread is formed. The common point of rolling (rubbing) thread processing is that the number of rolling revolutions does not need to be too much. If it is too much, the efficiency will be low, and the surface of the thread teeth will easily cause separation or random buckle. On the contrary, if the number of revolutions is too small, the diameter of the thread is easy to be out of round, and the pressure at the initial stage of rolling increases abnormally, resulting in a shortening of the life of the die. Common defects of rolled threads: cracks or scratches on the surface of the thread part; random buckles; out of roundness of the thread part. If these defects occur in large numbers, they will be discovered during the processing stage. If the number of occurrences is small, the production process does not notice these defects and then circulates to users, causing trouble. Therefore, the key issues of processing conditions should be summarized, and these key factors should be controlled in the production process.
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.
The conventional auger bit structure 1 includes a rod body 11, a screw head 12 provided on one end of the rod body 11, a drill tail 13 provided on the other end of the rod body 11, and a plurality of threads 14 arranged around the rod body 11; Wherein, the periphery of the drill tail 13 defines a parting line 15, and the parting line 15 makes the drill tail 13 symmetrically divided into a side 131 and a side 132, and a cutting end 133 is formed at the junction of the end of the side 131 and the end of the side 132, respectively. The cutting end 133 is concavely provided with a quarter-turn chip flute 134 in the same direction of the helix, and the edge 132 continues the chip flute 134 and has a quarter-turn chip flute 135 with different helical curvatures. , using the chip groove 134 and the chip groove 135 to be connected by different helical curvatures, so that the drill tail 13 can form a symmetrical and complete chip groove of 190 degrees.
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