Shaft parts are a common type of parts, its structure is a rotating body, the length is generally greater than the diameter, in a variety of mechanical equipment is widely used to support the transmission parts, transmission torque and load.The processing of shaft parts should follow certain rules, you can understand the specific processing steps and need to pay attention to some problems through this article.
The basic processing route of shaft parts
The main machining surface of shaft parts is the outer circle surface and the common special surface, so we should choose the most suitable machining method according to the requirements of various precision levels and surface roughness.Its basic processing route can be summarized as four.
First of all, it is the processing route from rough car to semi-fine car and then to fine car. This is also the most important process route for the needle cylindrical processing of commonly used shaft parts.Secondly, it is from rough car to semi-finished car, then to rough grinding, and finally, it adopts the processing route of fine grinding. For the parts with higher requirements of ferrous metal materials and precision, and smaller requirements of surface roughness and need to be hardened, this processing route is the best choice, because grinding is the most ideal subsequent processing process.The third route is from rough car to semi-finished car, then to finished car, diamond car, this processing route is specially used for processing non-ferrous metal materials, because the hardness of non-ferrous metal is small, easy to block the gap between the sand, the use of grinding is usually not easy to get the required surface roughness, must use precision car and diamond car procedures;The last processing route is from rough car to semi-finished car, then to rough grinding, fine grinding, and finally finishing processing. This route is often used for parts with hardened ferrous metal materials, high precision requirements, and low surface roughness value requirements.
2. Preprocessing of shaft parts
Shaft parts in the turning of the cylindrical, the first to carry out some preparatory process, this is the shaft parts of the pre-processing process.The most important preparation process is the school.Because the workpiece blank in the process of manufacturing, transportation and storage, often bending deformation.In order to ensure reliable clamping and uniform distribution of machining allowance, in cold state, through a variety of presses or straightening machine to straighten.
Three, shaft parts processing positioning standards
Firstly, the center hole of the workpiece is used as the positioning datum for machining.In the machining of shaft parts, the coaxiality of each outer circle surface, cone hole and thread surface and the perpendicularity of the end to the rotating axis are important embodments of position accuracy.These surfaces are generally designed based on the center line of the shaft, with the center hole positioning, in line with the principle of reference coincidence.The center hole is not only the positioning datum for turning processing, but also the positioning datum and inspection datum for other processing processes.When using two center hole positioning, it can also maximize the processing of multiple outer circles and end faces in a single clamping.
The second is the outer circle and the center hole as the processing positioning reference.This method effectively overcomes the shortcomings of the center hole positioning rigidity is not good, especially when machining heavy workpiece, the center hole positioning will cause clamping instability, cutting parameters can not be too large.Using the outer circle and the center hole as the positioning reference does not have to worry about this problem.During rough machining, the cylindrical surface of the shaft and a center hole are used as the positioning reference to bear a large cutting torque in machining, which is the most common positioning method for shaft parts.
The third is the two outer circle surface as the processing positioning benchmark.When machining the inner hole of hollow shaft, the center hole cannot be used as the positioning reference, so the two outer round surfaces of the shaft should be used as the positioning reference.When machining machine tool spindle, the two supporting journal is often used as the positioning datum, which can effectively ensure the coaxiality requirements of the cone hole relative to the supporting journal, and eliminate the errors caused by the non-coincidence of the datum.
Finally, the cone plug with center hole is used as the positioning reference for machining.This method is most commonly used in machining cylindrical surfaces of hollow shafts.
Iv. Clamping of shaft parts
The machining of cone plug and cone sleeve mandrel must have high machining precision, the center hole is not only the positioning datum for its own manufacture, but also the reference for the finishing of outer circle of hollow shaft, it must ensure that the cone surface on the cone plug or cone sleeve mandrel has high coaxiality with the center hole.Therefore, when choosing the clamping method, we should pay attention to reduce the installation times of the cone block as far as possible, so as to reduce the repeated installation error of parts.In actual production, after the installation of the cone block, generally speaking before the completion of the processing, will not be removed or replaced in the middle of the processing.