Machining performance is not only related to the interests of the enterprise, but also to safety, which can effectively reduce the probability of safety accidents while bringing economic benefits to the enterprise. Therefore, it is especially important to avoid the deformation of parts during the machining process. Operators need to consider various factors and take appropriate measures to prevent deformation during the machining process so that the finished part can be used properly. In order to achieve this goal, it is necessary to analyze the causes of the phenomenon of deformation in the machining of parts and to find reliable measures for the problem of deformation of parts, with a view to laying a solid foundation for the realization of the strategic goals of modern enterprises.
Internal force action leads to change in machining accuracy of parts
When lathe machining, usually the effect of centripetal force is used, and the three-jaw or four-jaw chuck of the lathe is used to clamp the part tightly, and then the mechanical part is machined. At the same time, in order to ensure that the parts do not loosen when the force is applied and to reduce the effect of internal radial force, it is necessary to make the clamping force greater than the cutting force of the machine. The clamping force increases with the increase of the cutting force and decreases with it. Such an operation can make the mechanical parts in the process of machining force stability. However, when the three-jaw or four-jaw chuck is released, the machined part will be far from the original, either polygonal or oval, with large deviations.
Heat treatment processing is easy to produce deformation problems
For the sheet-type mechanical parts, due to its very large length and diameter, it is easy to bend the straw hat after heat treatment. On the one hand, the phenomenon of bulging out in the middle and the plane deviation increases, on the other hand, due to the influence of various external factors, the bending phenomenon of the parts. These deformation problems are not only due to changes in the internal stress of the parts after heat treatment, but also the lack of solid expertise of the operators, who do not quite understand the structural stability of the parts, thus increasing the probability of deformation of the parts.
Elastic deformation caused by external forces
There are several main reasons for the elastic deformation of parts in machining. First, if the internal structure of some parts contains thin sheets, there will be higher requirements for the operation method, otherwise, when the operator is positioning and clamping the parts, it cannot correspond with the design between the drawings, which will easily lead to the generation of elastic deformation. Second, the unevenness of the lathe and fixture, so that the parts in the fixed on both sides of the force is not uniform, resulting in the cutting of the force on the side of the small role in the force will appear under the action of the translation of the parts deformation. Third, the positioning of the parts in the process is not reasonable, so that the rigid strength of the parts is reduced. Fourth, the presence of cutting forces is also a cause of elastic deformation of the part. These different causes of elastic deformation, all illustrate the effect of external forces on the quality of machining of mechanical parts.
Mechanical parts processing deformation improvement measures in the actual parts processing, resulting in parts deformation of many factors. In order to fundamentally solve these deformation problems, operators need to carefully explore these factors in practice and develop improvement measures in conjunction with the essence of their work.
Use special fixtures to reduce clamping deformation
In the process of machining mechanical parts, the requirements for refinement are very strict. For different parts, the use of different special fixtures can make the parts less likely to be displaced during processing. In addition, before processing, the staff also need to carry out the corresponding preparatory work, fully check the fixed parts, check the correct position of the mechanical parts against the drawings, in order to reduce the clamping deformation.
Trimming process
Parts are prone to deformation after heat treatment, which requires measures to ensure the safety performance of the parts. After the machining of mechanical parts and natural deformation, the use of professional tools to trim. In the processing of the processed parts after the dressing process, you need to follow the standard requirements of the industry to ensure the quality of the parts and extend their service life. This method is most effective when performed after the part has been deformed. If the part is deformed after heat treatment, it can be tempered after quenching. This is because residual austenite is present in the part after quenching, and these substances are then converted to martensite at room temperature, and the object then expands. When processing parts, every detail should be taken seriously so that the probability of deformation of the parts can be reduced, the design concept on the drawings can be grasped, and according to the production requirements, the products produced can be made to meet the standards to improve economic efficiency and work efficiency, thus ensuring the quality of mechanical parts processing.
Improve the quality of the blank
During the specific operation of various equipment, upgrading the quality of the blanks is a guarantee to prevent the deformation of the parts so that the processed parts meet the specific standard requirements of the parts and provide a guarantee for the use of the parts at a later stage. Therefore, the operator needs to check the quality of different blanks and replace the problematic ones in time to avoid unnecessary problems. At the same time, operators need to choose reliable blanks in conjunction with the specific requirements of the equipment in order to ensure that the quality and safety of the processed parts meet the standard requirements and thus extend the service life of the parts.
Increase part stiffness and prevent excessive deformation
In the machining of mechanical parts, the safety performance of the parts is influenced by many objective factors. In particular, after heat treatment of the part, the stress contraction phenomenon can lead to deformation of the part. Therefore, in order to prevent deformation, the technician needs to choose a suitable heat-limited treatment to change the stiffness of the part. This requires the application of the appropriate heat-limiting treatment in combination with the properties of the part, thus ensuring safety and reliability. Even after heat treatment, no significant deformation occurs.
Measures to reduce clamping forces
When machining parts with poor rigidity, it is necessary to take measures to increase the degree of rigidity of the part, for example, by adding auxiliary supports. Also pay attention to the contact area between the tightening point and the part, according to the different parts, choose different clamping methods, such as processing thin-walled sleeve class parts, you can choose to have a flexible shaft device for clamping, pay attention to the location of the tightening should choose a more rigid part. And for long shaft type of mechanical parts, you can use the two end positioning method. For the very large diameter parts, the need to use the two ends of the clamping method, can not use "one end of the clamping, one end of the suspension" method. In addition, when machining cast iron parts, the design of the fixture should be based on the principle of increasing the rigidity of the cantilevered part. A new type of hydraulic clamping tool can also be used to effectively prevent quality problems caused by clamping deformation during the machining process.
Reducing cutting forces
The cutting angle should be closely integrated with the machining requirements in order to reduce the cutting forces. You can try to increase the front angle of the tool and the main deflection angle, so that the cutting edge is sharp, and a reasonable tool in the turning of the size of the turning force is also critical. For example, in the turning of thin-walled parts, if the front angle is too large, it will make the wedge angle of the tool larger, speed up the wear rate, deformation and friction will also be reduced, and the size of the front angle can be selected according to the different tools. If you choose high-speed tools, the front angle is 6 ° to 30 ° best; if you use carbide tools, the front angle is 5 ° to 20 ° best.