An shaft workpiece having a ratio of the length L to the diameter d of the workpiece greater than 25 (i.e., the long neck ratio L/d > 25) is referred to as an elongated shaft. The shape of the slender shaft is not complicated, but due to its low rigidity, it is affected by cutting force, gravity, cutting heat and other factors during turning. It is easy to produce bending deformation and vibration, taper, waist drum shape, bamboo shape and other defects. It is difficult to guarantee the processing accuracy or even the processing. Although the processing of the slender shaft is difficult, it has the commonality of machining ordinary workpieces (such as: cutting method, workpiece mounting, turning selection and clamping); selecting and processing various high-quality shaft parts to identify Jianke machinery, Professional quality assurance! Jianke Machinery are reliable Swiss type CNC automatic lathe supplier, Swiss type automatic lathe supplier. This paper discusses some difficulties and solutions in the process of slender shaft turning: grasping the commonality of turning, combined with the individuality of the slender shaft, solving the three key factors of stiffness, thermal deformation elongation and reasonable selection of the geometric parameters of the turning tool Technology, the turning of the slender shaft is also easy.
First, the problems encountered in the process of slender shaft turning
An shaft workpiece having a ratio of the length L to the diameter d of the workpiece greater than 25 (i.e., the long neck ratio L/d > 25) is referred to as an elongated shaft. The slender shaft has poor rigidity, and the rigidity of the process system using machine tools, tools, jigs, and workpieces is insufficient, and vibration and deformation are easily generated during cutting, which causes processing difficulties. The main problems encountered during processing are:
1. The workpiece is subjected to cutting resistance to generate vibration and bending deformation, which reduces geometric accuracy and surface finish.
2. The cutting heat absorbed by the workpiece during the cutting process will cause the workpiece to have a large axial line expansion, aggravate the bending deformation, increase the vibration, and even cause the workpiece to squash between the two tips, resulting in inability to process.
3. The longer the ratio of long neck to neck, the greater the self-gravity, the greater the centrifugal force generated by the workpiece at high speed, and the upper and lower jumps will seriously affect the processing quality.
4. The improper selection of the geometric angle of the tool, the amount of cutting and the processing method will increase the cutting force, and the deformation and vibration will be intensified.
5, the workpiece bending and vibration, the turning must use a lower speed and depth of cut, limiting the increase in production efficiency.
6. Under the action of radial cutting force, the workpiece has a small shape at both ends and a large middle, and it is easy to produce a “knife” phenomenon.
7, improper adjustment of the machine tool, easy to produce cone error; improper adjustment of the fixture, easy to cause bending and produce “bamboo”, “diamond” and so on.
Second, the solution to the problem
In production practice, in order to ensure the machining accuracy and surface quality of the slender shaft and improve production efficiency, we have taken the following measures:
1. In order to compensate for the lack of rigidity of the slender shaft, in the turning, the support frame should be used to improve the rigidity of the workpiece and reduce the deformation.
2, pay attention to the specific operating methods, there are strict process requirements and measures to ensure the rigidity of the entire process system, so that the workpiece to obtain the necessary geometric accuracy and surface finish.
3. Turning from left to right in the opposite direction; reducing internal stress and bending deformation, ensuring straightness and dimensional accuracy, high processing efficiency and strong adaptability.
4. Reasonable selection of cutting amount, as well as tool geometry and parameters.
Third, the selection and use of tools for Swiss type cnc automatic lathe and swiss type cnc sliding head automatic lathe
Since the rigidity of the elongated shaft is insufficient, the radial cutting force is required to be as small as possible. Therefore, the cutting edge of the tool is required to be sharp, the cutting is light, the chip removal is smooth, and the durability is high.
The utility model can maintain a certain contact area between the turning tool and the shaft member, and the cutting edge is turned on the shaft member to prevent the sickle from being criticized when the turning force changes. The main declination is small to form a thin and small deformation, which is beneficial to improve the surface finish of the machined surface, and the rake angle is γ=30°, which makes the cutting light.
Fourth, choose a reasonable cutting amount
When turning a slender shaft, a support frame can be used to increase the rigidity of the workpiece.
In summary, machining a slender shaft is a difficult process, but by using the above-mentioned series of methods, from the workpiece clamping support to the use of a reasonable selection of tool geometry and other key technologies, the surface of the workpiece is solved. The quality and elongation of the heat deformation ensure the rigidity of the machine tool – the tool – the fixture – the process system of the workpiece. Choose to process a variety of high-quality shaft parts to identify Jianke machinery, professional quality assurance! Jianke Machinery company is reliable Swiss type cnc automatic lathe manufacturers ,producing swiss type cnc sliding head automatic lathe and swiss type cnc automatic lathe.In the processing of the slender shaft, we have adopted some of the measures discussed in this paper to ensure the processing quality, high-speed turning, and improve production efficiency, and achieved satisfactory results. We will encounter problems and difficulties in our work, but as long as we apply our own knowledge, technical experience and scientific development concept to guide our work ideas and continue to innovate, we can overcome all difficulties.
Post time: Sep-10-2018