Considerations of cnc turning

The ideal maching procedure should not only ensure that the qualified workpiece conforms to the pattern, but also make the function of the CNC machine tool be applied and fully utilized. CNC machine tools is a highly efficient automation equipment, which is more efficient than ordinary machine tools 2 to 3 times, to give full play to the characteristics of CNC machine tools, the workpiece must be programmed before the process analysis, according to specific conditions, select the economy , A reasonable process program. CNC processing technology to consider the ills are the impact of CNC machine tool processing quality, production efficiency and processing costs an important factor.

CNC maching process division in the CNC machine tools on the processing of parts, processes are more concentrated, a clamping should be completed as much as possible all the processes, the commonly used process division principles are the following two. To ensure the accuracy of the principle of CNC machining with the conditions of the process, rough, finishing often in a clamping to complete, to ensure the accuracy of parts processing, thermal deformation and cutting force on the deformation of the parts of the greater impact on the processing accuracy should be coarse , Finishing separately. To improve the efficiency of the principle of NC processing, in order to reduce the number of tool changes, saving tool change time, should be used with the same processing of the processing of all the finished parts, and then another knife to process other parts. At the same time should try to reduce the empty stroke, with the same knife processing parts of the workpiece, should be the shortest route to reach the processing site. In actual production, CNC maching often press the tool or processing surface division process.

tooling knife point selection CNC machining, the NC program should describe the tool relative to the workpiece movement trajectory. In CNC turning, the formation of the workpiece surface depends on the movement of the edge of the envelope of the location and shape, but in the programming, just describe the tool system on a selected point of the track can be. The tool point of the tool is the point on the tool that represents the position of the tool at the time of programming. The maching path described by the program is the trajectory of the point. In the NC turning, theoretically, you can choose any point on the tool as a knife point, but in order to facilitate programming and ensure the processing accuracy, the choice of knife point has some requirements and skills.

and so on the amount of knife back to try the method shown in Figure 1, said the end of the knife, the use of tool preset instrument on the knife, measuring P1 point than the measurement P2 point convenient, so select P1 for the knife point than P2 good, but if the tool Position adjustment and compensation is to try to determine the method, and ring groove round processing accuracy is higher than the large round precision, then select P2 for the knife point than P1 good. 3 cutting the end of the cutting position of the tool When a large surface of the outer surface of the processing allowance to be more than a few times when the knife cutting, from the second knife began to pay attention to prevent the knife to the end of the back when the amount of knife The As shown in Figure 2, the tool is delimited with 90 ° main declination, and the reasonable arrangement should be a short distance e (e = 0.05) ahead of the cutting end of each knife. If e = 0, that is, each knife is terminated in the same axial position, the main cutting edge of the tool may be subject to instantaneous heavy load impact. Such as the end of the cutting position to make layers of the arrangement of the settlement, is conducive to extend the roughing tool life.

“to knife” when the knife to determine the value of the thin-walled workpiece, especially difficult to cut the material of thin-walled parts, cutting “knife” phenomenon is serious, resulting in the size of the workpiece to be changed, The hole becomes smaller. “Let the knife” is mainly caused by the elastic deformation of the workpiece when the “knife” and the degree of cutting when the knife is closely related. Using the “back to eat knife depth method”, with a knife to make a small range of corrections to reduce the “knife” on the processing accuracy of the impact. As shown in Figure 3, the outer diameter of the outer dimension is A and the double-sided margin is 2t. In the case of cutting, half of the value of t is taken as the amount of kneading knife at the time of cutting, and the cutting is carried out on the full length of the surface. After the test is cut, the program is scheduled to stop and the outer dimension is equal to A + t. The size of the error adjustment tool tool compensation value, and then continue to run the program to complete the finishing knife. Since the finishing process is the same as the cutting speed and the same cutting speed and feed rate, the cutting resistance is the same and the corresponding elastic deformation of the workpiece is the same. The input value of the tool is just enough to offset the ” Resulting in deformation, to ensure the accuracy of the workpiece size of turning.

when the chip breaking problem CNC turning is automated processing, if the tool chip breaking performance is bad, will seriously hinder the normal processing. To solve this problem, we should first try to improve the cutting machine itself, the chip breaking performance, followed by a reasonable choice of the amount of cutting tools to avoid the normal processing of the strip to prevent the formation of chips. CNC turning, the ideal chip is the length of 50 ~ 150mm, the diameter of the spiral-like chips, or pagoda-shaped chips, they can be regularly excluded in a certain direction, easy to collect and clear. If the chip is not ideal, if necessary, can be arranged in the program to suspend, forced chip: you can also use the chip to enhance chip breaking effect. Use the upper press clamp to position the blade, the pressure plate can be used together with the chip and the blade together: the hole inside the hole, you can use the tool face down the cutting method to improve chip removal.