CNC Lathe In-depth understanding of the principle of CNC lathe for the operator to maintain a clear idea of the knife, proficiency in the operation of the knife and put forward a new CNC Lathe approach to the tool is instructive. The essence of the tool is to determine the location of the program origin of the workpiece coordinate system which varies with the program in the unique machine tool coordinate system. The main work of the tool is to obtain the machine coordinate of the starting point of the reference Knife program and to determine the tool bias of the non reference knife relative to the reference knife. In this paper, the following conventions are used to illustrate the principle and thinking of the cutter: using the central China century star teaching turning system HNC 21t (Application software version number 5.30), the right end of the workpiece center as the origin of the program, using G92 instructions to set up the workpiece coordinate system; the diameter programming, the program starting point H's workpiece coordinates are ($number); The turret is fitted with four knives: No. 1th knife is 90 ° CNC Lathe outside the round rough Vehicle knife, 2nd reference knife for 90 ° outside the Round precision vehicle Knife, 3rd knives for cutting knives, 4th knives for 60 degrees Triangular threaded knives (the same is the case with the full text).
The base knife according to "manually test the workpiece's outer circle and end face, record the display (CRT) to show the test point A's X, z CNC Lathe machine coordinates → to launch the program origin o machine coordinates → to launch the program at the beginning H machine tool coordinates" thinking to the knife. According to the relationship between point A and O point of machine tool coordinates: Xo-φ Dizo Zizza, can launch the program Origin o of machine coordinates. According to the workpiece coordinates of H relative to O Point ($number), CNC Lathe the machine coordinate of H point is finally introduced: Xh 100 φ D Zh Za 50. The workpiece coordinate system established in this way is the workpiece coordinate system based on the tip position of the datum cutter.
Because each knife clamping in the tool holder X, z direction of the elongation and position is different, when the non-standard knife to the processing position, the tip position B relative to a point is biased, the original set of the workpiece coordinate system is no CNC Lathe longer applicable. In addition, each tool in the use of the process will also appear different degrees of wear, so the knife bias and wear values need to be compensated. The basic principle of obtaining each knife bias is that each knife is aligned to a datum point on the workpiece (such as a point or O point in Fig. 1), because of the different coordinates of the machine tool displayed by CRT, the machine coordinate of the tool at that point is calculated by manual calculation CNC Lathe or system software minus the machine coordinate of the same point, and the tool offset of the non reference knife is obtained.
By the influence of many factors, manual test on knife cutting precision is very limited, this stage of the knife is called rough knife. For more accurate results, as shown in Fig. 3, a simple automatic test-cutting procedure is designed in the range of machining allowance before machining, CNC Lathe through the train of thought of "automatic test → measurement → error Compensation", the beginning position of the program and the tool offset of the non-standard knife are repeatedly revised, so that the error of the programmed instruction value and the actual measuring value achieves the accuracy requirement, and the knife in this stage is called the precision tool. Since the starting point of the base knife program is precisely positioned to obtain an accurate non-fiducial knife bias, the former is generally corrected and then corrected.