Why need to use Tool instrument for CNC machining ?

　　In numerical control machining, how to determine the programming, the position of the tool is zero? This needs to use the tool described below - Tool instrument.

　　Tool instrument, also known as tool preconditioning instrument, full name tool preconditioning measuring instrument. It is used to measure and (or) adjust the radial and axial dimensions of the cutting edges of various machining centers and axis boring and milling tools of CNC machine tools in the pre-adjustment of the machine. The measured tool is fixed on the main shaft of the instrument and can rotate around its axis. According to the direct measurement method, the aiming device is positioned to zero, and the measurement moves along the radial and axial direction of the measured tool. The measurement results are given by the corresponding measurement system.

　　1. Measure and compensate tool deviation in ±X, ±Z and Y axes

　　The measurement and compensation of tool deviation value in five directions can effectively eliminate the error and low efficiency caused by manual tool adjustment. Whether adopt what kind of cutting tools (cylindrical hole, grooving, wok, end face, threads or turning center of milling, drilling power tool), when the workpiece contour milling or turning, all participants in the cutting blade point or tool axis, must be through adjusting or compensation, make its precise position in theoretical point or axis of workpiece coordinate system of the same line. For dynamic rotary cutting tools, offset values in the tool length direction should be measured and compensated, as well as offset values in the tool diameter direction (offset values of the two radii where the tool is bounded by the axis line). Otherwise the machine cannot process the workpiece with the correct size. In the machine tool without the installation of tool instrument, the offset value of each tool, is to each tool carefully after the trial cut, the workpiece size measurement, calculation, compensation (manual knife) can be obtained, time-consuming and laborious, a little careless will scrap the workpiece. When the cutter is replaced, the work must be repeated. Therefore, the tool is one of the longest occupation of machine tool auxiliary work.

　　Using the tool tool, because of the tool can automatically set up the offset value of the tool to the workpiece coordinate system, so as to automatically establish the workpiece coordinate system. In this case, there is no need to use "G50 instruction" to establish the workpiece coordinate system in the machining program.

　　2, automatic monitoring, alarm and compensation of tool wear or damage in the process of processing

　　It is very troublesome to complete the compensation of the wear value on the machine tool without the tool counter. It is necessary to stop the machine tool for several times to measure the size of the workpiece manually, and to manually modify the tool complement parameters of the wear value obtained. After the installation of knife instrument, the problem is much simpler, especially after the installation of HPPA type or HPMA type more convenient. The former, as long as according to the wear law of the tool, after finishing a certain number of workpiece stop machine tool, with the tool instrument again tool process can be; The latter, as long as the program is set to complete the number of processing cycles after the implementation of an automatic knife, you can complete the knife repair work.

　　For tool breakage alarm or replacement after tool wear to a certain extent, is based on the tool allows the amount of wear and tear, set a "threshold", once the knife error exceeds the threshold value of the instrument to detect, that the cutting tool has been damaged or wear more than the allowed value, the machine automatic alarm downtime, then force for cutting tool replacement.

　　3. Compensation for variation of tool offset value caused by thermal deformation of machine tool

　　Machine tool in the process of working cycle, all kinds of heat generated, resulting in the deformation of machine tool, especially the thermal elongation of the lead screw, so that the position of the tip of the change, the result is that the dimensional accuracy of the workpiece will be affected. In the machine tool installation tool instrument, the above problems can be easily solved. Nothing more than the change of tip position caused by thermal deformation, as the tool wear value, through the tool instrument to measure the tool offset value, can be solved.