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How many kinds of CNC machine tools? What are the categories in processing?

2019-08-12 02:03:40

       With the improvement of China's machine tool manufacturing industry, CNC machine tools have been put into various parts processing and automated production lines. It is an indispensable connecting device for major smart factories in the future. Due to the wide variety of CNC machine tools, there are two major categories of sheet metal equipment for gold cutting equipment. At the same time, according to its control principle, function and components, it is classified from different angles. Below we give classification from the functional manifestation of actual part processing:

       First, the numerical control machine tool with point control in the machining of the part hole system. Point-controlled CNC machine tools mainly include CNC drilling machines, CNC boring machines, CNC punching machines and coordinate measuring machines. The printed circuit board drilling machine is the simplest point-controlled CNC machine tool. The point-controlled CNC machine tool is used to machine the hole system in the plane. It controls the two coordinate axes in the machining plane (one coordinate axis is the feed motion in one direction) to drive the relative movement of the tool and the workpiece from a coordinate bus ( One coordinate axis is the feed motion in one direction. The tool moves relative to the workpiece, moves from one coordinate position (coordinate point) to the next coordinate position, and then controls the third coordinate axis for cutting. This type of machine tool requires a higher positioning accuracy in the sitting position. In order to improve the production efficiency, the machine adopts the set maximum feed speed for positioning movement, and advances the classification or continuous speed reduction near the positioning point, so that the low speed approaches the end point, thereby reducing Inertial overshoot of moving parts and resulting positioning errors. During the positioning and movement process, the CNC machine tool does not perform the cutting process, and there is no requirement for the motion track.

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       Second, the CNC machine tool should be controlled at most in the cutting process. The linear control CNC machine can control the appropriate feed rate of the tool or table, and move linearly and cut along the direction parallel to the coordinate axis. The feed speed can be adjusted within a certain range according to the cutting conditions. The simple CNC lathe with linear control has only two axes and can be used to machine the step shaft. The linearly controlled CNC milling machine has three axes that can be used for planar milling. The modern combined machine tool adopts the CNC feed servo system, and the drive power head carries a plurality of axle boxes along the axial direction for cutting machining. It can also be regarded as a linear control CNC machine tool.

       Third, CNC machine tools for complex parts controlled by curves and contours. Contour control CNC machine tools are divided into CNC machine tools for plane contour machining and CNC machine tools for space contour machining. The CNC machine tool for plane contour machining has a CNC lathe for turning curved surface parts and a CNC milling machine for milling the contour of the curved surface, and the contour shape of the machined part. The contour of the part can consist of a straight line, an arc or any plane curve (such as a parabola, Archimedes spiral, etc.). Regardless of the line segment of the part contour, a small straight line is used to approximate the curve contour during machining. When milling the contour surface with a cylindrical milling cutter on a CNC milling machine, the numerical control system controls the tool center relative to the workpiece in unit time, and simultaneously moves △xi, △y1i in the direction of the two coordinate axes, and the combined displacement ΔLi of the workpiece in the tool. Then, the point I' on the equidistant line of the contour curve is moved to the point J', so that a small straight line IJ is machined on the workpiece to approximate the IJ arc on the contour curve. By continuously controlling the two relative displacement components △xi and △yi, a polyline composed of a plurality of small straight lines can be processed to approximate the curve contour. The feed component △xi, △yi, the offset of the tool center to the part contour determined by the combined feed speed unit time, the mathematical formula y=f(x) of the contour curve, the tool radius R and the machining allowance δ Conditions such as =R+6) are determined and obtained by the CNC system in real time. Such operations are called interpolation operations and tool radius compensation operations

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