The now ceramic and diamond cutting tool, which is capable to achieve even higher speeds and supplies, it constantly substitutes carbide tools in many regions. This term is relative with respect to the prospect for the development of cutting and its application. A simple increase in the speed of rotation of turning spindle will not make it possible to obtain advantage from the application of high-speed working (VSO). Many companies tried to use VSO only then in order to ascertain that it for them was unfit. A more thorough study shows that they tried to process more rapidly and it came out unsuccessfully, because they carried out strategy VSO only partially. In certain cases failure can be attributed to the incomprehension of the essence of concept VSO in its full weight. For the successful application OF VSO is required its complete understanding. For this purpose let us examine one of the most frequently used operations - milling.

  When the discussion deals with VSO, most incorrectly understood regions - working feed and speed of rapid adjustments. The higher speeds are better only in one. For example, in the machine tool created for the rapid adjustments knots can move from one point to another with speed, for example 60 m/min, i.e., it is considerably more rapid than on the slow machine tool. But when on the rapid machine tool it is necessary to move knot up to the short distance, on it is not possible to move knot with the same speed, as the knot of less high-speed machine tool is moved. Acceleration is reason. With the same engines the knots of "slow" machine tool are accelerated to the maximum speed more rapidly than more high-speed machine tool it will be able "to crawl" to the full speed (fig 1).

  The laws of physics dictate, that the same engine can drive away much more rapid, if it is connected with the reducer, calculated for the lower speed. If during the motion of any transportation means you sometimes used the change-gear lever, then to you this will be understandably. In the ride around the city more low gear ensure better acceleration, whereas the fourth or fifth transfer they ensure the highest speed during the motion along the highway, but these speeds are useless during the motion in the plugs. However, for the machine tool with the computer device CHPU (UCHPU) engine for each coordinate axis has only one gear ratio. All designers select speeds and range of the accelerations of machine tool, thinking that they are optimum. It is difficult to say that they did have in the form, selecting such operating range? Probably, they attempted to please to their divisions of sale and marketing, which requested to raise maximum speeds and supplies.

  The exponential dependence of acceleration on the power means that in order to twice increase acceleration, it is necessary four times to raise power (Fig. 1). And vice versa, with the same power an increase in the maximum speed twice requires a fourfold increase in the period of acceleration/deceleration. Therefore, more "slow" machine tool can in the reality be more productive (high-speed), than machine tool with the more high-speed range.

Fig 1. Influence of the maximum speed of machine tool on acceleration. You will focus attention, that the machine tool with a maximum speed of 60 m/min four longer is accelerated to the speed of 15 m/min, than machine tool with a maximum speed of 15 m/min: 1 - speed; 2 - time; 3 - for the same speed of distance/time of acceleration it is four times more.

  During the milling with the use of computer UCHPU it is possible to smoothly coordinate motion along three linear axes for treating the network circuits. For example, milling circle realizes as a constant process, i.e., as the "servo" cutting, but inside the program UCHPU it is crushed to complex routine and corrections. It is clear for the programmer and the operator that three-coordinate UCHPU calculates displacements over the family of the points, which are located approximately in the circle. The quality of such an interpolation (degree of approximation) depends on the accuracy of work UCHPU, which constantly is measured.

  The higher the speed UCHPU, the smoother interpolation. When machine tool with UCHPU mills arc into 8"with 200 pulses per minute, you see smooth motion, but UCHPU actually carry out a series of short linear steps. Speed UCHPU determines the length of step. Old and slower UCHPU on the round outline frequently give a faceting or a series of flattenings. Another UCHPU, newer, but relatively slower in comparison with commercially available most those moving rapidly, either slow down or they partially compensate error by means of the tarry, although a certain error in this case nevertheless remains. The length of the segments of interpolation can be calculated, if the operating speed of machine tool is known. With the use of a feed range of 200 pulses per minute and the temporary discretion 3 s linear segment or chord are 0,25 mm (0,010"). This index - high speed operation, characteristic for the most popular European high-speed systems for control.

  However, the very high-speed industrial systems for control demonstrate speed on the order of 400 s (0,0004 s). An increase in the speed 7,5 times ensures as a result the chord length of segment into 35 m (Fig. 2).

Fig. 2. Control with the speed in 3 ms ensures the value of the chord of segment in 0,25 mm during the supplying of 5 000 mm/min. With higher-speed UCHPU with the speed in 0,4 ms during the same supply is ensured smoother arc with the segment of altogether only 35 m: 1 - error in the chord of the segment.

  The more precise outline of the processed surface independently of its size is the obvious advantage of this increase. An increase in the accuracy is less obvious advantage with shortening of cycle time. The doubling of speed gives as a result a fourfold increase in the accuracy. The almost 10-fold jump of speed with 3 ms to 0,4 ms, theoretically increases it approximately 56. With the complex working of outline stringent requirement for UCHPU - this is smooth motion from point to point from that moment, when program CAD-CAM generates the large mass of the individual trajectories of tool with very short linear steps between them. The higher the speed UCHPU, the more rapidly move the tool and, correspondingly, the higher the rate of working.

  With the working with UCHPU there is always a need for forcing cutting tools to make precision details, but it is not simple rapidly to be moved. In the most extraordinary cases, processing sharp angle, for example, more high speed CHPU "stops" thinner. Work with the rarer stoppages during the continuation of cutting not only makes it possible to make a detail more rapidly, but also prolongs the period of the service of tool and increases its productivity, because this tool less is blunted. Although the majority of producers do not want so that the surfaces of details would be superfluous smooth, which worsens their quality, nevertheless as a result of smoother displacements rises the accuracy of processing and the period of the service of machine tool is prolonged. "Рrognostication" is key to the realization of this important function (Fig. 3).

Fig. 3. Prognostic analysis of the geometry of the cutting edge of cutter for obtaining the correct profile of the detail: 1 - direction of supply; 2 - real result; 3 - moved away material; 4 - calculated surface; 5 - profile of detail; 6 - profile of the cutting (central line) tool; 0.10' ' = 2,5 mm.

  Prognostication also can lead to the confusion, at least because this is - two-step process. During the first stage of milling plane in two coordinates (two-coordinate milling) with the compensation for radius/diameter of cutter with the use of codes G41 for the compensation to the left and G42 for the compensation to the right preliminarily analyze the geometry of the front surface of cutter in order to avoid the distortions of cutting tool in the section and to ensure obtaining the drive circuit of detail. In the second stage the advances analyze over their deviation from the current predetermined trajectory. They are evaluated, taking into account the programmed value of supply and the productivity of machine tool. Supply then is regulated for each segment of displacement in order to guarantee optimum speed and accuracy. Depending on one or other totality or another of characteristics UCHPU the forecast or geometric comprehension can widely vary on the productivity and the effectiveness.

  Concept can be complicated and its fulfillment for the producer OF UCHPU is hindered. In some practical cases this second stage is not important, but for the high-speed machining of network circuits forecast can be the most important element, which ensures the association of the speed and accuracy in one computer UCHPU. Prognostication becomes basis for the high-speed working because of the high density of the massif of data. With the use of old, slower models UCHPU the knots of machine tool move sufficiently slowly, why displacements along the axes can be stopped in the limits of any single block. On the new machine tools with the speed of displacement it is main into several ten it is meter per minute by them it is required great distance in order to stop. And with the dense, sequential displacements, required for achievement of high accuracy with working of network circuits, it is now and then difficult to calculate time or distance to the stoppage along the axis in order to obtain the necessary accuracy. This can sound in the manner that if forecast decreased productivity, after endowing by supply, in order to ensure accuracy. Or vice versa, this is - the optimization of productivity. The same forecast, which "slowed down" program UCHPU for treating the sharp it was angular, at the same time preserves the highest speeds of displacements over the coordinates with less radical changes in the direction of motion.

  Where you, possibly, forced were to select slower supplies with the programming in order to mill network circuit, effective forecast will help you to optimize the programmed supply for the concrete cutter and in accordance with the workable material and will allow UCHPU to make decisions about that, where it must be slowed down. Idea lies in the fact that the forecast attempts to improve situation, assigning the rate of the programmed feed and without imperiling in this case the accuracy of displacement. An increase in the continuous or effective supply to the average level, supported during entire process of processing, is result. Regardless of the fact, how is high speed UCHPU, the actual time of milling because of the physical limitations in the acceleration cannot coincide with the theoretical time of cutting, obtained by means of programs CAD/CAM. The degree of approximation of the actual time of working to theoretical is the result of the supply constantly supported at the assigned level. The nearer it will be to the programmed rate of feed, the higher the productivity and the durability of cutting tool will be!