Basic functions of CNC lathe
the basic functions of CNC lathe include preparation function (g function), auxiliary function (m function), feed function (F function), tool function (t function) and spindle function (s function)
2.2.1 preparation function (G function)
preparation function is also called G function (or G code), which is a command used to command the working mode of lathe or control the working mode of system, The G function consists of the address symbol g and the following two digits (00-99). There are 100 functions from G00 to G99, which are used to command different actions of the machine tool, such as using G01 to command the straight-line learning of the motion coordinates
g codes can be divided into single g codes and modal g codes. Single g codes are only valid in the commanded program segment, while modal g codes are valid until the same group of G codes appear
at present, ISO code is widely used in CNC lathe G code at home and abroad, but its standardization degree is not high, and there are few designated function codes, which refer to (codes that cannot be used for other functions), and there are many non CNC system G code functions that do not specify a generation '' (codes that may specify other functions in the future) and never specify a code (codes that do not specify their functions in the future) are not consistent, This makes the programming of different CNC systems quite different, so it must be used according to the specific provisions of the manual of the CNC system used. This paper introduces that the programming of gsk928ta and GSK980T has great differences in G function. See the programming introduction in Chapter 4 for details
2.2.2 tool function (t function)
tool function is also called t function, which is used to command the address word of tool number and automatic compensation group number used in machining. Its automatic compensation content mainly refers to the tool position deviation and tool radius compensation of the tool. In the numerical control lathe, the subsequent digits of the address character t mainly have the following two provisions
① two digit regulation, such as the economic CNC system of gsk928ta introduced in this book, adopts the two digit regulation: the first digit generally represents the tool number, usually 0~8, a total of 9 digits, of which 0 represents no tool rotation, the last digit represents the grouping number of tool compensation, usually 0-8, a total of 9 digits, of which 0 represents zero compensation. Example: T23 means turning tool 2 to the cutting position and implementing the provisions of the third group of tool compensation value
② four digits: for CNC lathes or turning centers with more tools, the NC system generally stipulates that the subsequent digits are four digits, the first two digits are the tool number, and the last two digits are the formation number of tool compensation or the formation number of sharp arc radius compensation, which is the tool while the new energy number is "whatever it takes". For example, the GSK980T system introduced in this book adopts the four digit rule. However, the maximum number of tools that the system can provide can only be set to 8
example: t0203 means turning No. 2 to the cutting position and executing the third group of tool compensation values
2.2.3 spindle function (s function)
spindle speed refers to the function used to clamp different types of harness commands. It is represented by the address s and the numbers behind it. At present, there are S2 (two digits) and S4 (four digits) representations, namely sxX and Sxxx. General economic CNC lathes generally use one or two agreed codes to control the high-speed and low-speed of a certain gear of the spindle. For CNC lathes with stepless speed regulation function, Then the given rotation speed (r/min) of the main axis that will also affect the structure and function of the soil ecosystem can be directly expressed by the subsequent numbers. In addition, for the NC lathe with constant linear speed cutting function, the s command in its processing program can command the constant rotation speed r/min, or the constant linear speed (M/min) during turning, that is, when turning, its spindle rotation speed will automatically change with the change of turning diameter, Always keep the linear speed at a given constant value
① s two digits: domestic CNC lathes are generally represented by a code agreed by one or two digits. The gsk928ta CNC system introduced in this paper corresponds to the 6-level spindle mechanical shift provided by the machine tool (each gear is high, pay attention to the speed and low speed required by the maximum input limit of the instrument). S1 specifies high speed, S2 specifies low speed, and M code specifies the spindle rotation direction, m3 forward rotation, M4 reverse rotation, high speed here, Low speed is only relative to a certain mechanical gear of the machine tool
② four digits of S: use address s and the following four digits to directly command the number of revolutions (RPM) of the axis. For example, s1200 indicates that the constant speed of the spindle is 1200 revolutions per minute. For the numerical control system with the constant linear speed control function, the linear speed behind s is constant. With the change of turning diameter, the spindle speed is calculated according to the given linear speed, so that the instantaneous position of the tool maintains a constant relationship with the workpiece surface. Use G96 (constant linear speed control command) and g97 (specify spindle speed) to cooperate with s code to specify the speed of spindle
example: g96s18 indicates that the cutting speed is 18 meters/minute
g97s1200 indicates that the spindle speed of G96 is 1200 rpm
the use of specific spindle functions also requires the instructions of the parameter control system
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