General roughing 0.8 mm, semi-finishing 0.4 mm, finishing 0.2 mm.
Introduction of tool radius compensation
CNC machine tools in the process of machining, it is the control of the tool center trajectory, for the sake of convenience, the user is always according to the contour of the part to prepare machining programs, and thus in order to process the desired contour of the part, the tool center must be offset to the inside of the part by a tool radius value; in the outer contour machining, the tool center must be offset to the outside of the part by a tool radius value. In order to process the desired contour of the part, the tool center must be offset to the inside of the part a tool radius value; in the outer contour processing, the tool center must be offset to the outside of the part a tool radius value. As shown in Figure 3-25. This according to the program prepared by the contour of the part and pre-set offset parameters, the CNC device can automatically generate real-time tool center trajectory function is called tool radius compensation function. In the figure, the solid line is the contour of the part to be machined, and the dotted line is the tool center trajectory. According to ISO standards, when the tool center trajectory in the programming track (part contour) in the forward direction of the right, known as the right tool complement, with the G42 instruction to achieve; vice versa, known as the left tool complement, with the G41 instruction to achieve.
Main use
(1) Due to tool wear or tool radius change caused by tool change, do not have to reprogramming, just modify the corresponding offset parameters can be.
(2) The reservation of machining allowance can be realized by modifying the offset parameter, instead of having to prepare a program for roughing and finishing.
Commonly used methods
(A) B tool complement
Features: tool center track of the segments are connected to the transition arc.
Advantages:Algorithm is simple, easy to implement.
Disadvantages:
(1) When machining the outer contour, the tool always cuts at one point due to the circular arc connection, and the sharp corners of the outer contour are machined into small rounded corners.
(2) the inner contour machining, the programmer must be added by an auxiliary transition arc, and must ensure that the transition arc radius is greater than the tool radius. This: one is to increase the difficulty of programming; second, a little negligence, the transition arc radius is smaller than the tool radius, will be due to tool interference and overcutting, so that the processed parts scrap.
(ii) C tool patch
Features: tool center track segments using a straight line connection between the transition. Direct real-time automatic calculation of the tool center track transfer intersection.
Advantages:Sharp corners of good workmanship; in the processing of the inner contour, can realize the overcutting automatic forecast.
The difference between the two kinds of tool mending in the processing method:
B tool mending adopts the processing method of reading a section, calculating a section and walking a section. Therefore, it is not possible to anticipate the effect of the next section of the trajectory caused by the tool radius on this section of the trajectory.
C tool mending adopts the method of processing two segments at a time. First, the segment is processed, and then the next segment is used to determine the transition state between the segments of the tool center trajectory, so as to complete the processing of this segment of the knife mending operation.
Parameters and settings
(1) Tip radius After compensating for the size of the tip radius, the tool will automatically deviate from the radius distance of the part contour. Therefore, the tip radius size must be entered into the system's memory. General roughing 0.8 mm, semi-finishing 0.4 mm, finishing 0.2 mm.
(2) the shape and position of the tool The shape of the tool is different, the decision of the tip of the arc is located in a different position, the implementation of tool compensation, the tool will automatically deviate from the direction of the part contour is also different. Therefore, the parameters representing the shape and position of the turning tool should also be entered into the memory.
Significance
Tool tip arc radius compensation greatly improves the numerical accuracy of the workpiece during machining of the workpiece on a CNC lathe. It is much simpler and easier to write the program and saves a lot of time. Production of the same specification workpiece, the use of tool position compensation of the production enterprise can save more time, for the strengthening of enterprise competition is particularly important. Zhuzhou Cemented Carbide Group, as the leader of China's cutting tool enterprises in this regard has been doing a good job, by advancing with the times, the introduction of the most advanced technology to overcome the problems in the production of production, the production efficiency increased by several times. Tool compensation in CNC lathes reduces manpower and material resources and brings great benefits to shop floor management. Simplified programs help the tool to produce consistent workpieces despite wear.