When CNC machining is carried out in CNC machining center, due to tool wear, regrinding or replacement of new tools, the parameters of related tools in the programmed machining program will be changed, and the tool running path will be changed. If the adjustment is not enough, the final machining accuracy of the workpiece will be affected. For example, calculate the tool path from the beginning, and correct the program. In this way, it is not only time-consuming and laborious, but also has a high error rate. The most convenient way is to call the tool radius compensation performance of CNC system. When programming the workpiece, we only need to prepare the processing program according to the appearance of the workpiece. The system will automatically calculate the tool center path, so that the tool deviates from the appearance of the workpiece by a radius value. Even if the tool parameters are changed, only the detailed tool parameters need to be changed without changing the whole machining program. This greatly improves the machining efficiency of the machining center.
1、 Establishment and revocation of tool radius compensation
In short, tool radius compensation can be divided into left compensation and right compensation. Farewell is defined by G41 and G42. When the tool center track is located on the right side of the part appearance, it is called the tool radius right compensation; otherwise, it is called the tool radius left compensation.
1. The establishment of tool radius compensation
The establishment of tool radius compensation is a process that the tool center track changes from coincide with the programmed path to deviate from a tool radius value with the programmed path when the tool approaches the workpiece at the feed speed from the starting point. G41 is responsible for the left compensation of tool radius; G42 is responsible for the right compensation of tool radius.
2. Cancellation of tool radius compensation
The cancellation of tool radius compensation is the same as the process of creating tool radius compensation. After the final section of tool radius compensation path of the workpiece is processed, the tool withdraws the workpiece and returns to the withdrawal point. In this process, the tool radius compensation should be cancelled, and its instructions are defined by G40. The undercut point shall also be located outside the part appearance, and the undercut point of the parts machined at intervals shall be close to the undercut point, which may be the same as the undercut point, and of course may not be the same.
2、 Concerns in CNC machining tool radius compensation input
The change of tool radius compensation usually occurs after machining in machining center for a period of time. For a continuous program segment, when the tool radius compensation amount changes, the vector at the end of a program segment needs to be calculated with the tool compensation amount specified in the program segment.
In the process of NC programming, we usually input the compensation amount of the tool radius into the compensation code as a positive value. If the compensation amount of the tool radius is set as a negative value, under the condition that the target of the tool path is fixed, it is equivalent to exchanging the compensation position command in the NC program, G41 and G42. It is possible that the processing center originally processed the outside of the workpiece into the inside plus There are some unexpected problems, so we must pay attention to the configuration of two compensation targets when inputting radius compensation.