When CNC machining is performed in a cnc machining center, due to tool wear, regrinding, or replacement of a new tool, the parameters of the tool in the programmed machining program will change, and its tool trajectory will change. If it is not adjusted in time, it will affect the workpiece Final machining accuracy. For example, recalculate the tool trajectory and modify the program. This is not only time consuming and laborious, but also has a very high error rate. The most convenient method is to call the tool radius compensation function of the CNC system. When programming the workpiece, we only need to compile a machining program based on the contour of the workpiece. The system will automatically calculate the tool center trajectory to make the tool deviate. A radius value of the workpiece contour. Even when the tool parameters change, only the specific tool parameters need to be changed, and there is no need to change the entire cnc machining program. This greatly improves the machining efficiency of the machining center.
Creation and cancellation of tool radius compensation
In simple terms, tool radius compensation is divided into two types: tool radius left compensation and right compensation. Defined by G41 and G42 respectively. When the tool center track is located to the right of the part contour along the tool forward direction, it is called the right compensation of the tool radius; otherwise it is called the left compensation of the tool radius.
1.The establishment of tool radius compensation
The establishment of tool radius compensation is a process in which the tool center path transitions from coincidence with the programmed path to a deviation from the programmed path when the tool approaches the workpiece at the feed rate from the starting point. Tool radius left compensation is performed by G41; tool radius right compensation is performed by G42.
2.Cancellation of tool radius compensation
The cancellation of tool radius compensation is similar to the process of establishing tool radius compensation. After the last segment of the tool radius compensation trajectory is processed, the tool is evacuated from the workpiece and returned to the retract point. In this process, the tool radius compensation should be cancelled. The command is G40. Define it. The retraction point should also be located outside the part contour, which is closer to the exit point of the contour of the machined part. It can be the same as the starting point, but it can also be different.
Precautions when inputting Cnc machining tool radius compensation
The change of the tool radius compensation amount generally appears after cnc machining the machining center for a period of time. For continuous blocks, when the tool radius compensation amount changes, the vector at the end of a block must be calculated with the tool compensation amount specified by the block.
When programming the NC program, we generally enter the tool radius compensation amount as a positive value in the compensation code. If the tool radius compensation amount is set to a negative value, it is equivalent if the direction of the tool path is unchanged. In order to interchange the compensation position command in the NC program with G41 and G42, there may be unexpected problems when the machining center originally processes the outside of the workpiece into the inside, so unexpected problems must be observed when entering the radius compensation. Set of directions.