Explain how cutter compensation (G41/G42) functions when machining an internal profile with a tool diameter smaller than the profile width.

Cutter compensation (G41/G42) is used when machining an internal profile with a tool diameter smaller than the profile width to ensure the finished part dimensions match the programmed dimensions. Without cutter compensation, the toolpath would need to be manually offset by the radius of the cutter, which is time-consuming and prone to errors. G41 activates cutter compensation to the left of the programmed path, while G42 activates cutter compensation to the right. When machining an internal profile, such as a pocket, G42 is typically used. The CNC control system automatically adjusts the toolpath so that the center of the cutter is offset from the programmed profile by an amount equal to the cutter radius. This ensures that the edge of the cutter follows the programmed profile exactly. Before activating cutter compensation, the tool diameter must be accurately entered into the tool offset table of the CNC control. When the G41 or G42 code is encountered in the CNC program, the control system retrieves the tool diameter from the offset table and calculates the necessary offset. It's important to note that cutter compensation is typically activated and deactivated using G40 (cutter compensation cancel) at a lead-in and lead-out point away from the actual profile to avoid gouging the part. For example, if you are milling a rectangular pocket and using G42, the tool path is adjusted outward so that the cutter's edge creates the correct inside dimensions of the rectangle. The programmed coordinates represent the *desiredshape, while the *actualtool movement is offset to account for the tool's size.