Modern CNC systems have some specially designed functions to simplify the manual programming. However, since most of these functions are system oriented, it is not intended to discuss them here in detail. The following paragraphs give a brief description of commonly used functions in modern CNC system. The user should refer to the programming manuals of the machine for the detail programming and operation.
- Mirror Image
This is the function that convert the programmed path to its mirror image, which is identical in dimension but geometrical opposite about one or two axes
- Pocketing Cycle
Pocketing is common process in machining. This is to excavate the material within a boundary normally in zigzag path and layer by layer. in a pocketing cycle, the pattern of cutting is pre-determined. The user is required to input parameter including the length, width and depth of the pocket , tool path spacing, and layer depth. The CNC system will then automatically work out the tool path.
- Drilling, Borring, Reaming and Tapping cycle
This is similar to pocketing cycle. In this function, the drilling pattern is pre- determine by the CNC system. What the user has to do is to input the required parameter such as the total depth of the hole, the down feed depth, the relief heigth and the dwell time at the bottom of the hole.
- Programme repetition and Looping
in actual machining, it is not always possible to machine to the final dimension in one go. This function enables the looping of a portion of the programme so that the portion can be executed repeatedly.