About Post-Processing

For a general understanding of how post-processing works, it is important to first discuss the software that is used to create the specific files associated with, or needed for post-processing.

Computer Aided Drafting And Design (CAD)

The first software application that is used in the post-processing journey is Computer Aided Drafting and Design (CAD). A design engineer uses CAD software to create a part drawing, containing all features and dimensions required to manufacture a part. Some of the more common drawing file extensions are IGES, DXF and STEP to name a few.

Computer Aided Manufacturing (CAM)

Computer Aided Manufacturing (CAM) evolved from the need to manufacture parts using numerically controlled machine tools. Once the CAD model is complete, it can be imported into the CAM software for further use. Using the various functions within the CAM software, the programmer selects various lines, circles, surfaces or other entities from the CAD model and then develops cutting sequences, or tool paths, that simulate actual machining of those entities.

Cutter Location File (CL file)

For most CAM applications, the tool path that is generated for each cutting sequence is placed into a file in a specific order and syntax, almost like a structured language. This file is called a Cutter Location Data (CLDATA) File, or CL file for short. It contains various APT-like commands, as well as XYZ coordinate values. To control machines with rotary axes, it also contains tool vector IJK values used to determine the angle of the tool in relation to the part. APT, CL, CLD, CLS, NCI and NCL are some of the more common CL file extensions you might see.

Post-Processing and the CL file

The most important file required by Icam Post GENER is the previously discussed CL file. GENER reads each statement or command contained within the CL file and post-processes or translates each of those statements or commands into CNC machine code. This CNC machine code (also referred to as G-Code output) is created based on the content of the CL file and in combination with the settings within the QUEST post-processor file.

When a command from the CL file is incorrect, or certain settings have not been selected in the QUEST post-processor file, GENER will output error messages indicating that it either does not recognize a particular CL file statement or command, or that it cannot create output because a particular function has not been selected in QUEST. It is important to understand that GENER will always output correct G-code as long as the CL file statements and syntax are correct.