Programming instructions
 ADT-CNC4620 Programming Manual 
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4. CNC Process Knowledge 
1.  What is the content of CNC programming? 
A: Analyze part drawing, determine process and path, calculate the coordinates of tool track, write 
processing program, enter programs into CNC system, check the program, cut for testing, etc. 
2.  What is the objective of CNC processing analysis? And the content? 
A: To process parts on the CNC machine tool, it is required to analyze and treat the process 
according to part drawing, create CNC process, and then prepare processing program. The entire 
process is automatic. The content includes machine tool cutting amount, work step arrangement, 
feeding path, processing margin, tool size and model, etc.  
3.  What is tool setting point? What is the influence of tool setting point selection to programming? 
A: Tool setting point is the start point of the tool relative to workpiece motion during CNC 
processing. This start point is also the program start of programming. If the tool setting point is 
selected properly, it is convenient for mathematic processing and programming; easy to align on the 
machine tool; convenient for checking and reduce processing error during processing.  
4.  What are machine tool coordinate system and workpiece coordinate system? And their 
differences? 
A: Machine tool coordinate system is also called mechanical coordinate system, which is the 
feeding coordinate system of the moving parts of the machine tool, and the coordinate axes and 
direction are standard. The coordinate origin is set by the manufacturer, and is called machine tool 
(or part) origin. Workpiece coordinate system is calso called as programming coordinate system, 
which is used for programming.  
5.  Please simply describe the tool position, tool change point and workpiece coordinate origin. 
A: Tool position point is the reference point to confirm the tool position. If the CNC machine tool 
with multi-tool processing needs to change tool during processing, it is also required to set a tool 
change point during programming. Tool change point is the reference point to change tool position. 
The positions of tool change points shouldn’t interfere with each other. The origin of workpiece 
coordinate system is also workpiece home or programming home; the position is set by the 
programmer at the design and process reference position of the workpiece for size calculation.  
6.  What is the effect of tool compensation and what are compensation instructions? 
A: Tool compensation usually includes length compensation and radius compensation. Tool length 
compensation can be tool length compensation or position compensation. With tool radius 
compensation: execute roughing and finishing with the tool of same program and same size; 
program with part profile directly to avoid calculating tool center track; if the diameter is changed 
due to tool abrasion or change, it doesn’t need to modify the program, and only needs to enter the 
value of tool radius change in tool parameter setting state; with tool compensation function, use 
same program to process the internal and external profiles of same nominal size.  
7.  What is separated roughing and finishing? And the advantages? 
A: When determine the part processing flow, the roughing and finishing should be executed 
separately, execute the finishing after the roughing of every surface, and do not execute both 
roughing and finishing on the machine tool, which is called separated roughing and finishing. This 










