TABLE OF CONTENTS In a typical CNC lathe work, it is not unusual in fact, it is quite common to fully complete machining of the required part by clamping it more than once. CNC machine shops are used to a certain terminology when it comes to this type of machining. The main objective is to focus on the difference between reversing the part in the same setup and having two separate setups. For the purposes of this chapter, two terms will be used, with the following meaning:
First chucking / Second chucking ... one setup part is reversed in the middle of program
First operation / Second operation ... two setups only a portion of the program is completed
These are by no means firmly established terms, but they are used in CNC machine shops quite frequently, even if the local meaning may be a bit unclear. Using these terms in this chapter with a specific definition should make it easier to distinguish between the two different types of machining.
On the basic level, there are two types of jaws for CNC lathes hard jaws and soft jaws. As the material they are made of indicates, hard jaws are generally used for roughing and semifinishing toolpaths, whereby soft jaws are used for semifinishing and finishing toolpaths. Because of their hard material, hard jaws will bite into the material and, in many cases, leave a physical mark on the part diameter, as they are mainly used...
