İhsan Gökhan Serin - 503111309 - 2nd Week's Unanswered Terms

Turret ( Device )

Previous Answer:

Unlike machining centers, CNC lathe do not have a magazine that can hold dozens or even hundreds of tools. Lathe tools are placed into a turret, which can usually hold eight, ten, twelve or fourteen tools, depending on the size of the machine.
Turret is designed in such a way that it can hold all three types of lathe tools- external tools, internal tools, and tools that are used only at the machine centerline.
The arrangement of tools is very flexible in order to provide the best combination for any machining job. Both right hand and left hand tools can be setup in the turret.
(Smid P. , CNC control setup milling and turning, p152)

New Answer: (Better)

Turrets are the indexable tool posts on many CNC Turning machines. Tools and Toolholders are mounted in Turrets. When a tool change is required, the Turret indexes to the required position, enabling the desired tool to be in the correct position to machine the next operation. Turrets are designed in “octagonel drums” (8 tool positions), “dodecagonal durms” (12 tool positions), and other combinations, allowing workpieces to be machined with as many tools as possible in one part clamping. Most important of all the dimensions entered for the working environment is the dimension for the longest and largest tool mounted on the Turret. When the Turret is indexing, assurance that every tool has clearance of all components in the work area is a priority. See Figure 3.15.

(James Madison, CNC Machining Handbook, pg  39,44)

Chuck ( Device ) 

Previous Answer:

Universal and independent chuks are used to hold the workpiece while it is being machined.

The jaws of a 3-way jaw chuck can be simultaneously moved an equal distance toward or away from the center, by turning a chuck key.

Because the 3-way chucks has one less jaw, it cannot grip the workpiece as tightly as 4-way jaw chuck. This type of chuck is best used for holding round stock. Another advantage of a 4-way jaw chuck is that the four jaws can be adjusted independently of each other. A workpiece that is either square,cylindirical or of irregular contour can be held securely and centered accurately.

(Harold V. Johnson, Manufacturing Process 2nd Edition, pg.262-263)

New Answer: (Better)

The chuck, Figure 22.8 (b), is available in several designs, with three or four jaws to grasp the cylindrical work part on its outside diameter. The jaws are often designed so they can also grasp the inside diameter of a tubular part. A self-centering chuck has a mechanism to move yhe jaws in or out simultaneously, thus centering the work at the spindle axis. Other chucks allow independent operation of each jaw. Chucks can be used with or without a tailstock center. For parts with low length-to-diameter ratios, holding the part in the chuck in a cantilever fashion is usually sufficient to withstand the cutting forces for long workbars, the tailstock center is needed for support.

(Mikell P. Groover,  Fundamentals of Modern Manufactuing, pg 506-507)