Kinematics and productivity are described by formulas showing relationships between various parameters, which are required to setup turning operations. Kinematics and productivity include:
Cutting speed
Spindle speed
Feed rate and feed speed
Depth of cut
Metal removal rate
Machining time when cutting along the workpiece centerline
Machining time when facing, cutting off, and deep grooving.
Cutting speed is one of the most commonly used programmable parameters for CNC lathes. The relationship between cutting speed V c (dependent variable), machine tool spindle speed n (independent variable), and the workpiece diameter D (independent variable) is expressed by formulas,
Customary U.S. units of measure:
| (3.1) |  |
Where D is in inches, n is in rpm or rev/min, 12 is a factor converting inches into feet.
Metric units of measure:
| (3.2) |  |
Where D is in millimeters (mm) and 1000 is a factor converting mm into meters (m).
For example, D = 3.0 in. (76.2 mm) and n = 670 rpm (rev/min). What is V c?
From formula (3.1): The cutting speed
From formula (3.2): The cutting speed
If the cutting speed V c (sfm or m/min) and the workpiece diameter D (in. or mm) are independent variables, then the formula for spindle speed n (rpm or rev/min) can be derived from formulas (3.1) and (3.2),
Customary U.S. units of measure:
| (3.3) |  |
For example, V c = 526 sfm and D =...
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