The cutting conditions will affect the value of this surface speed for mild steel. A cutting speed for mild steel of 100 ft/min is the same whether it is the speed of the cutter passing over the workpiece, such as in a turning operation, or the speed of the cutter moving past a workpiece, such as in a milling operation. 5 Interrelationship of theory and practiceĬutting speed may be defined as the rate at the workpiece surface, irrespective of the machining operation used.The phrases "speeds and feeds" or "feeds and speeds" have sometimes been used metaphorically to refer to the execution details of a plan, which only skilled technicians (as opposed to designers or managers) would know. In practice, lack of rigidity is usually the limiting constraint. Of course, in reality those other variables are dynamic and not negligible, but there is still a correlation between power available and feeds and speeds employed.
If variables such as cutter geometry and the rigidity of the machine tool and its tooling setup could be ideally maximized (and reduced to negligible constants), then only a lack of power (that is, kilowatts or horsepower) available to the spindle would prevent the use of the maximum possible speeds and feeds for any given workpiece material and cutter material.
When the workpiece does not rotate ( e.g., in milling), the units are typically distance per time (inches per minute or millimeters per minute ), although distance per revolution or per cutter tooth are also sometimes used. Feed rate units depend on the motion of the tool and workpiece when the workpiece rotates ( e.g., in turning and boring), the units are almost always distance per spindle revolution (inches per revolution or millimeters per revolution ). Feed rate (also often styled as a solid compound, feedrate, or called simply feed) is the relative velocity at which the cutter is advanced along the workpiece its vector is perpendicular to the vector of cutting speed. It is expressed in units of distance across the workpiece surface per unit of time, typically surface feet per minute (sfm) or meters per minute (m/min). Each, however, can also be considered and analyzed in its own right.Ĭutting speed (also called surface speed or simply speed) is the speed difference ( relative velocity) between the cutting tool and the surface of the workpiece it is operating on. They are often considered as a pair because of their combined effect on the cutting process. The phrase speeds and feeds or feeds and speeds refers to two separate velocities in machine tool practice, cutting speed and feed rate. This velocity is called the "feed" by machinists. The arrow colinear with the slot that has been milled represents the linear velocity at which the cutter is advanced laterally (usually mm/min or inch/min for milling may also be measured as mm/rev or inch/rev). The tangential arrow represents the tangential linear velocity (m/min or sfm) at the outer diameter of the cutter, called the "cutting speed", "surface speed", or simply the "speed" by machinists. The circular arrow represents the angular velocity of the spindle (rev/min), called the "spindle speed" by machinists. Arrows show the vectors of various velocities collectively known as speeds and feeds. Milling cutter paused after taking a cut.
0 kommentar(er)
