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Cutting speed may be defined as the rate at the workpiece surface, irrespective of the machining operation used. 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.
SFM is a combination of diameter and the velocity of the material measured in feet-per-minute as the spindle of a milling machine or lathe. 1 SFM equals 0.00508 surface meter per second (meter per second, or m/s, is the SI unit of speed). The faster the spindle turns, and/or the larger the diameter, the higher the SFM.
The machinability rating is determined by measuring the weighted averages of the normal cutting speed, surface finish, and tool life for each material. [9] Note that a material with a machinability rating less than 100% would be more difficult to machine than B1112 and material with a value more than 100% would be easier.
Surface cutting speed (V c) This is the speed at which each tooth cuts through the material as the tool spins. This is measured either in metres per minute in metric countries, or surface feet per minute (SFM) in America. Typical values for cutting speed are 10m/min to 60m/min for some steels, and 100m/min and 600m/min for aluminum.
The result was a heat treatment process that transformed existing alloys into a new kind of steel that could retain its hardness at higher temperatures, allowing cutting speed to be tripled from 30 surface feet per minute to 90. A demonstration of cutting tools made from the new steel caused a sensation at the 1900 Paris Exhibition. [5]: 200
I had proposed that the article currently titled Surface feet per minute be merged into the "#Cutting speed" section of Speeds and feeds. My reasoning was that cutting speed along the workpiece surface is the underlying concept that is being treated, and the units of measurement (sfm or m/min, inch or metric, G20 or G21) are secondary.
The tolerances that are normally achieved with surface grinding are ±2 × 10 −4 inches (5.1 μm) for grinding a flat material and ±3 × 10 −4 inches (7.6 μm) for a parallel surface. [4] The surface grinder is composed of an abrasive wheel, a workholding device known as a chuck, either electromagnetic or vacuum, and a reciprocating table.
Pressurized electrolyte is injected at a set temperature into the area being cut, at a feedrate equal to the rate of "liquefication" of the anode material. The gap between the tool and the workpiece varies within 80–800 micrometers (0.003–0.030 in.) [ 1 ] As electrons cross the gap between the tool and workpiece, material from the workpiece ...