Cutting speed

The relative speed between the cutting tool and workpiece is known as the cutting speed and is expressed in metres per minute. In turning, the cutting speed is the surface speed of the work, i.e. the speed of a point on the circumference. In milling and drilling, it is the surface speed of the cutting tool. 

As an example, we shall find the cutting speed S of a workpiece of diameter d mm being turned at N rev/min as shown in Fig. 7.20. 

The distance travelled by a point on the circumference in one revolution = the circumference = n d mm. 

In one minute the workpiece turns through N revs, so the distance travelled by the same point in one minute = ndN mm/min. 

But cutting speed S is expressed in metres per minute, so, dividing by 1000, we get 

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Tool life tests are used to evaluate the effects of changes in tool materials, cutting variables, processing history, workpiece composition, or workpiece microstmcture. Tool life, T, and cutting speed, can be related by the following equation ... 

High Speed Steels. Toward the latter part of the nineteenth century, a new he at-treatment technique for tool steels was developed in the United States (3,17) that enabled increased metal removal rates and cutting speeds. This material was termed high speed steel (HSS) because it nearly doubled the then maximum cutting speeds of carbon—low alloy steels. Cemented carbides and ceramics have since surpassed the cutting speed capabiUties of HSS by 5—15 times. 

P (blue) ferrous metals with long chips POl Steel, steel castings finish turning and boring high cutting speeds small chip section accuracy of dimensions and ... 

Best cutting speed Corrosion effect of Drilling Milling... 

Schneider, m. cutter tailor. Schneld-fabigkeit,/. cutting quality, -flamme, /. cutting flame, -gescbwindigkeit, /. cutting speed. 

It machines in a similar manner to soft copper, and high-speed-steel tools with high cutting speeds are most satisfactory. Trichloroethane is recommended as a cutting medium and the work must be kept well flooded at all... 

An illustration of the impact that improved hardness has had on technology is presented in Figure 1.1. This shows the dramatic increase in performance of machine cutting tools (lathes, milling machines, saws, drills, and the like) as the tools became harder. It also shows how very fast cutting speeds have become. The top cutting speed (>5000 m/sec) is about 16% of the speed of sound in air ... 

Figure 1.1 Improvement in cutting speeds with tool hardness. During two centuries of development machine tool performance increased by a factor of about 5000. Adapted from Riedel, 2000, p. 550.

The authors have devised a new method of application that gives astonishing results. Instead of increase of tool life of 50 to maybe 150%—all they have hitherto been able to accomplish between different cutting liquids—increases of 500 to 800% at the same cutting speed are being obtained or the cutting speed can be doubled with the same life. 

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