Productivity in Grinding - Increase in Material Removal Rate

DEVELOPMENTS IN PRODUCTIVITY

1915 Guest
It appears to be accepted that the work surface speed is the controlling feature.

Formerly it was the practice to run work at surface speeds from 150 feet per minute upwards to twice that amount or more. To-day the speeds used are much lower, but are very varied, some authorities advocating speeds from 10 to 20 and others from 60 to 70 feet per minute. The intermediate
portion of that extreme range is that which is most usually used. 

The following firms, who manufacture and use grinding machines, recommend the work surface speeds given

AUTHORITY                     WORK SURFACE SPEED

                                       IN FEET PER MINUTE.

Brown & Sharpe                      35-65

The Churchill Tool Co., Ltd.        35-70

Greenwood & Batley                  25

Alfred Herbert, Ltd. (Mr. Darby shire) 25

The Landis Tool Co.                  25


Where a different work speed can be used for finishing it should be higher than for the roughing out ; from 25 to 75 per cent, increase is reasonable. A still more may frequently be used with advantage and without introducing troubles from vibration. With this view  most authorities agree, but some  like Mr. Darbyshire, of Messrs.. Alfred Herbert's, and Mr. Edge, of the British Abrasive Wheel Co., among them advise a 25 per cent, reduction of the work speed for finishing.


2009
Huge increases in productivity have been achieved in grinding due to advances in grinding
wheel technology. The developments in wheel technology were supported by parallel developments in the machines and auxiliary equipment employed. Grinding wheels operated  at low wheel speeds in the early twentieth century. Now  advanced conventional abrasives and superabrasives operate at high wheel speeds.  Over this period, material removal rates have increased for some grinding
processes by a staggering 10 to 100 times.

GRINDING  WHEELS TREND TOWARD HIGHER SPEEDS

Vitrified CBN wheel speeds have risen significantly.  In 1980, 60 m/s was considered high speed; by 1990, 80 m/s was becoming common in production; by 1995, the speed reached 120 m/s; and then by 2000, the speed was 160 m/s. Further reports are available that  several machines for vitrified wheels are entering production for grinding cast iron at 200 m/s. Speeds of up to 500 m/s have been reported experimentally with plated CBN [Koenig and Ferlemann 1991].


Conventional vitrified bonded wheels generally default to a maximum wheel speed of 23 to 35
m/s depending on bond strength and wheel shape. Certain exceptions exist; thread and flute grinding
wheels tend to operate at 40 to 60 m/s and internal wheels up to 42 m/s. (A full list is given in
ANSIB7.1 2000 Table 23.)