Page 200 - Mechanical Engineer's Data Handbook

188 MECHANICAL ENGINEER’S DATA HANDBOOK

Metal removal rate in milling

Metal removal rate
Material being cut (mm3 kW-’min-’)

Mild steel 18 900
Alloy steel 10 500
Cast steel 12 600
Grey cast iron 12 600
Stainless steel 8400
Copper 18900
Aluminium 42 OOO
Magnesium 42 OOO
Titanium 10 500

5.5 Grinding

5.5. I Grinding machines

Grinding machines produce flat, cylindrical and other
surfaces by means of high-speed rotating abrasive
wheels. Grinding is a means of giving a more accurate
finish to a part already machined, but is also a
machining process in its own right. The main types of
machine are: the ‘surface grinding machine’ for flat
surfaces; and the ‘cylindrical grinding machine’ for
cylindrical surfaces. More complex shapes are pro- -
duced by shaped wheels called ‘contour grinding
wheels’. ‘Bench’ and ‘pedestal’ grinders are used for . .-
tool sharpening, etc.
5.5.2 Grinding wheels
Standard grinding wheel
Typical materials for wheels are bonded abrasive
powders such as aluminium oxide (A1203), silicon
carbide (Sic) and diamond dust.

Contour grinding wheels Steel Heel coated with abrasive