Diamond Fine Boring Machines

Diamond Fine Boring Machines

Diamond Fine Boring Machines - The term Diamond boring, or fine boring or precision boring is applied particularly to the boring of holes on machines designed for high speeds, using carbide or diamond boring tools, Light cuts and fine feeds are employed in precision boring and to obtain the best results, the cutting edge must be lapped to a high polish, so that there will be no grinding: marks on the cutting edge. A high degree of accuracy is obtained in boring holes in parts made of bronze, aluminium, bakelite, copper etc.

Precision boring machines are used for boring of automobile and airplane engine cylinders. The general practice is to precision bore a cylinder and then finishes it by honing.

Diamond boring machines are used for

(i) fine boring of accurate cylindrical and taper holes

(ii) turning and

(iii) facing operations.

Precision boring machines may have either vertical or horizontal spindles. In automotive cylinder boring, the general practice is to use a machine having parallel spindles equaling the number of bores in the cylinder casting.

These spindles are fixed at the required center distance and all of the holes are bored simultaneously.

Shows diamond boring machines.

Vertical Diamond Boring Machine

Horizontal Diamond Boring Machine

Table width may vary from 320 to 800 mm.

Cutting speeds of 150-300 m/min.

Feed rate 0.0-0.1 mm/revolution.

Depth of cut 0.1- 0.3 mm.

Geometrical accuracy of machined holes of 100-200 mm in diameter is 0.01-0.005 mm.

Vertical single spindle machines have a divided drive for the principal movement, i.e., the spindle is rotated from the speed gearbox through a belt drive.

In high precision horizontal machines, there is no speed gearbox, and the drive motor is installed separately from the machine, transmitting rotation to the boring spindles through a belt drive only.

The feed movement in vertical single spindle machines is imparted to the spindle and in horizontal single and double end machine to the table, carrying a work fixture. The table is imparted a complex succession of work and rapid traverse movement, advancing the workpiece being machined to one set of spindle heads and then to the other, opposite, set. In special diamond boring machines, the feed movement is imparted to the spindle heads, while the workpiece remains stationary. A hydraulic drive, providing stepless feed variation, is most commonly used.