Superfinishing Machines
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Superfinishing Machines
Superfinishing Machines - Fig shows a machine for surer finishing cylindrical work pieces.
Superfinishing Machine
| 1 - Head Stock | 3 - Holders |
| 2 - Dog Drive plate | 4 - Tailstock |
The workpiece is mounted between the centres of bead stock 1 and tailstock 4. The workpiece receives rotation from dog drive plate 2, as is done in a common lathe. The abrasive stones or blocks or sticks are clamped in special holders 3, to which an axial reciprocating movement is imparted along the workpiece surface,
This movement is effected by means of a hydraulic drive, which also serves to advance the abrasive blocks to the workpiece and press them slightly to the surface being finished, There is a separate electric motor to provide the abrasive blocks with the oscillating movement in special guideways by means of an eccentric.
Movements in Superfinishing of Shaft
| A - Reciprocating of abrasive block | B - Oscillation of abrasive Block | C - Rotation of Work piece |
Movements in Superfinishing of Internal Surface
| A - Reciprocating of abrasive block | B - Oscillation of abrasive Block | C - Rotation of Work piece |
Movements in Superfinishing of Flat Surface
| A - Oscillation of abrasive Block | C - Rotation of Work piece |
| B - Rotation of abrasive block | D - Oscillation of work piece |
Rotational speed of the work piece is 2 to 20 m/mill longitudinal feed rate 0'1 to 0'15 mm per revolution. Frequency of oscillation of abrasive blocks 5001800 per min.Superfinishing is done with abrasive blocks accomplishing oscillating and reciprocating movements with a high frequency and small amplitude along the surface of the rotating workpiece.
Soft onegram loosely bonded abrasive sticks are pressed in operation to the work surface by means of springs or a hydraulic device. A mixture of kerosene and oil is used as the cutting fluid.The machining allowance is not assigned since the process of superfinishing consists in removing the microirregularities remaining after the previous machining operations.
When these peaks of irregularities on the work surface are cut away by the abrasive sticks (during superfinishing operation), applied with a controlled pressure; and when a certain degree of smoothness is achieved, the controlled viscosity lubrication establishes a continuous lubricating film between the abrasive stone and the workpiece and separates them so that no further cutting action occurs and the process of stock removal ceases automatically, Thus with a given pressure lubricant, and the abrasive stone, each workpiece can be finished to the same degree of smoothness.
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