Controllable magnetic field-assisted finishing apparatus for inner surface and method

A finishing method, the method being carried out by a controllable magnetic field-assisted finishing apparatus for an inner surface, the apparatus comprising:

• a housing;
• ball screw mechanisms;
• a workpiece;
• a centering clamp;
• a connecting plate;
• a magnetic field generating device;
• a chuck clamp;
• a displacement platform;
• and
• a base;
• wherein the magnetic field generating device comprises:
• electromagnetic coils;
• coil connecting plates;
• a magnetic yoke;
• nuts;
• springs and bolts;
• wherein:
• the magnetic field generating device is fixed through the connecting plate on one of the ball screw mechanisms that is located on a top of the housing;
• the magnetic yoke is fixedly connected to an end of each of the electromagnetic coils;
• the electromagnetic coils are fixedly connected to the coil connecting plates in one-to-one correspondence through corresponding ones of the bolts that are each mounted with the springs and the nuts;
• an end of the workpiece is fixed through the centering clamp;
• another end of the workpiece is clamped on the chuck clamp;
• and
• the centering clamp and the chuck clamp are fixedly connected to the displacement platform;
• wherein the method comprises:
• placing a magnetic finishing medium in a region, which is to be processed, of the inner surface of the workpiece;
• fixing the workpiece through the centering clamp and the chuck clamp, to complete localization and clamping;
• and attaching the magnetic field generating device to an outer surface of the workpiece through the springs;
• driving the magnetic field generating device by the one of the ball screw mechanisms to move to the region where the magnetic finishing medium is placed;
• operating the electromagnetic coils at a predetermined sequence, a predetermined current value and a predetermined frequency value, to generate a rotating magnetic field;
• and applying a finishing action force formed by the rotating magnetic field to the magnetic finishing medium;
• applying a drive signal to the chuck clamp and the displacement platform;
• performing a workpiece rotation;
• and making the displacement platform to perform a feed movement;
• implementing a relative movement between the magnetic finishing medium and the inner surface of the workpiece by cooperating the rotating magnetic field generated by the electromagnetic coils with the workpiece rotation and the feed movement of the displacement platform;
• changing in real time an energizing sequence as well as the predetermined current value and the predetermined frequency value of the electromagnetic coils based on a machining quality requirement on the inner surface of the workpiece and a roughness change during machining, to form another rotating magnetic field;
• dynamically adjusting another finishing action force applied to the magnetic finishing medium and optimizing a machining form of the magnetic finishing medium, in cooperation with a movement of the chuck clamp and a movement of the displacement platform, to make the magnetic finishing medium to form a plurality of movement tracks;
• and
• powering off the electromagnetic coils;
• and removing the magnetic finishing medium attached to the inner surface of the workpiece.