Surface contact magneto-rheological flat polishing device and method with uniform magnetic field

Abstract

The invention discloses a surface contact magneto-rheological flat polishing device and method with a uniform magnetic field. The surface contact magneto-rheological flat polishing device with the uniform magnetic field comprises a polishing head, a polishing groove fixed onto a main shaft and a magnetic pole arranged under the polishing groove. The magnetic pole maintains a certain gap from the outer surface of the bottom of the polishing groove; the polishing head comprises a workpiece shaft and a non-magnetic-conducted clamp fixed to the lower end of the workpiece shaft, and a soft magnetic plate is arranged between the non-magnetic-conducted clamp and the workpiece shaft; the polishing head is arranged above the polishing groove; the uniform magnetic field is formed between the magnetic pole and the soft magnetic plate; and the polishing groove is filled with magneto-rheological fluid. The surface contact magneto-rheological flat polishing device and method with the uniform magnetic field can achieve the large-area uniform polishing of a super-smooth large-size flat element and improve the polishing efficiency effectively; reduces the complexity of the motion mode of a workpiece to simplify the device structure; enables the magnetic field to be not easy to attenuate and obtains the uniform magnetic field with a magnetic pole gap of 30 mm; and can achieve demagnetization easily.

Description

technical field [0001] The invention mainly relates to the technical field of magnetorheological polishing, in particular to a surface-contact magnetorheological planar polishing device and method for large-size planar parts. Background technique [0002] With the continuous advancement of modern information electronics technology, optical technology and semiconductor lighting technology, there are more and more applications of ultra-smooth large-size (greater than 2 inches) planar components, such as the surface of optical disc molds, the epitaxial surface of sapphire substrates, single crystal silicon Chip surface, various display panels, etc. The processing batch of this kind of components is large, and it belongs to plane processing, and its surface must meet the requirements of ultra-smoothness, minimal residual stress, and extremely thin surface damage layer. At present, the methods for polishing ultra-smooth surfaces mainly include: mechanical polishing, mechanical ch...

AI Technical Summary

Problems solved by technology

[0004] In the published information, the invention patent of the University of Rochester in the United States (patent ZL96198445.7) is a method for magnetorheological finishing of the surface of a workpiece. In this method, the magnetorheological fluid is placed on the surface of a rotating wheel to drive the magnetorheological fluid Entering the magnetic field, the workpiece and the magnetic field maintain a certain gap. The magnetorheological fluid passes through the gap and undergoes a rheological reaction under the action of the magnetic field to form an instantaneous polishing tool, which can remove the material on the surface of the workpiece and the contact part. This method is a point contact Although the traditional polishing method has high processing accuracy and surface quality, the processing efficiency is low and the processing cost is high, so it is not suitable for non-deterministic and efficient batch polishing of large-size planar components

[0005] Another invention patent (patent US5577948) of the University of Rochester in the United States discloses another magnetorheological polishing equipment and method. In this method, the magnetorheological fluid is placed in a rotating polishing tank, and various forms of magnetic fields are arranged at the bottom of the polishing tank. (Single magnetic pole, multiple magnetic poles or yoke), the magnetorheological fluid enters the gap between the workpiece and the magnetic field driven by the polishing tank, and a rheological reaction occurs to achieve deterministic polishing. This method can achieve a large Area magnetization, but the magnetic field strength decays quickly in the direction perpendicular to the surface of the magnetic pole. The bottom of the polishing groove must be designed to be very thin, the manufacturing cost is high, and the magnetic field is uneven. The hardness of the polishing tool formed after the magnetorheological fluid is hardened is uneven. To achieve large-area uniform polishing of large-size planar components requires complex movement of the workpiece and complex equipment structure design

[0006] In China, the invention patent of Guangdong University of Technology (patent ZL200620155638.3) discloses a magneto-rheological effect plane grinding and polishing device. Above the workpiece, it can rotate around the main shaft and move along the X and Y directions. The magnetic grinding tool can be configured with a dot matrix magnetic field or a circular distributed magnetic field. The magnetorheological fluid is injected between the magnetic grinding tool and the workpiece with a nozzle. After the rheological reaction occurs, an array of magneto-rheological effect grinding brushes or a continuous magneto-rheological effect grinding belt is formed to achieve the effect of high-efficiency grinding of the processing plane. This method realizes a surface-contact polishing with high polishing efficiency, but the The generated magnetic field is not uniform. In order to achieve large-area uniform polishing of large-sized planar components, the movement of the workpiece is required to be relatively complicated, which makes the structure of the equipment complicated. After the processing is completed, it is not easy to demagnetize, and the magnetorheological fluid will adhere to the magnetic field. grinding tool

[0007] The invention patent of Xi'an Technological University (patent ZL200820228337.8) discloses a ring-belt rotary magnetorheological polishing method. In this method, the magnetorheological fluid is placed between the inner and outer magnetic poles of the ring yoke and hardened to form a ring-belt polishing method. The tool, the ring belt polishing tool, is driven by the inner magnetic pole to realize the rotation, and produces relative motion with the workpiece to achieve polishing. This method is a surface contact polishing, and the processing efficiency has been greatly improved compared with the point contact polishing. , but the formed magnetic field is not a uniform magnetic field, and the size of the workpiece is limited by the size of the outer magnetic pole, so it is not suitable for large-area uniform polishing of large-sized planar components

[0008] To sum up, the existing surface contact magnetorheological polishing technology is difficult to form a uniform magnetic field and achieve uniform polishing because the magnetic field does not adopt the configuration of opposing magnetic poles. At the same time, there are problems such as fast magnetic field attenuation and difficult degaussing.

Images