CN1328007C - Ultrasonic magnetic rheological composite polishing method and polisher thereof - Google Patents

Abstract

The present invention provides an ultrasonic magnetic rheological composite polishing method and a device, which relates to the technical fields of ultraprecision machining and optical machining. The method of the present invention adopts a hollow revolving polishing tool head (5) with a small diameter, magnetic rheological fluid (13) mixed with an abrasive is filled in the revolving polishing tool head (5), a certain magnetic field is exerted, and the magnetic rheological fluid (13) forms a flexible polishing tool with a certain removing capability on the revolving polishing tool head (5). Meanwhile, ultrasonic vibration is exerted, and the function of polishing removal is realized. The upper end of an ultrasonic generator (3) is fixedly connected with the output end of an electric main shaft (1) in the device of the present invention, the lower part of the ultrasonic generator is free sheathed with an electromagnet (4), and the lower end of the ultrasonic generator is fixedly connected with the revolving polishing tool head (5). The polishing method of the present invention adopts the hollow revolving tool head with a small diameter, the polishing of concave curved surfaces a with smaller curvature radius, especially the processing of deep concave optical elements can be realized, ultraprecision machining applied to free curved surface optical elements can be popularized, and the removal efficiency of polishing can be improved. The polishing device has the advantages of simple and compact structure, convenient operation and high machining precision.

Description

Ultrasonic magnetorheological composite polishing method and device

Technical field:

The invention relates to the technical fields of ultra-precision processing and optical processing, in particular to a method for ultra-precision processing the surface of optical glass and other material devices through ultrasonic magneto-rheological composite polishing and a device designed for realizing the method.

Background technique:

With the wide application of aspheric devices, not only the requirements for its precision and reliability are increasing, but also the ability of high-efficiency and batch production is required. As the most important process of optical precision machining, polishing is mainly to remove the surface damage layer produced by the previous processing process, correct the surface shape error, and reduce the surface roughness of the workpiece. Magneto-rheological polishing (MRF) technology is a new technology for optical aspheric surface processing that has appeared abroad in recent years. In 1992, Wm I.Kordonski and I.Prokhorov in Belarus first applied magnetorheological technology to the precision processing of optical glass devices. In 1995 In 2011, COM (Thecenter for Optical Manufacturing) of the University of Rochester in the United States cooperated with Kordonski to apply magnetorheological technology to optical processing for the first time, and conducted a large number of experimental studies on optical polishing (MRF) technology based on magnetorheological change. . The magnetorheological polishing technology realizes the mechanical and chemical comprehensive removal of optical materials, not only improves the polishing efficiency, makes the polishing process easy to control, and does not produce a surface damage layer, it is suitable for the processing performance of modern optical systems on optical devices. need. The basic principle of magnetorheological polishing is to inject magnetorheological fluid containing a certain concentration of fine abrasives into the polishing area, and at the same time apply a controllable high-gradient magnetic field in this area. Under the action of the magnetic field, the magnetorheological fluid in this area produces Rheological effect, the viscosity increases rapidly in milliseconds, and a semi-solid polishing tool is formed on the surface of the polishing wheel, which is driven by the polishing wheel to achieve polishing under the action of fluid dynamic pressure. Magneto-rheological polishing technology has been successfully researched by Rochester University Optical Manufacturing Center (COM) and QED company, and has achieved good results in optical aspheric surface processing. It is considered a revolutionary change in optical precision polishing technology abroad. It makes the polishing technology move from manual skill to science, and greatly improves the efficiency of optical aspheric surface processing. However, due to the limitation of the radius of the polishing wheel, this method is more suitable for processing convex curved surfaces, planes and concave curved surfaces with large curvature radii, and cannot process concave curved surfaces with small curvature radii (the latest Q22-XE CNC magnetic The rheological polishing machine tool can process the minimum concave surface with a radius of curvature of 15mm), especially it cannot process deep concave surfaces.

Invention content:

The technical problem to be solved by the present invention is to overcome the defects of current magnetorheological polishing technology, provide an ultrasonic magnetorheological composite polishing method and device, which can realize ultra-precision processing of small curvature radius deep concave aspheric optical elements, and popularize and apply Ultra-precision machining of free-form optical components. The steps of the polishing method of the present invention are as follows: 1. Add magnetorheological polishing liquid mixed with abrasives into the stirring, constant temperature and constant viscosity control device, and fix the workpiece on the fixture of the workpiece numerical control work table; start the pump to make the mixing The magnetorheological polishing liquid with abrasives flows out from the inner hole of the tool head through the circulation pipeline and so on by the pressure of the pump. 2. Start the electric spindle and ultrasonic generating device, and at the same time energize the electromagnet, so that the viscosity of the magnetorheological polishing fluid on the surface of the tool head increases rapidly within milliseconds and becomes semi-solid, forming a flexible polishing head. Rotate and vibrate at high frequency. 3. The spindle CNC workbench controls the position of the polishing head, and the processed workpiece is driven by the workpiece CNC workbench to form the required processing trajectory and finally obtain a high-precision optical surface. 4. The magnetorheological fluid after polishing enters the recovery tank, flows into the stirring, constant temperature and constant viscosity control device, and then is pumped out, enters the rotary joint through the circulation pipeline, flows out from the inner hole of the tool head through the internal passage, and repeats this process , so as to realize the cyclic use of magnetorheological fluid and maintain stable polishing characteristics. The vibration frequency of the ultrasonic generating device is ≥16 kHz; the rotation speed of the tool head is ≤10000 rpm; the magnetic induction of the electromagnet is ≥1000 Gauss. The polishing device of the present invention consists of an electric spindle 1, a spindle numerical control workbench 2, an ultrasonic generator 3, an electromagnet 4, a hollow tool head 5, a fixture 7, a workpiece numerical control workbench 8, a bed 9, a recovery tank 10, stirring, Constant temperature and constant viscosity control device 11, lower circulation pipeline 12, pump 14, upper circulation pipeline 15, rotary joint 16 and internal passage 17, characterized in that the right end of the spindle CNC workbench 2 is fixed to the left end of the upper part of the bed 9 Connection, one side of the electric spindle 1 is fixedly connected to the left end of the spindle CNC workbench 2, the upper end of the ultrasonic generator 3 is fixedly connected to the output end of the electric spindle 1, and the upper end of the hollow tool head 5 is fixed to the lower end of the ultrasonic generator 3 connection, the electromagnet 4 is placed in the lower part of the ultrasonic generating device 3 (it is necessary to ensure that the skeleton of the electromagnet does not contact the ultrasonic generating device), the electromagnet is either fixed on the electric spindle 1, or fixed on the spindle CNC workbench 2, and can be controlled The strength of the magnetic field around the tool head to control the rheological properties of the magnetorheological fluid (permanent magnets can also be used). The lower end of the workpiece numerical control workbench 8 is fixedly connected with the upper end of the base of the bed 9, the lower end of the fixture 7 is fixedly connected with the upper end surface of the workpiece numerical control workbench 8, and the recovery tank 10 is fixed on the workpiece numerical control workbench 8 on the periphery of the fixture 7. The upper end of the circulation pipeline 12 is connected with the lower end of the recovery tank 10, the lower end of the lower circulation pipeline 12 is connected with the upper end of the stirring, constant temperature and constant viscosity control device 11, and the lower end of the upper circulation pipeline 15 is connected with the stirring, constant temperature and constant viscosity control device 11. The lower side of the viscosity control device 11 is connected, the pump 14 is connected in series on the upper circulation pipeline 15, the rotary joint 16 is fixed on the upper end of the electric spindle 1, the upper end of the upper circulation pipeline 15 is connected with the rotary joint 16, and the electric spindle 1 , The ultrasonic generating device 3 and the hollow tool head 5 are provided with an internal passage 17, and the upper end of the internal passage 17 communicates with the rotary joint 16. The stirring, constant temperature and constant viscosity control device 11 consists of a motor and a reducer 22, a transmission shaft 23, a stirring blade 24, a cooling device 25, a temperature sensor 26, a temperature control device 27, a viscosity control device 28, and a magnetorheological fluid carrier liquid replenishment device 29. The pipeline 30, the viscosity detection device 31 and the box body 32 are composed. The motor and the reducer 22 are arranged at the center of the upper part of the box body 32, the upper end of the transmission shaft 23 is fixedly connected with the output shaft of the motor and the reducer 22, the lower end of the transmission shaft 23 is fixedly connected with the stirring blade 24, and the cooling device 25 is fixed in the box The bottom of body 32 outer walls, temperature control device 27 are arranged on the side of casing 32 tops, and temperature sensor 26 is located at the bottom in casing 32, and temperature sensor 26 is electrically connected with temperature control device, and temperature control device 27 is connected with cooling device 25. Electrically connected, the viscosity control device 28 and the magnetorheological fluid carrier liquid replenishment device 29 are respectively arranged on the other side of the upper part of the casing 32, the viscosity detection device 31 is located at the bottom of the casing 32, the viscosity detection device 31 and the viscosity control device 28 is electrically connected, the viscosity control device 28 is electrically connected to the magnetorheological fluid carrier liquid replenishment device 29 , and a pipeline 30 is connected between the magnetorheological fluid carrier liquid replenishment device 29 and the box body 32 . The polishing method of the present invention has the following advantages: ultrasonic magneto-rheological composite polishing is used, the energy is concentrated on the processing area, and the processing quality and efficiency are improved; the hollow polishing tool head with a small diameter is suitable for processing concave holes with a small radius of curvature. Curved optical elements are especially suitable for the processing of deep concave optical elements; combined with numerical control technology, not only spherical surfaces but also aspheric surfaces can be processed, and it can be widely used in the processing of free-form optical elements. The polishing device of the invention has the advantages of simple and compact structure, convenient operation and high processing precision. The invention has great application value in the field of ultra-precision processing of aspheric optical elements. Experiments prove that the surface roughness of the optical glass (K9) polished by the method of the present invention has reached nanometer level.

Description of drawings:

FIG. 1 is a schematic structural view of a polishing device of the present invention, and FIG. 2 is a schematic structural view of a third embodiment. Fig. 3 is a schematic structural diagram of Embodiment 4. FIG. 4 is a structural schematic diagram of the stirring, constant temperature and constant viscosity control device 11 .

Detailed ways:

Embodiment 1: The steps of the polishing method in this embodiment are as follows: 1. Add magnetorheological polishing liquid mixed with abrasives into the stirring, constant temperature and constant viscosity control device, and fix the workpiece on the fixture of the workpiece numerical control worktable ; Start the pump, so that the magnetorheological polishing liquid mixed with abrasive flows out from the inner hole of the tool head through the circulation pipeline and so on by the pressure of the pump. 2. Start the electric spindle and ultrasonic generating device, and at the same time energize the electromagnet, so that the viscosity of the magnetorheological polishing fluid on the surface of the tool head increases rapidly within milliseconds and becomes semi-solid, forming a flexible polishing head. Rotate and vibrate at high frequency. 3. The spindle CNC workbench controls the position of the polishing head, and the processed workpiece is driven by the workpiece CNC workbench to form the required processing trajectory and finally obtain a high-precision optical surface. 4. The magnetorheological fluid after polishing enters the recovery tank, flows into the stirring, constant temperature and constant viscosity control device, and then is pumped out, enters the rotary joint through the circulation pipeline, flows out from the inner hole of the tool head through the internal passage, and repeats this process , so as to realize the cyclic use of magnetorheological fluid and maintain stable polishing characteristics. The vibration frequency of the ultrasonic generating device is ≥ 16 kHz, generally 16-1000 kHz; the rotation speed of the tool head is ≤ 10000 rpm; the magnetic induction of the electromagnet is ≥ 1000 Gauss, generally 1000-20000 gauss.

Specific embodiment two: (referring to Fig. 1, Fig. 4) ultrasonic magneto-rheological compound polishing device, it is made of electric spindle 1, spindle numerical control workbench 2, ultrasonic generating device 3, electromagnet 4, hollow tool head 5, clamp 7 , workpiece CNC workbench 8, bed 9, recovery tank 10, stirring, constant temperature and constant viscosity control device 11, lower circulation pipeline 12, pump 14, upper circulation pipeline 15, rotary joint 16 and internal passage 17. It is characterized in that the right end of the spindle numerical control table 2 is fixedly connected with the left end of the upper part of the bed 9, one side of the electric spindle 1 is fixedly connected with the left end of the spindle numerical control table 2, and the upper end of the ultrasonic generator 3 is fixed with the output end of the electric spindle 1 Connect, the upper end of the hollow tool head 5 is fixedly connected with the lower end of the ultrasonic generating device 3, and the electromagnet 4 is empty in the ultrasonic generating device 3 bottom (need to ensure that the skeleton of the electromagnet does not contact the ultrasonic generating device), the electromagnet or be fixed on On the electric spindle 1, or fixed on the spindle CNC workbench 2, the magnetic field intensity around the tool head can be controlled to control the rheological characteristics of the magnetorheological fluid (permanent magnets can also be used). The lower end of the workpiece numerical control workbench 8 is fixedly connected with the upper end of the base of the bed 9, the lower end of the fixture 7 is fixedly connected with the upper end surface of the workpiece numerical control workbench 8, and the recovery tank 10 is fixed on the workpiece numerical control workbench 8 on the periphery of the fixture 7. The upper end of the circulation pipeline 12 is connected with the lower end of the recovery tank 10, the lower end of the lower circulation pipeline 12 is connected with the upper end of the stirring, constant temperature and constant viscosity control device 11, and the lower end of the upper circulation pipeline 15 is connected with the stirring, constant temperature and constant viscosity control device 11. The lower side of the viscosity control device 11 is connected, the pump 14 is connected in series on the upper circulation pipeline 15, the rotary joint 16 is fixed on the upper end of the electric spindle 1, the upper end of the upper circulation pipeline 15 is connected with the rotary joint 16, and the electric spindle 1 , The ultrasonic generating device 3 and the hollow tool head 5 are provided with an internal passage 17, and the upper end of the internal passage 17 communicates with the rotary joint 16. The stirring, constant temperature and constant viscosity control device 11 consists of a motor and a reducer 22, a transmission shaft 23, a stirring blade 24, a cooling device 25, a temperature sensor 26, a temperature control device 27, a viscosity control device 28, and a magnetorheological fluid carrier liquid replenishment device 29. The pipeline 30, the viscosity detection device 31 and the box body 32 are composed. The output shaft of the motor and reducer 22 is connected to the upper end of the transmission shaft 23, and the lower end of the transmission shaft 23 is connected to the stirring blade 24. In this way, the motor and the reducer 22 can drive the stirring blade 24 to rotate to realize the stirring of the magnetorheological fluid. The cooling device 25 surrounds the outer wall of the box body 32, the temperature sensor 26 detects the temperature of the magnetorheological fluid and transmits it to the temperature control device 27, and then the temperature control device 27 controls the cooling device 25, thereby realizing the constant temperature control of the magnetorheological fluid. The viscosity control of the magnetorheological fluid is realized as follows: the viscosity detection device 31 detects the viscosity of the magnetorheological fluid, and transmits the detection result to the viscosity control device 28, and the viscosity control device 28 controls the carrier liquid of the magnetorheological fluid carrier liquid replenishment device 29 Outflow, the carrier liquid flows into the tank 32 through the pipeline 30 at the lower end of the magnetorheological fluid carrier liquid replenishment device 29 . In this way, through stirring, constant temperature and constant viscosity control, it is ensured that the magnetorheological fluid always has stable polishing properties. If the surface of revolution is processed, a three-coordinate numerical control system (consisting of the workpiece numerical control workbench 8 and the spindle numerical control workbench 2) is required; if a free-form surface is processed, a five-coordinate numerical control system is required. The processing end of the hollow tool head 5 is spherical, and the magnetorheological fluid 13 is distributed on the spherical surface of the hollow tool head 5 to act on the workpiece 6 on the fixture 7 during processing.

Specific embodiment three: (see Fig. 2) The difference between this embodiment and specific embodiment one is that the electric spindle 1 is replaced by the motor 18, the shaft coupling 19, the headstock 20, and the main shaft 21, and the output end of the motor 18 is connected to the main shaft The input ends of the boxes 20 are connected by a coupling 19, and the main shaft 21 on the headstock 20 is fixedly connected with the ultrasonic generator 3, and other components and connections are the same as in the second embodiment.

Embodiment 4: (see FIG. 3 ) The difference between this embodiment and Embodiment 1 is that the electric spindle 1 and the rotary joint 16 are eliminated, and the ultrasonic generating device 3 is fixed on the left end of the spindle CNC workbench 2 . Other compositions and connections are the same as in the first embodiment.

Claims (4)

1, ultrasonic magnetic rheology composite polishing method is characterized in that step is as follows: one, adding is mixed with the Magnetorheologicai polishing liquid of abrasive material in stirring, constant temperature and permanent viscosity control device, and workpiece is fixed on the anchor clamps of workpiece numerical control table, NC table face; Start pump, make the Magnetorheologicai polishing liquid that is mixed with abrasive material pressure, flow out through the endoporus from tool heads such as circulation line by pump; Two, start electric main shaft, ultrasonic generator,, the Magnetorheologicai polishing liquid viscosity on tool heads surface is increased at Millisecond in the time rapidly, become semi-solid, form the flexible polishing head, with the tool heads rotation and make dither simultaneously to electromagnet energising; Three, the position of main shaft numerical control table, NC table control rubbing head, processing work is driven by the workpiece numerical control table, NC table, forms the machining locus that requires, and finally obtains high-precision optical surface; Four, the magnetic flow liquid after the polishing enters accumulator tank, flows into stirring, constant temperature and permanent viscosity control device, is extracted out by pump again, enters swivel joint by circulation line, and through internal path, the endoporus outflow from tool heads so repeatedly, recycles magnetic flow liquid; The vibration frequency of described ultrasonic generator 〉=16 kilo hertz; The rotary speed of described tool heads≤10000 rev/min; The magnetic induction intensity of described electromagnet 〉=1000 Gausses.

2, ultrasonic magnetic rheology composite polishing device, it is by electric main shaft (1), main shaft numerical control table, NC table (2), ultrasonic generator (3), electromagnet (4), the tool heads of hollow (5), anchor clamps (7), workpiece numerical control table, NC table (8), lathe bed (9), accumulator tank (10), stir, constant temperature and permanent viscosity control device (11), following circulation line (12), pump (14), cocycle pipeline (15), swivel joint (16) and internal path (17) are formed, the right-hand member that it is characterized in that main shaft numerical control table, NC table (2) is fixedlyed connected with the left end on lathe bed (9) top, one side of electricity main shaft (1) is fixedlyed connected with the left end of main shaft numerical control table, NC table (2), fixedly connected with the output of electric main shaft (1) in the upper end of ultrasonic generator (3), fixedly connected with the lower end of ultrasonic generator (3) in the upper end of the tool heads of hollow (5), electromagnet (4) sky is enclosed within ultrasonic generator (3) bottom, fixedly connected with the base portion upper end of lathe bed (9) in the lower end of workpiece numerical control table, NC table (8), fixedly connected with the upper surface of work numerical control table, NC table (8) in the lower end of anchor clamps (7), accumulator tank (10) is fixed on the peripheral workpiece numerical control table, NC table (8) of anchor clamps (7), the upper end of following circulation line (12) is connected with the lower end of accumulator tank (10), the lower end and the stirring of following circulation line (12), the upper end of constant temperature and permanent viscosity control device (11) is connected, the lower end and the stirring of cocycle pipeline (15), the downside of constant temperature and permanent viscosity control device (11) is connected, be serially connected with pump (14) on the cocycle pipeline (15), swivel joint (16) is fixed on the upper end of electric main shaft (1), the upper end of cocycle pipeline (15) is connected with swivel joint (16), electricity main shaft (1), be provided with inner passage (17) in the tool heads (5) of ultrasonic generator (3) and hollow, the upper end of inner passage (17) is connected with swivel joint (16).

3, ultrasonic magnetic rheology composite polishing device according to claim 2 is characterized in that the processing end of the tool heads (5) of hollow is sphere.

4, ultrasonic magnetic rheology composite polishing device according to claim 2, it is characterized in that stirring, constant temperature and permanent viscosity control device (11) are by motor and decelerator (22), power transmission shaft (23), stirring vane (24), cooling device (25), temperature sensor (26), temperature control equipment (27), viscosity control device (28), magnetic flow liquid carrier fluid supplementary device (29), pipeline (30), viscosity measurements device (31) and casing (32) are formed, motor and decelerator (22) are arranged on the center on casing (32) top, fixedly connected with the output shaft of motor and decelerator (22) in the upper end of power transmission shaft (23), fixedly connected with stirring vane (24) in the lower end of power transmission shaft (23), cooling device (25) is fixed on the bottom of casing (32) outer wall, temperature control equipment (27) is arranged on a side on casing (32) top, temperature sensor (26) is located at the bottom in the casing (32), temperature sensor (26) is electrically connected with temperature control equipment, temperature control equipment (27) is electrically connected with cooling device (25), viscosity control device (28) and magnetic flow liquid carrier fluid supplementary device (29) are separately positioned on the opposite side on casing (32) top, viscosity measurements device (31) is located at the bottom in the casing (32), viscosity measurements device (31) is electrically connected with viscosity control device (28), viscosity control device (28) is electrically connected with magnetic flow liquid carrier fluid supplementary device (29), is connected with pipeline (30) between magnetic flow liquid carrier fluid supplementary device (29) and the casing (32).

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