CN110732933B

CN110732933B - Polishing liquid supply and recovery polishing tool head device suitable for large-caliber optical element

Info

Publication number: CN110732933B
Application number: CN201911009252.XA
Authority: CN
Inventors: 辛强; 刘海涛; 万勇建
Original assignee: Institute of Optics and Electronics of CAS
Current assignee: Institute of Optics and Electronics of CAS
Priority date: 2019-10-23
Filing date: 2019-10-23
Publication date: 2021-07-16
Anticipated expiration: 2039-10-23
Also published as: CN110732933A

Abstract

The invention discloses a polishing liquid supply and recovery polishing tool head device suitable for a large-caliber optical element, and relates to the technical field of high-efficiency polishing of optical elements. The polishing solution is supplied with and is retrieved first device of polishing tool and adopt to let in the polishing solution along polishing dish axial through-hole feed liquor mode to retrieve the polishing solution in the polishing dish edge outside, the polishing solution seals inside the device, has showing the cyclic utilization who has increased the polishing solution. Meanwhile, the polishing pad of the polishing device adopts radial and circumferential grooves, so that polishing liquid enters a processing area under the action of conveying pressure and tool rotation centrifugal force, the higher the rotation speed of the tool head is, the more favorable the polishing liquid enters the processing area, the spiral grooves in the same direction as the rotation direction can also effectively increase the residence time of polishing abrasive materials in the processing area, the diffusion permeability and the uniform distribution of the polishing liquid to the processing area are improved, the material removal efficiency and uniformity can be effectively improved, the stability and the consistency of removal functions are ensured, and the optical processing certainty is improved.

Description

Polishing liquid supply and recovery polishing tool head device suitable for large-caliber optical element

Technical Field

The invention relates to the technical field of high-efficiency polishing of optical elements, in particular to a polishing liquid supply and recovery polishing tool head device suitable for large-caliber optical elements.

Background

With the continuous deepening of scientific research on astronomical observation and cosmic space detection, the performance requirements of the adopted optical system are higher and higher, the imaging resolution and the light collecting capability are required to be improved so as to improve the observation capability, and the increase of the clear aperture is an effective way to improve the imaging resolution and the light collecting capability, so that the size of a primary mirror in the optical observation system is larger and larger. The increase of the size of the primary mirror leads to longer and longer processing period, and restricts the rapid construction of the optical system. Therefore, it is urgently needed to develop a new tool so as to improve the processing efficiency of the primary mirror, and to quickly and inexpensively complete the construction of a large-scale optical system with time and economic cost saved.

The technological process of optical mirror surface production mainly includes mirror surface milling and grinding formation, coarse grinding, fine grinding and polishing. The mirror surface has high efficiency in milling, rough grinding and fine grinding, a surface sub-surface damage layer is inevitably generated, the final polishing process is an effective method for reducing and eliminating the surface and sub-surface damage, and is an effective processing mode for reducing surface defects such as pits, spots, scratches and the like of the mirror surface, but the efficiency is very low. The working principle of the polishing tool is that the polishing tool is controlled by a computer to perform revolution and rotation movement, polishing liquid is driven by the relative movement of the polishing tool and the mirror surface, and material removal is realized by virtue of the physical and chemical actions of abrasive materials between the polishing liquid and the mirror surface. The material removal function can be expressed by Preston formula Z (x, y) ═ k P (x, y) V (x, y), and it can be seen from the formula that improving the relative motion between the polishing tool and the mirror surface is an effective way to improve the processing efficiency.

Because the polishing solution used by the polishing tool head is mainly added from the outside of the tool head, the polishing solution cannot effectively permeate into a processing area due to the increase of the rotating speed, and the condition that the polishing solution cannot permeate is more obvious under the condition that the size of the polishing tool is also increased, and the problem of processing a large-caliber high-quality optical mirror surface can be caused. Because the polishing liquid is added from the outside of the tool head, the polishing liquid can effectively permeate into a polishing working area under the condition that the rotating speed of the tool head is low, the tool can stably work, and the polishing and the definite shape modification of the optical mirror surface are realized. However, when the revolution and rotation speeds of the polishing tool head are increased sharply, due to the close fit between the tool head and the mirror surface and the high-speed centrifugal force, the external circulating polishing solution cannot permeate into the processing area effectively, so that no polishing solution exists in the processing area, the mirror surface is not only subjected to dry grinding, the temperature of the processing area rises sharply, a large number of surface defects are formed, and the surface shape of the mirror surface is damaged due to the uncertainty of the material removal function. Therefore, the problems of effective adding and uniform distribution of the polishing liquid of the polishing tool head with high rotation speed are urgently needed to be solved.

Disclosure of Invention

The invention aims to solve the problems that polishing solution cannot permeate into a processing area and the distribution of the polishing solution is not uniform in the processing process of a polishing tool head of a large-caliber optical element, and the device can realize timely addition and effective recycling of the polishing solution by feeding the liquid into the center of the tool head and recycling the edge; and the polishing liquid in the processing area is timely added by means of the centrifugal force generated by the high-speed rotation of the tool head and the surface structure of the tool head, so that the polishing liquid is uniformly distributed in the processing area, and the high-quality processing of the optical mirror surface is realized.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the polishing solution supply and recovery polishing tool head device suitable for the large-aperture optical element comprises a polishing solution recovery ring 1, a ball head shaft 2, a connecting bolt 3, an inner rubber ring 4, an outer rubber ring 5, a polishing pad back plate 6 and a polishing pad 7.

The ball head shaft 2 is connected with a motion input mechanism which provides revolution, rotation and pressure through threads 21, and the ball head shaft 2 can realize revolution motion and axial motion. The ball 25 at the end of the ball shaft 2 is engaged with the ball socket 63 of the polishing pad backing plate 6 by the connection of the internal thread 32 of the connecting bolt 3 with the external thread 62 on the polishing pad backing plate 6. The pin 24 of the ball stud 2 is embedded into the pin counter sink 61 of the polishing pad back plate 6 for matching, and the polishing pad 7 is glued on the polishing pad back plate 6. The movement input by the movement mechanism is transmitted to the polishing pad back plate 6 through the shifting pin 24, so that the revolution and rotation movement of the polishing back plate 6 is realized. The polishing pad back plate 6 carries the polishing pad 7 in motion, and material removal is achieved by relative motion between the polishing pad 7 and the mirror surface to be machined.

The ball head shaft 2 of the invention further adopts a hollow structure, and under the condition that the ball head structure of the pin can apply normal force and realize the rotation of the polishing disk, polishing liquid can be conveyed into a polishing area through the axial through hole 26 of the ball head shaft 2, and the defect that the polishing liquid cannot effectively enter the polishing area under the action of high-speed rotation of the polishing disk is effectively overcome through the liquid conveying mode of an internal center.

The polishing solution recovery ring 1 penetrates through the counter bore 11 through a bolt to be fixed on a motion output mechanism box body, the inner rubber ring 4 is tensioned on an inner step of the polishing solution recovery ring 1 through elastic force, the lower edge of the inner rubber ring 4 is matched with the upper surface of the polishing pad back plate 6, the outer rubber ring 5 is tensioned on an outer step of the polishing solution recovery ring through elastic force, and the lower surface of the outer rubber ring 5 is flush with the bottom surface of the polishing disc.

The invention has the beneficial effects that:

the polishing solution is added and integrated in the polishing device, is conveyed into the polishing pad through the solution conveying pipeline along the inner axis of the polishing tool, is diffused along the radial processing area by utilizing the dual functions of pumping pressure and tool rotation centrifugal force, and is uniformly distributed under the radial and circumferential grooves of the polishing pad, so that the diffusion permeability and uniform distribution of the polishing solution to the processing area are improved, the material removal efficiency and uniformity can be effectively improved, the stability and consistency of a removal function are ensured, and the optical processing certainty is improved.

Drawings

FIG. 1 is an exploded view of an apparatus for supplying and recovering polishing slurry to and from a polishing tool head according to the present invention;

FIG. 2 is a view of a slurry recovery ring;

FIG. 3 is a ball nose shaft view;

FIG. 4 is a view of a connecting bolt;

FIG. 5 is a view of an inner rubber ring;

FIG. 6 is a view of the outer rubber ring;

FIG. 7 is a diagram of a polishing pad backing plate;

FIG. 8 is a diagram of a polishing pad;

FIG. 9 is a schematic diagram of the operation of the polishing liquid supply and recovery polishing tool head device of the present invention.

In the figure: the polishing pad comprises a polishing solution recovery ring 1, a ball shaft 2, a connecting bolt 3, an inner rubber ring 4, an outer rubber ring 5, a polishing pad back plate 6, a polishing pad 7, a polishing solution recovery cavity 8, a counter bore 11, a polishing solution outlet 12, an outer rubber ring fixed ring step 13, a polishing solution recovery hole 14, an inner rubber ring fixed ring step 15, a thread 21, a ball shaft thread tightening structure 22, a ball shaft body 23, a pin 24, a ball head 25, an axial through hole 26, a through hole 31, an internal thread 32, a pin counter groove 61, an external thread 62, a ball socket 63, a polishing pad back plate central hole 64, a polishing pad central hole 71, a polishing pad radial groove 72 and a polishing pad annular groove 73.

Detailed Description

In order to better illustrate the technical solutions and advantages of the present invention, specific embodiments are described with reference to fig. 1 to 9. This section presents exemplary embodiments of the present invention, which can be optimized according to the processing requirements of the optical element, and falls within the scope of the present invention.

As shown in fig. 1, the polishing solution supply and recovery polishing tool head device suitable for large-aperture optical elements of the present invention comprises a polishing solution recovery ring 1, a ball stud shaft 2, a connecting bolt 3, an inner rubber ring 4, an outer rubber ring 5, a polishing pad back plate 6 and a polishing pad 7.

As shown in FIG. 2, the polishing solution recycling ring 1 is connected with the motion output mechanism box through a counter bore 11, and the polishing solution recycling holes 14 are uniformly distributed on the lower bottom surface of the polishing solution recycling ring, and the number of the polishing solution recycling holes is generally more than 3 to ensure the recycling uniformity of the polishing solution. The polishing solution recycling hole 14 conveys recycled polishing solution back to the polishing solution recycling barrel through a pipeline connected with the polishing solution outlet 12, and the inner rubber ring 4 is fixed on the inner rubber ring fixing ring step 15 under the tensioning action of the rubber ring, so that the diameter of the inner rubber ring 4 is smaller than that of the inner rubber ring fixing ring step 15, and the polishing solution recycling hole can be fixed on the polishing solution recycling ring 1 through the tensioning force. The outer rubber ring 5 is fixed on the outer rubber ring fixing ring step 13 through the tensioning action of the rubber ring, so that the diameter of the outer rubber ring is smaller than that of the outer rubber ring fixing ring step 13, and the outer rubber ring can be fixed on the polishing solution recovery ring 1 through the tensioning force.

Ball axle 2 is the hollow ball axle, and ball axle 2 is connected with drive mechanism through screw thread 21, and the rotary motion that traditional mechanism provided guarantees that ball axle 2 can realize high-speed rotary motion, and the axis body 23 of ball axle must be longer than connecting bolt 3's thickness more than 20mm with the whole length of bulb 25 to guarantee that ball axle 2 and connecting bolt 3 do not take place to interfere in the motion process. The size of the ball head shaft thread tightening structure 22 needs to be smaller than the diameter of the through hole 31 of the connecting bolt 3, the ball head shaft thread tightening structure can penetrate through the through hole 31, the length of the poking pin 24 needs to be larger than the diameter of the through hole 31 by more than 2mm, meanwhile, the poking pin 24 needs to be smaller than the diameter of the connecting thread by more than 2mm, and the diameter of the poking pin 24 needs to be smaller than the poking pin sinking groove 61 of the polishing. The polishing liquid is fed into the polishing zone through the axial through-hole 26 of the ball spindle 2.

The ball shaft 2 is connected to the external thread 62 of the polishing pad back plate 6 through the connecting bolt 3, the pin 24 is sunk in the pin sunk groove 61, and the ball diameter of the ball shaft ball 25 is matched with the ball socket 63. Under the fastening action of the connecting bolt 3, the axial pressure provided by the transmission mechanism and the limiting action of the ball shaft shifting pin 24, the ball head 25 of the ball shaft is matched with the ball socket 63, and the axial through hole 26 of the ball shaft 2 is ensured to be communicated with the central hole 64 of the polishing pad back plate.

Under the natural state that the power transmission mechanism does not apply axial pressure, the lower bottom surface of the outer rubber ring 5 tensioned on the polishing solution recovery ring 1 is flush with the lower bottom surface of the assembled polishing pad 7, and the lower bottom surface of the inner rubber ring 4 is attached to the upper surface of the polishing pad back plate 6.

The size of the polishing pad 7 is the same as that of the bottom surface of the polishing pad back plate 6, the upper surface of the polishing pad 7 is glued with the lower bottom surface of the polishing pad back plate 6, and meanwhile, the size of the polishing pad central hole 71 is the same as that of the polishing pad back plate central hole 64. The polishing pad 7 is provided with a radial groove 72 and an annular groove 73, wherein the radial groove can be a radial groove or a spiral groove which is opposite to or the same as the rotation direction of the polishing pad 7.

The polishing liquid recovery ring 1 is a stationary device. The ball head shaft 2, the connecting bolt 3, the polishing pad back plate 6 and the polishing pad 7 are connected together through the functions of threads, pin pulling, gluing and the like to form a movement mechanism, so that the rotary movement around the axis of the ball head shaft 2 and the up-and-down movement along the axis can be realized, and the up-and-down movement in the axial direction is generally within the range of 5-50 mm.

During the processing, the lower bottom surface of the polishing pad 7 and the lower bottom surface of the outer rubber ring 5 are attached to the surface of a processed workpiece. The transmission mechanism applies rotation and axis pressure to the whole moving mechanism, and the whole moving mechanism moves upwards, so that the lower bottom surface of the inner rubber ring 4 is tightly attached to the upper surface of the polishing pad back plate 6, and the lower bottom surface of the outer rubber ring 5 is tightly attached to the surface of a processed workpiece, so that a polishing solution recovery cavity 8 is formed. The polishing solution is conveyed to a processing area where the polishing pad 7 is contacted with a workpiece through the axial through hole 26 of the ball head shaft 2, flows into the polishing solution recovery cavity 8 through the radial groove 72 and the annular groove 73 of the polishing pad under the conveying pressure of the polishing solution, is recovered through the recovery holes 14 uniformly distributed on the lower bottom surface of the polishing solution recovery ring under the negative pressure action of an external polishing solution recovery device, and is conveyed back into the polishing solution circulating barrel through a pipeline connected with the polishing solution outlet 12, so that the recovery and the cyclic utilization of the polishing solution are completed.

The centrifugal force generated by the rotation of the moving mechanism and the transmission pressure of the polishing solution act to facilitate the diffusion and permeation of the polishing solution from the central hole of the polishing pad to the processing area through the grooves on the bottom surface of the polishing pad, and the uniform distribution of the polishing solution in the processing area is facilitated. The polishing pad 7 can adopt a radial ray groove and a spiral groove with the same or opposite rotating direction with the moving mechanism, and the grooves can realize the uniform distribution of the polishing solution, wherein the spiral groove with the same rotating direction has better effect.

Furthermore, the slurry inlet and outlet of the device can be switched, i.e., slurry can also enter the device from the slurry outlet 12 and be pumped out of the device from the axial through hole 26, thereby achieving the purpose of recycling and reusing the slurry.

Claims

1. A polishing liquid supply and recovery polishing tool head device suitable for a large-caliber optical element is characterized in that: the device comprises a polishing solution recovery ring (1), a ball head shaft (2), a connecting bolt (3), an inner rubber ring (4), an outer rubber ring (5), a polishing pad back plate (6) and a polishing pad (7), wherein,

the ball head shaft (2) is connected with a transmission mechanism which provides revolution and rotation and pressure through threads (21), the ball head shaft (2) can realize rotary motion and axial motion, a ball head (25) at the tail end of the ball head shaft (2) is connected with external threads (62) on a polishing pad back plate (6) through internal threads (32) of a connecting bolt (3), a poking pin (24) of the ball head shaft (2) is matched with a poking pin counter sink (61) of the polishing pad back plate (6), the ball head (25) is matched with a ball socket (63) of the polishing pad back plate (6), a polishing pad (7) is glued on the polishing pad back plate (6), the motion provided by the transmission mechanism is transmitted to the polishing pad back plate (6) through the poking pin (24) to realize revolution and rotation motion of the polishing pad back plate (6), the polishing pad back plate (6) carries the polishing pad (7) to move, material removal is achieved by relative movement between the polishing pad (7) and the mirror surface to be machined;

the polishing solution recovery ring (1) is fixed on a motion output mechanism box body by penetrating through a counter bore (11) through a bolt, an inner rubber ring (4) is tensioned on an inner step of the polishing solution recovery ring (1) through elastic force, the lower edge of the inner rubber ring (4) is matched with the upper surface of a polishing pad back plate (6), an outer rubber ring (5) is tensioned on an outer step of the polishing solution recovery ring through elastic force, and the lower surface of the outer rubber ring (5) is flush with the bottom surface of a polishing disc;

the polishing solution recovery ring (1) is a static device, the ball head shaft (2), the connecting bolt (3), the polishing pad back plate (6) and the polishing pad (7) are connected together through threads, a shifting pin and a gluing effect to form a movement mechanism, so that the rotation movement around the axis of the ball head shaft (2) and the up-and-down movement along the axis can be realized, and the up-and-down movement in the axial direction is within the range of 5-50 mm;

the polishing pad (7) is provided with a radial groove (72) and an annular groove (73), wherein the radial groove can be a radial groove or a spiral groove which is opposite to or the same with the rotation direction of the polishing pad (7).