JP5121304B2 - Polishing method and polishing apparatus - Google Patents

Description

  The present invention relates to a polishing technique, for example, a technique effective when applied to polishing of optical parts and the like.

  For example, when polishing an optical component such as a lens, the surface to be processed which is the optical functional surface of the optical component and the processing surface of the processing tool are brought into contact with each other, and the shape of the surface of the processing tool is changed. It is transferred to the processing surface and processed.

  When such a polishing process is performed, a phenomenon in which shavings, tool wear (generally referred to as sludge) or an abrasive adheres to the tool surface easily occurs. Also, if a local high pressure or high temperature condition occurs at the interface between the work surface of the optical component and the work surface of the processing tool during the polishing process, the work surface of the work tool will change and become locally hardened or glossy. Occurs. Furthermore, it has been empirically found that once this phenomenon occurs, it tends to expand with the progress of processing. When such a phenomenon occurs, a large number of scratches are likely to occur on the processing surface of the optical component.

  In particular, in recent years, high-precision lenses using low-dispersion glass have been used in camera lenses and microscope lenses. However, low-dispersion glass generally has a much higher degree of wear than ordinary optical glass, so there are scratches. Tends to occur and the defect rate tends to increase. In particular, in high-speed polishing with a polishing dish using a polyurethane sheet or a fixed abrasive tool in which abrasive grains are dispersed on a resin base material, a large number of deepening occurs due to clogging of the processing tool or vibration (so-called chatter) caused by polishing resistance. Scratches occur.

As a countermeasure against these technical problems, for example, a polishing method called submerged polishing disclosed in Non-Patent Document 1 is known.
Namely, an abrasive in which abrasive grains are dispersed by providing a holding base for holding a workpiece immersed in an abrasive stored in a ball field container, and a rotating shaft for rotating the holding base for rotating the workpiece. Polishing is performed in a state where the workpiece and the processing tool are immersed in the liquid.

  However, in the method disclosed in Non-Patent Document 1, the sludge generated when the workpiece is polished due to a so-called laminar flow state in which the abrasive always flows in a fixed direction around the axis of the rotating shaft is the workpiece. There is a concern that the sludge stays in the vicinity, and this sludge is interposed between the work surface of the workpiece and the polisher and scratches the work surface.

  In addition, the abrasive grains in the abrasive that have deteriorated due to the workpiece polishing process stay in the vicinity of the workpiece, and the abrasive grains that can contribute to the processing flowing near the inner wall surface of the container do not flow to the workpiece processing surface. If you are working with abrasive grains that are constantly deteriorated, the processing ability will decrease or if you process for a long time, the abrasive grains in the abrasive will settle on the bottom of the container and will not contribute to the processing .

  Furthermore, since the polishing tool in the liquid is configured so that the entire processing tool such as a polisher is immersed in the polishing liquid, the rotation speed of the processing tool cannot be increased due to the influence of the viscous resistance of the polishing agent. Compared with polishing, the time required for processing becomes very long (for example, several hours to several tens of hours), which is extremely inefficient.

  On the other hand, Patent Document 1 discloses that a laminar flow state abrasive that rotates and flows in a ball field container is disturbed by fins fixed in the container to promote mixing to be in a turbulent state. By removing sludge that tends to stay in the vicinity and supplying abrasive grains in the abrasive that do not contribute to the processing to the processing surface, an attempt is made to eliminate the disadvantages of the submerged polishing method as in Non-Patent Document 1. A polishing method is provided.

However, in the case of this Patent Document 1, although the processing efficiency is improved as compared with the above-mentioned Non-Patent Document 1, it is still a submerged polishing, and the processing time by high-speed polishing is not changed as described above. However, it is difficult to shorten the length, and it is still inefficient compared with a general polishing method that does not depend on in-liquid polishing.
New Technology Development Center Co., Ltd., published in September 1985, Akira Kobayashi, “Practical Manual for Ultraprecision Machining Technology”, page 77, lines 5-10 JP-A-8-323612

An object of the present invention is to provide a technique capable of polishing an optical component having a relatively high degree of wear without damaging it in a short processing time.
Another object of the present invention is to provide a technique capable of improving yield and productivity in a polishing process of an optical component having a relatively high degree of wear.

A first aspect of the present invention is a polishing method for performing a polishing process by bringing a processing tool into contact with a surface to be processed of an optical component and moving the optical component and the processing tool relative to each other while supplying a processing liquid. ,
(A) a step of performing a polishing step while supplying only a machining fluid containing an abrasive;
(B) a step of finishing the step, supplying a lubricating oil together with the machining liquid, and performing the polishing while reducing an adhesion force between the work surface and a working surface of the processing tool by the lubricating oil ; ,
A polishing method is provided.

According to a second aspect of the present invention, in the polishing method according to the first aspect,
The lubricating oil is composed of a low viscosity mineral oil,
Provided a polishing method for intermittently spraying and supplying the mineral oil when vibration due to an increase in sliding resistance between the optical component and the processing tool occurs or when a sign of occurrence of the vibration is detected To do.

According to a third aspect of the present invention, in the polishing method according to the first aspect,
The optical component provides a polishing method having physical properties with a degree of wear of 200 or more and / or a Knoop hardness of 550 or less.

According to a fourth aspect of the present invention, in the polishing method according to the first aspect,
The processing tool provides a polishing method which is a processing tool based on a resin.
A fifth aspect of the present invention provides a holder for supporting an optical component;
A processing tool slidably contacted with the processing surface of the optical component;
A first nozzle for supplying a processing liquid containing an abrasive between the processing tool and the optical component;
A second nozzle for supplying lubricating oil between the processing tool and the optical component;
A drive mechanism for relatively moving the optical component and the processing tool;
The process liquid is discharged from the first nozzle and the lubricant is not discharged from the second nozzle, and the process is terminated, and the process liquid is discharged from the first nozzle and the lubricant is discharged from the second nozzle. A supply control valve for switching between the process of discharging from,
A polishing apparatus is provided.

According to a sixth aspect of the present invention, in the polishing apparatus according to the fifth aspect,
A sensor for detecting a vibration of at least one of the processing tool and the holder and / or fluctuation of a rotational load;
A supply control valve for controlling the supply of the lubricating oil;
Processing control means for controlling the opening of the supply control valve based on fluctuations in the vibration and / or rotational load detected via the sensor;
A polishing apparatus is provided.

According to a seventh aspect of the present invention, in the polishing apparatus according to the sixth aspect,
The lubricating oil is composed of a low viscosity mineral oil,
When the processing control means detects vibration due to an increase in sliding resistance between the optical component and the processing tool via the sensor, or detects a sign of occurrence of the vibration, the mineral oil is intermittent. There is provided a polishing apparatus for controlling the supply control valve so as to be sprayed and supplied.

According to an eighth aspect of the present invention, in the polishing apparatus according to the fifth aspect,
The optical component provides a polishing apparatus having physical properties with a degree of wear of 200 or more and / or a Knoop hardness of 550 or less.

According to a ninth aspect of the present invention, in the polishing apparatus according to the fifth aspect,
The processing tool provides a polishing apparatus which is a processing tool based on a resin.

ADVANTAGE OF THE INVENTION According to this invention, the technique which can grind | polish without damaging an optical component with a comparatively big abrasion degree in a short processing time can be provided.
In addition, it is possible to provide a technique capable of improving yield and productivity in a polishing process of an optical component having a relatively high degree of wear.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a polishing apparatus that performs a polishing method according to an embodiment of the present invention. FIG. 2 shows the physical properties of an optical component to be processed by the polishing apparatus according to the embodiment. It is a graph which shows an example of a physical property.

The polishing apparatus M according to the embodiment includes a processing tool 1, a drive shaft 1 b (drive mechanism), a holder 3, a Kanzashi 4 (drive mechanism), a first nozzle 5, and a second nozzle 7.
A lens 2 to be processed, such as an optical component, is held by a holder 3 and supported by a cantilever 4 via a universal joint 4a so as to be tiltable and rotatable, and is in contact with a machining surface 1a of the machining tool 1 so as to be swingable. ing.

  The processing tool 1 includes a processing surface 1a that is in sliding contact with the processing surface 2a of the processing lens 2 held by the holder 3. On the back side of the processing surface 1a, the processing tool 1 is supported and rotationally displaced. Further, a drive shaft 1b that gives a rocking displacement is connected.

The polishing process is performed while supplying the processing liquid 6 containing the abrasive from the first nozzle 5 to the processing surface 1 a of the processing tool 1.
In the case of the embodiment, a second nozzle 7 is provided in addition to the first nozzle 5, and if necessary, for example, lubricating oil 8 made of a low-viscosity mineral oil is applied to the working surface 1 a of the working tool 1. For example, it can be sprayed and supplied in the form of a mist.

  That is, in the case of the polishing apparatus M of the embodiment, for example, the lubricating oil 8 is intermittently sprayed from the second nozzle 7 to the processing surface 1a simultaneously with the supply of the processing liquid 6 during the polishing process. While polishing.

As a result, the machining fluid 6 and the lubricating oil 8 are supplied between the workpiece surface 2 a of the workpiece lens 2 and the machining surface 1 a of the machining tool 1 during polishing.
In the case of the present embodiment, the processing tool 1 is constituted by a polyurethane sheet pan that is frequently used in high-speed polishing as an example.

  When a certain period of time has elapsed after the start of processing, sludge adheres to the processing surface 1a of the processing tool 1 as the processing surface 2a of the processing lens 2 becomes mirror-finished, and at the same time, as the adhesion increases. Vibration (so-called chattering) occurs and becomes a factor that hinders smooth polishing. At this time, in the present embodiment, the lubricating oil 8 is intermittently sprayed from the second nozzle 7 onto the working surface 1a at the same time while continuing the above polishing process.

  According to the present embodiment, since the lubricating oil 8 is supplied to the contact surface between the processing surface 2a of the processing lens 2 and the processing surface 1a of the processing tool 1, the processing surface is processed by the lubricating effect of the lubricating oil 8. The adhesion force between 1a and the work surface 2a is reduced, and sludge discharge promotion and chatter vibration can be suppressed.

  In this case, the lubricating oil 8 must easily penetrate between the work surface 2a and the working surface 1a, and desirably has a low viscosity so as not to reduce the polishing rate. Further, since the lubricating oil 8 is intermittently sprayed from the second nozzle 7 onto the working surface 1a, only a very small amount of the lubricating oil 8 necessary for lubrication can be supplied. There is no reduction, and further, the amount of use of the lubricating oil 8 can be saved, and the machining fluid 6 and the lubricating oil 8 can be easily separated.

  According to the present embodiment, for example, even if the configuration of a normal polishing apparatus M that does not immerse the processing tool 1 and the lens 2 to be processed into the polishing liquid is maintained, the processing efficiency is not reduced. High-speed polishing can be performed by relatively high-speed rotation of the processing tool 1 while preventing the lens 2 from being scratched.

FIG. 2 shows a graph of the abrasion degree Aa and Knoop hardness HK, which are physical properties of the optical glass.
As shown in FIG. 2, the low-dispersion glass group G2 has a wear degree Aa and Knoop hardness HK that are completely different from those of the general optical glass group G0, as well as the glass group G1 that is easily damaged. Form different groups.

  That is, the group G2 of low dispersion glass and the group G1 of easily scratched glass have an abrasion degree Aa of 200 or more, and the value of the abrasion degree Aa is different from that of a general optical glass group G0 having the value less than 200. Clearly different.

  Similarly, regarding the Knoop hardness HK, the group G2 of the low dispersion glass and the group G1 of the glass that is easily damaged are approximately 550 or less, whereas in the case of the general optical glass group G0, , Dispersed in a wide range of 450 to 800.

  The low-dispersion glass group G2 and group G1 have a soft surface and are likely to be worn, so that the work surface 2a is easily damaged by chatter vibration and sludge. In the present embodiment, as described above, Further, since the vibration is suppressed by supplying the lubricating oil 8 made of mineral oil or the like having a low viscosity to the processing surface 1a of the processing tool 1 and the processing surface 2a of the processing lens 2, the processing lens 2 is, for example, Even in the case of a low-dispersion glass having an abrasion degree Aa of 200 or more and a Knoop hardness HK of 550 or less, high-speed polishing can be performed efficiently without damaging the work surface 2a during polishing.

  That is, even when the lens 2 to be processed is made of a glass material including the group G2 of low dispersion glass and the glass group G1 that is likely to be scratched, the generation of scratches on the processing surface 2a is minimized. Polishing is possible.

  In other words, in the polishing process of the lens 2 to be processed that is made of low-dispersion glass or glass that is easily damaged, it is possible to improve the yield of the lens 2 to be processed and the productivity by improving the throughput.

  In the above-described example, a polyurethane sheet dish is used as the processing tool 1 and the case where the polishing is performed by supplying the processing liquid 6 containing an abrasive such as abrasive grains is exemplified. Instead of the processing tool 1 in FIG. 1, a processing tool 1-1 having a structure in which abrasive grains are dispersed in a resin base material can be used.

  In the fixed abrasive machining using the machining tool 1-1, the contact force between the lens 2 to be machined and the machining tool 1-1 is further increased as compared with the free abrasive machining shown in the above-described embodiment, and the machining surface 2a is subjected to contact. Although it becomes easy to enter a damage | wound, adhesive force is reduced by supplying the lubricating oil 8 which consists of a low-viscosity mineral oil like this Embodiment. The method for supplying the lubricating oil 8 may be continuously or intermittently supplied without spraying depending on the strength of the adhesion between the processing tool 1 and the lens 2 to be processed.

As a result, even in the fixed abrasive machining using the machining tool 1-1, it is possible to suppress the occurrence of chatter vibration and perform high-speed polishing without causing scratches on the workpiece surface 2a of the lens 2 to be processed.
FIG. 3 is a schematic cross-sectional view showing a configuration of a polishing apparatus which is a modification of the present embodiment. In the case of the polishing apparatus M1 of this modification, in addition to the configuration of the polishing apparatus M illustrated in FIG. 1 described above, a processing control unit 10 (processing control means), a supply control valve 11, and a sensor 12 are provided.

The sensor 12 has a function of detecting chatter vibrations of the processing tool 1 and fluctuations in the rotational load of the drive shaft 1b, which is a precursor.
The supply control valve 11 is provided in the second nozzle 7 and has a function of controlling whether or not the lubricant 8 supplied from the second nozzle 7 is supplied and the supply amount.

  The processing control unit 10 is composed of, for example, a microcomputer and the like, and based on information input from the sensor 12 (such as chatter vibrations and fluctuations in the rotational load of the drive shaft 1b that is a precursor thereof) By controlling the opening degree, it has a function of controlling the supply start and stop timing and supply amount of the lubricating oil 8 supplied from the second nozzle 7 to the working surface 1a.

  And the process control part 10 monitors the chatter vibration and the precursor phenomenon of the processing tool 1 through the sensor 12 during the polishing process, and opens the supply control valve 11 when the chatter vibration or the precursor phenomenon is detected. The operation of supplying the lubricating oil 8 to the working surface 1a is automatically performed.

Thereby, the supply operation | movement of the lubricating oil 8 with respect to the working surface 1a can be optimized automatically.
As described above, according to the above-described embodiment of the present invention, for example, when polishing the lens 2 to be processed and the like made of a glass material having a high degree of wear and being easily damaged, such as low dispersion glass. In the general high-speed polishing using the processing tool 1-1 or the processing tool 1-1 using the fixed abrasive grains without depending on the low-speed polishing processing such as submerged polishing with a processing speed limitation, the lens 2 to be processed A polishing process that does not cause defects such as scratches on the processed surface 2a can be realized.

  Needless to say, the present invention is not limited to the configuration exemplified in the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a schematic sectional drawing which shows an example of a structure of the grinding | polishing apparatus which implements the grinding | polishing method which is one embodiment of this invention. It is a graph which shows an example of the physical property of the optical component of the process target of a grinding | polishing apparatus. It is a schematic sectional drawing which shows the modification of the grinding | polishing apparatus which is one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing tool 1-1 Processing tool 1a Processing action surface 1b Drive shaft 2 Processing lens 2a Processing surface 3 Holder 4 Kanzashi 4a Universal joint part 5 1st nozzle 6 Processing fluid 7 2nd nozzle 8 Lubricating oil 10 Processing control part 11 Supply control valve 12 Sensor M Polishing device M1 Polishing device

Claims (9)

A polishing method in which a processing tool is brought into contact with a processing surface of an optical component, and polishing is performed by relatively moving the optical component and the processing tool while supplying a processing liquid,
(A) a step of performing a polishing step while supplying only a machining fluid containing an abrasive;
(B) a step of finishing the step, supplying a lubricating oil together with the machining liquid, and performing the polishing while reducing an adhesion force between the work surface and a working surface of the processing tool by the lubricating oil ; ,
Polishing method characterized by performing. The polishing method according to claim 1,
The lubricating oil is composed of a low viscosity mineral oil,
The mineral oil is intermittently sprayed and supplied when vibration due to an increase in sliding resistance between the optical component and the processing tool occurs or when a sign of occurrence of the vibration is detected. Polishing method. The polishing method according to claim 1,
The polishing method according to claim 1, wherein the optical component has a physical property with an abrasion degree of 200 or more and / or Knoop hardness of 550 or less. The polishing method according to claim 1,
The polishing method, wherein the processing tool is a processing tool based on a resin. A holder for supporting optical components;
A processing tool slidably contacted with the processing surface of the optical component;
A first nozzle for supplying a processing liquid containing an abrasive between the processing tool and the optical component;
A second nozzle for supplying lubricating oil between the processing tool and the optical component;
A drive mechanism for relatively moving the optical component and the processing tool;
The process liquid is discharged from the first nozzle and the lubricant is not discharged from the second nozzle, and the process is terminated, and the process liquid is discharged from the first nozzle and the lubricant is discharged from the second nozzle. A supply control valve for switching between the process of discharging from,
A polishing apparatus comprising: The polishing apparatus according to claim 5, further comprising:
A sensor for detecting a vibration of at least one of the processing tool and the holder and / or fluctuation of a rotational load;
A supply control valve for controlling the supply of the lubricating oil;
Processing control means for controlling the opening of the supply control valve based on fluctuations in the vibration and / or rotational load detected via the sensor;
A polishing apparatus comprising: The polishing apparatus according to claim 6, wherein
The lubricating oil is composed of a low viscosity mineral oil,
When the processing control means detects vibration due to an increase in sliding resistance between the optical component and the processing tool via the sensor, or detects a sign of occurrence of the vibration, the mineral oil is intermittent. A polishing apparatus, wherein the supply control valve is controlled so as to be sprayed and supplied. The polishing apparatus according to claim 5, wherein
The polishing apparatus according to claim 1, wherein the optical component has physical properties with a degree of wear of 200 or more and / or a Knoop hardness of 550 or less. The polishing apparatus according to claim 5, wherein
The polishing apparatus, wherein the processing tool is a processing tool based on a resin.

Images