JP2006198746A - Method for finishing cutting surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate rainbow color exhibited by reflected light from a machined surface formed by cutting without manual polishing. <P>SOLUTION: Cutting streaks on the machined surface are eliminated or deformed in the range from top parts of crest parts of the cutting streaks to bottom surfaces of trough parts by colliding particles (media 2) such as polishing materials against the machined surface of a workpiece 9 formed by the cutting. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface finishing technique, and more particularly to a technique for finishing a machined surface, which is suitable for forming an optical element itself or a molding die of an optical element.

  Conventionally, in a mold used for molding a plastic lens which is an optical element, an electroless nickel plating layer made of Ni (nickel) and P (phosphorus) capable of ultra-precise cutting is provided on the mold, In general, an optical mirror surface is processed by cutting.

Further, when a small amount of plastic lens is manufactured, the plastic itself is directly ultra-precisely cut into an optical mirror surface.
In these cutting processes, using a diamond cutting tool with good edge contour accuracy, cutting depth is set to several micrometers, and the feed rate is set to several millimeters per minute, the roughness Ra is several nanometers. An optical mirror surface of about a meter can be obtained (see Non-Patent Document 1, for example).
Supervised by Akira Kobayashi, “Ultra Precision Production Technology System (Volume 1) Basic Technology”, Fuji Techno System, October 22, 1995, p. 67-68

  On the processed surface formed by the above-described cutting, regular cutting streaks created by the cutting tool are formed. When white light is incident on such a processed surface, the reflected light from the processed surface may exhibit a rainbow color due to interference of light at regular cutting streaks.

This iridescent color may cause a problem in product function depending on the use of the optical element. In such a case, it is necessary to remove the cutting streak by performing polishing after cutting.
However, this polishing process is required to maintain the shape created by ultra-precise cutting while preventing the optical mirror surface from being scratched. Has been made. For this reason, there are problems such as poor yield, high cost of processed products as a result of processing man-hours, variations in quality due to manual processing, and limited processing workers to skilled technicians.

  The present invention has been made in view of the above-described problems, and a problem to be solved is to eliminate the fact that reflected light from a processed surface formed by cutting processing exhibits a rainbow color regardless of hand polishing. That is.

  A finishing method of a cutting surface which is one aspect of the present invention is to cause a particle to collide with a processing surface of a workpiece formed by cutting, so that the cutting streaks on the processing surface are It is characterized in that it is removed or deformed within the range from the top of the crest of the cutting streak to the bottom of the trough, and this feature solves the aforementioned problems.

In the above-described finishing method according to the present invention, the cutting streaks may be removed using a material harder than the workpiece as the particles.
Further, in the above-described finishing method according to the present invention, the cutting streak may be deformed by using a material having the same or soft material as the workpiece as the particle.

  Moreover, in the finishing method according to the present invention described above, a particle in which second particles made of a material harder than the workpiece are held around the first particles made of an elastic body as the particles. You may make it use.

Moreover, in the finishing method according to the present invention described above, particles having a size equal to or smaller than the pitch of the cutting streaks may be used as the particles.
Further, in the above-described finishing method according to the present invention, the workpiece may be a molding die having a molding surface formed by cutting or an optical element having an optical mirror surface formed by cutting.

  According to the present invention, it is possible to eliminate the fact that the reflected light from the processed surface formed by the cutting process exhibits a rainbow color without depending on hand polishing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 conceptually shows an example of the configuration of an apparatus for injecting particles such as abrasives (hereinafter referred to as media).
In the media tank 1, a belt conveyor 3 is provided for transporting the media 2 accumulated at the bottom of the media tank 1 upward.

  A projection unit 4 is installed near the top of the belt conveyor 3. The projection unit 4 includes a hopper 5, an impeller 6, a nozzle 7, and a motor (not shown) that rotates the impeller 6.

A workpiece (workpiece) 9 is placed on the mesh plate 10 in the processing chamber 8.
The operation of the media ejection device having the above configuration will be described.
The media 2 accumulated at the bottom of the media tank 1 is conveyed upward in the media tank 1 as the belt conveyor 3 rotates. At the position where the belt conveyor 3 has passed the apex (the highest point) and the traveling direction has started to move downward, the media 2 falls obliquely downward due to the gravity acting on the media 2 itself and the rotation of the belt conveyor 3. To do.

A hopper 5 is disposed at the drop position of the medium 2. Therefore, most of the falling media 2 is collected in the hopper 5.
The medium 2 that has passed through the hopper 5 in the downward direction passes through the nozzle 7 at a high speed and is projected from the tip of the nozzle 7 by the centrifugal force of the impeller 6 that rotates at high speed. The work 9 is processed by arranging the work 9 in the projection direction of the medium 2.

  The projected media 2 passes through the gap of the mesh plate 10 and accumulates at the bottom of the media tank 1. Therefore, thereafter, the medium 2 circulates in the apparatus by the action of the belt conveyor 3.

Next, the processing method in the present Example with respect to the workpiece | work 9 performed using this media ejection apparatus is demonstrated, referring FIG.2, FIG.3 and FIG.4.
Here, the workpiece 9 will be described below as a mold for molding an optical element. The workpiece 9 is formed by forming a molding surface by applying an electroless nickel plating made of Ni (nickel) and P (phosphorus) to a steel material as a base material, and uses a diamond cutting tool having a good cutting edge contour accuracy. In addition, ultra-precise cutting was performed under conditions of a cutting depth of several micrometers and a feed rate of several millimeters per minute.

  As shown in FIGS. 2 and 3, on the surface of the work 9 (work surface 11), cutting streaks 12, to which the tip shape of the diamond bite is transferred, periodically exist at intervals of a pitch 13. ing. This pitch 13 corresponds to a tool feed amount per one rotation of the workpiece at the time of cutting. Further, as shown in FIG. 3, the height difference from the peak of the cutting streak 12 to the bottom of the trough is defined as the cutting streak depth 14.

  Such a workpiece 9 is arranged at a predetermined position of the media ejection device shown in FIG. 1, and the media ejection device is operated, so that the workpiece 9 is made of a material harder than the material of the workpiece 9 (ie, the cutting striation 12). The media 2 (for example, abrasive particles such as diamond, alumina, silicon carbide, chromium oxide, etc.) having a pitch of 13 or less is ejected from the nozzle 7 to collide with the work surface 11.

  Thereby, the peak part of the cutting streak 12 is removed preferentially, and as shown in FIG. 4, it becomes the workpiece | work surface 15 which has a random unevenness | corrugation. It should be noted that the removal amount at this time is such that the particle size and projection of the media 2 are within a range that does not exceed the range from the top of the crest 12 to the bottom of the trough (that is, the depth 14 of the cut). Adjust speed and projection time.

  As described above, according to the present embodiment, by projecting the medium 2 made of a material harder than the material of the workpiece 9 onto the workpiece surface 11, the crests of the cutting streaks 12 having a regular structure are removed. Since the workpiece surface 15 has random irregularities, the light incident on the machining surface of the workpiece 9 after machining is irregularly reflected, so that the reflected light from the machining surface does not exhibit a rainbow color.

  Also in the present embodiment, the workpiece 9 is processed using the media ejection device shown in FIG. However, in the present embodiment, media 2 (for example, particles of nylon, polycarbonate, polyester, etc.) made of a material that is not harder than the material of the workpiece 9 and having a thickness of several micrometers or less (that is, the pitch 13 or less of the cutting streak 12) is used. Use.

  When the workpiece 9 is arranged at a predetermined position of the media ejection device shown in FIG. 1 and the media ejection device is operated, the media 2 ejected from the nozzle 7 collides with the workpiece surface 11 at a high speed. Then, the crests of the cutting streaks 12 are dipped, and the workpiece surface 15 having random irregularities as shown in FIG. It should be noted that the deformation amount at this time is such that the particle size and projection of the media 2 are within a range that does not exceed the range from the top of the crest 12 to the bottom of the trough (that is, the depth of the cut crest 14). Adjust speed and projection time.

  As described above, according to the present embodiment, by projecting the media 2 made of a material that is not harder than the material of the workpiece 9 onto the workpiece surface 11, the crests of the cutting streaks 12 having a regular structure are deformed. Since the workpiece surface 15 has random irregularities, the light incident on the machining surface of the workpiece 9 after machining is irregularly reflected, so that the reflected light from the machining surface does not exhibit a rainbow color. Furthermore, since the medium 2 made of a material that is not harder than the material of the work 9 is used, the surface of the work 9 is not scratched, so that the appearance quality is not impaired.

  Also in the present embodiment, the workpiece 9 is processed using the media ejection device shown in FIG. However, in the present embodiment, as shown in FIG. 5, around particles (elastic body particles 16) made of an elastic body such as rubber and having a size of several millimeters or less (that is, a pitch 13 or less of the cutting streak 12), Holds particles (abrasive particles 17) made of a material harder than the material of the workpiece 9 (for example, diamond, alumina, silicon carbide, chromium oxide, etc.) of several micrometers or less (that is, the pitch 13 or less of the cutting marks 12). The media 2 is used.

  When the workpiece 9 is arranged at a predetermined position of the media ejection device shown in FIG. 1 and the media ejection device is operated, the media 2 ejected from the nozzle 7 collides with the workpiece surface 11, thereby The crests are removed preferentially, and the workpiece surface 15 having random irregularities as shown in FIG. 4 is obtained as in the first and second embodiments. It should be noted that the removal amount at this time is such that the particle size of the particles 16 and the particles so that the removal amount does not exceed the range from the top of the crest 12 to the bottom of the trough (that is, the depth 14 of the cutting streak). 17 particle size, projection speed, and projection time are adjusted.

  As described above, according to the present embodiment, the media 2 holding the abrasive particles 17 made of a material harder than the material of the workpiece 9 is projected around the elastic particles 16 onto the workpiece surface 11. Since the crests of the cutting streaks 12 having a typical structure are removed and the workpiece surface 15 has random irregularities, the light incident on the machining surface of the workpiece 9 after machining becomes irregularly reflected. The reflected light from the rainbow does not appear iridescent. Further, when the media 2 collides with the surface of the work 9, the impact speed of the media 2 rapidly decreases due to the elastic force of the elastic particles 16, so that the surface of the work 9 is not deeply scratched. Appearance quality is not impaired.

  As described above, according to each of the above-described embodiments, since the removal amount or deformation amount of the cutting streak 12 is processed within a range not exceeding the cutting streak depth 14, the shape created by the ultra-precise cutting process is formed. The rainbow color can be removed while maintaining. In other words, the quality and yield rate are improved, the number of processing steps is greatly reduced, and even an inexperienced worker can easily perform processing compared to the work that is required by hand polishing. Thus, a high-quality optical element can be provided at a low cost.

  In each of the above-described embodiments, the mold for forming an optical element is the workpiece 9. However, an optical element having an optical mirror surface obtained by directly ultra-precise cutting an optical material itself such as plastic is defined as the workpiece 9, and each of the above-described components. Of course, it is also possible to manufacture the optical element by finishing the optical mirror surface of the optical element by the processing method according to the embodiment.

  In addition, the present invention is not limited to the above-described embodiments, and various improvements and changes can be made without departing from the gist of the present invention.

It is a conceptual diagram of a media ejection apparatus. It is a figure which shows the state of the workpiece | work surface after cutting. It is sectional drawing of the workpiece | work surface after cutting. It is sectional drawing of the workpiece | work surface after finishing. FIG. 10 is a diagram illustrating a medium used in Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Media tank 2 Media 3 Belt conveyor 4 Projection unit 5 Hopper 6 Impeller 7 Nozzle 8 Processing chamber 9 Work piece 10 Mesh plate 11 Work surface 12 Cutting stripe 13 Pitch 14 Cutting stripe depth 15 Post-working workpiece surface 16 Elastic particle 17 Abrasive particles

Claims (6)

  By causing particles to collide with the processed surface of the workpiece formed by cutting, the cutting streaks on the processing surface are removed within the range from the top of the crest to the bottom of the trough. Alternatively, a method of finishing a cutting surface, wherein the cutting surface is deformed.   The finishing method according to claim 1, wherein a material that is harder than the workpiece is used as the particles.   The finishing method according to claim 1, wherein a material that is the same as or soft to the workpiece is used as the particles.   The finish according to claim 1, wherein a material in which second particles made of a material harder than the workpiece are held around the first particles made of an elastic body is used as the particles. Processing method.   The finishing method according to any one of claims 1 to 4, wherein particles having a size equal to or smaller than a pitch of the cutting striations are used as the particles. The said workpiece is a shaping | molding die which formed the shaping | molding surface by cutting, or the optical element which formed the optical mirror surface by cutting, The one of Claim 1 to 5 characterized by the above-mentioned. Finishing method.

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