JP2010076025A - Precision machining method of cutting blade of rotary multi-blade tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precision machining method capable of reducing the dimensional difference from the center of rotation of a cutting blade of a rotary multi-blade tool by forming cyclic grooves specific to each cutting blade in the rotary multi-blade tool, specifying the outermost circumferential cutting blade and determining the target machining amount from a machining striation, and successively repeating the working. <P>SOLUTION: In the precision machining method of the cutting blade of the rotary multi-blade tool, comb-blade grooves of different patterns are formed on a circumferential surface ridge or an end face ridge of each cutting blade of the rotary multi-blade tool by each cutting blade, a sample is cut by using the rotary multi-blade tool, the outermost circumferential cutting blade is specified from the pattern of the width of the lowest valley of a worked surface, and the specified outermost circumferential cutting blade is worked by the amount of the difference between the lowest valley and the highest hill of the working surface with an optional excessive working amount β added thereto. By successively repeating this work, the height of the cutting blade is aligned at high accuracy. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a precision machining method for a high-precision rotary multi-blade tool capable of cutting with high machining accuracy and excellent surface roughness, such as a tool used for machining an optical element.

In some cases, a sawtooth waveform is required for processing an X-ray mirror, a liquid crystal backlight, or the like.
FIG. 1 illustrates a processing model of a hologram optical element of an X-ray mirror. FIG. 1A is a perspective view illustrating a state in which the X-ray hologram optical element is cut with a rotary multi-blade tool. ) Is a perspective view showing a state of machining with one cutting edge in a rotary multi-blade tool, (c) is an enlarged view of the tip of the cutting edge, and (d) is an enlarged view of a cross section of the optical element. Yes.
The present inventor has developed a rotary multi-blade tool using a single crystal diamond cutting edge, and in this connection, the diamond cutting edge may be described as an example below, but the same applies to other tools. .

  FIG. 2 shows an enlarged view of a sawtooth groove machined with a rotary multi-blade tool. A thin line shows each cutting edge, and a thick line shows the shape of the valley. When a sawtooth waveform is machined using a rotary multi-blade tool, if the heights of the cutting edges are not uniform as shown in FIG. 2, the sawtooth valley width of the workpiece is widened and is not sharpened. In addition, although there are a plurality of cutting edges, the number of cutting edges that actually contribute to the processing is reduced, which causes vibration.

It is necessary to align the heights of a plurality of single-crystal diamond cutting edges (hereinafter, simply referred to as “cutting edges”) of a rotary multi-blade tool that is processed to process a brittle ceramic material with high quality. .
Conventionally, in a tool having a blade portion on the outer peripheral end face of a rotating base metal, a single layer of superabrasive grains having a uniform average particle diameter is fixed to the blade portion by metal plating, and the fixed superabrasive particles are fixed to a predetermined reference line. A rotary multi-blade tool having a variation within ± 5 μm is known (hereinafter referred to as conventional technology; for example, see Patent Document 1).
Japanese Unexamined Patent Publication No. 9-47968

In the above-mentioned prior art, the variation in the height of the cutting edge is adjusted within ± 5 μm, but the height of the cutting edge cannot be adjusted by submicron.
In order to solve this, the following three typical methods are conceivable.
1. The cutting edge that has been processed in advance is aligned with the cutting edge with submicron accuracy and bonded to the base.
2. After attaching the cutting blade to the pedestal, the height of the pedestal is controlled by piezo or the like.
3. After attaching the multi-blade tool to the shaft, the outermost peripheral cutting edge is identified and the outermost peripheral cutting edge is repeatedly ground to align the cutting edge height.
The present invention relates to the above-mentioned “3.” In a rotary multi-blade tool, a periodic groove unique to each cutting edge is provided, the outermost cutting edge is specified from the machining streak, the target machining amount is determined, An object of the present invention is to provide a precision machining method capable of reducing the difference in dimension from the rotation center of the cutting edge of the rotary multi-blade tool by sequentially repeating this process.

  In order to achieve the above object, the precision machining method of the cutting edge of the rotary multi-blade tool according to the present invention is a comb-like groove having a different pattern depending on the cutting edge on the peripheral edge line or end face ridge line of each cutting edge of the rotary multi-blade tool. The sample is cut using this rotary multi-blade tool, the outermost peripheral cutting edge is identified from the pattern of the lowest valley width of the processed surface, and the outermost peripheral cutting edge is processed. It is characterized by aligning the cutting edge height with high accuracy by sequentially repeating the process of adding an optional excess machining amount β to the difference between the lowest valley and the highest mountain on the surface. .

The precision machining method of the cutting edge of the rotary multi-blade tool of the present invention has the following excellent effects.
(1) The height difference of the cutting edge of the rotary multi-blade tool can be adjusted to submicron.
(2) The sawtooth-shaped valley bottom width of the workpiece is narrowed and can be processed sharply.
(3) Since a plurality of cutting edges contribute to actual machining, vibration during machining can be suppressed.

  Hereinafter, with reference to the drawings, an embodiment of the precision machining method of the cutting edge of the rotary multi-blade tool of the present invention will be described in detail. However, the present invention is not limited to this and is not interpreted. Various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art without departing from the scope of the invention.

  FIG. 3 is a perspective view showing a state where the rotary multi-blade tool is mounted on the rotary shaft. In the thing of FIG. 3, the rotary multiblade tool is comprised by the eight cutting blades. The number of cutting edges is not limited to this.

4A and 4B show a single cutting edge 1. FIG. 4A is a view seen from the rotational direction, FIG. 4B is a side view of FIG. 4A, and FIG. 4C is a front view of FIG. .
In FIG. 4, (A) is the end face, (B) is the peripheral face, (C) is the rake face, (D) is the end face cutting edge angle, (E) is the peripheral face cutting edge angle, and (F) is the end face clearance angle. , (G) is the circumferential clearance angle, (H) is the edge ridgeline, and (R) is the circumferential ridgeline.
The cutting edge 1 in FIG. 4 shows a case where there are a peripheral surface (b) and an end surface (b), but there are also a tool having only a peripheral surface (b) and a tool having only an end surface (b).

[Summary of the Invention]
The processing of the cutting edge 1 is performed in order to align the height from the center of rotation to the end surface ridge line (H) and the peripheral surface ridge line (L), and the end surface (A) of the cutting edge having a high end surface (A) and the peripheral surface (B) ) Polishing the peripheral surface (b) of the cutting edge having a high height.
That is, the highest cutting edge is identified, the target machining amount of the identified highest cutting edge is obtained, and the highest cutting edge is expressed as target machining amount + excess machining amount β (hereinafter simply referred to as “β”). In some cases, the cutting edge height is made uniform by repeating the polishing process sequentially.

(Generation of cutting edge)
After polishing the end ridge line (chi) and peripheral ridge line (re) of the target cutting edge 1 into a highly accurate straight line, a large or small comb blade is formed on the end ridge line (chi) and peripheral ridge line (re) with a laser or the like. Periodic grooves are inserted. In this case, the groove may be only a large groove or a small groove. Thereafter, the cutting edge height is measured without rotating the shaft on which the rotary multi-blade tool is mounted, and processing for aligning the cutting edge height is performed. The comb blade pattern (cycle) is different for each cutting edge.

[Avoiding adverse effects of comb blades]
If machining is performed with only one comb blade, the valley portion of the comb blade is raised on the machining surface and the remaining machining surface roughness is deteriorated. By disposing a plurality of comb blades at different periods, deterioration of the processed surface due to the valleys of the comb blades is prevented.

[Example of comb blade]
In FIG. 5, the enlarged view of the peripheral surface ridgeline (re) of the cutting blade 1 is shown. The same applies to the end surface ridge line (H), but for the convenience of description, the peripheral surface ridge line (L) will be described as an example. The comb-shaped groove shown in FIG. 5 is a combination of one large groove 2 having a triangular shape (here, a triangular shape formed by laser processing is illustrated but may be a square shape or the like) and two small grooves 3. It has been repeated.
FIG. 6 shows a dimensional model of one cycle of the comb blade. One cycle is before the right large groove 2 on the right side. When the distances from the left end of the large groove 2 on the left side to the bottoms of the large grooves 2 and the small grooves 3 and 3 are A, B and C, and the period is D, the cutting edge 1 has a small groove corresponding to the large groove 2 and the small grooves 3 and 3 and a hill. It has cutting edge parts 4, 5, and 6.

[Example of comb blade cycle]
FIG. 7 shows eight comb blade models representing an enlarged view of the ridge line of the circumferential ridge line (re) assuming a rotary multi-blade tool composed of eight cutting edges. FIG. 7 shows a cutting cycle model of 1 cycle + α including the large groove 3 of the next cycle, and the combination of dimensions of the large groove 2, the small groove 3 and the hills 4, 5, 6 is changed.

  FIG. 8 shows eight comb blade models showing the relationship between the length of the groove and the hill in the horizontal direction. The problem here is not the absolute value of the numerical value but the relative value of the dimensions of all the comb blades. Shaded areas indicate grooves and open areas indicate hills. A model with a width of one cycle consisting of large and small grooves and cutting edge hills is shown. The large groove width in the figure is set to about twice the small groove width, but the actual large groove width is assumed to be 20 to 200 μm. ing.

In FIG. 8, in order to specify the highest cutting edge among the eight comb blades, that is, the outermost peripheral cutting edge, the time when the lengths of the hills 4, 5, 6 are short on the basis of the hill length is 0. In this case, 0 to 7 are shown in binary notation, where 1 is a long time. Binary numbers are discriminated from the long part and short part of the hill, but in the example, the whole period is adjusted. Is adjusted for a longer time so as not to be confused by discrimination.
One example of the comb blade processing cycle method is a method of changing the cycle because only binary numbers are used, or a method of changing the entire cycle. Further, these methods may be combined and either one of them may be employed. In the example of FIG. 8, a binary number and the entire period are combined.

[Identification of outermost cutting edge by comb blade]
FIG. 9 shows a model of the machined surface when a sample 7 having good shape transfer such as oxygen-free copper is cut using a rotary multi-blade tool provided with a comb blade. Many cutting edges of the rotary multi-blade tool are involved in the machining surface 8. The width of the lowest valley of the processed surface is the processed surface by the outermost peripheral cutting edge.

  FIG. 10 shows a processing model when the sample 7 is cut using three comb blades 10, 11, and 12. When the machining surface by the comb blades 10, 11, and 12 is 8, it can be specified that the comb blade 12 is the outermost peripheral cutting edge from the dimensions of the peaks 14, 16, 18 and the valleys 15, 17, 19 of the machining surface 8.

[Target processing amount of outermost cutting edge with comb blade]
A target machining amount E of the outermost peripheral cutting edge is obtained from the shape of the machining surface 8 in FIG. The target machining amount E is obtained as a difference in height between the lowest surface of the machining surface 8 and a high mountain.

[Treatment method when the comb blade height is equal]
In FIG. 10, the distance from the rotation center is premised on that the resolution of the measuring instrument is sufficiently high and there is no cutting edge of the same height.
In the unlikely event that the distance from the center of the two cutting edges is the same as the resolution of the measuring instrument, the two outer cutting edges can be identified from the least common multiple of the period of the two large grooves. In this case, it is necessary to change the cutting edge height by changing the processing amount of the two outermost cutting edges.
At first glance it seems to contradict the purpose of aligning the heights, but when two or more cutting edges are aligned at a height higher than the resolution of the measuring instrument, or when the two common cutting edges cannot be obtained with the least common multiple Is to change the processing amount of all cutting edges. The amount of machining should be within the target accuracy of the machining process. For example, 0, 0.1, 0.2, 0.3,... Μm.

[Method of aligning the cutting edge height by specifying the outermost cutting edge]
The outermost peripheral cutting edge is polished by about β more than the target processing amount E. The purpose of machining by as much as β is (1) to prevent the cutting edge heights from being aligned, and (2) to quickly converge the cutting edge height. The value of β is arbitrarily determined by the operator. Moreover, it does not need to be constant in each processing.
The aim is to align the cutting edge height with high accuracy by repeating machining and specifying the outermost cutting edge and gradually reducing the difference in cutting edge height.

[Processing accuracy improvement model with comb blade]
Table 1 shows an improvement model of processing accuracy by a comb blade.
Polishing of single crystal diamond is finished in four steps of 4, 2, 0.5, and 0.1 μm, as indicated by the larger abrasive grain size distribution. In Table 1, the difference in height of all cutting edges targeted in each process is represented as target accuracy. In this method, the machining efficiency is good in rough machining of 4 μm, but it is difficult to control the dimensions. On the other hand, in the finishing process using ultrafine particles of 0.1 μm, the dimension control is easy, but the machining efficiency is very poor. It is preferable to move to the next step by reducing the difference in distance from the rotation center of the cutting blade group as young as possible.
When the outermost peripheral cutting edge is specified and processed, the numerical value of the cutting edge and the target processing amount + β is recorded, and after all the cutting edges are processed, the process proceeds to the next step. By recording β, the difference in the height of the cutting edge can be estimated. Machining is completed after processing to the desired accuracy.
In practical use, accuracy up to 10 nm is often not required.

It is a figure which illustrates the processing model of the hologram optical element of an X-ray mirror. It is an enlarged view of the saw-tooth groove processed with the rotary multi-blade tool. It is a perspective view which shows the state with which the rotary multiblade tool was mounted | worn with the rotating shaft. 1 shows a single cutting edge, where (a) is a view seen from the direction of rotation, (b) is a side view of (a), and (c) is a front view of (a). It is an enlarged view of the peripheral surface ridgeline of a cutting edge. It is explanatory drawing which shows the dimension model of the comb blade of 1 period. It is a perspective view which shows the eight comb blade models which represent the ridgeline enlarged view of a surrounding surface ridgeline. It is explanatory drawing which shows eight comb blade models which show the relationship between the length of a groove | channel and a hill in a horizontal direction. It is a perspective view which shows the model of the processing surface when a sample is cut using the rotary multiblade tool which provided the comb blade. It is explanatory drawing which shows the process model when the sample is cut using three comb blades.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cutting edge 2 Large groove 3 Small groove 4 Cutting edge hill 5 Cutting edge hill 6 Cutting edge hill 7 Sample 8 Processing surface 10 Comb blade 11 Comb blade 12 Comb blade 14 Pile of processing surface 15 Valley of processing surface 16 Cutting surface Mountain 17 Valley of machining surface 18 Mountain of machining surface 19 Valley of machining surface

Claims (1)

  Comb-like grooves with different patterns are formed by the cutting edges on the peripheral ridge line or end face ridge line of each cutting edge of the rotary multi-blade tool. The outermost peripheral cutting edge is identified from the pattern of the lowest valley width, and an arbitrary excess machining amount β is added to the difference between the lowest valley and the highest peak of the machining surface with respect to the identified outermost circumferential cutting edge. A precision machining method for the cutting edge of a rotary multi-blade tool, characterized by aligning the cutting edge height with high precision by sequentially repeating the process of machining as much as is added.