JP2008194779A - Diamond reamer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diamond reamer capable of solving the problem where circularity of the hole of a workpiece becomes polygonal and the problem where high efficiency machining cannot be performed due to the vibration caused by dynamic unbalance generated as the number of rotation is increased. <P>SOLUTION: The diamond reamer is equipped with a self guide function and a cutting function for respective three blades at the same time. The three blades employs an equally divided system so as to divide the outer periphery of the diamond reamer into three parts or unequally divided system. When using for a high efficiency machining in high speed rotation, the equally divided system capable of improving the dynamic balance is preferable. For the phenomenon where polygonal hole is generated due to the occurrence of chattering, the unequally divided system is preferable. In that case, it responds to the high speed rotation by providing the dynamic unbalance amount to the portion other than blades. The outer periphery of any one blade of three blades is preferably set to be the margin width of 0.02-0.1 mm and the outer periphery of other two blades is preferably set to be the margin width of 0.2-0.5 mm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a diamond reamer that not only enables high-efficiency cutting but also provides high-precision machining accuracy.

Generally, a hole processed by a drill or the like is not highly accurate, and a good finished surface cannot be obtained. There are various finishing methods for finishing such prepared holes to the required dimensional accuracy and surface roughness. However, the most easily used machining method is the reaming method. Are known. Holes finished with a reamer are characterized by high dimensional accuracy, roundness and very good surface roughness.
In particular, a 4-blade 8-point guide (double land, sub-land) is used for high-precision finishing of holes. When high efficiency is prioritized, there are many examples that use a reamer with a 4-blade 8-point pad. There is a problem that the roundness of the hole of the workpiece processed by the blade runout of the cutting tool tends to become a polygon. Highly accurate holes can be obtained by strictly managing these. The roundness obtained at that time is 2 to 4 μm.
(For example, see Patent Document 1)

Furthermore, in particular, a single-blade gun reamer is used for high-precision finishing of holes. A single-blade gun reamer has one blade with a cutting function and the other is a self-guided function, which eliminates the problems of multiple blades. Greatly inferior to the blade. Furthermore, since it is not axially symmetric, the dynamic balance is poor and vibration occurs as the rotational speed is increased. Therefore, there is a big problem that high-efficiency machining with an increased rotational speed is not possible. The roundness that can be obtained with a single blade gun reamer is 1.5 to 3.0 μm.
(For example, see Patent Document 2)

JP 2003-340646 A JP-A-8-52617

  The present invention is intended to solve the above problems. In other words, it solves the two problems that the roundness of the hole of the machined workpiece becomes a polygon and the problem that the dynamic balance is bad and the vibration is generated as the rotation speed is increased, so that high-efficiency machining cannot be performed. It is.

The present invention is a diamond reamer having three blades, each of which has a self-guide function and a cutting function at the same time.
Here, the three blades are of an equal division type so as to divide the outer periphery of the diamond reamer into three equal parts, or an unequal division type. When the rotational speed is increased and used for high-efficiency cutting, it is preferable to use an equally divided type that can increase the dynamic balance. Moreover, it is preferable to use an unequal division type for the phenomenon in which chattering occurs and a polygonal hole is generated. In this case, a dynamic unbalance amount is provided in a portion other than the blade (a considerable amount is added or deleted) to cope with high-speed rotation.
Further, each of the three blades has a self-guide function and a cutting function at the same time. That is, since each of the three blades has a margin width on the outer periphery, this acts as a self-guide function, and since each has a cutting edge, this acts as a cutting function.

In detail, the present invention is characterized in that the blade material is one selected from sintered diamond, polycrystalline diamond and single crystal diamond, or two or more.
Depending on the material of the workpiece, hardness, required hole expansion, roundness, surface roughness, processing conditions, etc., one or two of sintered diamond, polycrystalline diamond and single crystal diamond is used as appropriate. Select one or more.

More specifically, the outer periphery of any one of the three blades has a margin width of 0.02-0.1 mm, and the outer periphery of the remaining two blades has a margin width of 0.2-0. It is characterized by being 5 mm.
The present invention adopts a minimum number of contacts for determining a circle, that is, a three-point support (three-point pad) design, and one of the three locations has an outer margin width of 0.1 mm or less. The blade has a higher cutting ability than the other two. Further, the other two pads also form a blade at the tip portion, and this portion is also involved in the cutting, and high-efficiency cutting can be realized. As shown in Fig. 1, the chamfered parts at the three tips are two places where the cutting ability of the cutting edge with a small outer margin margin is higher than the other two places, and the cutting force is intentionally (forced by design) with a larger outer margin. The pad is designed to be pressed against the inner peripheral surface of the workpiece. Due to this effect, it is possible to maintain a stable processing accuracy in which the cutting tool does not shake during the cutting process (no shaking).
Here, the outer periphery of any one of the three blades cannot serve as a pad if the margin width is less than 0.02 mm. On the other hand, if it exceeds 0.1 mm, the cutting ability decreases, which is not preferable. The margin width is more preferably 0.02 to 0.08 mm, and most preferably 0.02 to 0.05 mm.
Further, if the margin width is less than 0.2 mm on the outer periphery of the remaining two blades, the pad effect cannot be sufficiently obtained, and the blades may fluctuate during cutting, which is not preferable. On the other hand, if the thickness exceeds 0.5 mm, the cutting resistance increases, which may cause burns on the processed surface. The margin width is more preferably 0.2 to 0.4 mm, and most preferably 0.25 to 0.4 mm.

  It is possible to provide a diamond reamer that not only enables high-efficiency cutting but also provides high-precision machining accuracy. In particular, it is possible to provide a diamond reamer capable of obtaining extremely good results by cutting a nonferrous metal material such as an aluminum alloy or a copper alloy. In particular, it can contribute to the production of various mass-produced parts at low cost and high efficiency.

  The best mode for carrying out the invention will be described in the Examples section.

A diamond reamer having a diameter D of 40 mm and three blades shown in FIGS. 1 to 3 with an equally divided type and using sintered diamond as the blade material was manufactured. The smallest margin width is the A blade, the margin width Ma is 0.05 mm, the remaining two are the B blade, and the margin width Mb is 0.4 mm. In addition, each dimension of the blade is as follows. g was 0.25 mm, c was 0.08 mm, d was 0.1 mm, e was 6 mm, f was 1 mm, α was 60 °, β was 15 °, and γ was 5 °.
This diamond reamer was attached to a machining center, and an aluminum alloy was subjected to a cutting test to confirm the effect of the present invention. The details of the test cutting conditions are as follows.
The cutting speed was 180 m / min, the feeding speed was 460 mm / min, the feeding amount was 0.12 mm / rev, the machining allowance was 0.4 mm in diameter, and emulsion water-soluble oil was used as the cutting fluid. As a result of processing, the roundness of the hole was 1.8 μm, and the surface roughness was 0.8S.

Using the diamond reamer of Example 1, the test was performed under the same conditions as in Example 1 except for the cutting conditions. The details of the test cutting conditions are as follows.
The cutting speed was 300 m / min, the feeding speed was 770 mm / min, the feeding amount was 0.12 mm / rev, the machining allowance was 0.4 mm in diameter, and an emulsion water-soluble oil was used as the cutting fluid. As a result of processing, the roundness of the hole was 2.0 μm, and the surface roughness was 0.8S.

Using the diamond reamer of Example 1, the test was performed under the same conditions as in Example 1 except for the cutting conditions. The details of the test cutting conditions are as follows.
The cutting speed was 500 m / min, the feeding speed was 1270 mm / min, the feeding amount was 0.12 mm / rev, the machining allowance was 0.4 mm in diameter, and emulsion water-soluble oil was used as the cutting fluid. As a result of processing, the roundness of the hole was 2.5 μm, and the surface roughness was 0.8S.

Comparative Example 1

A test was conducted in the same manner as in Example 1 using a single-blade gun reamer shown in FIG. The details of the test cutting conditions are as follows.
The cutting speed was 180 m / min, the feeding speed was 300 mm / min, the feeding amount was 0.08 mm / rev, the machining allowance was 0.4 mm in diameter, and an emulsion water-soluble oil was used as the cutting fluid. As a result of processing, the roundness of the hole was 1.8 μm and the surface roughness was 1.0S.

Comparative Example 2

A test was performed in the same manner as in Example 1 using a 4-blade 8-point pad diamond reamer shown in FIG. The details of the test cutting conditions are as follows.
The cutting speed was 180 m / min, the feeding speed was 460 mm / min, the feeding amount was 0.12 mm / rev, the machining allowance was 0.4 mm in diameter, and emulsion water-soluble oil was used as the cutting fluid. As a result of processing, the roundness of the hole was 2.5 μm, and the surface roughness was 0.8S.

Comparative Example 3

Further, the same test as in Example 1 was performed using a diamond reamer with a 4-blade 8-point pad as in Comparative Example 2. The details of the test cutting conditions are as follows.
The cutting speed was 300 m / min, the feeding speed was 770 mm / min, the feeding amount was 0.12 mm / rev, the machining allowance was 0.4 mm in diameter, and an emulsion water-soluble oil was used as the cutting fluid. As a result of processing, the roundness of the hole was 5.0 μm, and the surface roughness was 0.8S.

  From the above test results, it was found that according to the present invention, high-efficiency cutting can be performed, and the hole after the processing can obtain high-precision roundness and extremely good surface roughness.

The left view of the diamond reamer of Example 1 is shown. The side view of Example 1 is shown. The details of A blade and B blade of Example 1 are shown. A conventional single blade gun reamer is shown. A conventional 4-blade 8-point pad diamond reamer is shown.

Explanation of symbols

1 Diamond reamer Ma A blade margin width Mb B blade margin width

Claims (3)

A diamond reamer with three blades,
Each of the three blades has a self-guide function and a cutting function at the same time, and is a diamond reamer.   2. The diamond reamer according to claim 1, wherein a material of the blade is one selected from sintered diamond, polycrystalline diamond, and single crystal diamond, or two or more.   Among the three blades, the outer periphery of any one blade has a margin width of 0.02 to 0.1 mm, and the outer periphery of the remaining two blades has a margin width of 0.2 to 0.5 mm. The diamond reamer according to claim 1 or 2.

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