JPS5852031Y2 - Reamer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reamer, and particularly to improvements in a reamer for reaming aluminum alloys and the like.

A reamer is a rotary cutting tool that reams and widens a pre-prepared pilot hole to achieve a smooth finished surface. (the flank surface behind the cutting edge) is an important point.

This cutting edge part is located in the chamfer part that forms the mounting mold at the tip of the hammer, and serves to finish it to the specified size by boring out a pilot hole prepared in advance. It fertilizes the roughness of the hole wall that has occurred by scraping, regulates the size of the hole, and serves as a guide for the reamer and to prevent deformation of the workpiece.

The cutting edge is generally formed at an angle of 45 degrees, but for special purposes it is set at an angle suitable for the workpiece in the range of 40 to 50 degrees, and for synthetic resins, an even smaller angle is used.

The occurrence of wear on the cutting edge of a reamer is noticeable at the corner of the cutting edge, and in order to prevent this wear and to achieve a smooth finish on the wall of the machined hole, the corner is rounded, but machining this curved surface is difficult. , it tends to worsen the finished surface.

A polygonal cutting edge having two angles is sometimes used for the same purpose, but the disadvantage is that the cutting edge becomes long, making re-grinding inconvenient.

On the other hand, in conventional high-speed steel or cemented carbide reamers, a built-up edge is formed at the cutting edge and margin and work-hardened during the cutting operation.

This built-up cutting edge deteriorates cutting accuracy and surface roughness, lowering work efficiency, and furthermore, when the built-up cutting edge falls off, the cutting surface is seriously damaged.

Such wear and built-up edge problems are particularly serious when machining non-ferrous metals such as aluminum alloy (18% 5i-A, /,), and when high cutting accuracy and surface roughness are required, carbide The alloy reamer had a short lifespan and could only process 20 to 30 pieces, making it completely impossible to use it on a mass production line.

In order to eliminate this drawback, we used a tip in which an ultra-high-pressure sintered body of artificial diamond is fixed to a cemented carbide base (for example, one commercially available as Diamond Compax), which is a sintered body of artificial diamond. A reamer formed by brazing is considered.

According to this reamer, there are almost no built-up edges that occur during reaming work, improving cutting accuracy and surface roughness, lengthening the life of the tool itself, and increasing work efficiency.

However, this method requires a large number of ultra-high-pressure sintered bodies, making it unavoidably expensive.Also, since the reamer has a long blade and multiple blades, it is difficult to bond the carbide. - When used for machining reamed aluminum alloy (18% 5i-A, /,) with a shape similar to that of a reamer and an ultra-high l feeder, it has no affinity with cutting oil and has few diamond particles. Because of this, the cutting oil does not flow well and generates heat.

Temperature unevenness occurs depending on the binding and the conditions around the machined hole, and the roundness of the machined hole deteriorates based on the difference in thermal expansion, making it easy to chatter, making it difficult to guarantee the quality of the cutting process and making it impractical. .

The purpose of this invention is to provide a reamer that is as inexpensive as possible, provides good finishing accuracy and surface roughness, and is suitable for machining aluminum alloys and has a long life. However, in a back-tapered reamer that has multiple blade parts, some of the blade parts are cutting blades made of ultra-high pressure sintered body, and the other blade parts are made of guide blades made of cemented carbide. In addition, the guide blade is slightly retracted from the cutting blade in a direction parallel to the axis.

In this way, the highest hardness and wear resistance of diamond are utilized in the cutting edge, making it possible to perform reaming with less generation of built-up edges.In addition, the guide blade has a button that allows it to function as a guide during reaming and to cut the workpiece. Since the role of preventing objects from deforming is reduced, chattering and curling marks are prevented from occurring.
Good surface roughness, roundness, and dimensional accuracy without variation can be obtained, and the tool life can be significantly increased.
Since the ultra-high pressure sintered body has a small number of cutting edges, it can be provided at an extremely low cost.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIGS. 1 and 2 show a solid type reamer, and the tip thereof has six blades each having a grasshopper taper.

Among them, four blade parts 1, 2, 3, and 4 are guide blades made of cemented carbide, and two blade parts 3 and 6 are cutting blades made of ultra-high pressure sintered body.

The cutting blades 3 and 6 of this ultra-high pressure sintered body are formed by mounting a sintered body of artificial diamond on a blade base 8 on the circumference with the tip fixed to a cemented carbide base as the center axis. It is formed by being fixed.

The guide blades 1, 2, 4, and 5 are formed on a circumference centered on the axis, and as shown in FIG. The part that is attached to the main shaft) is moved back to the side.

In the implementation row shown in Figure 3, the retraction scale for a minute distance is 0.2
~0.3yu+, and grasshopper taper M is Ooo 0
It is 6/30.

In this way, the guide blades 1°2.4 and 5 are retracted by a certain distance on the blade portion having the grasshopper taper, so they are retracted by a very small amount in the radial direction than the cutting blades 3 and 6. .

Further, the angle θ of the chamfer portions of the cutting blades 3 and 6 and the guide blades L2 and 4°5 is set to 15 degrees.

With this configuration, when a workpiece with a pilot hole is reamed, the two cutting edges 3 and 6 at the tip are first hardened by the highest hardness characteristic of the ultra-high pressure sintered body. The guide blade L2, 4, and 5 act as guides to keep the blade from steadying, while the holder is able to fully demonstrate its sharpness and cut the pilot hole.
It also reduces the shedding of silicon contained in the work material.

In this way, the cutting edges 3 and 6 have the highest hardness and wear resistance,
In addition, by taking advantage of the characteristics of diamond, which produces fewer work-hardened built-up edges during cutting operations, it enables excellent rotary cutting with no variation in cutting precision such as surface roughness, roundness, and dimensional accuracy, and also extends the life of the tool. It improves it.

In addition, because we use the minimum number of ultra-high pressure sintered cutting edges necessary for cutting, and all other guide blades are made of low-cost cemented carbide, compared to using diamond cutting blades for all blades. This makes it extremely inexpensive.

However, if the above-mentioned guide blades L2 and 4.5 are not provided and all the blade parts are made of ultra-high pressure sintered material, the blade edge may chatter during cutting or the tool may crack after hole drilling is completed. Although it is impossible to reduce the return mark generated during pulling out by 0, OO 1 (111) tl, this embodiment has a feature that can prevent both chatter and return mark.

The reason for this is that the free end of the cantilevered rotary cutting tool is held by the workpiece itself, which increases rigidity and prevents center runout, as well as preventing heat generation from the rigidity of the workpiece during cutting. This is because the cutting blade can be extracted from the hole to be machined while the guide blade prevents contraction of the hole to be machined after expansion caused by elastic deformation.

According to an experiment using the reamer of this example, the machined hole diameter was 45 mm.
Me, rotation speed 4000 r, p, m, cutting speed 56.5 m
/mm, feed amount O025/rev, depth of cut 0.15
~0゜2, there is some puttiness due to the machine used under cutting conditions using water-soluble cutting oil, but the roundness is 0.0024 (2)
゜4μ) ~ 00005 (5μ), surface roughness 0.0003
(0°3μ) to 0.00095 (0.95μ) (including division marks), the variation in dimensional accuracy is almost unchanged from the original, and the life is 20~3μ compared to cemented carbide.
It has been found that when only 0 pieces can be processed, if the reamer of this embodiment is used, it is possible to continuously process 9000 pieces or more, and it can be used satisfactorily in a mass production line.

Next, a brazing type reamer having a two-stage blade portion will be explained based on FIGS. 4 to 6.

As shown in the figure, the reamer tip 20 has eight blades with a grasshopper taper, of which 11, 12, 13
, 15, 16, and 17 are guide blades made of cemented carbide, and the two blade parts 14° and 18 are cutting blades made of ultra-high pressure sintered body.

Similarly, six guide blades 21, 22, 23, 25° 26. 27 and two cutting edges 24, 28 are provided.

The guide blades in the tip portion 20 and the stepped portion 30 are both retracted by a distance on the blade portion having a grasshopper taper with respect to the corresponding cutting blade, and are retracted by a very small amount in the radial direction than the cutting blade. This is the same as in the previous implementation column.

This series of gluer can be applied to reaming stepped workpieces without any chatter or return marks, and there is no variation in cutting accuracy.Furthermore, it has been proven that it can be used as a permanent fixture for a long time. Similar to the example.

For the explanation above, we have shown an example in which the reamer tip is provided with four to six guide blades made of cemented carbide and two cutting blades made of ultra-high pressure sintered body. A specific example of the above example is
This is merely an example of the most preferable implementation of the present invention, and the present invention is not limited to this in any way.The number of cutting blades and guide blades, the number of stages including the tip, etc. are within the knowledge of those skilled in the art. It goes without saying that the present invention can be implemented with various modifications and improvements based on the above.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional view of a reamer showing an embodiment of the present invention, Fig. 2 is an end view of its cutting edge, and Fig. 3 is a cutting blade 3.
, 6 is an explanatory diagram showing the retreated position of the guide blade L2, 4°5 and the grasshopper taper with respect to the guide blade L2, 4°5. FIG. 4 is a partially omitted cross-sectional IIE plane view of another embodiment, FIG. 5 is an end view of FIG. 4, and FIG. 6 is a Vl-VI sectional view taken from FIG. 4. 3.6, 14, 18, 24, 2B... Cutting blade (ultra high pressure sintered body), 1, 2, 4, 5. lL12,13u15.16
, 1γ, 2L22, 23, 25°26.2γ... Guide blade (carbide), L... Slight retreat distance.

Claims (1)

[Claims for Utility Model Registration] A back-tapered reamer with multiple blades, some of which are cutting blades made of ultra-high pressure sintered body, and the other blades are guides made of cemented carbide. A part of the invention characterized in that the guide blade is set back from the cutting blade by a slight amount in a direction parallel to the axis.