JPH0768446A - Cutting method - Google Patents

Abstract

PURPOSE:To provide a cutting method by which moderate cooling is carried out according to a cutting condition and excellent cutting can be maintained. CONSTITUTION:In the case of a cutting method by which cutting is carried out by bringing a cutting tool 14 into pressure contact with the surface of a work 2, a spraying nozzle 20 that can jet a liquid toward a cutting point in a foglike state without receiving air supply, is provided, and cutting processing is conducted while foglike bodies are being jetted through this spraying nozzle 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting method in which a cutting tool is pressed against a surface of a workpiece to perform cutting.

[0002]

2. Description of the Related Art Conventionally, in a cutting process performed by various machine tools such as a milling machine, a machining center, a lathe, and a drilling machine, a cutting fluid is applied to a cutting point for cutting a workpiece to cool the cutting heat. However, since the above-mentioned liquid application is usually performed at a low pressure of about 0.1 to 1 kg / cm ² , the cooling effect is not sufficient. That is, the higher the cutting speed, the more S
In the cutting of carbon steel such as 45C, the cutting heat hardens the work surface as if it were hardened, and the chips with the cutting heat are scattered on the work table, and the work, or the work or cutting tool Since the mounting jig is covered, the covered part is heated and expands, and if you cut in that state, the processing dimensions will be incorrect, the work surface will melt due to the cutting heat, and the metal that has melted on the cutting blade of the cutting tool will So-called "configured cutting edge"
It was found that there are problems such as the formation of cracks and the inability to cut.

Therefore, it has been difficult to perform high-speed cutting in the conventional cutting process, but the present inventor has developed a new cutting method in order to meet the above-mentioned problems. That is, in this method, for example, in a horizontal milling machine, as shown in FIG. 4, cutting is performed while discharging a high pressure liquid of 10 kg / cm ² or more from a high pressure liquid nozzle 15 toward a cutting point by a milling cutter 14. The high-pressure liquid can effectively cool the cutting point and remove chips. In FIG. 4, 11 is a spindle that rotates at high speed in the main body 10, and 13 is an arbor for attaching a milling cutter that is detachably fitted in a tapered hole 12 at the tip of the spindle 11. 2 is a work piece.

[0004]

However, in the cutting process, the generation of cutting heat causes the above problems, but on the other hand, there is an advantage that the work is softened by the cutting heat and the cutting resistance is lowered. This is also true, and depending on the cutting conditions, in the cutting method shown in FIG. 4, the workpiece may be excessively cooled, the cutting resistance may not be reduced, and the cutting performance may be deteriorated. In particular, in the intermittent cutting in which the workpiece and the cutting edge collide intermittently to perform cutting, such as the above-mentioned milling or end milling, the cutting edge rapidly generates heat during cutting, and immediately after that, it is rapidly cooled by high pressure liquid. There is also a problem that cracks are likely to occur in the cutting blade because the rapid thermal changes that occur are repeated.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a cutting method capable of maintaining appropriate cutting by appropriately cooling according to cutting conditions.

[0006]

In order to achieve the above object, a cutting method of the present invention is a cutting method in which a cutting tool is pressed against a surface of a workpiece to perform cutting, and a liquid is directed toward a cutting point. A spray nozzle capable of spraying in a mist state without receiving air supply is provided, and a high-pressure liquid is supplied to the spray nozzle to perform cutting while spraying a mist.

[0007]

In other words, the inventor of the present invention uses a high-pressure liquid to suppress heat generation at the cutting point and heat generation of chips, because cooling is performed rapidly and excessively depending on cutting conditions, which causes a disadvantage. A series of studies were conducted on cooling means in which the above-mentioned demerits do not occur and a certain cooling effect can be obtained by reducing the cooling effect to some extent. And in the process, we considered using a spray nozzle that sprays the liquid in a mist state, but the normal spray nozzle is
Air is supplied from an air source (usually a supply pressure of about 1 to 10 kg / cm ² ) and the liquid is sucked and ejected by the atomization phenomenon due to the air flow, so the thrust of the atomized body that is ejected is low and it is sufficient for the cutting part. I found that I couldn't enter. Therefore, as a result of further research, when spraying a liquid in a mist state, a special spray nozzle that can atomize only the liquid supplied at high pressure without receiving air supply,
It has been found that when the atomized body is jetted toward the cutting point, cooling is performed, which has a slightly lower cooling effect than the rapid cooling effect by the high-pressure liquid, but can sufficiently prevent troubles due to heat generation. Reached

Next, the present invention will be described in detail based on embodiments.

[0009]

FIG. 1 shows an example in which the present invention is applied to a horizontal milling machine similar to that shown in FIG. 4. The basic structure is the same as that in FIG. 4, and the same parts are designated by the same reference numerals. . In this device, 20 is a spray nozzle capable of spraying a liquid in a mist state, so that a predetermined liquid such as water or water containing an extreme pressure additive is supplied at a high pressure and can be sprayed without receiving air supply. It has become. And this spray nozzle 20
As shown by the arrow P in FIG. 2, the milling cutter 14
The cutting blade 14a is set so as to aim at the cutting point from the rake face 30 side.

As described above, the spray nozzle 20 is capable of spraying only the liquid supplied at high pressure in the form of mist, unlike the normal spray nozzle, without receiving the air supply from the air source. Then, for example, the structure shown in FIG. 3A is used. The spray nozzle 20 is adapted to be attached to the liquid supply pipe 21 via a flange portion 20b, and an X-shaped whirler 22 is fitted in a space serving as a liquid passage in the nozzle body 20a. As shown in FIG. 3 (b), this whirler 22 has a semicircular portion 22 a that crosses half of the liquid passage obliquely formed and a semicircular portion 22 b that crosses the other half obliquely formed in the opposite direction. Has become X-shaped. Therefore, the liquid introduced into the spray nozzle 20 is divided into a liquid flow swirling as shown by an arrow A and a liquid flow swirling as shown by an arrow B when passing between the whirls 22. Split 2
The liquid streams come out while colliding with each other at the nozzle injection ports, and thereby spraying with a uniform flow rate distribution is made. The liquid supply to the spray nozzle 20 is
It is preferable to set a high pressure of usually 3 kg / cm ² or more, particularly 5 kg / cm ² or more.

The spray nozzle 20 has a function of repelling the generated chips, and at the same time, cools the portion of the workpiece 2 into which the cutting edge of the cutting blade 14a is about to enter to suppress heat generation gently. Therefore, generation of thermal influence on the workpiece 2 and the cutting blade 14a is suppressed.
And even if the workpiece 2 is carbon steel such as S45C, it does not become hard as hardened, and the surface of the workpiece 2 is not melted by cutting heat to form a "constituent edge". . Further, the sliding portion of the lathe and the like will not be covered with the high temperature chips and thermally expanded, so that the processing dimension will not be distorted. Furthermore, the so-called "No. 2" blade edge (the blade that collides with the surface of the workpiece 2 and bites into it is "No. 1", which was easily damaged in the past, and "No. 2" forms the cutting edge angle with this No. 1 blade. The other side) is less likely to be damaged. However, the direction of the atomized body sprayed by the spray nozzle is not necessarily limited to the rake face side of the cutting blade 14a, and the cutting point may be aimed from an appropriate direction depending on the processing conditions.

In addition to the above spray nozzle 20, FIG.
A high-pressure liquid nozzle 15 as shown in FIG. The high-pressure liquid nozzle 15 may be ejected from any direction as long as it is aimed near the cutting point. For example, the spray nozzle 2 may be used.
It can be arranged in the same direction as 0 to switch between atomized body ejection and high-pressure liquid ejection as necessary. Further, the high pressure liquid nozzle 15 may be provided so as to aim at the cutting point from the cutting blade flank 31 side, as shown by an arrow Q in FIG. By discharging the high-pressure liquid from the flank 31 side, the cutting point and the cutting tip of the cutting blade 14a can be cooled from the immediate vicinity, and the cooling effect of the spray nozzle 20 is further reinforced. However, depending on the cutting conditions, the high-pressure liquid nozzle 15 may not be used, and even if it is used, the liquid discharge pressure can be adjusted.

Further, as described above, discharging the high-pressure liquid from the cutting edge flank 31 side is suitable for continuous cutting in which the amount of heat generation increases with time, but for intermittent cutting. It is desirable to make the cooling effect slower so that the temperature does not change rapidly. Therefore, it is preferable to use the special spray nozzle 20 for the nozzle on the side of the cutting blade flank 31 as well as the nozzle on the side of the rake face, and place importance on the lubricating effect rather than the cooling effect.

Further, the spray nozzle 20 need not necessarily be the one shown in FIG. For example, the flange portion 14b may be omitted and the mounting portion may be a screw-in type.

Further, the cutting blade 1 of the milling cutter 14 described above.
4a may be made of any material, for example, an ultrafine particle cemented carbide obtained by sintering tungsten carbide particles and cobalt particles (having an average particle size of 0.3 to 1.0).
It is preferable to use μ, the mixing ratio of tungsten carbide particles and cobalt particles is 85 to 90% by weight of tungsten carbide and 15 to 10% by weight of cobalt). That is, although the above ultrafine particle cemented carbide has conventionally been advantageous in that it is hard and has high toughness, it is vulnerable to heat, and thus it can be conventionally used only at low temperatures (low speed cutting). When the spray from the high pressure liquid and the high pressure liquid discharge from the high pressure liquid nozzle 15 are used together, the workpiece 2
Also, the cutting blade 14a is not excessively cooled, a proper cooling effect is obtained, and good cutting can be maintained for a long period of time without damaging the cutting edge of the cutting blade 14a even when cutting at high speed. .

The above embodiment shows an example in which the present invention is applied to a horizontal milling machine, but of course, it is applied to various cutting machines such as a vertical milling machine, a drilling machine, a planing machine, a lathe, or a machining center. can do.

[0017]

As described above, the cutting method of the present invention is
Since the liquid is atomized and ejected toward the cutting point without being supplied with air, the cooling effect is slightly lower than the rapid cooling effect of the high-pressure liquid, but there are problems caused by sufficient heat generation. Preventable cooling can be provided. Therefore, in continuous cutting, it is possible to intentionally allow a certain amount of heat to soften the workpiece and reduce the cutting resistance, and in intermittent cutting, the cutting blade repeats rapid temperature changes due to gentle cooling. Can be prevented and the tool life can be extended.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment in which the present invention is applied to a horizontal milling machine.

FIG. 2 is an explanatory view of a main part of the above embodiment.

FIG. 3A is an explanatory view of a structure of a spray nozzle used in the above embodiment, and FIG. 3B is an explanatory view of a whirler fitted in the spray nozzle.

FIG. 4 is an explanatory view of a conventional horizontal milling machine.

[Explanation of symbols]

 2 Workpiece 14 Milling cutter 14a Cutting blade 20 Spray nozzle

Claims (3)

[Claims] 1. A cutting method in which a cutting tool is pressed against a surface of a workpiece to perform cutting, wherein a spray nozzle capable of spraying a liquid toward a cutting point in a mist state without receiving air supply is provided. A cutting method characterized in that a high-pressure liquid is supplied to a spray nozzle to perform cutting while spraying an atomized body from the spray nozzle. 2. The cutting method according to claim 1, further comprising a high-pressure liquid nozzle that discharges a high-pressure liquid together with the spray nozzle, ejects a mist from the spray nozzle according to claim 1, and discharges the high-pressure liquid nozzle from the high-pressure liquid nozzle. The cutting method according to claim 1, wherein the cutting process is performed while discharging the high-pressure liquid. 3. The liquid supply pressure to the spray nozzle is 3 kg / c.
The cutting method according to claim 1 or 2, which is set to m ² or more.