JPH0425309A - Cutting method and device therefore - Google Patents

Abstract

PURPOSE:To enable satisfactory cutting work by using a cutting tool provided with a blade made of super-fine grain sintered hard alloy and jetting high pressure liquid having at least 10kg/cm<2> of jet pressure toward a cutting point as cooling water. CONSTITUTION:A cutting edge 14a made of super-fine frain sintered hard alloy is used, and high pressure liquid having at least 10kg/cm<2> of jet pressure is jetted toward a cutting point of a contact point of the cutting edge 14a with a workpiece 2. Thus, the cutting point is instantly cooled by the high pressure liquid to prevent the exothermic reaction in the cutting point from the transmission to the workpiece 2 and the interior of the cutting edge, so that the workpiece 2 and cutting edge 14a are not subjected to the thermal damage. Thus, high speed cutting is performed so that even the hard workpiece 2 can be satisfactorily cut for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a cutting method for performing cutting using a milling machine, a machining center, etc., and an apparatus used therefor.

[Conventional technology]

In cutting processes such as milling and end milling, a rotary tool with multiple cutting blades on the outer periphery or end face of a cylinder is used, and the tool is pressed against the workpiece while rotating at high speed, and the cutting blades intermittently machine the workpiece. It is designed to cut the surface of objects. For example, a flat milling cutter used for surface cutting is generally shown in Figure 3 (front view) and Figure 4 (right side view).
The cutting blade 1 protrudes from the circumferential surface at predetermined intervals and collides with the workpiece 2 intermittently to perform cutting. In addition, when cutting harder materials, a front view that can efficiently perform plane cutting perpendicular to the rotation axis is available, as shown in Figure 5 (front view) and Figure 6 (right side view). A milling cutter is used. Most of the above-mentioned face milling cutters are of the implanted type, in which the cutting blade 1a made of a carbide material is screwed onto the circumference of the tip of the milling cutter body at predetermined intervals, and the cutting blade 1a is made of expensive cemented carbide. Since the price is not very high even if it is used, it is widely used instead of materials such as high-speed steel.

As a cemented carbide for such a cutting tool, tungsten carbide (WC) particles and cobalt (co) particles with an average particle size of 2 to 5μ are combined with tungsten carbide 90
Examples include those blended and sintered at a ratio of ~98% by weight and 1-10-2% by weight for edges.

[Problems that the invention attempts to solve]

However, although such cutting tools with cemented carbide cutting blades have the advantage of excellent impact resistance and low wear, they are vulnerable to temperature changes, so they cannot be used with multiple cutting blades intermittently, such as milling cutters and end mills. When grinding is performed by directly colliding with the workpiece, if cutting is performed while spraying cooling water (wet method), the cutting edge will alternate between being at a high temperature at the cutting point and being cooled by the cooling water, resulting in this rapid It has the disadvantage of cracking due to repeated thermal changes. Therefore, when using such a cutting tool made of cemented carbide, the cutting is usually performed using a dry method without using cooling water. However, if cooling water is not used, there will be operational problems. In other words, ■ Chips generated by cutting cannot be removed, and the cutting edge of the cutting tool gets caught in the chips, resulting in a chipped edge. ■ When cutting carbon steel such as 345C, the surface of the workpiece is hardened by the cutting heat. As the chips become hard and difficult to perform surface finishing operations such as polishing, the surface of the workpiece is coated with cutting heat, causing the workpiece itself to heat up and expand. Misalignment occurs, ■The surface of the workpiece melts due to cutting heat,
There are problems such as molten metal adhering to the cutting edge of a cutting tool, forming a so-called "built-up edge" and making cutting impossible.

In order to avoid such problems, some methods are used to perform cutting while applying oil to the cutting part, but oil has a weak cooling power, and the heat generated during cutting can cause a fire if oil is used. It can be dangerous.

On the other hand, in order to compensate for the drawbacks of the above-mentioned cutting tools made of cemented carbide, cutting tools made of ultra-fine particle cemented carbide have been developed in which the particle diameter of each particle constituting the alloy is extremely small. In other words, this material has an overall average particle diameter of around 0.5μ, and has a higher cobalt content (approximately 12% by weight) compared to conventional cemented carbide, so it has high toughness. It has the excellent property of being difficult to break.

However, on the other hand, it is sensitive to heat and the cutting edge will break if it is not cut at low temperatures.Although it is possible to apply cooling water (normal pressure), it is difficult to increase the machining speed because it is necessary to suppress heat generation. ing.

As described above, with conventional cutting methods, it is difficult to effectively cut by taking advantage of the characteristics of cemented carbide, and a solution to this problem has been desired.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a method that allows effective cutting with a cutting tool made of cemented carbide, and a device used therein.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for cutting a workpiece by intermittently colliding a cutting blade with the workpiece, the cutting blade being made of ultrafine particle carbide. A material made of alloy is used, and a discharge pressure of 1 is applied toward the cutting point, which is the contact point between the cutting edge and the workpiece.
The first gist is a cutting method in which high-pressure liquid of 0 kg/afi or more is projected, and the cutting method includes a workpiece support means for supporting the workpiece, and a plurality of blades formed in the circumferential direction, whose cutting edges rotate to move the workpiece into the workpiece. A cutting tool configured to perform cutting by intermittently colliding with an object, a rotary drive means for rotating the cutting tool at high speed, and a rotary drive means for appropriately moving the cutting point of the cutting blade and the workpiece. A cutting device equipped with a moving means, wherein each month of the cutting tool is made of ultrafine cemented carbide, and a high-pressure liquid with a discharge pressure of 10 kg/cm2 or more is projected toward the cutting point. The second gist is the cutting equipment used.

[Effect]

That is, the present inventor conducted a series of studies on a method for effective cutting with a cutting tool made of cemented carbide.

As a result, we now use a cutting tool with a blade made of ultra-fine cemented carbide, which could only perform low-temperature cutting, and project high-pressure liquid with a discharge pressure of 10 kg/cm2 or more toward the cutting point as cooling water. Then, the cutting point is instantly cooled by the high-pressure cutting fluid, and there is almost no heat transfer to the workpiece and the inside of the cutting tool cutting edge, so the cutting tool cutting edge is always kept in a low temperature state. The present invention was achieved by discovering that a cutting blade made of cemented carbide performs very good cutting without undergoing significant thermal fluctuations.

Next, the present invention will be explained in detail based on examples.

〔Example〕

FIG. 1 shows an example in which the present invention is applied to a horizontal milling machine. This device has the same basic configuration as a normal horizontal milling machine, including a spindle 11 that rotates at high speed within a main body 10, and an arbor for attaching a milling cutter that is removably fitted into a tapered hole 12 at the tip of the spindle 11. 13, and a milling cutter 14 attached to the tip of this taper 13.
It is equipped with In this figure, the milling cutter 14 is a face milling cutter, and cuts the vertical surface of the workpiece 2 attached to a table (not shown) while feeding the workpiece 2 in the X, Y, and Z directions. It is now possible to do so. Moreover, 15 is a high-pressure water discharge nozzle especially provided in the present invention.

A predetermined cooling aqueous solution such as water containing an extreme pressure additive is 10 to 2
It is designed to be discharged at a high pressure of 0.00 kg/cd.

There is no problem with the discharge direction of the discharge nozzle 15 as long as it is directed toward the cutting point, but in particular, the direction of rotation of the milling cutter 14 is taken into consideration, as shown in FIG. 2, which is a cross-sectional view taken along line A-A' in FIG. Then, from now on, the cutting blade 14a is applied to the workpiece 2.
By projecting high-pressure water in the direction where the water is trying to enter,
This is preferable because it can effectively cool the cutting point and remove chips. Alternatively, a nozzle 15 for projecting high-pressure water in the direction in which the cutting edge 14a is about to enter the workpiece 2 is provided, and another nozzle 15' is provided as shown by the chain line in FIG. By cutting edge 14
By projecting high-pressure water also in the direction immediately after a emerges from the workpiece 2, chips can be removed more effectively.

Further, each cutting edge 14a of the milling cutter 14 needs to be made of ultrafine cemented carbide. As mentioned above, the ultrafine particle cemented carbide is composed of, for example, sintered tungsten carbide particles and cobalt particles, and has an average particle diameter of 0.3 to 1.0μ,
Generally, the blending ratio of tungsten carbide particles and cobalt particles is set to 85 to 901% by weight of tungsten carbide and 15 to 10% by weight of cobalt.

When cutting is performed using this horizontal milling machine device while discharging high-pressure water from the high-pressure cutting water discharging nozzle 15, the high-pressure water instantly cools the cutting point and acts against the workpiece 2 and the cutting edge 14a. Even though the cutting blade 14a of the milling cutter 14 can be used only at low speeds, the cutting edge of the cutting blade 14a can be cut at high speeds without damaging the cutting edge. Good cutting quality can be maintained over a long period of time. To give a more specific example, for a 355C workpiece, with a φ10 end mill 2-blade cutter, the cutting speed is 10 Q m/aiin,
1 incision.

When cutting with a cutting width of 2 mm, the cutting feed rate is set to 500.
mm/minm/m type. In addition, since the cutting heat is not stored, the workpiece 2 is made of wire steel such as 345C.
It does not become hard like hardening, making it easier to perform surface finishing work such as polishing. Furthermore, the surface of the workpiece 2 will not melt due to cutting heat and a built-up cutting edge J will not be formed. Moreover, since the high-pressure water instantly removes chips from the cutting point, the cutting edge 14a There is no possibility that the workpiece 2 will be bitten and cause the blade to spill, or that the workpiece 2 itself will not thermally expand and the machining dimensions will be distorted.Furthermore, due to the action of the pressurized water, the so-called "2"
(The blade that collides with the surface of workpiece 2 and bites into it is
No. J, and "No. 2" refers to the blade on the other side that forms the tip angle of the cutting edge with this No. 1 blade).

In the above embodiment, the present invention is applied to a horizontal milling machine, but of course it can also be applied to a vertical milling machine or a machining center. In addition, as a cutting tool, a face milling cutter 14 is used in the above embodiment, but in addition to various milling cutters, end mills, hobs, etc.
Any tool may be used as long as it rotates and causes its cutting blade to collide with the workpiece 2 intermittently to perform cutting.

〔Effect of the invention〕

As described above, the present invention uses a cutting tool equipped with a blade made of ultrafine cemented carbide, and projects high-pressure liquid with a discharge pressure of 10 kg/cd1 or more as cooling water toward cutting. It is something. Therefore, according to the present invention, the cutting point is instantly cooled by the high-pressure liquid, and almost no heat generated at the cutting point is transmitted to the workpiece or cutting tool cutting edge, so that neither the workpiece nor the cutting edge is thermally damaged. I never receive it. As a result, cutting tools made of ultrafine grain cemented carbide, which were previously only capable of low-temperature cutting, i.e., low-speed cutting, are now capable of high-speed cutting, making it possible to perform good cutting over a long period of time even on hard workpieces. became.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the essential parts of an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line AA', FIGS. 3 and 4 are explanatory diagrams of a conventional flat milling cutter, and FIG. and FIG. 6 are explanatory diagrams of a conventional face milling cutter.

Claims (3)

[Claims] (1) A method of cutting by intermittent collision of a cutting blade with a workpiece, in which the cutting blade is made of ultrafine cemented carbide, and the contact point between the cutting blade and the workpiece is A cutting method characterized in that a high-pressure liquid with a discharge pressure of 10 kg/cm^2 or more is projected toward a certain cutting point. (2) A workpiece support means for supporting a workpiece, and a cutting device configured to have a plurality of blades formed in the circumferential direction and whose cutting edges intermittently collide with the workpiece as it rotates to perform cutting. A cutting device comprising a tool, a rotary drive means for causing the cutting tool to rotate at high speed, and a moving means for appropriately moving the cutting blade and the cutting point of the workpiece, the cutting device comprising: A cutting device characterized in that the blade is made of ultra-fine particle cemented carbide and is configured to project high-pressure liquid with a discharge pressure of 10 kg/cm^2 or more toward the cutting point. (3) The ultrafine particle cemented carbide has an average particle diameter of 0.3 to
The cutting device according to claim 2, wherein the cutting device is composed of 1.0 μm tungsten carbide particles and cobalt particles.