JP2005022064A - Coating drilling tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating drilling tool excellent in chip discharging property of a groove without requiring a post-process of removing bulky articles. <P>SOLUTION: In the coating drilling tool, assuming an arithmetical mean roughness of an outer peripheral margin section 2 of the coating drilling tool is Ra(M) and an arithmetical mean roughness of the groove is Ra(F), 0.03 μm < Ra(M) < 0.3 μm and 0.01 μm < Ra(F) < 0.15 μm. The postprocessing is not required, the controlled surface roughness of the groove 3 causes improvement of the chip handling property and deficit resistance and chipping resistance in drilling. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a covering drilling tool such as a drill, a gun drill, and a reamer used for drilling. Specifically, by forming an excellent surface state in the outer peripheral margin and the groove, it has excellent chip evacuation, suppresses sudden chipping and chipping during processing, and has a stable long life The present invention relates to a covering drilling tool.

There is a coated tool that has improved welding resistance by removing macro particles on the surface of the coating (see, for example, Patent Document 1). However, there is a problem that peeling occurs from the concave portion (the portion from which the macro particles have been removed) after the removal of the macro particles, and chip clogging occurs suddenly and chipping occurs at the cutting edge, resulting in a short life.

Further, a drill for deep hole drilling has been proposed in which the fine protrusions of the groove portions of the PVD-coated drill are removed by post-processing to try to improve the chip dischargeability (see, for example, Patent Document 2). However, by performing the process uniformly without limiting the processing site, the process is strongly performed even in the margin portion that does not have an influence on the chip disposal, and as a result, more than necessary. In addition, since the surface roughness becomes smooth, the cutting area with the work material increases and the cutting resistance increases, which may in turn lead to a decrease in life. Although a method of masking the outer peripheral margin portion and processing only the groove portion is conceivable, it is extremely difficult to mask the outer peripheral margin portion of all the drills. In addition, the techniques described in Patent Documents 1 and 2 have a problem that costs are increased because separate processing is performed after coating.

JP-A-7-157862 JP 2000-52119 A

In recent years, unmanned manufacturing sites have progressed, and a coated drilling tool that can be machined with high reliability for a long time has been demanded. As a conventional technique, a method has been proposed in which coarse particles present in a coating are removed by post-treatment to improve the tool life. However, these methods have problems such as formation of recesses in the coating and cost. Therefore, an object of the present invention is to provide a covered drilling tool that does not require a post-process for removing coarse particles and is excellent in chip evacuation of a groove.

The present inventor has studied the PVD method for a covering drilling tool for many years, and has improved the outer peripheral margin and groove surface of the covering drilling tool by improving Ar bombarding in place of the conventionally employed metal bombardment. It was found that by making the state optimal for drilling, chipping resistance and chipping resistance were improved and stable long-life processing was possible.

The present invention relates to a coated drilling tool in which a base material is coated with a PVD method, the arithmetic surface roughness Ra (M) of the outer peripheral margin of the coated drilling tool, the arithmetic surface roughness of the groove of the coated drilling tool When expressed as Ra (F), it is a covered drilling tool characterized by 0.03 μm <Ra (M) <0.3 μm and 0.01 μm <Ra (F) <0.15 μm.

Here, the arithmetic surface roughness Ra (M), Ra (F) and the maximum heights Rz (M) and Rz (F) in the surface roughness are measured as shown in FIGS. This is performed at the outer margin portion 2 and the groove portion 3 at a position (AA ′ line) that is 1 to twice the drill diameter d. As a measuring method, either a stylus roughness meter or a laser roughness meter may be used.

When the arithmetic surface roughness Ra (M) of the outer peripheral margin portion is 0.3 μm or more, chipping due to dropping of the surface convex portion is likely to occur. On the other hand, when Ra (M) is 0.03 μm or less, the contact area between the work material and the coating surface is increased, and the cutting resistance is increased to easily cause defects. Therefore, 0.03 μm <Ra (M) <0.3 μm.

When the arithmetic surface roughness Ra (F) of the groove is 0.15 μm or more, the convex portions on the surface of the coating film increase, and particles fall off due to the flow of the chips, and defects due to chip clogging are likely to occur. On the other hand, when Ra (F) is 0.01 μm or less, the contact area between the chip and the coating surface is increased, the frictional resistance is increased, and chip clogging is likely to occur. Therefore, 0.01 μm <Ra (F) <0.15 μm.

For the coated drilling tool of the present invention, the maximum height in the surface roughness of the outer peripheral margin of the coated drilling tool is represented by Rz (M), and the maximum height in the surface roughness of the groove of the coated drilling tool is represented by Rz (F). When 0.03 μm <Rz (M) <3.0 μm and 0.01 μm <Rz (F) <3.0 μm, chipping originating from the coarse particles of the coating is eliminated and more stable processing is achieved. Is preferable.

In the manufacturing process of the coating drilling tool by the PVD method, the bombardment treatment with the atmospheric gas is performed as the pretreatment of the coating, and the atmospheric gas pressure at that time is adjusted to set the length of the mean free process of the atmospheric gas of the base material drilling tool. By setting the conditions according to the groove width, the coated drilling tool of the present invention can be obtained. Specific examples of the bombardment method using the atmospheric gas include a three-pole DC sputtering method using a hot filament. As the atmospheric gas during bombardment, an inert gas is preferable, and Ar is particularly preferable among them. Moreover, W is preferable as the hot filament material. Further, it is preferable that the bias voltage V (bias) applied to the substrate during the bombardment process with the atmospheric gas is 150V <V (bias) <450V. This is because the etching rate increases at 450V or higher and the surface roughness of the substrate becomes rough, and at 150V or lower, the etching rate decreases, thereby increasing the processing time and lowering the production efficiency.

The coating of the coated drilling tool of the present invention is not particularly limited as long as it is a hard coating, but is a group 4a, 5a, 6a element of the periodic table, aluminum, silicon carbide, nitride, oxide, and their mutual solid solutions. Since it is excellent in abrasion resistance, it is preferable that it is 1 or more types selected from these. Specific examples include TiC, TiN, TiCN, TiCNO, TiAlN, TiAlCN, TiAlCNO, TiAlSiN, TiSiN, CrSiN, TiCrN, and Al ₂ O ₃ . Among them, TiAlN is particularly preferable because it is excellent in oxidation resistance and wear resistance.

As the base material of the coated drilling tool of the present invention, cemented carbide, cermet, and tool steel are preferable. Specifically, representative examples are WC-Co, WC- (WTiTa) C-Co, and WC-TaC-Co. Cermets such as cemented carbide, TiC—Mo—Ni, TiCN—WC—TaC—Ni—Co, and tool steels such as high speed tool steel, alloy tool steel, and carbon tool steel. Among them, a cemented carbide containing WC as a main component is particularly preferable because it has high toughness and wear resistance.

The shape of the coated drilling tool of the present invention may be any tool shape used for drilling, and examples thereof include a drill, a gun drill, and a reamer. Among them, since the drill discharges a large amount of chips from the groove portion, the effect of the present invention is high, and it is very preferable to apply the present invention to the drill. One of the uses of the coated drilling tool of the present invention is to drill a metal material.

The coated drilling tool of the present invention is superior in chip evacuation property, chipping resistance, and chipping resistance of the groove as compared with the conventional coated drilling tool. The controlled surface roughness of the groove has the effect of improving chip disposal and the effect of improving chipping resistance and chipping resistance in drilling.

As a base material, a commercially available solid drill (φ 8.0 mm, composition: 90 wt% WC-10 wt% Co, hardness: HRA = 91.5, groove width: 5 mm) is prepared and coated As the coating apparatus, an arc ion plating apparatus capable of mounting a four-pole target was used. First, a base material drill was inserted into the apparatus to make a vacuum of 1 × 10 ⁻³ Pa, heated to 500 ° C. with an in-furnace heater, and then subjected to the conditions of B to I except for A under the conditions shown in Table 1. The materials are subjected to bombarding, and then the materials A to I are coated on the substrates A to I under the coating conditions (target type, atmospheric gas, pressure, bias voltage, treatment time) shown in Table 1. A coated drill was obtained. The arc current during various bombardment treatments and coating treatments was 100 A in all of A to I. Ar bombard was surface-treated by a three-pole DC sputtering method using a W filament.

Arithmetic mean roughness Ra (M) of outer peripheral margin portion and maximum height Rz (M) in surface roughness, arithmetic mean roughness Ra (F) and surface roughness of groove portion in the obtained A to I coated drills The maximum height Rz (F) was measured using a laser roughness meter, and the results are shown in Table 2.

Using the obtained A to I coated drills, drilling was continuously performed under the conditions of work material: S45C, cutting peripheral speed: 80 m / min, hole depth: 40 mm, and dry processing. Table 3 shows the number of holes that can be processed until a sharp torque increase occurs due to chipping, breakage, or chip clogging. When it was normal up to the 400 hole machining, the average flank wear amount of the cutting edge was also shown.

As shown in Table 3, the inventive product can process 2 to 100 times as many holes as the comparative product. The inventive product was free from defects, cutting edge chipping, and clogging of chips as compared with the comparative product, and stable long-life processing was possible.

The side view of this invention covering drilling tool. A position (A-A 'line) twice the diameter d from the tip is shown. Sectional drawing in the A-A 'line of this invention covering drilling tool.

Explanation of symbols

1 Tip 2 Peripheral margin 3 Groove

Claims (4)

A coated drilling tool in which a base material is coated with a PVD method, wherein the arithmetic average roughness of the outer peripheral margin of the coated drilling tool is Ra (M), and the arithmetic average roughness of the groove of the coated drilling tool is Ra ( A coated drilling tool represented by F3: 0.03 μm <Ra (M) <0.3 μm and 0.01 μm <Ra (F) <0.15 μm. When the maximum height in the surface roughness of the outer peripheral margin portion of the above-described coated drilling tool is represented as Rz (M), and the maximum height in the surface roughness of the groove portion of the coated drilling tool is represented as Rz (F), 0.03 μm < 2. The coated drilling tool according to claim 1, wherein Rz (M) <3.0 μm and 0.01 μm <Rz (F) <3.0 μm. The film is one or more selected from Group 4a, 5a, and 6a elements of the periodic table, aluminum, silicon carbide, nitride, oxide, and their mutual solid solutions. The covered drilling tool according to 1 or 2. The said base material consists of 1 type chosen from cemented carbide, cermet, and tool steel, The covering drilling tool of any one of Claims 1-3 characterized by the above-mentioned.

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