JP6437828B2 - CUTTING TOOL BLANK, CUTTING TOOL BLANK MANUFACTURING METHOD, CUTTING TOOL, AND CUTTING TOOL MANUFACTURING METHOD - Google Patents

Description

  The present invention relates to a cutting tool blank used for a cutting tool such as a drill or an end mill, a manufacturing method of a cutting tool blank, a cutting tool, and a manufacturing method of a cutting tool.

  As a drill used for drilling, a solid drill in which a flute groove is formed from the tip of the tip is known. For example, it is used for drilling a substrate on which an electronic component is mounted. And since the hole diameter processed with the miniaturization of an electronic component is small, the thing with a small diameter of a drill is requested | required.

  In order to manufacture such a drill, for example, as in Patent Document 1, a blank obtained by cutting a fired molded body formed into a fiber shape by extrusion molding into a predetermined length is manufactured, and the blank is made of stainless steel or the like. After joining to a shank, the method of giving a step process, a flute groove, etc. to a blank and completing a drill is employ | adopted. Further, as a blank forming method, a press forming method as in Patent Document 2 has been studied.

  Moreover, although it is requested | required that the abrasion resistance of a cutting blade should be improved, since there exists a tendency for toughness to fall when the hardness of a raw material is raised, there existed a problem that a drill became easy to break.

JP 2003-277807 A JP 2007-2111259 A

  However, in the extrusion molding as in Patent Document 1, it is necessary to cut the fibrous extruded body into a predetermined length as described above, and the shape of the cut surface is crushed. It was necessary to cut again a predetermined length from the surface to the end after firing. Moreover, the wear resistance of the cutting edge could not be improved while suppressing breakage of the drill.

  In the method of Patent Document 2, it is necessary to extrude a pressed elongated shaped product with an elongated lower punch. However, when the diameter of the shaped product is reduced, there is a problem that the mold is easily damaged. Moreover, the wear resistance of the cutting edge could not be improved while suppressing breakage of the drill.

The blank for a cutting tool of the present embodiment is made of a cemented carbide containing WC and Co, has a long cylindrical shape, and contains Co at one end A of both ends of one end A and the other end B in the longitudinal direction. as the amount Co _a is less than the Co content Co _B at the other B unit, the one end a portion diameter _{d a} of, when the diameter of the other end part B was _{d B,} d a _{/ d} B = 1 0.02 to 1.20.

Moreover, the manufacturing method of the blank for cutting tools of this embodiment produces the 1st raw material powder for producing the one end A part side including WC powder, and the other end B part side including WC powder and Co powder. A step of preparing a second raw material powder for charging, a step of feeding the first raw material powder into the gap of the die of the press mold, and an upper punch is lowered from above to be put into the gap of the die Pressurizing the first raw material powder to form the lower part of the molded body, extracting the upper punch from the gap, and applying the second raw material powder to the gap having the pressed lower part of the molded body A step of pressing, a step of lowering the upper punch from above and pressurizing a laminate of the lower part of the molded body and the upper part of the molded body made of the second raw material powder introduced into the gap of the die, and the laminated body The molded body made of the gold Taking out from, and a step of firing the shaped body.

  Further, in the cutting tool according to the present embodiment, the other end B of the cutting tool blank is joined to a shank, and the cutting tool blank is subjected to blade processing.

  Moreover, the manufacturing method of the cutting tool of this embodiment discriminate | determines one end A and the other end B of the said blank for cutting tools in the said joining apparatus at the process thrown in in a joining apparatus at random, and predetermined direction , A step of bringing the other end B of the cutting tool blank into contact with a shank and joining, and a step of applying a blade to the portion including the one end A of the cutting tool blank. To do.

  The blank for a cutting tool of the present embodiment has a high hardness because the Co content at one end A is small, and when the cutting edge of the cutting tool is formed at the one end A, the wear resistance of the cutting edge is high. Further, the other end B portion has a high Co content and thus has high toughness. For example, when the flute portion of a drill is formed at the other end B portion, the fracture resistance of the flute portion is high. As a result, the cutting tool of this embodiment manufactured with this cutting tool blank has high wear resistance of the cutting edge and high breakage resistance.

  Moreover, the manufacturing method of the blank for cutting tools of this embodiment can control Co content after baking to a desired range, and also adjusts the density distribution of a molded object, The blank for cutting tools after baking Can be controlled.

  Furthermore, the manufacturing method of the cutting tool of this embodiment can easily discriminate between the one end A and the other end B of the cutting tool blank, and easily cuts by aligning the one end A and the other end B with an automatic machine or the like. Tools can be manufactured.

It is a side view about an example of the blank for cutting tools of this embodiment. It is a schematic diagram for demonstrating the structure of a metal mold | die about an example of the method of shape | molding the blank for cutting tools of this embodiment. It is a side view about an example of the drill which joined the cutting tool blank of FIG.

  It demonstrates based on the side view about an example of the blank for drills joined to the shank of this embodiment of FIG.

  A cutting tool blank (hereinafter simply abbreviated as “blank”) 2 used in the drill 1 of FIG. 1 is a long cylindrical column made of a cemented carbide containing WC and Co, and a cutting edge is formed in the longitudinal direction. One end A portion and the other end B portion joined to the shank 3.

According to this embodiment, the ratio _Co A / Co _B with Co content Co _B in Co content Co _A and the other B unit at one part A of the two ends is 0.1 to 0.6. Thus, when the cutting edge of the drill 1 is formed at one end A, the wear resistance of the cutting edge is high. Moreover, since the other end B portion has a high Co content, the toughness is high, and when the flute portion of the drill 1 is formed at the other end B portion, the fracture resistance of the flute portion is high. As a result, the cutting tool of this embodiment manufactured with this cutting tool blank has high wear resistance of the cutting edge and high breakage resistance. _A particularly desirable range of the ratio Co _A / Co _B is 0.2 to 0.5.

In this embodiment, Co _A is 0.1 mass%-10 mass%, and Co _B is 3 mass%-30 mass%. More preferably, Co _A is 0.5% by mass to 5% by mass, and Co _B is 5% by mass to 20.0% by mass. As a method for measuring Co _A and Co _B , a method of performing composition analysis of the A part at one end and the B part at the other end by ICP analysis can be applied. The length of one end A part and the other end B part at the time of composition analysis is as short as possible within the range that can be analyzed. Moreover, in order to confirm the composition change of the longitudinal direction of the blank 2, it can confirm by observing the side surface of the blank 2 while shifting a measurement position with an electron microscope, and semi-quantitatively analyzing the composition in each region by EPMA analysis.

Further, in the present embodiment, when the diameter of the end part A and d _A, the diameter of the other end part B and d _B, a long shape ratio of 3 or more in length L with respect to d _A, d _A / a d _B = 1.02~1.20. Accordingly, it is possible to easily distinguish between the one end A portion and the other end B portion having different Co contents, and the cutting edge of the cutting tool can be reliably formed on the one end A portion. That is, when d _A / d _B is less than 1.02, it is impossible to distinguish the one end A portion from the other end B portion. When d _A / d _B exceeds 1.20, the polishing allowance when manufacturing the cutting tool increases, and the processing cost increases. _A more desirable range of d _A / d _B is 1.03 to 1.10.

In a more preferred embodiment of the present embodiment, the blank _2, d A, is in both 2mm or less _{d B,} when the longitudinal length is L, the ratio of length L to _{d A} (L / _{d A)} is 3 or more. The blank 2 having this shape is difficult to produce by extrusion molding. That is, it is difficult to change the Co content in the one end A portion and the other end B portion, and it is also difficult to change d _A and d _B. On the other hand, the blank 2 having this shape can be produced by press molding. And by adjusting manufacturing conditions, such as a shape of a metal mold | die and baking conditions, while suppressing the defect | deletion of a metal mold | die and a molded object, the composition and shape of the blank after baking are controlled in a predetermined range. _A desirable range of the ratio (L / d _A ) is 5-15.

According to the present embodiment, the diameter including the one end A portion and the diameter a is 0.95 or more in proportion to the diameter of the one end A portion and the other end B portion, and the diameter is the diameter of the one end A portion. And a region b less than 0.95. At this time, longitudinal length of _{L A} region a, when the longitudinal length of said region b was _{L B,} ratio _{L A / (L A + L} B) is in the 0.3 to 0.6 is there. If it is this range, the abrasion resistance of the cutting edge of the reground drill 1 is also high, and the fracture resistance of a flute part can be improved. _A desirable range of the ratio L _A / (L _A + L _B ) is 0.3 to 0.5.

According to this embodiment, when the minimum diameter at the center C in the longitudinal direction is d _C, a d _A> d _C. Thereby, after joining the blank 2 to the shank 3, the grinding allowance at the time of carrying out a blade process to the blank 2 can also be made small.

In further desirable embodiments of the present embodiment, in the region a, diameter, toward the other end part B d _B has become continuously smaller from one end A part d _A. The phrase “continuously small” means that there is no step where the diameter changes discontinuously, and thereby breakage of the blank 2 can be suppressed.

The preferred dimensions of the blank 2 are d _A and d _B of 0.2 to 2 mm, a length L of 3 to 20 mm and d _A / d _B when used for drills for printed circuit board processing. = 1.02 to 1.20, and a _d a _{/ d} C = _{1.00~1.10. A} particularly desirable range of d _A for blank 2 is 0.3 to 1.7 mm. d _A may exceed 2 mm in other applications, and the preferred range of d _A in such a case is 0.2 to 20 mm.

  Moreover, in the blank 2 of this embodiment, the average particle diameter of the WC particles in the A part at one end is larger than the average particle diameter of the WC particles in the B part at the other end. As a result, chipping during machining of the cutting edge 5 of the drill 1 formed by machining the blank 2 can be suppressed, and the flute groove forming portion 6 has high rigidity, so that flute groove formation during machining of the cutting edge 5 of the drill 1 is achieved. The misalignment of the portion 6 can be suppressed, and the processing dimension accuracy of the flute groove forming portion 6 can be increased.

  Furthermore, the present embodiment is a drill used for drilling a printed circuit board, but the present invention is not limited to this. For example, a drill for metal processing, a medical drill, an end mill, and a throw for inner diameter processing. It can be applied as a cutting tool for turning such as away chips.

(Blank manufacturing method)
An example of a method for producing the cutting tool blank will be described. First, raw material powder such as WC powder for preparing a cemented carbide forming a blank and a cutting tool is prepared. In this embodiment, two types of raw material powders are prepared.

  That is, as the raw material powder, a first raw material powder containing WC powder and producing one end A side, and a second raw material powder containing WC powder and Co powder and producing the other end B side are prepared. . The first raw material powder may contain Co powder in addition to the WC powder, but the content of Co powder in the first raw material powder is less than the content of Co powder in the second raw material powder. The content of the Co powder in the first raw material powder is a ratio with respect to the content of the Co powder in the second raw material powder, and is 0 to 0.5, particularly 0 to 0.3. Further, in the first raw material powder and the second raw material powder, in addition to the WC powder and the Co powder, any one of the carbides, nitrides, and carbonitride powders of Group 4, 5 and 6 metals of the periodic table other than WC Additives may be added.

  For example, the amount of WC powder in the first raw material powder is 90 to 100% by mass, the amount of Co powder is 0 to 8% by mass, and the amount of additives is 0 to 5% by mass in total. The amount of WC powder in the second raw material powder is 65 to 95% by mass, the amount of Co powder is 5 to 30% by mass, and the amount of additives is 0 to 10% by mass in total. A binder and a solvent are added to this to produce a slurry. This slurry is granulated into granules and formed into molding powder.

  On the other hand, a press mold (hereinafter simply referred to as a mold) is prepared, and the granules are put into the gap 22 of the die 21 of the mold 20. And a molded object is produced by dropping and pressurizing the upper punch 24 from the upper part of the granule thrown into the space 22 of the die 21.

  In the molding method of the present embodiment, the first raw material powder 30 is put into the gap 22 of the die 21 of the mold 20 and the upper punch 24 is lowered from above to be put into the gap 22 of the die 21. Pressurizing the first raw material powder 30 to form the molded body lower portion 31, extracting the upper punch 24 from the gap portion 22, and applying the second raw material powder to the gap portion 22 having the pressurized molded body lower portion 31. 33, and the upper punch 24 is lowered from above to pressurize the laminated body of the molded body lower portion 31 and the molded body upper portion 34 made of the second raw material powder 33. And a step of taking out the molded body 35 made of the laminate from the mold 20.

The molded body 35 has an elongated shape, and the Co content at one end A is less than the Co content at the other end B. In addition, after the molded body lower part 31 made of the first raw material powder 30 is molded in advance, the second raw material powder 33 is put into the upper part of the molded body lower part 31 and molded, so that one end A side and the other are baked during firing. Co diffusion between the end B side can be suppressed. As a result, it becomes easy to adjust the distribution of the predetermined Co content.

  In this embodiment, when a sintered body having a diameter of 2 mm or less is obtained, the upper punch 24 is moved downward by 0.1 mm to 2 mm from the holding position of the upper punch 24 during pressurization. An additional load is applied to 24 and the load on the lower punch 23 is reduced. With this molding condition, the pressure unevenness of the molded body 35 can be improved, the lower punch 23 can be prevented from being damaged when the molded body 35 is pulled out, and the shape of the blank 2 after firing the molded body 35 is set to a predetermined value. It can be a shape.

  That is, when the compact 35 for obtaining a sintered body having a diameter larger than 2 mm is produced by press molding, the granules are uniformly introduced when the powder is introduced into the mold 20. If a molded body 35 for obtaining a sintered body having a thickness of 2 mm or less is produced by press molding, in the conventional method, when the powder is charged into the mold, the granules are not uniformly charged. In the present embodiment, by controlling the molding conditions, the molded body 35 can be produced and the blank 2 having a predetermined shape can be obtained.

At this time, as shown in FIG. 2, it may have been smaller than the diameter D _B of the upper punch 24 side diameter D _A of the lower punch 23 side of the molded body 35. In the molded body obtained by the above molding, a desirable range of the ratio D _A / D _B in the present embodiment is 0.80 to 0.99. As a result, the d _A / d _B ratio can be controlled within a predetermined range. That is, the d _A / d _B ratio can be controlled within the range of 1.02 to 1.20 depending on the difference in firing shrinkage between the one end A portion and the other end B portion during firing. When poured height of the first raw material powder 30 _{H A,} poured the height of the second raw material powder 30 was _{H B,} the ratio _{H A / (H A + H} B) is 0.2 to 0.7. Further, in the molded body, for example, a third raw material powder having a content of Co powder between the first raw material powder and the second raw material powder between the first raw material powder and the second raw material powder, etc. Other raw material powders may be present.

In order to increase the manufacturing efficiency and prevent the upper punch from tilting and lowering, the mold is provided with a plurality of sets of upper punch, gap, and lower punch to form a plurality of molded bodies at a time. can do. The number of sets of the upper punch, the gap, and the lower punch is, for example, 4 to 144. Further, the side shape of the mold may be a straight shape having the same diameter from the upper punch to the lower punch. Alternatively, since less upon firing shrinkage in a more susceptible lower punch side of the pressure than the upper punch side, d _{A /} d _B is the size ratio between the amount by adding the calcined after the punch-side and the lower punch side As shown in FIG. 2, the powder filling portion (gap portion) 22 of the die 21 is filled with granules within the range in which the ratio is within a predetermined range, and the granules are formed between the upper punch 24 and the lower punch 23. the in pressurized mold 20 for press molding, it may have been smaller than the diameter D _B of the upper punch 24 side diameter D _a of the lower punch 23 side.

  And a molded object is taken out from a metal mold | die, and it becomes the blank 2 by sintering HIP baking. At this time, in this embodiment, while the temperature increase rate in the said baking is 6 degreeC / min-30 degreeC / min, baking temperature is 1350 degreeC-1580 degreeC, and baking time is 15 minutes-45 minutes. This makes it possible to easily adjust the Co content of the one end A portion and the other end B portion, and because the sinterability of the first raw material powder and the second raw material powder is different. The other end B portion has a different shrinkage rate and the molded body is deformed, and the other end B portion has a smaller diameter than the one end A portion. That is, part of Co at the other end B portion is diffused toward the one end A portion by firing, so that the other end B portion contracts more than the one end A portion. Thereby, the shape of the sintered body can be controlled.

Here, when the heating rate is slower than 6 ° C. / min, too much progress diffusion of Co during firing, Co concentration in the sintered body becomes uniform, than d B _/ d _A ratio 1.02 Becomes smaller. Heating rate is 30
If it is faster than ° C./minute, one end A part of the sintered body may be deformed.

  Furthermore, if desired, a coating layer (not shown) can be formed on the surface of the drill 1.

  According to the manufacturing method of the blank 2 of this embodiment described above, since the blank 2 is formed by press molding, the manufacturing process is easy with fewer forming steps than extrusion molding. Moreover, since the dimensional change of the blank 2 after baking the molded object of the blank 2 is small, the dimensional accuracy of the blank 2 is high. Therefore, the blank 2 can be made into a shape with less cutting allowance with respect to the shape of the drill 1. Furthermore, since the blank 2 formed by press molding can reduce the amount of binder added during molding compared to extrusion molding, defects such as voids and residual carbon in the sintered body (blank 2) This makes it a highly reliable material that is unlikely to exist. Further, in the blank 2 molding step, density unevenness in the molded body can be adjusted, so that stable molding in which chipping or the like hardly occurs is possible.

Also, when d _A blank 2 is 2mm or less, the density difference of the molded body is caused by a molded body by press molding. Therefore, the end portion (one end A, the other end B) of the blank 2 tends to sinter the cemented carbide more than the center portion C. Among these, when the shape of the molded body is D _B > D _A , sintering proceeds at the one end A portion than at the other end B portion. In this embodiment, while adjusting the state of the granules used at the time of molding, and pressurizing with the upper and lower punches, by applying an additional load only with the upper punch, it is possible to suppress the breakage of the mold, and the blank 2 The density of the molded body at both ends can be adjusted. As a result, the average particle diameter of the WC particles of the cemented carbide constituting the fired blank 2 can be adjusted as described above.

(Manufacturing method of cutting tool)
The blank 2 obtained by the above process is randomly put into the bonding apparatus in units of tens or hundreds. The blank 2 is aligned longitudinally in the joining device. In the present embodiment, the dimensions of both ends are confirmed by image data or the like, and the one end A and the other end B are specified by the dimensional difference between d _A and d _B. According to the present embodiment, since there is a dimensional difference between d _A / d _B = 1.02 to 1.20 and one end A and the other end B, it is possible to easily distinguish the one end A from the other end B. Based on this specification, the one end A portion and the other end B portion can be automatically arranged in a certain direction.

  The arranged blanks are automatically brought into contact with a predetermined position of the neck portion 7 following the shank 3 separately prepared, and then joined by a laser or the like. Thereafter, the joined blank 2 is subjected to blade processing. At this time, as shown in FIG. 1, the configuration of the drill 1 is such that one end A is on the cutting edge 5 side of the drill 1 and the other end B is on the shank 3 side of the drill 1.

(Cutting tools)
A cutting tool such as a drill 1 is produced by cutting the blank 2. The shape of the drill 1 in FIG. 3 includes a cutting edge 5 at one end A portion, and the body 8 is constituted by the cutting edge 5, the flute groove forming portion 6 that follows it, and the neck portion 7. The cutting edge 5 and the flute groove forming part 6 are processed parts. And it has the shank 3 following the body 8. FIG. Here, the blade edge 5 has a central axis and is a portion that first contacts the work material while rotating, and requires high chipping resistance and wear resistance. The flute groove forming portion 6 has a function of discharging chips generated by processing backward, and the neck portion 7 is a connection for adjusting the processing diameter of the drill 1 (the diameter of the flute groove forming portion 6) and the diameter of the shank 3. The shank 3 is a part for fixing the drill 1 to the processing machine.

  The drill 1 obtained by the above method includes a processing portion including a cutting edge 5 made of cemented carbide and a flute groove forming portion 6. In a desirable form of this embodiment, the maximum diameter of the processed portion is 2 mm or less.

  Further, in the cutting tool 1 using the blank 2 of this embodiment, the average particle diameter of the WC particles in the cutting edge 5 of the cutting tool 1 is larger than the average particle diameter of the WC particles in the flute groove forming portion 6. Therefore, the flute groove forming portion 6 has high rigidity, and chipping at the cutting edge 5 is suppressed. In the present embodiment, the one end portion A and the other end portion B are defined as being up to 10% of the total length of the blank. Further, the central portion C is defined between the one end A portion and the other end B portion. That is, the central portion C is a region having a length of 80% with respect to the entire length of the blank 2.

  Alternatively, the neck 7 and the shank 3 may be formed of an inexpensive material such as steel, alloy steel, or stainless steel, and the blank 2 may be joined to the tip of the neck 7. In addition, you may form from the blade edge 5 of the drill 1 to the shank 3 with a blank. Further, the drill 1 may have a shape in which the neck portion 7 is omitted.

The amount of metallic cobalt (Co) powder, chromium carbide (Cr ₃ C ₂ ) powder, vanadium carbide (VC) powder, and the balance of tungsten carbide (WC) powder having an average particle size of 0.3 μm as shown in Table 1 Two kinds of mixed powders of the first raw material powder and the second raw material powder shown in Table 1 were prepared at a ratio. To each mixed powder, a binder and a solvent were added and mixed to prepare a slurry, and granules having an average particle diameter of 70 μm were prepared with a spray dryer.

A mold shown in FIG. 2 equipped with a die having 144 voids is prepared, the first raw material powder shown in Table 1 is charged and temporarily molded by applying pressure, and the lower part of the molded body is molded, followed by molding. The second raw material powder shown in Table 1 was filled above the lower part of the body and press-molded to form a molded body in which the lower part of the molded body and the upper part of the molded body were laminated, and taken out from the mold. At this time, the shape of the molded body is as follows: the diameter D _A on the lower punch side of the molded body shown in Table 1, the diameter D _B on the upper punch side, the length _{HA of the} lower portion of the molded body, and the length H _{B of the} upper portion of the molded body. It was. And this molded object was heated up in the vacuum at the temperature increase rate shown in Table 1, and sintered HIP baking was carried out at the temperature shown in Table 1 for 30 minutes, and it was set as the blank.

The longitudinal direction of the resulting blanks, one end A, the other end B, describing the dimensions measured Table 2 for the minimum diameter of the central portion _{C (d A, d B,} d C). Moreover, each part of the blank was cut out, ICP analysis was performed, and Co content in each part was measured. At this time, the microstructure of the cemented carbide is observed at 5000 times using a scanning electron microscope (SEM), and the Co content is preliminarily confirmed by EPMA analysis. Then, only necessary portions are cut out and ICP analysis is performed. went. Further, based on the preliminary check was calculated _{L A} and _{L B.} Further, both ends of the blank were observed with an SEM, and the average particle diameters of WC particles at one end A and the other end B were calculated by a Luzex analysis method. The results are shown in Table 2.

  And when this drill was used and the drill was produced, sample No. In 6 to 12, it was difficult to discriminate between one end A and the other end B, and it took time and effort to apply markings in advance.

About the obtained drill, the drilling test was done on the following conditions. The results are shown in Table 2.
(Drilling test conditions)
Work material: FR4 / 6-layer plate, 1.6 mm thick, double-ply drill shape: φ0.3 mm undercut type Rotation speed: 200 krpm
Feeding speed: 2.4 m / min.
Evaluation item: Number of products that can be drilled (pieces)

From Tables 1 and 2, Co _A is the same as Sample No. Co _B. In 6-12, the number of drills was small. On the other hand, the sample numbers of Co _A are less than Co _B and d _A / d _B = 1.02-1.20. In 1 to 5 and 13, the number of drills was large. In particular, the sample No. 1 having a ratio (Co _A / Co _B ) of 0.1 to 0.5 and a ratio L _a / (L _a + L _b ) of 0.3 to 0.6. In 1-3, 5, and 13, the number of drills was particularly large. Sample No. In each of 1 to 5 and 13, the ratio (L / d _A ) was 3 or more. Furthermore, sample no. In each of 1 to 5 and 13, it was confirmed that in the region a, the diameter continuously increased from one end A to the other end B.

Sample No. 1 of Example 1 Sample No. 1 of Example 1 except that the average particle diameter of the WC powder was 0.8 μm with respect to the first raw material powder and the second raw material powder used in FIG. Using the raw material powder having the same specifications as in Sample No. 1, In the same manner as in No. 1, a long cylindrical molded body with D _A = D _B = 6 mm and L = 30 mm was produced. H _A = 10 mm and H _B = 20 mm. Sample No. The sintered body was obtained by firing at the same temperature increase rate and firing temperature as in No. 1. d _A = 5.1 mm, d _B = 4.8 mm, d _A / d _B = 1.06, L _A = 15 mm, L _B = 9.3 mm, L _B / (L _A + L _B ) = 0.38, Co _A = 1.7% by mass, Co _A = 7.1% by mass, the average particle size of WC particles at part A at one end was 0.85 μm, and the average particle size of WC particles at part B at the other end was 0.80 μm. It was. The obtained sintered body was joined to the tip of the stainless shank, and an end mill blade could be formed.

1 Drill (cutting tool)
2 Blank (blank for cutting tool)
The A end B and the other end C central portion 3 the shank 5 cutting edge 6 flutes groove forming portion 7 minimum diameter _{D A} molded article lower punch side of the diameter _{d C} central portion having a diameter _{d B} end B of the neck portion 8 body _{d A} first end A punch side diameter on the diameter D _B moldings

Claims (10)

It is made of a cemented carbide containing WC and Co, has a long cylindrical shape, and in the longitudinal direction, the Co content in mass% at one end A portion of both ends of one end A and the other end B is Co _A , When the Co content in mass% in the other end B portion of both ends is Co _B , the Co _A is less than the Co _B , the diameter of the one end A portion is d _A , and the other end B portion when the diameter was _{d B, d a / d B} = 1.02~1.20 a is a cutting tool blank. Before SL Co _A and the Co _B and the ratio _(Co A / Co _B) the cutting tool blank according to claim 1, wherein 0.1 to 0.6. Wherein _{d A,} wherein with _{d B} is both 2mm or less, when the longitudinal length is L, the ratio of the length L with respect to the _{d A} (L / _{d A)} is 3 or more according to claim 1 or 2. A blank for a cutting tool according to 2. Including the one end A portion, the diameter is 0.95 or more in the ratio to the diameter of the one end A portion, and the other end B portion, the diameter is the ratio to the diameter of the one end A portion. A region b of less than 0.95, and the ratio La / (L _a + L _b ), where L _{a is} the length in the longitudinal direction of the region _a and L _b is the length in the longitudinal direction of the region b. The blank for a cutting tool according to any one of claims 1 to 3, wherein is 0.3 to 0.6.   The blank for a cutting tool according to claim 4, wherein in the region a, the diameter continuously decreases from one end A portion toward the other end B portion. It is a method of manufacturing the blank for cutting tools in any one of Claims 1 thru | or 5, Comprising: The 1st raw material powder for producing one end A part side including WC powder, and other including WC powder and Co powder A step of preparing a second raw material powder for producing the end B portion side, a step of introducing the first raw material powder into a gap of a die of a press mold, and a lower punch from above to lower the die. Pressurizing the first raw material powder charged into the gap, forming a lower part of the molded body, extracting the upper punch from the gap, and the gap having the pressed lower part of the molded body And adding a laminate of the lower part of the molded body, which is introduced into the gap of the die by lowering the upper punch from above, and the upper part of the molded body made of the second raw material powder. Pressing and the laminate The manufacturing method of the blank for cutting tools which comprises the process of taking out the molded object which consists of these from the said metal mold | die, and the process of baking the said molded object.   The method for producing a blank for a cutting tool according to claim 6, wherein a temperature increase rate in the firing is 6 ° C / min to 30 ° C / min and a firing temperature is 1350 ° C to 1580 ° C.   The manufacturing method of the blank for cutting tools of Claim 6 or 7 with which the diameter of the lower end of the said molded object is smaller than the diameter of the upper end of the said molded object in the said laminated body.   A cutting tool in which the other end B of the cutting tool blank according to any one of claims 1 to 5 is joined to a shank, and the cutting tool blank is subjected to a cutting operation.   A step of randomly inserting the cutting tool blank according to any one of claims 1 to 5 into a joining device, and determining one end A and the other end B of the cutting tool blank in the joining device, A step of aligning in the direction, a step of bringing the other end B of the cutting tool blank into contact with a shank and joining, and a step of applying a blade processing to a portion including the one end A of the cutting tool blank; The manufacturing method of the cutting tool which comprises.