JP2012131015A - Super hard alloy baseplate outer circumference cutting blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting blade capable of precisely finishing the dimension of a workpiece by only a cutting operation and capable of eliminating a post-processing step after cutting.SOLUTION: The super hard alloy baseplate outer circumference cutting blade includes a cutting blade part 20 on the outer circumferential edge of a thin circular ring-shaped baseplate 10 formed of a cemented carbide. The cutting blade part includes: cBN abrasive grains and/or diamond abrasive grains formed by pre-coating with a magnetic material; a metal or alloy formed by electroplating or electroless plating which connects between the abrasive grains and between the abrasive grains and the baseplate; and a metal and/or alloy with a melting point of ≤350°C impregnated between the abrasive grains and between the abrasive grains and the baseplate.

Description

  The present invention relates to a cemented carbide base plate outer periphery cutting blade suitable for cutting rare earth sintered magnets.

  Various methods such as inner circumference cutting and wire saw cutting have been performed for cutting rare earth permanent magnets (sintered magnets). Among these, cutting with an outer peripheral blade is the most widely adopted cutting method. This method has a low cutting machine price, and when using a carbide blade, the cutting allowance is not so large, the dimensional accuracy of the crop is good, the processing speed is relatively fast, etc., and it is excellent in mass production As a processing method, it is widely used for cutting rare earth sintered magnets.

  As outer peripheral blades used for cutting rare earth permanent magnets, Patent Document 1: JP-A-9-174441, Patent Document 2: JP-A-10-175171, Patent Document 3: JP-A-10-175172, etc. A technique is disclosed in which diamond abrasive grains, cBN abrasive grains, and the like are fixed to the outer peripheral portion of a cemented carbide base plate by phenol resin, Ni plating, or the like. The use of cemented carbide for the base plate has improved the mechanical strength of the base plate compared to conventional alloy tool steel and high-speed steel. Yield improvement and processing cost reduction by high-speed processing became possible.

  In this way, cutting blades using a cemented carbide base plate show cutting and processing performance superior to conventional outer peripheral blades, but the demand for cost reduction from the market does not stop, and even higher precision and faster processing The development of a high-performance cutting wheel that achieves this is eagerly desired.

JP-A-9-174441 JP-A-10-175171 JP-A-10-175172 JP 2005-193358 A JP 7-207254 A Japanese Patent No. 2942989 JP 2005-219169 A International Publication No. 96/23630 Pamphlet JP 2009-172751 A

  The applicant previously has a technique for fixing diamond abrasive grains with a resin such as phenol resin on the outer periphery of a ring-shaped cemented carbide base plate, and an appropriate Young's modulus on the outer periphery of the cemented carbide base plate. The technique which fixes abrasive grains, such as a diamond abrasive grain and a cBN abrasive grain, with a metal binder was proposed (patent document 9: Unexamined-Japanese-Patent No. 2009-172751).

  The outer peripheral cutting blade used for cutting the rare earth sintered magnet is composed of two parts, a cutting blade part and a base plate. By replacing the base plate that occupies most of the peripheral cutting blade with a high-rigidity cemented carbide, the mechanical strength is improved, compared with the peripheral cutting blades using the conventional alloy tool steel and high-speed steel as the base plate, Cutting accuracy has been improved. In addition to this cemented carbide base plate, the mechanical strength of the outer peripheral cutting blade is improved by changing the binder to a metal with an appropriate Young's modulus, and the conventional phenol resin or polyimide resin is bonded with abrasive grains. Compared to the resin bond outer peripheral cutting blades used as the material, three performance enhancements have been achieved: improved processing accuracy, improved material yield through thinner blades, and reduced processing costs through higher cutting speed.

  Furthermore, regarding the manufacture of the cemented carbide outer peripheral cutting blade, a magnetic field is formed in the vicinity of the outer peripheral edge of the base plate, and the magnetic field acts on the abrasive film coated with a magnetic material in advance to magnetize the film, The manufacturing cost of the cemented carbide outer peripheral cutting blade can be reduced by the method of manufacturing the outer peripheral cutting blade in which the abrasive grains are attracted to the outer peripheral portion of the base plate and plated in this state to fix the abrasive grains.

The cemented carbide base plate outer periphery cutting blade provided by the above-described technology is a high performance outer peripheral cutting blade, but in the rare earth sintered magnet cutting process, the magnet is cut obliquely or the cut surface of the magnet In some cases, the dimensional accuracy may deteriorate due to, for example, a trace of the outer peripheral cutting blade remaining. Specifically, using a cemented carbide base plate outer peripheral cutting blade having an outer diameter of 80 to 200 mm, a thickness of 0.1 to 1.0 mm, and an inner hole diameter of 30 to 80 mm, the cutting volume per unit time is 200 mm ³ / When high-speed, high-load cutting processing of min or more is performed, the dimensional tolerance may be 50 μm or more. When dimensional accuracy deteriorates, it is necessary to increase the number of processes such as lapping to precisely polish the cut surface of the magnet, and it is necessary to perform dressing using a grindstone on the outer peripheral cutting blade and to change the cutting conditions It is.

  This means that, for example, linear motors and hard disk VCMs (voice coil motors) that require strict control of the clearance between the yoke and magnet can achieve both high dimensional accuracy, including flatness of the cut surface, and reduction in production costs. This is an obstacle when processing the required magnets.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a cemented carbide base plate outer peripheral cutting blade capable of processing a rare earth sintered magnet having high dimensional accuracy.

  The phenomenon that the rare earth sintered magnet is cut obliquely is that the cutting edge shape of the outer cutting blade is not symmetrical, and the blade advances in a direction that makes it easy to cut, or when the outer cutting blade is attached to the processing machine. This is thought to be caused by the warping of the blade. In addition, the phenomenon in which the traces remain on the magnet is newly generated from the previous cut surface by the outer peripheral cutting blade that cut the magnet obliquely for the above-mentioned reason, by suddenly changing the traveling direction during the cutting. It is thought that this occurs when the joint with the cut surface does not connect smoothly but becomes a step.

  The advancing direction of the outer cutting blade suddenly changes during cutting, for example, when a part of the blade edge is deformed or dropped for some reason, or when the tip shape of the cutting blade portion changes suddenly, Since the feed speed of the outer peripheral cutting blade is faster than the grinding speed, the cutting edge of the outer peripheral cutting blade is deformed, and the internal force generated on the outer peripheral cutting blade due to the deformation becomes larger than the force (external force) that the outer peripheral cutting blade receives from the work piece. When the force that deformed the cutting edge is released, sludge generated during cutting or foreign matter from the outside of the system is clogged in the kerf, which is considered to occur when the outer peripheral cutting blade is prevented from advancing. . Therefore, in order to eliminate the cut mark generated in such a situation, the cutting edge portion is not affected even when the tip shape of the cutting edge portion changes abruptly and a force that changes the advancing direction of the cutting edge is applied during cutting. It is effective to deform to some extent and to smoothly connect the cut surfaces.

  In the outer peripheral cutting blade in which the abrasive grains are fixed to the base plate by electroplating or electroless plating to form the cutting edge portion, the abrasive grains having a certain size are used as the abrasive grains. Between the abrasive grains and between the abrasive grains and the base plate, only a part can be contacted, and the gap between them is not completely filled with plating. Therefore, even after plating, the cutting blade portion has a gap, that is, a gap communicating with the surface of the cutting blade portion.

  If the load on the outer cutting blade during cutting is small, even if these gaps exist, high-precision cutting can be performed without causing large deformation due to the force received during cutting, but the cemented carbide base plate will be deformed. In a situation where a high-load cutting is performed, a part of the cutting edge may be deformed or fall off. A method for increasing the strength of the blade edge is effective to prevent the blade edge from being deformed or dropped off, but the cutting blade portion also needs elasticity to deform and smoothly connect the cut surface, as will be described later. It turned out that it cannot respond only by making it high intensity | strength so that it may be hard to deform | transform.

  Therefore, the present inventors diligently studied in order to achieve the above object, and examined the configuration of the cutting blade portion that achieves both high strength and elasticity, and the mechanical properties of the cutting blade portion. A cemented carbide base in which a gap existing between the abrasive grains and the base plate is utilized, and a cutting blade part impregnated with metal and / or alloy is effective in this gap. The outer peripheral cutting blade is effective for improving the dimensional accuracy of the magnet to be cut, and the method of impregnation with metal and / or alloy is effective for the high-precision and inexpensive manufacturing of the outer peripheral cutting blade. The headline and the present invention were made.

Therefore, this invention provides the following cemented carbide base plate outer periphery cutting blades.
Claim 1:
A cutting blade formed on the outer peripheral edge of a circular ring-shaped thin plate made of a cemented carbide having a Young's modulus of 450 to 700 GPa and having an outer diameter of 80 to 200 mm, an inner diameter of 30 to 80 mm, and a thickness of 0.1 to 1.0 mm A cemented carbide base plate outer peripheral cutting blade having a portion,
The cutting blade part is
Diamond abrasive grains and / or cBN abrasive grains, which are previously coated with a magnetic material,
A metal or an alloy formed by electroplating or electroless plating that connects between the abrasive grains and between the abrasive grains and the base plate;
A cemented carbide base plate outer peripheral cutting blade comprising a metal and / or alloy having a melting point of 350 ° C. or less impregnated between the abrasive grains and between the abrasive grains and the base plate.
Claim 2:
The metal to be impregnated is at least one selected from Sn and Pb, and the alloy to be impregnated is an Sn—Ag—Cu alloy, Sn—Ag alloy, Sn—Cu alloy, Sn—Zn alloy and Sn—Pb alloy. The cemented carbide base plate outer periphery cutting blade according to claim 1, which is one or more selected from the group consisting of:
Claim 3:
The cemented carbide base plate outer periphery cutting blade according to claim 1 or 2, wherein the Poisson's ratio of the metal and the alloy to be impregnated is 0.3 to 0.48.
Claim 4:
The cemented carbide base plate outer periphery cutting blade according to any one of claims 1 to 3, wherein the base plate has a saturation magnetization of 40 kA / m (0.05 T) or more.
Claim 5:
The cemented carbide base plate outer periphery cutting blade according to any one of claims 1 to 4, wherein an average particle size of the abrasive grains is 10 to 300 µm.
Claim 6:
The cemented carbide base plate outer periphery cutting blade according to any one of claims 1 to 5, wherein a mass magnetic susceptibility χg of the abrasive grains is 0.2 or more.

  By adopting the cemented carbide base plate outer peripheral cutting blade of the present invention, it is possible to finish the dimension of the crop with high accuracy only by cutting operation, and the post-processing step after cutting can be omitted, so it has high dimensional accuracy. Rare earth magnets can be provided at low cost.

It is a figure which shows the outer periphery cutting blade of this invention, (A) is a top view, (B) is sectional drawing in line BB in (A), (C) is an expanded sectional view of the C section in (B). It is. It is a perspective view which shows one Example of the jig | tool used for this invention. It is an expanded sectional view of the front-end | tip part of the jig | tool main body which clamped the base plate of FIG. (A)-(D) are some omission cross-sectional views which respectively show the state of the cutting blade part formed in the base plate. 4 is a photomicrograph of the side surface of the cutting edge of the outer peripheral cutting blade of Example 1. FIG. It is a graph which shows the relationship between the cutting | disconnection number of the rare earth sintered magnet cut | disconnected using the outer periphery cutting blade manufactured in Examples 1-4 and the comparative example 1, and a cutting precision. It is a graph which shows the relationship between the deformation of the cutting edge part of the outer periphery cutting blade manufactured in Examples 1-4 and Comparative Example 1, and stress.

  For example, as shown in FIG. 1, the outer peripheral cutting blade of the present invention has diamond abrasive grains and / or cBN abrasive grains electroplated or deposited on the outer peripheral edge of a base plate 10 of a circular thin plate (circular ring-shaped thin plate). The cutting blade part 20 joined by a metal or an alloy (metal binder) formed by electroless plating is formed. An inner hole 12 is formed at the center of the base plate 10.

  The base plate has a thickness of 0.1 to 1.0 mm, preferably 0.2 to 0.8 mm, an outer diameter of 80 to 200 mm, preferably 100 to 180 mm, an inner hole diameter (inner diameter) of 30 to 80 mm, Preferably it has a dimension of 40-70 mm.

  The reason why the thickness is in the range of 0.1 to 1.0 mm and the outer diameter is 200 mm or less is that it is possible to manufacture an accurate base plate, and to cultivate a work (work) such as a rare earth sintered magnet with high dimensional accuracy over a long period of time. It is because it can cut stably. If the thickness is less than 0.1 mm, a large warp is likely to occur regardless of the outer diameter, so that it is difficult to manufacture an accurate base plate. If the thickness exceeds 1.0 mm, the cutting cost increases. The reason why the outer diameter is set to 200 mm or less depends on the size that can be manufactured by the current manufacturing technology and processing technology of cemented carbide. The diameter of the inner hole is set to φ30 to φ80 mm according to the thickness of the cutting blade mounting shaft of the processing machine.

  The material of the base plate is a cemented carbide, for example, Fe, Co, Ni, Mo, Cu, and carbide powders of metals belonging to the periodic table IVB, VB, VIB group such as WC, TiC, MoC, NbC, TaC, Cr3C2, etc. , Pb, Sn, or alloys that are sintered and bonded using these alloys are preferable, and among them, WC—Co, WC—Ti, C—Co, and WC—TiC—TaC—Co are representative. The one with Young's modulus of 450 to 700 GPa is used. Moreover, in these cemented carbides, what has the electrical conductivity of the grade which can be plated, or can give electrical conductivity with a palladium catalyst etc. is preferable. For imparting electrical conductivity with a palladium catalyst or the like, for example, a known material such as a conductive treatment agent used when plating on an ABS resin can be used.

  As for the magnetic characteristics of the base plate, it is preferable that the saturation magnetization is large in order to fix the abrasive grains to the base plate by magnetic attraction. However, even if the saturation magnetization is small, as described later, the magnet position and the strength of the magnetic field are strong. By controlling the thickness, it is possible to magnetically attract abrasive grains pre-coated with a magnetic material to the base plate, so that it may be 40 kA / m (0.05 T) or more.

  The saturation magnetization of the base plate is obtained by cutting a 5 mm square measurement sample from a base plate of a predetermined thickness, measuring the magnetization curve (4πI-H) between 24 and 25 ° C. using VSM, and measuring the magnetization value in the first quadrant. Can be the saturation magnetization of the base plate.

  It is also effective to chamfer or chamfer the outer peripheral portion of the base plate in order to increase the bonding strength with the cutting blade portion formed by abrading the abrasive grains with a metal binder. By applying these chamfers, even if the boundary between the base plate and the abrasive layer is accidentally ground excessively when adjusting the blade thickness, the metal binder remains on the boundary, preventing the cutting edge from falling off. it can. The chamfering angle and amount are determined according to the thickness of the base plate to be used and the average particle size of the abrasive grains to be fixed because the processable range depends on the thickness of the base plate.

  As abrasive grains for forming the cutting edge portion, diamond abrasive grains and / or cBN abrasive grains are used, but these abrasive grains need to be coated with a magnetic material in advance. The size and hardness of the abrasive grains coated with the magnetic material are determined according to the purpose.

  For example, diamond (natural diamond, industrial synthetic diamond) abrasive grains and cBN (cubic boron nitride) abrasive grains may be used alone, or mixed abrasive grains of diamond abrasive grains and cBN abrasive grains may be used. Is possible. Further, depending on the crop, it is possible to adjust the ease of cracking by using each abrasive grain alone or in combination from single crystals or polycrystals. Furthermore, sputtering a metal such as Fe, Co, Cr or the like on the surface of these abrasive grains to about 1 μm is also effective as a method for increasing the bond strength with a magnetic material to be described later.

  Although the magnitude | size of an abrasive grain is based also on the thickness of a baseplate, it is preferable that it is 10-300 micrometers by an average particle diameter. If the average particle size is less than 10 μm, the gap between the abrasive grains is reduced, so that clogging is likely to occur during cutting, and the cutting ability is reduced. If the average particle size exceeds 300 μm, the cut surface of the magnet There is a risk that problems such as roughening may occur. In such a range, the abrasive grains having a specific size may be used singly or in combination in consideration of cutting workability and life.

  The magnetic material that coats the abrasive grains can be magnetically attracted in a short time even with a base plate such as a cemented carbide with low saturation magnetization, and the mass magnetic susceptibility χg of the abrasive grains is such that it does not fall off when fixed by plating. 0.2 or more, preferably 0.39 or more, one metal selected from Ni, Fe and Co, an alloy consisting of two or more selected from these metals, or one of these metals or alloys An alloy of one or two selected from P and Mn is formed by a known method such as sputtering, electroplating, electroless plating, etc., so that the thickness of the film is 0.5 to 100% of the abrasive grain size, preferably 2 to Coat to 80%.

  Since the magnetic susceptibility of the abrasive grains depends on the magnetic susceptibility of the magnetic material to be coated and the thickness at the time of coating, it is necessary to consider the type of magnetic material so that the necessary attractive force can be obtained depending on the size of the abrasive grains. For example, even if the phosphorus content is high and the magnetic susceptibility is low, such as electroless nickel phosphorus plating, it is possible to increase the magnetic susceptibility to some extent by applying heat treatment, and on the coating with a low magnetic susceptibility. Since it is possible to form a multilayer with different magnetic susceptibility coatings so that a coating with a high magnetic susceptibility is applied, the adjustment is made within an appropriate range according to the situation.

  As described above, when the mass magnetic susceptibility χg of the abrasive grains is 0.2 or more, preferably 0.39 or more, the abrasive grains are rapidly magnetized by the magnetic field formed in the vicinity of the outer peripheral edge of the base plate described later. Therefore, the abrasive grains are magnetically attracted almost evenly in all portions of the gap 64 of FIG. 3 described later formed by the base plate and the permanent magnet holder (jig main body). If the mass magnetic susceptibility χg of the abrasive grains is less than 0.2, can the abrasive grains not be attracted well into the gaps and the abrasive grains fall off during plating, etc. to form an abrasive grain layer (cutting edge)? Or, since a hole or the like is generated in the abrasive layer, the mechanical strength of the abrasive layer may be weakened as a result.

  The mass magnetic susceptibility of the abrasive grains can be measured by the following method. First, spread out thinly and uniformly as much as possible in a resin container with an outer diameter of φ8mm, a height of about 5mm, and an inner diameter of φ6mm, and then remove it from the container and measure the weight of the abrasive Then, after returning to the container again, a paraffin having a melting point of about 50 ° C. is placed thereon, and the whole is put into an oven at 60 ° C. and heated. Next, the container is covered with the paraffin dissolved and cooled. Next, the initial magnetization curve (4πI-H) of the sample is measured at a temperature of 24 to 25 ° C. using a VSM (Vibrating Sample Magnetometer). The differential magnetic susceptibility in the initial magnetization curve is obtained from the slope at the inflection point of the curve, and divided by the sample weight to obtain the mass magnetic susceptibility χg of the abrasive grains. The magnetic field is calibrated with a Ni standard sample, and the density of the abrasive grains is measured using the tap bulk density.

  The thickness of the magnetic material to be coated has an influence on the size of the gap formed when the cutting blade portion is formed, and therefore it is necessary to make it particularly suitable. The minimum thickness is preferably 2.5 μm or more, which is a thickness that allows the entire abrasive grain to be coated with almost no gap even when coating by plating. For example, in the case of the maximum value 300 μm of the preferable average particle size range of the above-described abrasive grains, it may be 0.5% or more, particularly 0.8% or more. By making the coating thickness in this way, it is possible to obtain a holding force that can reduce the falling off of abrasive grains even when cutting as an outer peripheral cutting blade, and also to select the type of magnetic material to be coated appropriately Thus, the abrasive grains are attracted to or near the outer peripheral edge of the base plate by the magnetic field without falling off during the plating process.

  For example, if the maximum thickness is 10 μm, which is the minimum value of the preferable average particle size range of the above-mentioned abrasive grains, the portion that does not function effectively in the cutting process and the portion that hinders the self-generated action of the abrasive grains increase, and the processing capability decreases. Therefore, it is preferable that the average particle size is 100% with respect to the average grain size of the abrasive grains.

  The metal binder for bonding the abrasive grains is a plated metal (alloy) described later. For the formation of the cutting blade part, it is necessary to dispose a permanent magnet in the vicinity of the outer peripheral edge of the base plate. For example, the inner side from the outer peripheral edge of the base plate (on the rotating shaft side when the outer peripheral cutting blade is used) ) Or two or more permanent magnets having a residual magnetic flux density of 0.3 T or more in a space within a distance of 20 mm or less from the side of the base plate on the base plate surface or inside the outer peripheral edge. Magnetic attraction force is produced by forming a magnetic field of 8 kA / m or more in a space within 10 mm from at least the outer peripheral edge of the plate and further applying this magnetic field to diamond grains and / or cBN abrasive grains coated with a magnetic material in advance. By magnetically attracting and fixing these abrasive grains on or near the outer periphery of the base plate by the attraction force, electroplating or electroless plating is performed on the outer peripheral edge of the base plate in that state, Adopting a method of fixing on the outer peripheral edge of the base plate Kill.

  As a jig used at this time, a cover made of an insulator having an outer diameter larger than the outer diameter of the base plate, and a permanent magnet arranged and fixed to the cover so as to be inside the outer peripheral end of the base plate; A pair of jig bodies having the following can be used. Plating can be performed by holding a base plate between these jig bodies.

  FIGS. 2 and 3 show an example of a jig used for the plating. Reference numerals 50 and 50 denote a pair of jig bodies, and the jig bodies 50 and 50 are made of insulating covers 52 and 52, respectively. And permanent magnets 54 and 54 attached to these covers 52 and 52, and the base plate 1 is held between the jig main bodies 50 and 50. The permanent magnets 54 and 54 are preferably embedded in the covers 52 and 52, but may be provided so as to contact the base plate 1.

  The permanent magnet built in the jig needs to have enough magnetic force to keep the abrasive grains attracted to the base plate while depositing the metal binder by the plating method and fixing the abrasive grains. The required magnetic force depends on the distance between the outer peripheral edge of the base plate and the magnet, and the magnetization and magnetic susceptibility of the magnetic material previously coated with abrasive grains, but the residual magnetic flux density is 0.3 T or more, the coercive force is 0. Use a permanent magnet of 2 MA / m or more, preferably a residual magnetic flux density of 0.6 T or more and a coercive force of 0.8 MA / m or more, more preferably a residual magnetic flux density of 1.0 T or more and a coercive force of 1.0 MA / m or more. It is obtained by.

  The larger the value of the residual magnetic flux density of the permanent magnet, the larger the gradient of the magnetic field to be formed, which is advantageous when it is desired to attract the abrasive grains locally. Therefore, use a permanent magnet with a residual magnetic flux density of 0.3T or more to prevent the abrasive grains from coming off the base plate due to the stirring of the plating solution generated during plating or the vibration caused by the swing of the base plate and jig. Is preferred.

  The larger the coercive force, the stronger the magnetic attraction of the abrasive grains to the base plate for a long time even when exposed to a high-temperature plating solution, and the greater the degree of freedom with respect to the position, shape and size of the magnet used, and jig fabrication. Therefore, it is only necessary to select from those satisfying the required residual magnetic flux density.

  The permanent magnet coating should be selected under the condition that the elution of the coating material into the plating solution and the substitution of the metal species in the plating solution is as small as possible, considering the case where the magnet touches the plating solution. Increase corrosion resistance. For example, if the metal binder is deposited using a Ni plating solution, Cu, Sn, Ni metal, epoxy resin or acrylic resin coating is suitable.

  The shape, size, and number of permanent magnets built in the jig depend on the size of the cemented carbide used as the base plate, the position, direction, and strength of the desired magnetic field. For example, if you want to uniformly fix abrasive grains to the outer peripheral edge of the base plate, a ring-shaped or arc-shaped magnet that matches the outer diameter of the base plate, or a rectangular parallelepiped magnet with a side length of about several millimeters Are arranged continuously without gaps along the outer periphery of the base plate. In order to reduce the cost of the magnets, a space may be provided between these magnets to reduce the number of magnets.

  Also, depending on the residual magnetic flux density of the magnet used, a portion where the abrasive grains previously coated with the magnetic material are attracted and a portion where the abrasive particles are not attracted are provided by increasing the magnet spacing. It is also possible to form a rectangular cutting blade portion by forming a portion having a portion and a portion having no portion.

  The magnetic field generated in the outer peripheral edge of the base plate can be generated in various ways depending on the combination of the position of the permanent magnet fixed to the two jig bodies sandwiching the base plate and the direction of the magnetization direction. The magnetic field analysis and verification are repeated so that a magnetic field of 8 kA / m or more, preferably 40 kA / m or more is formed in a space within 10 mm from the outer peripheral edge. If the strength of the magnetic field is less than 8 kA / m, the attractive force of the abrasive grains that have been coated with the magnetic material is insufficient. Therefore, if plating is performed in this state, the abrasive grains move during plating, and there are many gaps. A cutting blade part may be formed, or an abrasive grain may be fixed in dendritic shape, and the dimension of a cutting blade part may become larger than desired. As a result, the cutting blade part falls off during the shaping process, or the time required for the shaping process becomes long, and the manufacturing cost may increase.

  The position of the permanent magnet is preferably as close as possible to the portion where the abrasive grains are to be attracted, but roughly, the distance from the base plate surface on the base plate surface inside the outer peripheral end of the base plate or inside the outer peripheral end is 20 mm. Within the space that is within, more preferably within the space that is within the distance of 10 mm. By arranging two or more permanent magnets having a residual magnetic flux density of 0.3 T or more (1 or more per jig body) at a specific position within this range so as to include all or part of the permanent magnet, Since a magnetic field of 8 kA / m or more can be formed at least in a space within 10 mm from the outer peripheral edge, not only materials such as alloy tool steel and high-speed steel that have a large saturation magnetization and are easy to induce magnetic force, Even with a material such as a hard alloy that has a low saturation magnetization and a small induction of magnetic force, a magnetic field with an appropriate magnetic force can be formed on the outer peripheral edge of the base plate. Since the coating film is magnetized by taking the abrasive grains coated in advance in the magnetic field, it is possible to attract and hold the abrasive grains on or near the desired outer periphery of the base plate. .

  The position of the magnet from the outer peripheral edge of the base plate is very close to the outer peripheral edge of the base plate, for example, 0.5 mm outside from the outer peripheral end (the side away from the rotation axis when the outer peripheral cutting blade is used). However, if it is not included in the above range, the magnetic field strength near the outer peripheral edge of the base plate will be strong, but a region in which the magnetic field gradient is reversed tends to occur. The abrasive grains are easy to fall off. In addition, if the distance from the outer peripheral edge exceeds 20 mm even if it is inside the outer peripheral edge of the base plate, the strength of the magnetic field that can be formed in a space within 10 mm from the outer peripheral end of the base plate is less than 8 kA / m. Therefore, there is a fear that the force for magnetically attracting the abrasive grains may be insufficient. In such a case, there is a method of increasing the size of the magnet in order to increase the strength of the magnetic field, but this method increases the overall magnetic field strength in the vicinity of the part where the abrasive particles are to be attracted. Abrasive grains tend to adhere to a position where it is not desired to be applied, which is not preferable. In addition, this method of enlarging the magnet is not very realistic because the jig for holding the magnet becomes large.

  The shape of the jig is matched to the shape of the base plate to be used. Further, the dimension is set so that the permanent magnet can be fixed to a desired position with respect to the base plate when the base plate is sandwiched by a jig. For example, when the base plate has an outer diameter of 125 mm and a thickness of 0.26 mm, and the permanent magnet has a size of L2.5 mm × W2 mm × t1.5 mm, a disc having an outer diameter of 125 mm or more and a thickness of about 20 mm is used. Can be used.

  More specifically, the outer diameter of the jig is not less than the outer diameter of the base plate + (the height of the abrasive grain layer × 2) so that the desired height (projection amount) of the abrasive grain layer can be secured. Although the thickness depends on the material, it should be strong enough to prevent warping or the like due to a sudden temperature change when taking it in and out of the high-temperature plating solution. The thickness of the jig in contact with the abrasive grains may be made thin so that the amount of the abrasive grain layer protruding in the thickness direction of the base plate (T3 in FIG. 1) may be obtained, or the thickness of the jig may be the same as the protruding amount. You may make it the same thickness as another part using a masking tape.

  The material of the jig is preferably an insulator from which no plating is deposited because the entire jig sandwiching the base plate is immersed in a high-temperature plating solution to deposit a metal binder, and among them, chemical resistance is about 90 ° C. It is desirable to have a heat shock resistance that can maintain a stable dimension even when repeatedly subjected to a rapid temperature change that occurs during loading and unloading into the plating solution. Further, even when immersed in a high-temperature plating solution, dimensional stability is required so that a warp is not caused by an internal stress accumulated during molding or processing and a gap is not formed between the base plate and the base plate. Of course, workability is also required that can process a groove for incorporating a permanent magnet at an arbitrary position with high accuracy without cracking or chipping.

  Specifically, engineering plastics such as PPS, PEEK, POM, PAR, PSF, and PES, and ceramics such as alumina can be used. Using such a material, the thickness and other dimensions are determined in consideration of mechanical strength, and a groove for holding a permanent magnet or a groove for receiving a power supply electrode or the like necessary when using an electroplating method is provided. Two pairs of jig bodies manufactured in this way are integrated with one base plate. When integrating, if it can be fastened by using an electrode or the like for energizing the base plate so that electroplating can be performed, both securing and fastening of the power feeding portion can be achieved, and the whole can be downsized. Of course, it is preferable to use a structure in which a jig can be connected as shown in FIG. 2, for example, as shown in FIG.

  That is, in FIG. 2, 56 and 56 are electroplating cathode bodies that also serve as base plate holders mounted at the center of the covers 52 and 52, respectively. These cathode bodies 56 and 56 are a pair of jig bodies. 50 and 50 are brought into contact with a conductive support bar 58 for supporting and fixing, and the support bar 58 can be energized. In addition, the jig shown in FIG. 2 has two pairs of jig bodies 50, 50 attached to the support bar 58 at a predetermined interval. In FIG. 2, 60 is a joint and 62 is an end cap. The jig shown in FIG. 2 is for electroplating. In the case of electroless plating, a cathode body is not necessary, and a non-conductive presser may be provided instead. The support rod is not necessarily conductive. Need not be.

  When plating using such a jig, the abrasive coated with the magnetic material is weighed with a balance if necessary, and the base plate is sandwiched between a pair of jig bodies holding permanent magnets. At this time, it is sucked and held in the gap formed by the outer periphery of the base plate and the jig. FIG. 3 illustrates this gap. Between the protrusions 52 a and 52 a protruding forward from the base plate 1 of the pair of jig main bodies 50 and 50 (covers 52 and 52) and the tip of the base plate 1. A gap 64 is formed in the gap, and the abrasive grains are magnetically attracted into the gap 64.

  The amount of abrasive grains to be held depends on the outer diameter and thickness of the base plate used, the size of the abrasive grains, and the desired height and width of the cutting edge. In addition, the abrasive grains are held and plating is repeated several times so that the amount of abrasive grains per unit volume can be made uniform at all positions on the outer periphery of the base plate and the abrasive grains can be firmly fixed by plating. It is also preferable to do this.

  Thus, the cutting blade portion is formed, and the volume ratio of the abrasive grains in the cutting blade portion is preferably 10 to 80% by volume, particularly preferably 30 to 75% by volume. If it is less than 10% by volume, the proportion of abrasive grains contributing to cutting is small, and the resistance during cutting increases. If it exceeds 80% by volume, the amount of deformation of the cutting edge during cutting is reduced, so that traces remain on the cut surface and deteriorate the dimensional accuracy and appearance of the crop. For these reasons, the cutting speed has to be slowed down. Therefore, it is preferable to adjust the volume ratio by changing the particle diameter by changing the thickness of the magnetic material coated on the abrasive grains according to the purpose.

  In addition, as shown in FIG.1 (C), the cutting blade part clamps the outer peripheral edge part of a base plate, and is formed ahead of the outer peripheral part of a base plate, and the thickness of a cutting blade part is formed. It is effective that the thickness is larger than the thickness of the base plate. Therefore, it is preferable to form the gap 64 shown in FIG.

  In this case, in FIG. 1C, the length H1 of the pair of sandwiching portions 22a and 22b for sandwiching the outer peripheral portion of the base plate of the cutting blade portion is 0.1 to 10 mm, particularly 0.5 to 5 mm. It is preferable. Further, the thickness T3 of the pair of sandwiching portions 22a and 22b is 5 μm (0.005 mm) or more, more preferably 5 to 2,000 μm, still more preferably 10 to 1,000 μm. The total thickness of the pair of sandwiching portions 22a and 22b (that is, the thickness of the portion where the cutting blade portion is thicker than the base plate) is preferably 0.01 mm or more, more preferably 0.01 to 4 mm, and still more preferably 0. 0.02 to 2 mm. If the length H1 of the clamping portions 22a and 22b is less than 0.1 mm, there is an effect of preventing chipping and cracking of the outer peripheral edge of the base plate, but there is little reinforcing effect of the base plate, and the base plate is deformed by resistance during cutting. May not be prevented. Moreover, when H1 exceeds 10 mm, there exists a possibility that the cost performance with respect to reinforcing a baseplate may fall. On the other hand, if T3 is less than 5 μm, the mechanical strength of the base plate cannot be increased, and cutting sludge may not be effectively discharged.

  4A to 4D, the sandwiching portions 22a and 22b may be formed of a metal binder 24 and abrasive grains 26 [FIG. 4A]. The base plate 10 may be covered only with the metal binder and further covered to form a layer of the metal binder and abrasive grains. [FIG. 4C]. It should be noted that the strength of the cutting blade can be further increased by depositing a metal binding material so as to cover the whole outside of FIG. 4 (C), as shown in FIG. 4 (D).

  Further, as shown in FIGS. 4B to 4D, as a method of forming the portion of the sandwiching portion in contact with the base plate 10 with only the metal binder 24, for example, the portion where the sandwiching portion of the base plate is to be formed. In this state, the plating is performed with the above-described jig mounted, the gap 26 filled with the abrasive grains 26, and plating is performed. After electrodeposition, for example, by masking the base plate 10 with the cover 52, 52 of FIG. 2 having an outer diameter that exposes the electrodeposition portion, and further plating, as shown in FIG. As the outermost layer of the cutting blade portion, a layer made of only the metal binder 24 can be formed.

  The protruding length (H2 in FIG. 1C) of the protruding portion protruding forward from the base plate 10 of the cutting blade portion 20 is 0.1 to 10 mm, particularly 0.3 depending on the size of the abrasive grains to be fixed. It is preferably ˜8 mm. If the protrusion length is less than 0.1 mm, the time until the cutting blade portion disappears due to impact or wear during cutting is short, resulting in a shortened blade life. Although it depends on T2 of 1), the cutting blade portion is likely to be deformed, and the dimensional accuracy of the cut magnet may be deteriorated due to a wavy cut surface. In addition, the cutting blade part is formed from the metal binder 24 and the abrasive grain 26 and the impregnation metal and / or impregnation alloy mentioned later.

  The metal binding material is a metal or alloy formed by plating, one metal selected from Ni, Fe, Co, Cu and Sn, an alloy consisting of two or more selected from these metals, or these metals or alloys An alloy of one of these and one or two selected from P and Mn is preferable, and this is deposited by plating so as to connect between the abrasive grains and between the abrasive grains and the base plate.

  There are two types of methods for forming a metal binding material by plating: an electrodeposition method (electroplating method) and an electroless plating method. In the present invention, it is easy to control the internal stress remaining in the binding material. The electrodeposition method with a low production cost and the electroless plating method that deposits the metal binder relatively uniformly as long as the plating solution enters, so that the gap included in the cutting edge is within the appropriate range described later. Are used alone or in combination.

  In the case of using an electroplating method using a single metal such as Ni plating or Cu plating, for example, Ni sulfamate plating solution, the concentration of nickel sulfamate as the main component, the current density during plating, and the temperature of the plating solution It may be carried out by adjusting the stress of the film by adding an organic additive such as orthobenzenesulfonimide and paratoluenesulfonamide, or adding elements such as Zn, S and Mn.

  In addition, in the case of alloy plating such as Ni-Fe alloy, Ni-Mn alloy, Ni-P alloy, Ni-Co alloy, Ni-Sn alloy, the content of Fe, Mn, P, Co, Sn in the alloy, The film stress is adjusted by adjusting the temperature of the plating solution to a suitable range. Of course, even in the case of these alloy platings, the combined use of organic additives capable of adjusting the stress is effective.

  The plating can be performed by a known method using a conventionally known plating solution for depositing a single metal or alloy and adopting normal plating conditions in the plating solution.

  Suitable electroplating solutions include, for example, nickel sulfamate 250 to 600 g / L, nickel sulfate 50 to 200 g / L, nickel chloride 5 to 70 g / L, boric acid 20 to 40 g / L, orthobenzene sulfone. Nickel electrosulfamate plating solution with appropriate amount of imide, copper pyrophosphate 30-150 g / L, potassium pyrophosphate 100-450 g / L, 25% aqueous ammonia 1-20 mL / L, potassium nitrate 5-20 g / L And an electropyrophosphate copper plating solution. The electroless plating solution includes 10-50 g / L of nickel sulfate, 10-50 g / L of sodium hypophosphite, 10-30 g / L of sodium acetate, 5-30 g / L of sodium citrate, An electroless nickel / phosphorous alloy plating solution with an appropriate amount of urea may be used.

  By such a method, diamond abrasive grains, cBN abrasive grains, or mixed abrasive grains of diamond abrasive grains and cBN abrasive grains are formed on the outer periphery of the base plate with a size close to the final shape with high accuracy.

  In the present invention, metal and / or an alloy having a melting point of 350 ° C. or less is impregnated in the gaps between the abrasive grains of the cutting blade portion and between the abrasive grains and the base plate obtained by the above-described method. Thereby, in the cemented carbide base plate outer periphery cutting blade of the present invention, a metal and / or alloy having a melting point of 350 ° C. or less is present between the grains and between the abrasive grains and the base plate inside and on the surface of the cutting blade portion. include.

  Examples of the impregnated metal include Sn and Pb, and examples of the impregnated alloy include Sn—Ag—Cu alloy, Sn—Ag alloy, Sn—Cu alloy, Sn—Zn alloy, and Sn—Pb alloy. One or more selected from these can be used.

  Specifically, as a method of impregnating the cutting blade part with metal or alloy, for example, φ0.1-2.0 mm, preferably φ0.8-1.5 mm linear, powdery, or the shape of the cutting edge A metal or alloy processed into a ring-shaped thin film with a thickness of 0.05 to 1.5 mm is placed on the cutting blade and heated above the melting point on a heater such as a hot plate or in an oven. There is a method in which the temperature is raised and the molten metal or alloy is impregnated in the cutting edge, and then gradually cooled to room temperature. In addition, after putting the outer peripheral cutting blade before impregnation into the lower mold with some clearance in the vicinity of the cutting blade part, fill the pre-measured metal or alloy and fit the upper mold, up and down It is also possible to use a method in which a metal or alloy is impregnated into the cutting blade, heated under moderate pressure, cooled, depressurized, and taken out from the mold. After heating, cool gradually so that no strain remains.

  In addition, when placing a metal or alloy on the cutting edge, for example, chlorine or fluorine is contained in advance for the purpose of fixing the metal or alloy to the cutting edge or improving the wettability of the cutting edge. It is also effective to apply commercially available solder flux.

  When impregnating a low melting point metal or alloy with a relatively high wettability, the base plate and the cutting blade part are heated by energizing the base plate with a metal such as stainless steel, iron, copper, etc. Can be impregnated by heating, and contacting the heated cutting blade with a molten metal in which a low melting point metal is melted.

  The cutting blade portion thus obtained is in a state in which abrasive grains, a magnetic material coated with the abrasive grains, a metal binder, a metal impregnated in the gap, and an alloy are appropriately dispersed.

  In addition, the following are suitable for the physical properties of the metal and alloy impregnated in these cutting blade portions. The melting point is that the cemented carbide base plate is distorted and the dimensional accuracy deteriorates, the mechanical strength changes, the difference in thermal expansion between the cemented carbide base plate and the cutting blade part becomes significant, and the cutting blade part is In order to prevent deformation and remaining distortion, 350 ° C. or lower, preferably 300 ° C. or lower is suitable.

  For the elasticity of metals and alloys, those having a Poisson's ratio of 0.3 to 0.48, preferably 0.33 to 0.44 are suitable. When the Poisson's ratio is lower than 0.3, the flexibility is poor and it is difficult to connect the cut surfaces smoothly. When the Poisson's ratio is higher than 0.48, other physical properties such as hardness are insufficient, so that the deformation of the cutting edge becomes too large. The Poisson's ratio can be measured by a pulse ultrasonic method using 15 × 15 × 15 mm samples of metals and alloys to be impregnated.

  The hardness of the metal and alloy may be such that even if the abrasive grains are worn, destroyed or dropped during cutting, the next abrasive grains are exposed and do not interfere with the action that contributes to cutting (the self-generating action of the abrasive grains) A material that is lower than the magnetic body covering the abrasive grains or the metal binding material fixing the abrasive grains is preferable. In addition, it is necessary to prevent strength change and corrosion even when exposed to processing oil or coolant used for cutting.

  The cutting blade part impregnated with a metal or alloy is adjusted to a desired dimension by grinding with a grindstone such as aluminum oxide, silicon carbide, or diamond, or electrical discharge machining, if necessary. At this time, depending on the blade thickness, chamfering C0.1 or more or R0.1 or more on the cutting edge reduces not only traces of the cut surface, but also reduces the chip end of the magnet. It is effective because it is possible.

  The cutting to which the outer peripheral cutting blade of the present invention is applied includes R-Co-based rare earth sintered magnets and R-Fe-B-based rare earth sintered magnets (R is a rare earth element including Y). It is effective in the cutting | disconnection with respect to at least 1 sort (s). These magnets are manufactured as follows, for example.

R-Co based rare earth sintered magnets include RCo ₅ and R ₂ Co ₁₇ systems. Among these, for example, the R ₂ Co ₁₇ system is composed of 20 to 28% R, 5 to 30% Fe, 3 to 10% Cu, 1 to 5% Zr, and the balance Co in mass percentages. The raw materials are weighed at such a component ratio, melted and cast, and the obtained alloy is finely pulverized to an average particle size of 1 to 20 μm to obtain an R ₂ Co _17- based magnet powder. Thereafter, it is molded in a magnetic field, further sintered at 1,100 to 1,250 ° C. for 0.5 to 5 hours, and then solutionized at a temperature 0 to 50 ° C. lower than the sintering temperature for 0.5 to 5 hours. Then, after aging at 700 to 950 ° C. for a certain time, an aging treatment for cooling is performed.

  The R-Fe-B rare earth sintered magnet is composed of 5 to 40% R, 50 to 90% Fe, and 0.2 to 8% B in terms of mass percentage. In order to improve magnetic properties and corrosion resistance, Additive elements such as C, Al, Si, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Zr, Nb, Mo, Ag, Sn, Hf, Ta, and W are added. The addition amount of these additive elements is 30% or less in terms of mass percentage in the case of Co, and 8% or less in terms of mass percentage in the case of other elements. The raw materials are weighed and melted and cast in such a component ratio, and the obtained alloy is finely pulverized to an average particle size of 1 to 20 μm to obtain an R—Fe—B magnet powder. Thereafter, it is molded in a magnetic field, further sintered at 1,000 to 1,200 ° C. for 0.5 to 5 hours, held at 400 to 1,000 ° C. for a certain time, and then subjected to aging treatment for cooling.

  Such an outer peripheral cutting blade of the present invention can cut out a rare earth magnet with high dimensional accuracy without leaving a trace on the cutting surface, particularly when the compression shear stress of the cutting edge is within a predetermined range, and is effective. It is. For example, in the outer peripheral cutting blade, after adjusting the thickness of the cutting blade portion to 0.1 to 1.0 mm, the outer diameter to 80 to 200 mm, and chamfering the blade edge to 0.1 or more with R or C, the outer peripheral cutting blade is horizontally Using a support jig that sandwiches the outer peripheral cutting blade from above and below with a circular iron plate with a thickness of 5 mm that exposes only the cutting edge, the base plate does not warp when pressed and is removed from the outer periphery of the cemented carbide base plate. At a position 0.3 mm away, the cutting blade portion is moved in the direction of the rotation axis of the outer cutting blade (cutting blade) with an indenter having a contact portion length (projection amount of the cutting blade portion -0.3 mm) and a width of 10 mm. It is pressed at a linear velocity of 1 mm / min in the thickness direction of the blade portion, and this is continuously measured until the cutting blade portion breaks, and the stress with respect to the moving amount of the indenter is measured. In this case, when the amount of movement of the indenter increases, a region where the graph shows linearity, that is, a region where the amount of movement of the indenter is proportional to the stress is confirmed. When calculating the slope of the proportional area between the amount of deformation and stress, a magnet with a range of 100 to 10,000 N / mm can cut out a magnet with high dimensional accuracy without leaving a trace on the cut surface, which is particularly effective. It is.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.

[Example 1]
A cemented carbide having a mass percentage of WC of 90% and Co of 10% was processed into a donut-shaped perforated disk having an outer diameter of φ125 mm, an inner diameter of φ40 mm, and a thickness of 0.3 mm to obtain a base plate. The base plate had a Young's modulus of 600 GPa and a saturation magnetization of 127 kA / m (0.16 T).

This base plate is masked with an adhesive tape so that only the inner 1.0 mm portion from the outer peripheral edge is exposed, immersed in a commercially available alkaline degreasing solution at 40 ° C. for 10 minutes, washed with water, and sodium pyrophosphate at 50 ° C. It electrolyzed, supplying with electricity at 2-8 A / dm < ² > to 30-80 g / L aqueous solution. Next, the cemented carbide base plate is ultrasonically cleaned in pure water, then immersed in a sulfamic acid watt nickel plating solution at 50 ° C., energized in a range of 5 to ²⁰ A / dm ² , and subjected to base plating, followed by masking. The tape was peeled off and washed with water.

  Next, a groove having an outer diameter of φ123 mm, an inner diameter of φ119 mm, and a depth of 1.5 mm is formed on one side of a PPS resin disk having an outer diameter of φ130 mm and a thickness of 10 mm, and the length is 2.5 mm × width 2 mm × thickness. After arranging 1.5mm permanent magnets (N39UH made by Shin-Etsu Rare Earth Magnet, Br = 1.25T) with the thickness direction being the depth direction of the disk at regular intervals, the grooves were made of epoxy resin. A cover in which the magnet was fixed by being buried was prepared, and the base plate was sandwiched between the two jig covers with the magnet side inside. At this time, the magnet was 1 mm away from the outer peripheral edge of the base plate toward the inner side of the base plate side surface. In addition, when the magnetic field analysis was carried out about the magnetic field formed in the space from the outer peripheral edge of a baseplate to 10 mm, the magnetic field intensity was 8 kA / m (0.01T) or more.

NiP-plated mass magnetic susceptibility χ g of 0.588 and diamond abrasive grains of 0.4 g having an average particle size of 135 μm were magnetically attracted to a recess made of a jig and a base plate so as to be even all around. Next, while the abrasive grains were magnetically attracted, the entire jig was immersed in a sulfamic acid watt nickel plating solution at 50 ° C., energized in the range of 5 to ²⁰ A / dm ² and electroplated, and then washed with water. Thereafter, 0.4 g of diamond abrasive grains were magnetically attracted, and the operation of plating and washing in the same manner as described above was repeated again.

The jig body was replaced with a PPS resin disk having an outer diameter of φ123 mm and a thickness of 10 mm so that both sides of the obtained abrasive layer were exposed, and immersed in a 50 ° C. sulfamic acid watt nickel plating solution, After energizing in the range of 20 A / dm ² to deposit the plating so as to cover the entire cutting blade, it was washed with water, removed from the jig, and dried.

  Next, a Sn-3Ag-0.5Cu alloy processed into a wire shape of φ1.0 mm was placed in a ring shape on the side surface of the cutting edge portion of the outer peripheral cutting blade, and put in an oven at 200 ° C. in that state, then the oven After confirming that the internal temperature reached 200 ° C., the temperature was raised to 250 ° C. and kept at 250 ° C. for about 5 minutes, and then the heating was turned off and the product was naturally cooled in an oven. The Sn-3Ag-0.5Cu alloy has a melting point of 220 ° C. and a Poisson's ratio of 0.35.

  Then, using a surface grinder, grind with a grindstone so that the protrusion of the abrasive layer from the cemented carbide base plate is 50 μm on one side, and adjust the protrusion and thickness of the abrasive layer, then wire electric discharge machining The outer diameter was adjusted and dressed to obtain a cemented carbide base plate outer peripheral cutting blade having an abrasive layer (cutting blade portion) having a thickness of 0.4 mm and an outer diameter of 127 mm. FIG. 5 shows a photomicrograph of the side surface of the cutting edge portion.

[Example 2]
A cemented carbide having a mass percentage of WC of 90% and Co of 10% was processed into a donut-shaped perforated disk having an outer diameter of φ125 mm, an inner diameter of φ40 mm, and a thickness of 0.3 mm to obtain a base plate.

This base plate is masked with an adhesive tape so that only the inner 1.5 mm portion from the outer peripheral edge is exposed, immersed in a commercially available alkaline degreasing aqueous solution at 40 ° C. for 10 minutes, washed with water, and sodium pyrophosphate at 50 ° C. It electrolyzed, supplying with electricity at 2-8 A / dm < ² > to 30-80 g / L aqueous solution. Next, the cemented carbide base plate is ultrasonically cleaned in pure water, then immersed in a sulfamic acid watt nickel plating solution at 50 ° C., energized in a range of 5 to ²⁰ A / dm ² , and subjected to base plating, followed by masking. The tape was peeled off and washed with water.

  Next, a groove having an outer diameter of φ123 mm, an inner diameter of φ119 mm, and a depth of 1.5 mm is formed on one side of a PPS resin disk having an outer diameter of φ130 mm and a thickness of 10 mm. The groove has a length of 1.8 mm × width of 2 mm × thickness. After arranging 105 mm permanent magnets (N32Z made by Shin-Etsu rare earth magnet, Br = 1.14T) per disc at equal intervals with the thickness direction being the depth direction of the disc, the grooves were made of epoxy resin. A cover in which the magnet was fixed by being buried was prepared, and the base plate was sandwiched between the two jig covers with the magnet side inside. At this time, the magnet was 1.5 mm away from the outer peripheral edge of the base plate toward the inner side of the base plate side surface. In addition, when the magnetic field analysis was carried out about the magnetic field formed in the space from a base plate outer periphery end to 10 mm, the magnetic field strength was 16 kA / m (0.02T) or more.

NiP-plated mass magnetic susceptibility χ g of 0.588 and diamond abrasive grains of 0.4 g having an average particle size of 135 μm were magnetically attracted to a recess made of a jig and a base plate so as to be even all around. Next, while the abrasive grains were magnetically attracted, the entire jig was immersed in a sulfamic acid watt nickel plating solution at 50 ° C., energized in the range of 5 to ²⁰ A / dm ² and electroplated, and then washed with water. Thereafter, 0.4 g of diamond abrasive grains were magnetically attracted, and the operation of plating and washing in the same manner as described above was repeated three times.

The jig body was replaced with a PPS resin disk having an outer diameter of φ123 mm and a thickness of 10 mm so that both sides of the obtained abrasive layer were exposed, and immersed in a 50 ° C. sulfamic acid watt nickel plating solution, After energizing in the range of 20 A / dm ² to deposit the plating so as to cover the entire cutting blade, it was washed with water, removed from the jig, and dried.

  Next, the Sn-3Ag alloy processed into a spherical shape with a particle size of 0.3 mm was placed on the entire circumference of the side surface of the cutting edge of the outer peripheral cutting blade, and placed in an oven at 200 ° C. as it was, and then the temperature inside the oven was After confirming that the temperature reached 200 ° C., the temperature was raised to 250 ° C. and maintained at 250 ° C. for about 5 minutes, and then the heating was turned off and the product was naturally cooled in an oven. The melting point of the Sn-3Ag alloy is 222 ° C. and the Poisson's ratio is 0.3.

  Then, using a surface grinder, grind with a grindstone so that the protrusion of the abrasive layer from the cemented carbide base plate is 50 μm on one side, and adjust the protrusion and thickness of the abrasive layer, then wire electric discharge machining The outer diameter was adjusted and dressed to obtain a cemented carbide base plate outer peripheral cutting blade having an abrasive layer (cutting blade portion) having a thickness of 0.4 mm and an outer diameter of 129 mm.

[Example 3]
A cemented carbide having a mass percentage of WC of 90% and Co of 10% was processed into a donut-shaped perforated disk having an outer diameter of φ125 mm, an inner diameter of φ40 mm, and a thickness of 0.3 mm to obtain a base plate.

This base plate is masked with an adhesive tape so that only the inner 1.0 mm portion from the outer peripheral edge is exposed, immersed in a commercially available alkaline degreasing solution at 40 ° C. for 10 minutes, washed with water, and sodium pyrophosphate at 50 ° C. It electrolyzed, supplying with electricity at 2-8 A / dm < ² > to 30-80 g / L aqueous solution. Next, the cemented carbide base plate is ultrasonically cleaned in pure water, then immersed in a sulfamic acid watt nickel plating solution at 50 ° C., energized in a range of 5 to ²⁰ A / dm ² , and subjected to base plating, followed by masking. The tape was peeled off and washed with water.

Next, the base plate is sandwiched between the jig main bodies used in Example 1, and 0.4 g of diamond abrasive grains having a mass magnetic susceptibility χg of 0.392 and an average grain size of 130 μm preliminarily NiP-plated are made of the jig and the base plate. Magnetic attraction was applied to the dent so that the entire circumference was even. Next, with the abrasive grains magnetically attracted, the entire jig was immersed in a copper pyrophosphate plating solution at 40 ° C., energized and electroplated in the range of 1 to ²⁰ A / dm ² , washed with water, and then cured. Removed from the ingredients and dried.

  Next, the Sn—Pb alloy processed into a wire shape of φ1.0 mm was placed in a ring shape on the side surface of the cutting edge portion of the outer peripheral cutting blade, and put in an oven at 200 ° C. as it was. After confirming that the temperature reached 200 ° C., the temperature was raised to 250 ° C. and maintained at 250 ° C. for about 5 minutes, and then the heating was turned off and the product was naturally cooled in an oven. Note that the melting point of the Sn—Pb alloy is 185 ° C. and the Poisson's ratio is 0.38.

  Then, using a surface grinder, grind with a grindstone so that the protrusion of the abrasive layer from the cemented carbide base plate is 50 μm on one side, and adjust the protrusion and thickness of the abrasive layer, then wire electric discharge machining The outer diameter was adjusted and dressed to obtain a cemented carbide base plate outer peripheral cutting blade having an abrasive layer (cutting blade portion) having a thickness of 0.4 mm and an outer diameter of 126 mm.

[Example 4]
A cemented carbide having a mass percentage of WC of 95% and Co of 5% was processed into a donut-shaped perforated disk having an outer diameter of φ125 mm, an inner diameter of φ40 mm, and a thickness of 0.3 mm to obtain a base plate. The base plate had a Young's modulus of 580 GPa and a saturation magnetization of 40 kA / m (0.05 T).

This base plate is masked with an adhesive tape so that only the inner 1.0 mm portion from the outer peripheral edge is exposed, immersed in a commercially available alkaline degreasing solution at 40 ° C. for 10 minutes, washed with water, and sodium pyrophosphate at 50 ° C. It electrolyzed, supplying with electricity at 2-8 A / dm < ² > to 30-80 g / L aqueous solution. Next, the cemented carbide base plate is ultrasonically cleaned in pure water, then immersed in a sulfamic acid watt nickel plating solution at 50 ° C., energized in a range of 5 to ²⁰ A / dm ² , and subjected to base plating, followed by masking. The tape was peeled off and washed with water.

  Next, the base plate is sandwiched between the jig main bodies used in Example 1, and 0.3 g of diamond abrasive grains having a mass magnetic susceptibility χg of 0.392 and an average grain size of 130 μm preliminarily NiP-plated are made of the jig and the base plate. Magnetic attraction was applied to the dent so that the entire circumference was even. Next, with the abrasive grains being magnetically attracted, the entire jig was immersed in an electroless nickel / phosphorous alloy plating solution at 80 ° C. to perform electroless plating, and then washed with water. Thereafter, 0.3 g of diamond abrasive grains were magnetically attracted, and the operation of plating and washing in the same manner as described above was repeated twice, removed from the jig, and dried.

  Next, a Sn-3Ag-0.5Cu alloy processed into a wire shape of φ1.0 mm was placed in a ring shape on the side surface of the cutting edge portion of the outer peripheral cutting blade, and put in an oven at 200 ° C. in that state, then the oven After confirming that the internal temperature reached 200 ° C., the temperature was raised to 250 ° C. and kept at 250 ° C. for about 5 minutes, and then the heating was turned off and the product was naturally cooled in an oven.

  Then, using a surface grinder, grind with a grindstone so that the protrusion of the abrasive layer from the cemented carbide base plate is 50 μm on one side, and adjust the protrusion and thickness of the abrasive layer, then wire electric discharge machining The outer diameter was adjusted and dressed to obtain a cemented carbide base plate outer peripheral cutting blade having an abrasive layer (cutting blade portion) having a thickness of 0.4 mm and an outer diameter of 127 mm.

[Comparative Example 1]
A cemented carbide having a mass percentage of WC of 90% and Co of 10% was processed into a donut-shaped perforated disk having an outer diameter of φ125 mm, an inner diameter of φ40 mm, and a thickness of 0.3 mm to obtain a base plate.

This base plate is masked with an adhesive tape so that only the inner 1.0 mm portion from the outer peripheral edge is exposed, immersed in a commercially available alkaline degreasing solution at 40 ° C. for 10 minutes, washed with water, and sodium pyrophosphate at 50 ° C. It electrolyzed, supplying with electricity at 2-8 A / dm < ² > to 30-80 g / L aqueous solution. Next, the cemented carbide base plate is ultrasonically cleaned in pure water, then immersed in a sulfamic acid watt nickel plating solution at 50 ° C., energized in a range of 5 to ²⁰ A / dm ² , and subjected to base plating, followed by masking. The tape was peeled off and washed with water.

Next, the base plate is sandwiched between the jig main bodies used in Example 1, and 0.4 g of diamond abrasive grains having a mass magnetic susceptibility χg of 0.392 and an average grain size of 130 μm preliminarily NiP-plated are made of the jig and the base plate. Magnetic attraction was applied to the dent so that the entire circumference was even. Next, while the abrasive grains were magnetically attracted, the entire jig was immersed in a sulfamic acid watt nickel plating solution at 50 ° C., energized in the range of 5 to ²⁰ A / dm ² and electroplated, and then washed with water. Thereafter, 0.4 g of diamond abrasive grains were magnetically attracted, and the operation of plating and washing in the same manner as described above was repeated again.

The jig body was replaced with a PPS resin disk having an outer diameter of φ123 mm and a thickness of 10 mm so that both sides of the obtained abrasive layer were exposed, and immersed in a 50 ° C. sulfamic acid watt nickel plating solution, After energizing in the range of 20 A / dm ² to deposit the plating so as to cover the entire cutting blade, it was washed with water, removed from the jig, and dried.

  Then, using a surface grinder, grind with a grindstone so that the protrusion of the abrasive layer from the cemented carbide base plate is 50 μm on one side, and adjust the protrusion and thickness of the abrasive layer, then wire electric discharge machining The outer diameter was adjusted and dressed to obtain a cemented carbide base plate outer peripheral cutting blade having an abrasive layer (cutting blade portion) having a thickness of 0.4 mm and an outer diameter of 127 mm.

  Table 1 shows the production yield of the cemented carbide base plate outer peripheral cutting blades of Examples 1 to 4 and Comparative Example 1. Here, the plating yield is the ratio of non-defective plating to the non-defective ones that are free of abrasive grains and missing the abrasive layer of the total number (15 each) that have been applied until the step of fixing the abrasive grains by plating. The processing yield is obtained by performing the post-plating process up to dressing on the obtained non-plated product, and treating the non-degraded abrasive layer as a non-defective product. The ratio of non-processed products to the total number is shown in 100 minutes. The overall yield is the product of the plating yield and the processing yield, and means the yield of non-defective products as a finished product of the outer peripheral cutting blade with respect to the base plate used for manufacturing the outer peripheral cutting blade.

  From Table 1, it can be seen that the yield of the example is better than that of Comparative Example 1, in particular, the yield in the processing after plating is good, and the production method of the present invention is also excellent in terms of productivity. .

  In FIG. 6, the result of having evaluated the cutting precision of a magnet when the operation which cut | disconnects a rare earth sintered magnet using a cemented carbide base plate outer periphery cutting blade is implemented. The evaluation method of cutting accuracy is as follows.

  First, the multi-cutting which assembled the cemented carbide base plate outer periphery cutting blades of Examples 1 to 4 and Comparative Example 1 by inserting two rotary shafts through the holes of the base plate, with a total of 10 pieces, each with a spacing of 1.5 mm. A blade was used. From this multi-cutting blade, an Nd-Fe-B rare earth sintered magnet having a rotation speed of 4,500 rpm, a feed rate of 30 mm / min, and a width (W) of 40 mm, a length (L) of 130 mm, and a height (H) of 20 mm. W40 mm × L (= thickness (t)) 1.5 mm × H 20 mm magnet cut out 1,010 times and cut between each of the two outer peripheral cutting blades of the examples and comparative examples. This was a cutting magnet. With respect to the cutting magnet, every 100 sheets from the first cut are defined as a dimension measurement cycle (10 cycles in total). The first and the last one were sampled from 1,001 to 1,010 sheets). For each of the 10 sheets in each cycle, the thickness (t) of a total of 5 points (1 in the center and 4 in the corners) is measured with a micrometer, and the difference between the maximum value and the minimum value among the 5 points is cut. As the accuracy (μm), an average value of the cutting accuracy of 10 sheets was calculated. FIG. 6 is a plot of this average value in each dimension measurement cycle.

  In the case of Comparative Example 1, the cutting accuracy is worse after the third cycle of dimension measurement (after the 301th cut), but in the case of Examples 1 to 4, the 10th cycle (up to the 1,010th cut) ) Until the cutting accuracy does not drop, and it can be seen that the use durability of the cemented carbide base plate outer peripheral cutting blade of the present invention is high.

  Moreover, the result of having evaluated the elasticity (flexibility) of the obtained outer periphery cutting blade is shown in FIG. Here, the compression shear stress of the cutting edge of the outer peripheral cutting blade was evaluated. In the outer peripheral cutting blade of each example, after the chamfering of the cutting edge is adjusted to 0.1 or more with R or C, the cutting blade portion is positioned at a position 0.3 mm away from the outer periphery of the cemented carbide base plate, The length of the contact part (the protruding amount of the cutting edge part -0.3 mm) and the indenter having a width of 10 mm were pressed at a linear speed of 1 mm / min in the rotation axis direction of the outer peripheral cutting blade (thickness direction of the cutting edge part). The stress with respect to the amount of movement of the indenter was measured using Shimadzu Corporation strength tester AG-1. The pressing was continued until the cutting edge was broken. In this measurement, a support jig that sandwiches the outer peripheral cutting blade from above and below with a circular iron plate having a thickness of 5 mm that exposes only the cutting blade portion horizontally is held so that the base plate portion does not warp when pressed. .

  As shown in FIG. 7, in any of the examples, when the amount of movement of the indenter increases, a region where the graph shows linearity, that is, a region where the amount of movement of the indenter is proportional to the stress is confirmed. Table 2 shows the result of calculating the slope (stress / movement of the indenter) of this linear region.

  In the evaluation by the above-described cutting, the magnet pieces obtained by cutting using the outer peripheral cutting blades of the examples all had good cutting surface appearance, but were cut using the outer peripheral cutting blades of the comparative examples. In the magnet piece obtained in this way, a sample having a cut (step) on the cut surface was generated after 3 cycles (after 301 sheets to be cut). Thus, the movement amount, stress, and inclination of the indenter shown by the above-described evaluation of the elasticity (flexibility) of the outer cutting blade are not too large, and the outer cutting blade of the present invention having a certain degree of flexibility cuts into the cutting surface. It was confirmed that a magnet with high dimensional accuracy can be cut out without leaving a trace.

  From the above results, by cutting with the cutting edge of the cemented carbide base plate of the present invention, the workpiece such as rare earth sintered magnets can be finished with high precision only by cutting, without performing finishing treatment after cutting. Therefore, it becomes possible to provide the crop with high dimensional accuracy.

DESCRIPTION OF SYMBOLS 1, 10 Base plate 12 Inner hole 20 Cutting edge part 22a, 22b Clamping part 24 Metal bonding material 26 Abrasive grain 50 Jig body 52 Cover 54 Permanent magnet 56 Cathode body for electroplating 58 Support bar 60 Joint 62 End cap 64 Crevice

Claims (6)

A cutting blade formed on the outer peripheral edge of a circular ring-shaped thin plate made of a cemented carbide having a Young's modulus of 450 to 700 GPa and having an outer diameter of 80 to 200 mm, an inner diameter of 30 to 80 mm, and a thickness of 0.1 to 1.0 mm A cemented carbide base plate outer peripheral cutting blade having a portion,
The cutting blade part is
Diamond abrasive grains and / or cBN abrasive grains, which are previously coated with a magnetic material,
A metal or an alloy formed by electroplating or electroless plating that connects between the abrasive grains and between the abrasive grains and the base plate;
A cemented carbide base plate outer peripheral cutting blade comprising a metal and / or alloy having a melting point of 350 ° C. or less impregnated between the abrasive grains and between the abrasive grains and the base plate.   The metal to be impregnated is at least one selected from Sn and Pb, and the alloy to be impregnated is an Sn—Ag—Cu alloy, Sn—Ag alloy, Sn—Cu alloy, Sn—Zn alloy and Sn—Pb alloy. The cemented carbide base plate outer periphery cutting blade according to claim 1, which is one or more selected from the group consisting of:   The cemented carbide base plate outer periphery cutting blade according to claim 1 or 2, wherein the Poisson's ratio of the metal and the alloy to be impregnated is 0.3 to 0.48.   The cemented carbide base plate outer periphery cutting blade according to any one of claims 1 to 3, wherein the base plate has a saturation magnetization of 40 kA / m (0.05 T) or more.   The cemented carbide base plate outer periphery cutting blade according to any one of claims 1 to 4, wherein an average particle diameter of the abrasive grains is 10 to 300 µm.   The cemented carbide base plate outer periphery cutting blade according to any one of claims 1 to 5, wherein a mass magnetic susceptibility χg of the abrasive grains is 0.2 or more.