DRESSING AND MANUFACTURE OF OUTER BLADE CUTTING WHEEL
An outer blade cutting wheel (1) comprising a base and a blade section (11) of metal or alloy-bonded abrasive grains is dressed by clamping the cutting wheel between a pair of circular jigs (2) such that the blade section (11) projects beyond the jigs, immersing the cutting wheel in an electropolishing liquid, positioning counter electrodes (4, 5, 6) relative to the blade section, and effecting electropolishing for thereby removing part of the metal or alloy bond and chips received in chip pockets until abrasive grains are exposed on the blade section surface.
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This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2012-001250 filed in Japan on Jan. 6, 2012, the entire contents of which are hereby incorporated by reference.
TECHNICAL FIELDThis invention relates to a method for dressing an outer-diameter blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide and a blade section formed on the outer periphery of the base, the blade section being an abrasive layer comprising abrasive grains and a metal or alloy bond for bonding the grains to each other and to the base.
BACKGROUND ARTFor cutting of rare earth permanent magnets (sintered magnets), the sawing method using outer-diameter blade cutting wheels is well known. By virtue of many advantages including an inexpensive cutting wheel, an acceptable cutting allowance on use of hard-metal blades, a high dimensional accuracy of workpieces, a relatively high machining speed, and a mass scale of manufacture, the outer blade cutting-off technique is widely employed in cutting of rare earth sintered magnets.
Patent Documents 1 to 3 disclose outer blade cutting wheels for use in cutting of rare earth permanent magnets. The known cutting wheel comprises a cemented carbide base and a blade section having diamond or CBN abrasive grains bonded to the outer periphery of the base by metal or alloy plating, typically nickel plating.
The outer blade cutting wheel is typically manufactured by providing a base in the form of an annular thin disc of cemented carbide, distributing diamond or CBN abrasive grains on the outer periphery of the base, and electroplating or electroless plating a metal or alloy to deposit a metal or alloy bond for bonding abrasive grains together or to the base to form an abrasive layer composed of abrasive grains and the metal or alloy bond. The abrasive layer constitutes a blade section. After the blade section is formed, the abrasive layer constituting the blade section is shaped and dressed to expose abrasive grains outside. As the cutting edge wears on use after the preparation, a dressing treatment like that at the end of preparation is taken at an appropriate time interval in order to restore the cutting edge.
The dressing treatment may be generally carried out by wire electrical discharge machining (EDM), or by using a dresser in the form of a grinding wheel of diamond, CBN, SiC or alumina grains, and grinding the surface of the abrasive layer to remove clogging chips or scrape the bonding material for thereby exposing new abrasive grains.
Whether or not the dressing treatment is satisfactory largely affects the cutting performance after preparation or after restoration, for example, leaving cutting marks on the cut surface or causing a difference in cutting accuracy. It is desired to have a method for dressing an outer blade cutting wheel which is capable of sufficient dressing to ensure that chips received in chip pockets in the blade section are shed and part of the bonding material is removed to expose new abrasive grains, for thereby improving the performance of the outer blade cutting wheel.
CITATION LIST
- Patent Document 1: JP-A H09-174441
- Patent Document 2: JP-A H10-175171
- Patent Document 3: JP-A H10-175172
- Patent Document 4: JP-A S63-216627
- Patent Document 5: JP-A H05-005605
The invention pertains to an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide and a blade section formed on an outer periphery of the base, the blade section being an abrasive layer comprising abrasive grains and a metal or alloy bond for bonding the grains to each other and to the base. An object of the invention is to provide a method for dressing the outer blade cutting wheel in a satisfactory and efficient manner so that the cutting wheel as dressed is ready for effective cutoff operation. Another object is to provide a method for manufacturing such an outer blade cutting wheel using the dressing method.
In conjunction with an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide and a blade section formed on an outer periphery of the base, the blade section being an abrasive layer comprising abrasive grains and a metal or alloy bond for bonding the grains to each other and to the base, the inventors have found that in dressing of the blade section of the outer blade cutting wheel, if part of the bond and chips received in chip pockets are dissolved away by electropolishing, then abrasive grains are effectively exposed and chip pockets are formed, achieving satisfactory truing.
Continuing further investigations on the efficient dressing of the blade section by electropolishing, the inventors have found that very efficient and consistent electropolishing is ensured by clamping the outer blade cutting wheel between a pair of circular jigs to hold the cutting wheel such that the opposed surfaces of the cutting wheel are covered over a predetermined range with the jigs and the blade section projects beyond the outer edge of the circular jigs, immersing the cutting wheel clamped between the jigs in an electropolishing liquid in an electropolishing tank, providing an electrode which is spaced apart from and encloses the outer circumference of the blade section and a pair of electrodes which are opposed to and spaced apart from the side surfaces of the blade section, as counter electrodes, and conducting electricity to the cutting wheel via the circular jigs and the counter electrodes. That is, efficient and satisfactory dressing operation is possible. It has also been found that in case electroplating or electroless plating is effected on the base having abrasive grains retained on its outer periphery in a plating bath, to deposit a metal or alloy bond for forming the blade section, the plating bath in the electroplating or electroless plating step may be used as the electropolishing liquid after the blade section is shaped or tailored by wire electrical discharge machining (EDM) and/or a grinding wheel.
Accordingly, in one aspect, the invention provides a method for dressing an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide having an outer periphery and a blade section formed on the outer periphery of the base, the blade section being an abrasive layer comprising abrasive grains and a metal or alloy for bonding the grains to each other and to the base, the method comprising the steps of:
clamping the outer blade cutting wheel between a pair of circular jigs to hold the cutting wheel such that the opposed surfaces of the cutting wheel are covered over a predetermined range with the jigs and the blade section projects beyond the outer edge of the circular jigs,
immersing the cutting wheel clamped between the jigs in an electropolishing liquid in an electropolishing tank,
providing an electrode which is spaced apart from and encloses the outer circumference of the blade section and a pair of electrodes which are opposed to and spaced apart from the side surfaces of the blade section, as counter electrodes, and
conducting electricity between the cutting wheel and the counter electrodes for electrolytically dissolving away part of the metal or alloy between abrasive grains and chips received in chip pockets in the blade section surface until abrasive grains are partially raised from the blade section surface.
In a preferred embodiment, the counter electrodes include a cage electrode which is spaced apart from and encloses the outer circumference of the blade section and a pair of annular electrodes which are opposed to and spaced apart from the side surfaces of the blade section.
In a preferred embodiment, the abrasive grains in the blade section are diamond and/or CBN grains, and the metal or alloy for bonding the grains to each other and to the base is formed by electroplating or electroless plating. In a preferred embodiment, the bonding metal is selected from Ni and Cu, and the bonding alloy is selected from Ni—Fe, Ni—Mn, Ni—P, Ni—Co and Ni—Sn alloys.
In a preferred embodiment, the blade section further comprises a metal or alloy infiltrated into voids between abrasive grains or between abrasive grains and the base. More preferably, the infiltrating metal is Sn and/or Pb, and the infiltrating alloy is selected from Sn—Ag—Cu, Sn—Ag, Sn—Cu, Sn—Zn and Sn—Pb alloys and mixtures thereof.
In another aspect, the invention provides a method for manufacturing an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide having an outer periphery and a blade section formed on the outer periphery of the base, the method comprising the steps of:
effecting electroplating or electroless plating on the base having abrasive grains retained on its outer periphery in a plating bath, to deposit a metal or alloy for bonding the abrasive grains to each other and to the base, for thereby forming an abrasive layer composed of the abrasive grains and the metal or alloy, the abrasive layer constituting the blade section,
tailoring the protrusion, thickness and outer diameter of the abrasive layer by wire electrical discharge machining and/or a grinding wheel, and
dressing the cutting wheel by the dressing method defined above, using the plating bath in the electroplating or electroless plating step as an electropolishing liquid, for thereby electrolytically dissolving away part of the metal or alloy between abrasive grains and chips received in chip pockets in the blade section surface until abrasive grains are partially raised from the blade section surface.
In a preferred embodiment, the abrasive grains are diamond and/or CBN grains.
In a preferred embodiment, the bonding metal is selected from Ni and Cu, and the bonding alloy is selected from Ni—Fe, Ni—Mn, Ni—P, Ni—Co and Ni—Sn alloys.
The manufacturing method may comprise, after the step of electroplating or electroless plating to form an abrasive layer composed of abrasive grains and the metal or alloy, the step of effecting further electroplating or electroless plating to form a plating cover for enhancing the bond strength between abrasive grains and between abrasive grains and the base; or the step of infiltrating a molten metal and/or alloy into voids between abrasive grains or between abrasive grains and the base and solidifying the metal and/or alloy therein. Preferably the infiltrating metal is Sn and/or Pb, and the infiltrating alloy is selected from Sn—Ag—Cu, Sn—Ag, Sn—Cu, Sn—Zn and Sn—Pb alloys and mixtures thereof.
ADVANTAGEOUS EFFECTS OF INVENTIONThe inventive method for dressing an outer blade cutting wheel comprising a cemented carbide base and a blade section composed of abrasive grains and a metal or alloy bond on the outer periphery of the base ensures efficient and satisfactory dressing of the blade section. A high-performance outer blade cutting wheel can be manufactured in an efficient and consistent manner.
It is noted that since the disc has a center and an outer circumference, the terms “radial” and “axial” are used relative to the center of the disc. And so, the thickness is an axial dimension, and the height is a radial dimension. Likewise the term “outer” or the like is used relative to the center of the disc.
As used herein, the term “electropolishing” refers to electrolytic polishing.
The invention pertains to an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide and a blade section formed on the outer periphery of the base, the blade section being an abrasive layer comprising abrasive grains and a metal or alloy for bonding the grains to each other and to the base. One embodiment of the invention is a method for dressing the blade section of the outer blade cutting wheel by electropolishing. The outer blade cutting wheel is held by clamping it between a pair of circular jigs and immersed in an electropolishing liquid in an electropolishing tank, where electropolishing is carried out.
The outer blade cutting wheel is held by clamping the cutting wheel between a pair of circular jigs such that the opposed surfaces of the cutting wheel are covered over a predetermined range with the jigs and the blade section projects beyond the outer edge of the circular jigs.
In
The cutting wheel 1 is placed between the circular jigs 2 and 2 as shown in
Since the retainer/electrode plates 21, 21 are in contact with the base of the cutting wheel 1 under an appropriate pressure, electricity may be conducted from the support 22 to the electrode plates 21, 21 via the power feed pieces 23, 23 whereby electric current may flow to the cutting wheel 1. Also, since the circular jigs 2, 2 have a smaller outer diameter than the cutting wheel 1, the opposed surfaces of the cutting wheel are covered over a predetermined range with the jigs and the blade section 11 on the outer periphery of the cutting wheel 1 projects beyond the outer edge of the circular jigs 2, 2 as best shown in
The cutting wheel 1 clamped between the circular jigs 2, 2 is immersed in an electropolishing liquid in an electropolishing tank. An electrode which is spaced apart from and encloses the outer circumference of the blade section 11 and a pair of electrodes which are opposed to and spaced apart from the side surfaces of the blade section are provided as counter electrodes. With this setting, electropolishing is carried out.
The electropolishing tank used herein may be similar to the electroplating bath used in forming the blade section by electroplating. One exemplary electropolishing tank is a box-shaped tank 3 equipped with an electric heater 31 for heating the bath and piping 32 for circulating the bath as shown in
Also the electrode which encloses the outer circumference of the blade section 11 at a certain spacing and serves as one counter electrode may be similar to the anode used in electroplating the blade section. One exemplary electrode is a cylindrical cage electrode 4 consisting of two large and small cylindrical frames 41 and 42 which each consists of a pair of rings and several columns connecting the rings and which are concentrically telescoped and linked by ties, as shown in
The pair of electrodes which are opposed to the side surfaces of the blade section 11 at a certain spacing and which also serve as counter electrodes may be, for example, annular electrodes 5, 6 as shown in
These counter electrodes 4, 5, 6 are composed of frames and meshes which are all formed of electroconductive metal material such as titanium, austenite stainless steel or nickel. Of these, titanium is most preferred for lightweight and corrosion resistance.
The cutting wheel 1 held by the circular jigs 2, 2 is received in the electropolishing tank 3, and the cage electrode 4 and annular electrodes 5, 6 are mounted in place. These members are positioned in such relationship, as shown in
The electropolishing liquid used in electropolishing may be selected from well-known electropolishing liquids, depending on the metal or alloy bond in the blade section 11. Typically an electropolishing liquid which readily dissolves away the metal or alloy bond is used. Also electrolytic conditions may be determined as appropriate in accordance with the type of bond and the degree of dressing. In an example where a single metal such as by nickel plating is used as the bond, an electropolishing liquid having the same composition as the nickel plating bath used for that nickel plating may be used. Specifically, a nickel plating bath containing 240 to 380 g/L of nickel sulfate, 40 to 90 g/L of nickel chloride, and 40 to 60 g/L of boric acid or a nickel sulfamate plating bath containing 450 to 650 g/L of nickel sulfamate, 5 to 15 g/L of nickel chloride, and 30 to 40 g/L of boric acid may be used as the electropolishing liquid. In the former example where the nickel plating bath is used as the electropolishing liquid, electropolishing may be effected at a current density of 1 to 10 A/dm2. In the latter example where the nickel sulfamate plating bath is used, electropolishing may be effected at a current density of 3 to 10 A/dm2.
Alternatively, an electroless nickel plating bath used in nickel deposition by electroless plating may be used as the electropolishing liquid. Specifically, an electroless nickel plating bath containing 20 to 25 g/L of nickel sulfate, 20 to 25 g/L of sodium hypophosphite, 5 to 10 g/L of sodium acetate, and 5 to 10 g/L of sodium citrate may be used as the electropolishing liquid. In this example, electropolishing may be effected at a current density of 0.3 to 1.0 A/dm2.
As alluded to above, the outer blade cutting wheel subject to the dressing method of the invention is one comprising a base in the form of an annular thin disc of cemented carbide and a blade section formed on the outer periphery of the base, the blade section being an abrasive layer comprising abrasive grains and a metal or alloy bond for bonding the grains to each other and to the base.
The abrasive grains and the metal or alloy bond used herein are not particularly limited. Examples of the abrasive grains include diamond grains, cubic boron nitride (CBN) grains, alumina grains, alumina based grains, SiC grains, and SiC based grains. Of these, diamond grains and/or CBN grains are preferred. The bonding metal or alloy is preferably a single metal or alloy to be deposited by electroplating or electroless plating though not limited thereto. More particularly, the metal is preferably selected from Ni and Cu. The alloy is preferably selected from Ni—Fe, Ni—Mn, Ni—P, Ni—Co and Ni—Sn alloys.
It is also acceptable that a metal or alloy infiltrates into microscopic voids between abrasive grains or between abrasive grains and the base. The infiltrating metal may be either one or both of Sn and Pb. The infiltrating alloy may be selected from Sn—Ag—Cu, Sn—Ag, Sn—Cu, Sn—Zn, and Sn—Pb alloys, for example, or a mixture thereof.
The dressing method of the invention is, of course, advantageously used in the dressing treatment of dressing a (worn) outer blade cutting wheel with a blunt cutting edge to restore a fresh cutting edge. Since the electroplating bath or electroless plating bath used in forming the blade section can be used as the electropolishing liquid, the dressing method of the invention may also be advantageously used in the dressing step of a process of manufacturing an outer blade cutting wheel by electroplating or electroless plating to deposit a metal or alloy bond around abrasive grains to form a blade section, tailoring the blade section, and dressing the blade section.
Namely, another embodiment of the invention is a method for manufacturing an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide having an outer periphery and a blade section formed on the outer periphery of the base, the method comprising the steps of effecting electroplating or electroless plating on the base having abrasive grains retained on its outer periphery in a plating bath, to deposit a metal or alloy for bonding the abrasive grains to each other and to the base, for thereby forming an abrasive layer composed of the abrasive grains and the metal or alloy, the abrasive layer constituting the blade section; tailoring the protrusion, thickness and outer diameter of the abrasive layer by wire electrical discharge machining and/or a grinding wheel; and dressing the cutting wheel by the dressing method of one embodiment, using the plating bath in the electroplating or electroless plating step as an electropolishing liquid. As used herein the term “protrusion” of the abrasive layer is a height of the abrasive layer as measured from the base surface in an axial direction of the base.
When electroplating or electroless plating is effected to deposit a metal or alloy on the base to form an abrasive layer serving as the blade section, the same jigs as the circular jigs used in the above dressing method may be used in the electroplating or electroless plating. In this case, however, the outer diameter of circular jigs 2, 2 is larger than the base 12, as shown in
The means for holding abrasive grains in the space between the outer peripheral portions of circular jigs 2, 2 may be magnetic attraction, for example. Magnetic holding may be achieved by previously coating abrasive grains with a magnetic material, and attaching permanent magnets to circular jigs 2, 2, for thereby holding the abrasive grains in the space by the magnetic attractive force.
In carrying out electroplating, a plating bath similar to the bath shown in
Once the abrasive layer composed of abrasive grains and the metal or alloy bond is formed by electroplating or electroless plating, additional electroplating or electroless plating may be carried out to form a plating cover for enhancing the bond strength between abrasive grains and between abrasive grains and the base. This cover plating may be carried out in the same manner as the previous electroplating or electroless plating. The only difference is that the outer diameter of the circular jigs 2, 2 is smaller than the cutting wheel so that the blade section 11 in the form of the abrasive layer projects beyond the outer edge of the jigs 2, 2 as shown in
Alternatively, once the abrasive layer composed of abrasive grains and the metal or alloy bond is formed by electroplating or electroless plating, a molten metal and/or alloy may be infiltrated into voids between abrasive grains and between abrasive grains and the base and solidified there. More particularly, in the outer blade cutting wheel having the blade section formed by bonding abrasive grains to the base via electroplating or electroless plating, since the abrasive grains used have a certain particle size, the abrasive grains are bonded such that contacts between grains and between grains and the base are only local. Voids are left between abrasive grains and between abrasive grains and the base. The electroplating or electroless plating is impossible to fully fill these voids with the plating metal or alloy. As a result, the blade section still contains voids in communication with its surface even after the plating. If such voids are filled with a metal or alloy, then the bond strength is improved and eventually a higher machining accuracy is available. The infiltrating metal or alloy preferably has a melting point of up to 350° C. while examples of the metal or alloy are the same as mentioned above.
The metal or alloy may be infiltrated into the abrasive layer or blade section, for example, by working the metal or alloy into a wire with a diameter of 0.1 to 2.0 mm, preferably 0.8 to 1.5 mm, particles, or a thin-film ring of the same shape and size as the blade section having a thickness of 0.05 to 1.5 mm, resting the wire, particles or ring on the blade section, heating the blade section on a heater such as a hot plate or in an oven to a temperature above the melting point, holding the temperature for letting the molten metal or alloy infiltrate into the blade section, and thereafter slowly cooling to room temperature. Alternatively, infiltration is carried out by placing the outer blade cutting wheel in a lower mold half with a clearance near the blade section, charging the mold half with a weighed amount of metal or alloy, mating an upper mold half with the lower mold half, heating the mated mold while applying a certain pressure across the mold, for letting the molten metal or alloy infiltrate into the blade section. Thereafter the mold is cooled, the pressure is then released, and the wheel is taken out of the mold. The cooling step following heating should be slow so as to avoid any residual strains.
Before the metal or alloy is rested on the abrasive layer or blade section, for example, a commercially available solder flux containing chlorine or fluorine may be applied to the blade section for the purpose of improving the wettability of the blade section or retaining the metal or alloy to the blade section.
After the abrasive layer or blade section is formed on the outer periphery of the base as mentioned above and before the dressing by the inventive method is applied to the blade section, the protrusion, thickness and outer diameter of the blade section are tailored by wire electrical discharge machining (EDM) or by grinding and polishing with a grinding wheel of aluminum oxide, silicon carbide or diamond. At this point, the blade section at the edge may be chamfered (beveled or rounded) to a degree of at least C0.1 or R0.1, though depending on the thickness of the blade section, because such chamfering is effective for reducing cut marks on the cut surface or mitigating chipping of a magnet piece at the edge. Thereafter, the blade section is subjected to dressing by the inventive method.
EXAMPLEExamples are given below by way of illustration and not by way of limitation.
Example 1A cemented carbide base in the form of an annular thin disc having an inner diameter of 60 mm and an outer diameter of 133 mm was held by clamping it between a pair of circular jigs as shown in
Next the base was held by clamping it between a pair of circular jigs as shown in
Next, the base having the blade section formed was held by clamping it between a pair of circular jigs as shown in
The side surface of the blade section of the resulting outer blade cutting wheel was observed under an optical stereomicroscope, with the micrograph shown in
Using the outer blade cutting wheel, a rare earth permanent magnet block (Nd—Fe—B magnet) was cutoff machined into magnet pieces under the following conditions.
An outer blade cutting wheel was manufactured as in Example 1 except that the electropolishing was omitted, and instead, the dressing was achieved by the grinding with grinding wheels and the machining by wire EDM. The protrusion, thickness and outer diameter of the abrasive layer were tailored (protrusion 50 μm) by grinding with grinding wheels, and the outer diameter was tailored by wire EDM.
The side surface of the blade section of the outer blade cutting wheel was observed under an optical stereomicroscope, with the micrograph shown in
Using the outer blade cutting wheel, a rare earth permanent magnet block (Nd—Fe—B magnet) was cutoff machined into magnet pieces under the same conditions as in Example 1.
An outer blade cutting wheel was manufactured as in Example 1 except that the cover plating was omitted, and instead, a Sn—Pb alloy was infiltrated into the abrasive layer or blade section. Infiltration of Sn—Pb alloy was carried out by resting the blade section-baring base on a hot plate at 230° C., heating the base for 5 minutes, melting a wire of Sn—Pb alloy having a diameter of 8 mm using a soldering iron at 230° C., applying the molten alloy to the hot blade section on the base, letting the alloy infiltrate, and allowing the blade section to cool down.
Using the outer blade cutting wheel, a rare earth permanent magnet block (Nd—Fe—B magnet) was cutoff machined into magnet pieces under the same conditions as in Example 1.
An outer blade cutting wheel was manufactured as in Example 2 except that the electropolishing was omitted, and instead, the dressing was achieved by the grinding with grinding wheels and the machining by wire EDM. The protrusion, thickness and outer diameter of the abrasive layer were tailored (protrusion 50 μm) by grinding with grinding wheels, and the outer diameter was tailored by wire EDM.
Using the outer blade cutting wheel, a rare earth permanent magnet block (Nd—Fe—B magnet) was cutoff machined into magnet pieces under the same conditions as in Example 1.
Japanese Patent Application No. 2012-001250 is incorporated herein by reference.
Although some preferred embodiments have been described, many modifications and variations may be made thereto in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.
Claims
1. A method for dressing an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide having an outer periphery and a blade section formed on the outer periphery of the base, the blade section being an abrasive layer comprising abrasive grains and a metal or alloy for bonding the grains to each other and to the base, said method comprising the steps of:
- clamping the outer blade cutting wheel between a pair of circular jigs to hold the cutting wheel such that the opposed surfaces of the cutting wheel are covered over a predetermined range with the jigs and the blade section projects beyond the outer edge of the circular jigs,
- immersing the cutting wheel clamped between the jigs in an electropolishing liquid in an electropolishing tank,
- providing an electrode which is spaced apart from and encloses the outer circumference of the blade section and a pair of electrodes which are opposed to and spaced apart from the side surfaces of the blade section, as counter electrodes, and
- conducting electricity between the cutting wheel and the counter electrodes for electrolytically dissolving away part of the metal or alloy between abrasive grains and chips received in chip pockets in the blade section surface until abrasive grains are partially raised from the blade section surface.
2. The dressing method of claim 1 wherein the counter electrodes include a cage electrode which is spaced apart from and encloses the outer circumference of the blade section and a pair of annular electrodes which are opposed to and spaced apart from the side surfaces of the blade section.
3. The dressing method of claim 1 wherein the abrasive grains in the blade section are diamond and/or CBN grains, and the metal or alloy for bonding the grains to each other and to the base is formed by electroplating or electroless plating.
4. The dressing method of claim 1 wherein of the metal or alloy for bonding the grains to each other and to the base, the bonding metal is selected from Ni and Cu, and the bonding alloy is selected from the group consisting of Ni—Fe, Ni—Mn, Ni—P, Ni—Co and Ni—Sn alloys.
5. The dressing method of claim 1 wherein the blade section further comprises a metal or alloy infiltrated into voids between abrasive grains or between abrasive grains and the base.
6. The dressing method of claim 5 wherein the infiltrating metal is Sn and/or Pb, and the infiltrating alloy is selected from the group consisting of Sn—Ag—Cu, Sn—Ag, Sn—Cu, Sn—Zn and Sn—Pb alloys and mixtures thereof.
7. A method for manufacturing an outer blade cutting wheel comprising a base in the form of an annular thin disc of cemented carbide having an outer periphery and a blade section formed on the outer periphery of the base, said method comprising the steps of:
- effecting electroplating or electroless plating on the base having abrasive grains retained on its outer periphery in a plating bath, to deposit a metal or alloy for bonding the abrasive grains to each other and to the base, for thereby forming an abrasive layer composed of the abrasive grains and the metal or alloy, the abrasive layer constituting the blade section,
- tailoring the protrusion, thickness and outer diameter of the abrasive layer by wire electrical discharge machining and/or a grinding wheel, and
- dressing the cutting wheel by the method of claim 1, using the plating bath in the electroplating or electroless plating step as an electropolishing liquid, for thereby electrolytically dissolving away part of the metal or alloy between abrasive grains and chips received in chip pockets in the blade section surface until abrasive grains are partially raised from the blade section surface.
8. The method of claim 7 wherein the abrasive grains are diamond and/or CBN grains.
9. The method of claim 7 wherein of the metal or alloy for bonding the grains to each other and to the base, the bonding metal is selected from Ni and Cu, and the bonding alloy is selected from the group consisting of Ni—Fe, Ni—Mn, Ni—P, Ni—Co and Ni—Sn alloys.
10. The method of claim 7, comprising, after the step of electroplating or electroless plating to form an abrasive layer composed of abrasive grains and the metal or alloy, the step of effecting further electroplating or electroless plating to form a plating cover for enhancing the bond strength between abrasive grains and between abrasive grains and the base.
11. The method of claim 7, comprising, after the step of electroplating or electroless plating to form an abrasive layer composed of abrasive grains and the metal or alloy, the step of infiltrating a molten metal and/or alloy into voids between abrasive grains or between abrasive grains and the base and solidifying the metal and/or alloy therein.
12. The method of claim 11 wherein the infiltrating metal is Sn and/or Pb, and the infiltrating alloy is selected from the group consisting of Sn—Ag—Cu, Sn—Ag, Sn—Cu, Sn—Zn and Sn—Pb alloys and mixtures thereof.
Type: Application
Filed: Jan 3, 2013
Publication Date: Jul 11, 2013
Applicant: SHIN-ETSU CHEMICAL CO., LTD. (Tokyo)
Inventor: Shin-Etsu Chemical Co., Ltd. (Tokyo)
Application Number: 13/733,388
International Classification: B24D 18/00 (20060101);