JP2000190230A - Disk type colored grinding wheel for cutting and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk type colored grinding wheel for cutting furnished with a adequate hardness as well as having a sufficient toughness, durability, and cutting sharpness, and its manufacturing method. SOLUTION: In the manufacturing method of a disk type colored grinding wheel for cutting formed by dispersing abrasive grains to a matrix of a phenolic resin, a grinding wheel is manufactured by applying a blank grinding wheel manufacturing process to semihot form a raw abrasive material including a paint, a resin raw material, and abrasive grains into a disk form at the forming temperature 60 to 70 deg.C, and a heat hardening process to raise a temperature of the blank grinding wheel from 135-145 deg.C to 155-165 deg.C taking 8 to 10 hours, and then holding the temperature 155 to 165 deg.C in the final 2 to 4 hours, so as to harden the phenolic resin, and at the same time, 0.6 to 1.0 wt.% of magnesium oxide is contained in the raw abrasive material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting disk-shaped colored whetstone used for cutting a workpiece made of metal, concrete, or the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A disk-type grinding wheel for cutting is used for cutting a workpiece made of metal, concrete, or the like by being set in a cutting machine and rotating, and is used for construction, shipbuilding, civil engineering, It is used in a wide range of fields such as electrical construction-related businesses.

[0003] In such a disc-shaped grinding wheel for cutting, it is necessary to use different types of hardness and particle size in accordance with the type of the work material, the required roughness of the cut surface, and the like. It is important for the work efficiency to be able to quickly identify the disc-type grinding wheel for cutting in accordance with the situation. In addition, if the cutting disc-type grindstone is color-coded according to its diameter, the diameter before wear can be easily known when worn by use, so that it is easy to judge the reduction in wear.

In this case, in a method of printing the hardness, the grain size, and the diameter on the surface of the grindstone, or by attaching a label indicating the hardness, the grain size, and the like to the surface of the grindstone, the label is peeled off or the print becomes faint with use. Therefore, it is difficult to quickly determine the whetstone and the wear loss.

[0005] Therefore, a colored cutting disc-shaped grindstone is manufactured, and the grindstone is identified based on color. The colored whetstone is formed by dispersing abrasive grains in a phenolic resin matrix, but after dehumidifying and sizing the original abrasive prepared by adding a pigment, semi-hot molding is performed at a molding temperature of 40 to 50 ° C. To make a disc-shaped raw whetstone,
It is manufactured by treating at 70 to 190 ° C. for 6 to 7 hours to cure the resin.

[0006]

Problems to be Solved by the Invention However, the conventional colored whetstone has a problem in that if it is fired at a low temperature in order to sharpen the color, the toughness and durability of the whetstone decrease. On the other hand, when firing at a high temperature, not only does the color not come out sharply, but also the hardness becomes too large, the cutting edge becomes poor at the time of cutting, and the cutting becomes difficult due to escape of the abrasive surface. There was also a problem. In addition, the incision does not go smoothly due to poor blade contact,
There was also a problem that the disk-type whetstone was warped.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a cutting disc having sufficient toughness, durability, and sharpness, and having appropriate hardness. An object of the present invention is to provide a mold coloring whetstone and a manufacturing method thereof.

[0008]

That is, according to the present invention, there is provided a method for producing a disk-shaped colored grinding wheel for cutting comprising abrasive grains dispersed in a phenol resin matrix, comprising:
A raw abrasive containing a resin raw material and abrasive grains is formed at a molding temperature of 60 to
Raw grinding stone manufacturing process of semi-hot molding into a disk at 70 ° C., and the above-mentioned raw grinding stone from 135 to 145 ° C. to 155 to 16
A thermosetting step of raising the temperature of the phenolic resin to 5 ° C. over 8 to 10 hours, and holding the last 2 to 4 hours at 155 to 165 ° C. to harden the phenolic resin; Of a colored disk wheel for cutting containing 0.6 to 1.0% by weight of

In the production method of the present invention, by maintaining the semi-hot molding base at 110 to 120 ° C.,
The molding temperature may be controlled at 60 to 70C. Further, it is preferable that the raw abrasive contains 0.2 to 0.6% by weight of iron oxide.

Further, according to the present invention, there is provided a disk-shaped colored grinding wheel for cutting manufactured by the above method.

Further, according to the present invention, the hardness is 5 to 20.
%, Toughness of 1 to 4 mm is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A disk-shaped colored grinding wheel for cutting is formed by dispersing abrasive grains in a phenol resin matrix. In the present invention, the disk-shaped colored grinding wheel for cutting comprises a pigment, a resin,
A raw grinding wheel manufacturing process of semi-hot molding a raw abrasive containing 0.6-1.0% by weight of magnesium oxide together with abrasive grains into a disk at a molding temperature of 60-70 ° C .; 8 to 10 from 145 ° C to 155 to 165 ° C
Rise over time, of which the last 2-4 hours
By maintaining the temperature at 5 to 165 ° C., it is manufactured through a thermosetting step of hardening the phenol resin.

The raw abrasive material is pigment, resin raw material, abrasive grains, etc.,
Contains 0.6 to 1.0% by weight of magnesium oxide. The purpose of adding magnesium oxide is to improve the sharpness by improving the hardness of the grindstone, and there is also an effect that if added together with creolites, the color becomes clearer. The content of 0.6 to 1.0% by weight is 0.1%.
If the amount is less than 6% by weight, the durability is lowered. If the amount is more than 1.0% by weight, the hardness becomes too large, the sharpness is lowered, and the curing reaction of the resin is hindered. The content of magnesium oxide is more preferably 0.7 to 0.9% by weight.

As the abrasive grains, alundum (Al ₂ O ₃ ,
96 wt%), white alundum (Al ₂ O ₃ , 98 wt%), sintered abrasive (Al ₂ O ₃ , 99 wt%), green carbon (SiO ₂ ) and the like can be used.

[0015] Phenol and formaldehyde are used as resin raw materials.

The pigment varies depending on the intended color.
In the case of red (JIS H: _3-5 R / V: _3-5 , C: _6-10 ), Fe ₂ O ₃ (Bengara) and yellow (JIS H: _4-5 YR)
/ V: _6-7 , C: _12-14 ), Fe _{2 O.H 2} O (yellow iron oxide), green (JIS H: _5-6 G / V: _2-3 ,
C: _6-10 ), CoO.nZnO (cobalt green), blue (JIS H: _3-6 B / V: _4-6 , C: _6-10 )
For the _{Na 6 Al 6 (SiO 4)} 6 · 2Na 3 O 4 ( group Zhou), white (JIS H: White, N: _{8.5 to 9.5,}
In the case of C: _3-5 ), TiO ₂ (titanium oxide) is preferably used. Preferably, the pigment is contained in the raw abrasive material in an amount of 0.2 to 0.6% by weight.

[0017] In addition, a filler, a curing aid, and the like may be added to the raw abrasive material as needed. Specifically, as a filler, creolites (Na
₃ AlF ₆ ), and barite (BaSO ₄ ), which contributes to stabilization of the hardness of the whole grindstone, is suitably used as a curing aid.

In the present invention, the raw abrasive material contains iron oxide in an amount of 0.1%.
It is preferable to contain 2 to 0.6% by weight. They are,
In addition to improving the color appearance, such as sharpening the color, it also has the function of improving the thermal conductivity of the grindstone and effectively releasing the frictional heat generated during cutting. 0.2 to 0.6
The reason for setting the weight% is that if the content is less than 0.2% by weight, the above effects cannot be sufficiently obtained, and if the content exceeds 0.6% by weight, the cost increases.

The mixture obtained by mixing these is dehumidified and sized to obtain a raw abrasive (glen). Dehumidification is performed, for example, in a low humidity, normal temperature environment of 50 to 60 Rh, about 20 ° C.
It is performed by leaving it for about an hour. The sizing is performed by passing the dehumidified mixture through a 20 to 40 mesh sieve. Sizing is an important step from the viewpoint of preventing the grinding stone from becoming brittle by removing free components remaining without being adsorbed by the abrasive grains.

A raw grindstone can be obtained by subjecting the raw abrasive to semi-hot molding into a disc at a molding temperature of 60 to 70 ° C. The semi-hot molding is performed using, for example, the apparatus shown in FIG. First, while keeping the press contact surface 5 warm,
By heating the substrate 4 to 110 to 120 ° C., the temperature of the substrate upper surface 11 is set to 60 to 70 ° C., and the molding temperature is adjusted. Next, the lower layer 8 is obtained by uniformly charging a half of the volume of the raw abrasive material into the disk-shaped whetstone mold 3. Next, a reinforcing material 6 made of glass cloth is laid on the entire upper surface of the lower layer 8, and the remaining half of the raw abrasive material is charged thereon, and the uppermost surface is leveled by a roller. Finally, press 2 is pressed to 180 kg for 3 to 4 seconds to obtain a raw whetstone.

The reason why the molding temperature is set to 60 to 70 ° C., which is about 20 ° C. higher than the conventional method, is to increase the density of the grindstone to improve the toughness and durability.

The raw whetstone is heated from 140 ° C. to 155 to 165
To 8 ° C. over 8 to 10 hours, and the last 2 to 4 hours of the above 8 to 10 hours are kept at 155 to 165 ° C. to thermally cure the resin, and a disc-shaped colored grinding wheel for cutting is obtained. can get. The heat treatment is performed in a state where the raw whetstones are stacked. Specifically, for example, as shown in FIG. 2, seven raw whetstones 14 are placed between eight leveling scissors plates 13 (thickness: 0.6 to 0.7 mm). Twenty sets of sets in which 13 and raw whetstones 14 are arranged alternately are laminated via a stable thick plate 12 (iron plate or cast plate having a thickness of 12 mm) and put into a firing furnace. In addition, it is preferable to use the thing made of iron excellent in thermal conductivity from the viewpoint of performing uniform heat treatment as the leveling scissors plate 13.

Prior to the above heat treatment for curing the resin, draining of the raw whetstone and melting of the resin are performed. For draining, for example, at 100 ° C. for 10 hours, and for melting of the resin, for example, At 130 ° C. for 7 hours. The draining of the raw grindstone, the melting of the resin, and the curing of the resin are continuously performed in the same firing furnace.

[0024] The curing temperature of the resin by heat treatment is 135-
The reason why the temperature was changed from 145 ° C. to 155 to 165 ° C. is that if the temperature is higher than 165 ° C., the surface hardens too quickly, and as shown in FIG. . When magnesium oxide is added, the hardness of the grindstone tends to be too large, but by performing the curing in the above temperature range, the influence on the hardness of magnesium oxide can be eliminated. Further, when the resin is cured at a high temperature, the freshness of the color of the colored whetstone is impaired, and it becomes difficult to obtain a vivid color. On the other hand, if the temperature is less than 135 ° C., the curing reaction of the resin becomes insufficient, and the hardness and toughness of the grindstone become insufficient. The curing temperature of the resin by heat treatment is 1
It is more preferred to start from 40 ° C. and increase to 160 ° C.

The curing time of the resin by the heat treatment is 8 to 10
And the last 2 to 4 hours are kept at 155 to 165 ° C., because the curing temperature is lower than before, and it is necessary to lengthen the curing time to obtain sufficient toughness. However, if it is less than 8 hours, sufficient toughness cannot be obtained, and it becomes a brittle and poorly durable grindstone. Even if heat curing is performed for more than 10 hours, further increase in toughness cannot be expected. is there.

Since the cutting disk-shaped colored grinding wheel manufactured by the above-described method has a vivid color, it is possible to quickly determine the grinding wheel having a different hardness or particle size according to the situation. Efficiency can be improved and inventory management becomes easier. In addition, since it has sufficient toughness and durability, the abrasive grains do not collapse during use. Furthermore, since it has an appropriate hardness, it has good blade contact and good sharpness, and the grinding stone does not warp due to cutting.

[0027]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 A disk-shaped colored grinding wheel for red cutting was manufactured, its density, hardness and toughness were measured, and a cutting test was performed. The manufacture of the grindstone was performed as follows.

First, for 80 kg of Alundum, 0.4 kg of iron oxide (Bengara) and 4 kg of hydrous phenol (BRL-219, manufactured by Showa Polymer Co., Ltd.) were charged into a 100-liter blender, and the mixture was added at 25 ± 5 ° C. Mix for minutes. It should be noted that hydrous phenol is a liquid phenol containing about 20% by weight of water, but if the abrasive grains are sufficiently wetted in advance with the liquid phenol, uniform and stable infiltration of the resin material into the abrasive grains becomes possible. . Hydrous phenol is preferably added in an amount of 2 to 5% by weight, but if it is less than 2% by weight, the toughness of the grindstone decreases, and if it exceeds 5% by weight, the hardness becomes too large and the sharpness decreases. is there.

Next, 3 kg of phenol (manufactured by Showa Polymer Co., Ltd., BRP-511) was added to the mixture thus obtained.
Epoxidized phenol (BRP-80 manufactured by Showa Polymer Co., Ltd.)
8) 7 kg, 4 kg of creolite, 0.8 kg of magnesium oxide and 0.8 kg of barite were mixed, put into a 150-liter blender, and mixed at 25 ± 5 ° C. for 5 minutes. The epoxidized phenol resin is obtained by introducing an epoxy group into the phenol resin, and has an effect of improving the toughness of the grindstone by forming crosslinks. The added amounts of phenol and epoxidized phenol are 2 to 5% by weight and 6 to 10%, respectively.
It is preferable that the content is less than the above-mentioned value, because if the value is less than the above value, the toughness of the grindstone is lowered. If the value is more than the above value, the hardness becomes too large and the sharpness is reduced. or,
It is preferable that the added amount of creolites is 3 to 7% by weight, but if it is less than 3% by weight, an appropriate hardness cannot be obtained, and if it is more than 7% by weight, the hardness becomes too large and the sharpness becomes sharp. Because it falls. It is preferable that the amount of barite added is 0.6 to 1.0% by weight.
If the content is more than the weight%, the hardness becomes too large, the sharpness is lowered, and the curing reaction of the resin is hindered.

Next, the above mixture is subjected to a humidity of 50-60.
After leaving it for about 4 hours under the condition of Rh and a temperature of about 20 ° C. for dehumidification, it was sieved with a 20 to 40 mesh sieve to obtain a raw abrasive (grain).

Next, the original abrasive material (glen) is heated at a molding temperature of 60%.
A raw grindstone was obtained by semi-hot molding into a disc at ~ 70 ° C. Semi-hot molding was performed using the apparatus shown in FIG. First, while keeping the press contact surface 5 at 50 to 60 ° C. and heating the substrate 4 to 110 to 120 ° C., the temperature of the substrate upper surface 11 was set to 60 to 70 ° C. Next, the lower layer 8 is formed by uniformly charging a half of the original abrasive material (glen) into the disk-shaped whetstone mold 3, and then a reinforcing material made of glass cloth is formed on the entire upper surface of the lower layer 8. 6 (manufactured by Safety Equipment Co., Ltd., # 4300, thickness 0.8 mm, diameter 400 m)
m, color R # 305), and the remaining half of the volume of raw abrasive (glen) was placed thereon, and then the top surface was leveled with a roller. Finally, press 2 was pressed to 180 kg for 3 to 4 seconds to obtain a raw grindstone. In addition, the mold 3 for the disc-shaped grindstone of the forming apparatus 1 was made of nitrided steel having a cavity 9 with a diameter of 305 mm and a depth of 5 mm. The base 4 has a diameter of 50
A 45 mm one made of 0 mm was used. The press 2 used had a curvature of the contact surface 5 of 500 mmR.

Finally, the resin is cured by subjecting the raw grindstone to a heat treatment, and has a diameter of 405 mm and a flange diameter of 50 m.
m, a disk-shaped colored grinding wheel for cutting having a thickness of 3.0 mm was obtained. As shown in FIG. 2, the heat treatment was performed using eight leveling scissor plates 13.
A set in which seven raw whetstones 14 were arranged between (a thickness of 0.7 mm, a diameter of 420 mm, made of 45C) so that the leveling scissors plate 13 and the raw whetstones 14 were alternately arranged was a stable thick plate 12.
(Thickness 12 mm, diameter 500 mm, made of casting)
0 sets were laminated and performed in a firing furnace. As shown in FIG. 3, the heat treatment was performed by increasing the temperature from 140 ° C. to 160 ° C. over 8 hours, and maintaining the temperature at 160 ° C. for the last 2 hours.

Prior to the above heat treatment, draining of the raw grindstone and melting of the resin were performed.
Melting of the resin was carried out at a temperature of 25 ° C. and a humidity of 40 RH for 4 hours by applying a pressure treatment at 70 ° C. for 1 minute at 180 kg.

The density of the obtained disk-shaped colored grinding wheel for cutting,
Hardness and toughness were measured by the following methods, and a cutting test was performed by the following methods.

(Measurement Method of Density (g / cm ₃ )) The weight W and apparent volume V of the grindstone were measured and calculated by the formula of W / V.

(Method of measuring hardness (%)) 65 mm × 65
When the mm × 60 mm L-type angle steel material was cut, the% wear value of the diameter of the test grindstone was measured and defined as hardness.

(Method of measuring toughness (mm)) 200 × 5
A test piece grindstone of 0 × 3 mm was cantilevered to the end of the table, and the amount of strain (bending amount) when a stress of 5 kg was applied to a free end at a distance of 100 mm from the fixed point was measured to determine the toughness.
A toughness of 2 mm or more was defined as “tough”, 1 mm or more and less than 2 mm as “normal”, and less than 1 mm as “fragile”.

(Method of cutting test) 65 mm × 65 mm ×
A 60 mm L-type angle steel material was cut ten times with the obtained grindstone, and the cutting speed was measured. The cutting machine used was made by Mitachi.

(Durability test method) The standard steel material was repeatedly cut with the obtained grindstone, and the judgment was made based on the number of cuts when the grindstone was used up to around the flange. That is,
The number of cuts of 25 or more was rated "excellent", the number of cuts of 16 or more and less than 24 was rated "normal", and the number of cuts of less than 16 was rated "poor".

Table 1 shows the measurement results of the density, hardness and toughness.
Table 2 shows the results of the cutting test.

(Comparative Example 1) A black disk-shaped colored grinding wheel for cutting was manufactured, and its density, hardness and toughness were measured, and a cutting test was performed. The manufacture of the grindstone was performed as follows.

First, for 100 kg of alundum, 0.3 kg of carbon and 4.5 kg of hydrous phenol were added for 10 kg.
The mixture was charged into a 0 l compounder and mixed at 25 ± 5 ° C. for 3 minutes.

Next, 13.5 kg of phenol, 0.7 kg of creolite, 3 kg of iron sulfide and 3 kg of barite were mixed with the mixture thus obtained, and the mixture was charged into a 150-liter blender. Mix for minutes.

The above mixture was dehumidified and sized in the same manner as in Example 1 to obtain a raw abrasive.

A raw grindstone was obtained in the same manner as in Example 1 using the above-mentioned raw abrasive. However, the temperature condition is about 4
The temperature of the base was 0 ° C., the temperature of the base was about 90 ° C., and the temperature of the upper surface of the base (forming temperature) was 80 to 90 ° C.

Finally, the resin is cured by subjecting the raw grindstone to heat treatment in the same manner as in Example 1, and the diameter is 400 m.
m, a disk-shaped colored grinding wheel for cutting having a thickness of 3.0 mm was obtained. However, the heat treatment was performed by increasing the temperature from 170 ° C. to 190 ° C. over 6 hours.

Prior to the heat treatment, the raw whetstone was drained and the resin was melted.
Melting of the resin was carried out at a temperature of 25 ° C. and a humidity of 40 RH for 4 hours by applying a pressure treatment at 70 ° C. for 1 minute at 180 kg.

The density of the obtained disk-shaped colored grinding wheel for cutting,
The hardness and toughness were measured in the same manner as in Example 1,
A cutting test was performed in the same manner as in Example 1.

Table 1 shows the measurement results of the density, hardness and toughness.
Table 2 shows the results of the cutting test.

(Comparative Example 2) A black disk-shaped colored grinding wheel for cutting was produced in the same manner as in Comparative Example 1. The density, hardness and toughness were measured by the same method as in Example 1, and a cutting test was performed by the same method as in Example 1.

Table 1 shows the measurement results of the density, hardness and toughness.
Table 2 shows the results of the cutting test.

[0053]

[Table 1]

[0054]

[Table 2]

As shown in Tables 1 and 2, the cutting-type colored wheel for cutting of the embodiment is superior to the disk-shaped colored wheel for cutting of the comparative example in toughness, cutting speed, and the like. It turns out that it is more than equivalent to the disk type coloring whetstone for cutting. The hardness was equivalent to that of the disk-shaped colored grinding wheel for cutting of the comparative example.

[0056]

EFFECTS OF THE INVENTION The disk-shaped colored grinding wheel for cutting manufactured by the method of the present invention can improve the working efficiency because it is possible to quickly determine the grinding wheels having different hardness and particle size according to the situation, Inventory management is also easy. In addition, if the cutting disc-type grindstone is color-coded according to its diameter, the diameter before wear can be easily known when worn by use, so that it is easy to judge the reduction in wear. In addition, since it has sufficient toughness and durability, the abrasive grains do not collapse during use. Furthermore, since it has an appropriate hardness, it has good blade contact and good sharpness, and does not warp the grindstone. Further, since the density is moderately high, it is not necessary to separately classify the hardness according to the work material.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an outline of a semi-hot molding apparatus.

FIG. 2 is a schematic cross-sectional view illustrating a method of firing a raw grindstone.

FIG. 3 is a graph showing an example of firing conditions for a disk-shaped colored grinding wheel for cutting.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semi-hot forming apparatus, 2 ... Press, 3 ... Die for disk grinding wheel, 4 ... Base, 5 ... Press contact surface part, 6 ... Reinforcement, 7 ...
Upper layer, 8 Lower layer, 9 Cavity, 10 Dowel pin with spring, 11 Base upper surface, 12 Stable thick plate, 13
... leveling scissors plate, 14 ... raw whetstone.

Claims (5)

[Claims] 1. A method for producing a disk-shaped colored grinding wheel for cutting comprising abrasive particles dispersed in a phenolic resin matrix, comprising the steps of: preparing a raw abrasive containing a pigment at a molding temperature of 60 to 70 ° C. Raw grinding stone manufacturing process of semi-hot molding in a shape and the raw grinding stone from 135 to 145 ° C to 155 to 165 ° C from 8 to 10
Rise over time, of which the last 2-4 hours
A cutting circle characterized by having a thermosetting step of hardening the phenolic resin by holding at 5 to 165 ° C, wherein the raw abrasive contains 0.6 to 1.0% by weight of magnesium oxide. Manufacturing method of plate-type colored whetstone. 2. A semi-hot molding substrate at 110 to 120 ° C.
The method for producing a disk-shaped colored grinding wheel for cutting according to claim 1, wherein the molding temperature is controlled to 60 to 70 ° C by maintaining the temperature at 60 ° C. 3. The method according to claim 1, wherein the raw abrasive contains 0.2 to 0.6% by weight of iron oxide. 4. A disk-shaped colored grinding wheel for cutting manufactured by the method according to claim 1, 2 or 3. 5. A disk-shaped colored grinding wheel for cutting, having a hardness of 5 to 20% and a toughness of 1 to 4 mm.