JP3795778B2 - Resinoid grinding wheel using hydrogenated bisphenol A type epoxy resin - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In particular, the present invention relates to a resinoid grinding wheel composed of abrasive particles having a particle size of # 800 or more bonded to each other using a hydrogenated epoxy resin as a binder.
[0002]
[Prior art]
For example, a resinoid grinding wheel in which abrasive grains are bonded with a synthetic resin binder (resin bond) is generally used for grinding with a large machining allowance such as roughing. Resinoid grinding wheels are suitably used for such grinding because synthetic resin binders that bond abrasive grains are used for vitreous bond (vitrified bond), metallic binder (metal bond), electrodeposition bonding, etc. This is because the modulus of elasticity is lower than that of the workpiece, so that the load acting on the abrasive grains from the work material during grinding can be reduced by elastic deformation of the binder. In particular, resinoid grinding wheels using an epoxy resin as a binder have a lower elastic modulus than those using a phenol resin as a binder, and are long in the above-described work utilizing the characteristics. Widely used for processing thin pipes. Among resinoid grinding wheels using such epoxy resins as binders, the above characteristics can be most remarkably achieved by the method of casting a liquid epoxy resin and abrasive grains into a mold after mixing them. The resinoid grindstone is produced by a combination of a low elastic modulus, which is a characteristic of an epoxy resin, and a physically strong bond due to wetting of abrasive grains and a binder obtained by this casting method. It is thought to give excellent grinding performance.
[0003]
[Problems to be solved by the invention]
However, for the purpose of improving the quality of the work surface of the work material, in resinoid grinding wheels that use epoxy resin as a binder with fine abrasive grains with a particle size of # 800 or more, clogging and welding of chips on the grindstone processed surface Therefore, the surface quality of the desired work material cannot be continuously obtained and the dressing is frequently required due to reasons such as uneven gloss on the work surface of the work material, spiral marks and scratches. There was a problem.
[0004]
The present invention has been made to solve such a problem, and the object of the present invention is to use a synthetic resin binder even in a resinoid grinding wheel using fine abrasive grains having a particle size of # 800 or more. An object of the present invention is to provide a resinoid grinding wheel having an appropriate holding force for abrasive grains and capable of continuously obtaining a good work surface quality by generating a cutting edge by itself.
[0005]
[Means for solving the problems]
The present inventor continues to study the above problems, and regarding the resinoid grindstone using an epoxy resin using fine abrasive grains having a particle size of # 800 or more as a binder, it is the abrasive grains and the binder that cause the above problems. It came to the view that the bond with the epoxy resin was too strong for fine abrasive grains having a particle size of # 800, preventing the self-growth of the cutting edge. In other words, the work that uses resinoid grinding wheels using fine abrasive grains is generally smaller than the case of coarse grains, and the number of abrasive grains involved in grinding on the work surface of the work material As a result, the amount of fine abrasive grains will inevitably increase. As a result, the load on one abrasive grain will be reduced, so that the bonding force that holds the abrasive grains will be the same for fine abrasive grains and coarse grains. However, since the force to drop off the abrasive grains was relatively small, it was considered that the cutting edge was not moderately self-generated.
[0006]
By the way, it is generally considered that the bonding force of the abrasive grains by the epoxy resin is dominated by the physical caulking force. To reduce this, it is necessary to lower the elastic modulus of the epoxy resin alone. . In order to lower the elastic modulus of epoxy resin mainly composed of bisphenol A, which is generally used as a synthetic resin binder for resinoid grinding wheels, a reactive diluent must be added at the manufacturing stage. The addition of a functional diluent reduces not only the modulus of elasticity of the synthetic resin binder but also the heat resistance, so the grinding performance of the resinoid grinding wheel is likely to vary due to temperature changes in the grinding fluid used during grinding. In addition to new problems related to performance, in the production of resinoid grinding wheels, the viscosity when mixed with a curing agent is increased, so mixing with abrasive grains is not performed sufficiently. There is a possibility that manufacturing problems such as abnormally promoting the curing of the resin may occur. The resin mixing viscosity (viscosity when the resin is mixed with a curing agent) for obtaining a sufficiently mixed state with fine abrasive grains having a particle size of # 800 or more is generally 1 Pa · s or less. In order to suppress this, in order to satisfy the condition that the single glass transition temperature after curing is 100 ° C. or higher, a material such as bisphenol A has a minimum elastic modulus of 3 GPa after curing.
[0007]
The present invention has been made against the background of the above circumstances. The gist of the present invention is a resinoid grinding wheel composed of abrasive grains having a particle size of # 800 or more bonded together by a synthetic resin binder. a is, the synthetic resin binder, and wherein the hydrogenated bisphenol a all SANYO to use base resin as a main raw material, the glass transition temperature of a single post-curing is made of a 100 ° C. or higher To do.
[0008]
【The invention's effect】
In this way, the synthetic resin binder uses a main agent mainly composed of hydrogenated bisphenol A, and since the glass transition temperature of a simple substance after curing is 100 ° C. or higher, Even with resinoid grinding wheels that use fine abrasive grains with a grain size of # 800 or more, there are problems related to the performance of the grinding stone, such as the grinding performance of the resinoid grinding wheel tends to vary due to changes in the temperature of the grinding fluid used during grinding. Therefore, it is possible to provide a resinoid grinding wheel in which the synthetic resin binder has an appropriate holding force with respect to the abrasive grains, and the cutting edge is allowed to grow spontaneously to continuously obtain a good work surface quality.
[0009]
Other aspects of the invention
Here, preferably, the synthetic resin binder has a viscosity of 1 Pa · s or less when the main agent and the curing agent are mixed. In this way, in the production of the resinoid grinding wheel 10, since the viscosity when mixing the main raw material of the synthetic resin binder and the curing agent is sufficiently low, mixing with the abrasive grains is suitably performed. Manufacturing problems such as abnormally accelerating the curing of the epoxy resin due to the heat of stirring are not generated.
[0011]
Preferably, the synthetic resin binder has a flexural modulus of a simple substance after curing of 2 GPa or less. In this way, even if it is a resinoid grinding wheel using fine abrasive grains having a particle size of # 800 or more, the synthetic resin binder has an appropriate holding force for the abrasive grains, and the cutting edge is allowed to grow spontaneously. It is possible to provide a resinoid grinding wheel capable of continuously obtaining good work material surface quality.
[0012]
【Example】
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 is a perspective view showing the shape of a resinoid grinding wheel 10 according to an embodiment of the present invention. In the figure, a resinoid grinding wheel 10 is a cylindrical grinding type disk-shaped grinding wheel which is integrally formed with dimensions of an outer diameter of 500 (mmφ) × thickness 150 (mm) × inner diameter of 200 (mmφ), for example. There is a mounting hole 12 provided in the central portion, which is attached to the main shaft of a grinding machine (not shown) and supplies a grinding liquid between the outer peripheral grinding surface 14 and the work material, and is held by a holding device (not shown). In a state where the cutting material is pressed against the outer peripheral grinding surface 14, it is rotated around its axis and used. As a result, the work surface of the work material is ground into the desired shape by the outer peripheral grinding surface 14.
[0014]
FIG. 2 is an enlarged view showing the configuration of the resinoid grinding wheel 10. In this figure, a resinoid grinding wheel 10 includes general abrasive grains such as SiC and fused alumina, and abrasive grains 16 which are superabrasive grains such as CBN and diamond, which are bonded to each other by a resin bond, that is, a synthetic resin binder 18. Thus, a large number of pores 22 are provided. In the resinoid grinding wheel 10 configured in this manner, the outer peripheral grinding surface 14 is brought into sliding contact with the work surface 24 of the work material 20 as described above, so that the cutting edges 26 of the abrasive grains 16 become the work material 20. The work surface 24 is ground. When a part of the abrasive grains 16 is crushed along with the grinding, the next cutting edge 26 is regenerated and the grinding performance is continued. The weight ratio of the synthetic resin binder 18 to the abrasive grains 16 or the whole is determined so as to exclusively and sufficiently bond the abrasive grains 16, and when the crushed abrasive grains 16 become small, the synthetic resin binder is used. Since the holding force of 18 is reduced, it is dropped together with the crushed abrasive grains 16 so that the next abrasive grains 16 are involved in grinding. At this time, the larger the number of the abrasive grains 16, that is, the smaller the particle diameter, the smaller the cutting edge 26 involved in the grinding and the more the number of cutting edges. Smooth surface quality of the workpiece can be obtained.
[0015]
The resinoid grinding wheel 10 of the present embodiment is manufactured as follows, for example. First, 26 parts by volume of a main ingredient mainly composed of hydrogenated bisphenol A such as hexahydrobisphenol A diglycidyl ether as the synthetic resin binder 18 and 9 parts by volume of an amine curing agent as a curing agent, for example, in a mixer Charged and stirred quickly. Subsequently, the synthetic resin binder raw material mixed in this manner has 20 parts by volume of fused alumina (Al ₂ O ₃ ) abrasive grains having a particle size of # 1000 as abrasive grains 16 and an organic balloon having an average particle diameter of about 100 μm. 15 parts by volume are further charged and stirred for a predetermined time, for example, about 10 minutes. The organic balloon is introduced for the purpose of forming pores 22.
[0016]
The main raw material of the synthetic resin binder 18 of this example includes a single glass transition temperature after curing of 115 ° C., a viscosity when mixed with a curing agent of 0.6 Pa · s, and a single bending elastic modulus after curing. Hydrogenated bisphenol A having a pressure of 1.8 GPa is used. Here, hydrogenated bisphenol A is a compound in which hydrogen is added to the double bond of bisphenol A, and some double bonds may remain. As described above, hydrogenated bisphenol A has a resin mixed viscosity (viscosity when the resin is mixed with a curing agent) of 1 Pa · s or less and a cured glass transition temperature of 100 ° C. or higher after curing. As described above, it has the characteristic that the flexural modulus of the single body can be suppressed to 2 GPa or less, so that it is used as the main raw material of the synthetic resin binder 18, so that fine abrasive grains with a grain size of # 800 or more are used. Even in the resinoid grinding wheel 10 using the No. 12, no problem in manufacturing occurs, the synthetic resin binder 18 has an appropriate holding force for the abrasive grains 12, and the cutting edge 26 is suitable as described above. It is possible to provide a resinoid grinding wheel 10 that is self-generated. That is, if the glass transition temperature after curing of the synthetic resin binder 18 is 100 ° C. or higher, there will be no variation in the grinding performance of the resinoid grinding wheel 10 due to the temperature change of the grinding fluid during grinding, and In the mixing step, when the viscosity of the grindstone raw material to be mixed is 1 Pa · s or less, mixing with the abrasive grains 12 is sufficiently performed, and the curing of the epoxy resin is abnormally accelerated by generating heat of stirring. Such a problem does not occur.
[0017]
Subsequently, 30 parts by volume of a foamed polystyrene resin (foaming ratio 10 times) having an average particle diameter of about 1 mm is added to the preparation mixed in the above step, and then further stirred for a predetermined time, for example, about 5 minutes. This foamed polystyrene resin functions to form huge pores (not shown) having a diameter larger than the pores 22 and functioning as chip pockets in the grindstone structure. The grindstone raw material thus adjusted is then cast into a predetermined mold, left to stand for about 24 hours at room temperature, cured to some extent, and then demolded, and further at about 160 ° C. for 3 hours. The resinous grinding wheel 10 is formed by performing the main curing treatment.
[0018]
Hereinafter, a grinding test performed by the present inventor will be described. First, an example sample which is an example of the present invention is prepared by the above steps, and subsequently, the same raw materials and steps as the above example samples are used except that bisphenol A is used as the main raw material of the synthetic resin binder 18. A comparative sample was prepared. Bisphenol A, which is a raw material for the comparative sample, has a flexural modulus of 2.9 GPa after curing, a viscosity of 0.5 Pa · s when mixed with a curing agent, and a glass transition temperature of 105 ° C. after curing. What was used. The shape of the example sample and the comparative example sample thus prepared was OD 455 (mmφ) × thickness 150 (mm) × inner diameter 228.6 (mmφ). A grinding test for verifying the effect of the present invention was performed under the test conditions shown below using the example sample and the comparative example sample.
[0019]
[Test conditions]
Grinding machine: Centerless grinder grinding wheel peripheral speed: 2000m / min
Work Material: S45C Raw Material Work Material Dimensions: φ15 × L100
Grinding method: Through feed grinding Work material feed speed: 5m / min
Adjustment whetstone: Rubber whetstone (outer diameter 255 mmφ, thickness 150 mm, inner diameter 127 mm)
[0020]
FIG. 3 is a diagram showing a relative positional relationship between the resinoid grinding wheel 10 and the work material 20 in this experiment, (a) is a plan view, and (b) is a front view. In the grinding test, as shown in FIG. 3A, between the resinoid grinding wheel 10 of the example sample or the comparative example sample and the adjusting wheel 30 for correcting when these samples are worn by grinding. The cylindrical workpiece 20 having an outer diameter of 15 (mmφ) × 100 (mm) in length is continuously fed in the direction indicated by the arrow in FIG. 3A, that is, in the direction of the rotational axis of the resinoid grinding wheel 10. Grinded. Here, as shown in FIG. 3, the adjusting grindstone 30 was used in a state where its axis was slightly inclined from the axial direction of the resinoid grinding grindstone 10. When the machining allowance provided on the work material 20 starts from the setting of 10 μmφ and the machining allowance becomes 5 μmφ, the work material 20 in the direction indicated by the arrow in FIG. Changes in the power consumption value (kW) of the grinding machine spindle relative to the number of workpieces 20 processed are repeated by moving the adjusting wheel 30 forward by 5 μm in the normal direction of the contact point and returning the machining allowance of the workpiece 20 to 10 μmφ again. The surface quality (μRz) of the work surface 24 of the work material 20 was evaluated.
[0021]
FIG. 4 is a graph showing the transition of the power consumption value of the grinding machine spindle with respect to the number of workpieces 20 obtained as a result of the grinding test. According to this graph, in the grinding with the resinoid grinding wheel 10 as an example sample, the initial power consumption value is about 30% lower than the grinding with the resinoid grinding wheel 10 as a comparative example sample. The power consumption value tends to gradually decrease as the number of processing increases. Thereby, in an example sample, it turns out that the grindstone is worn moderately by grinding. In the graph of the example sample, the power consumption value increases around 180 and 450. This is because the machining allowance of the work material 20 is 5 μmφ. This is because correction was made so that the machining allowance of the work material 20 was returned to 10 μmφ by advancing in the direction by 5 μm. As a result of this correction, the power consumption value once increased to a value almost close to the initial value, but the power consumption value gradually decreased as the number of machining operations increased. On the other hand, in the resinoid grinding wheel 10 which is a comparative example sample, the power consumption value tended to decrease as the number of workpieces 20 increased to about 130, but when this number was exceeded, The power consumption value gradually increased, and since the unevenness of gloss occurred on the work surface 24 of the work material 20 after finishing the 440th machining, the grinding was stopped. Moreover, in the comparative sample, the work material removal allowance did not decrease even when grinding was continued, and thus correction was not performed.
[0022]
Similarly, the state (ten-point average roughness) of the work surface 24 of the work material 20 with respect to the number of work pieces 20 obtained as a result of the grinding test is shown below.
[0023]
Number of processing (pieces) 1 150 300 440 450 600
Surface cut by sample (μRz) 0.32 0.30 0.29 ― 0.29 0.29
Machining surface by comparative sample (μRz) 0.35 0.33 0.32 0.30 ― ―
[Remarks]
In the grinding test using the comparative sample, since the unevenness of gloss occurred on the work surface of the work material after finishing the 440th work, the grinding was stopped.
[0024]
According to this result, in the grinding with the resinoid grinding wheel 10 as an example sample, there are no problems such as uneven gloss, spiral marks, scratches, etc. on the work surfaces 24 of all 600 work materials 20 that have been ground, While the desired surface quality was obtained, in the grinding with the resinoid grinding wheel 10 which is a comparative sample, as described above, the unevenness of gloss occurs on the work surface 24 of the work material 20 at the 440th and the state up to the 445th is shown. The gloss unevenness was not cured.
[0025]
From the above test results, by using hydrogenated bisphenol A as the main raw material of the synthetic resin binder 18, the synthetic resin binder 18 can be used even for the resinoid grindstone 10 using the fine abrasive grains 16 having a particle size of # 800 or more. It has been confirmed that the resinoid grinding wheel 10 that has an appropriate holding force with respect to the abrasive grains 16 and can continuously obtain good surface quality of the work material 20 by causing the cutting edges 26 to grow spontaneously can be provided.
[0026]
Thus, according to this example, hydrogenated bisphenol A used as the main raw material of the synthetic resin binder 18 has a viscosity of 1 Pa · s or less when mixed with a curing agent, and a single glass transition after curing. Resinoid grinding wheel using fine abrasive grains 16 with a grain size of # 800 or more because a material having a temperature satisfying a condition of 100 ° C. or more and having a flexural modulus of 2 GPa or less after curing can be easily obtained. Even if the synthetic resin binder 18 has a moderate holding power to the abrasive grains 16, the resinoid grinding can continuously obtain a good surface quality of the work material 20 by self-generating the cutting edge 26. A grindstone 10 can be provided.
[0027]
In addition, according to this example, the synthetic resin binder has a viscosity of 1 Pa · s or less when mixed with the main agent and the curing agent. Therefore, in the production of the resinoid grinding wheel 10, the synthetic resin binder is used. Since the viscosity at the time of mixing the 18 main raw materials and the curing agent is sufficiently low, the mixing with the abrasive grains 16 is suitably performed, and the curing of the epoxy resin is abnormally accelerated by the stirring heat at the time of mixing. There is no problem.
[0028]
Moreover, according to the present Example, since the synthetic resin binder has a single glass transition temperature after curing of 100 ° C. or higher, the resinous grinding wheel 10 has a temperature change of the grinding fluid used during grinding. There are no problems related to the performance of the grinding wheel, such as the grinding performance becoming more variable.
[0029]
In addition, according to the present example, the synthetic resin binder has a flexural modulus of 2 GPa or less after being cured, and therefore, resinoid grinding using fine abrasive grains 16 having a particle size of # 800 or more. Even with the grindstone 10, the synthetic resin binder 18 has an appropriate holding force with respect to the abrasive grains 16, and the resin blade 18 can continuously obtain a good surface quality of the work material 20 by generating the cutting edge 26 by itself. A grinding wheel 10 can be provided.
[0030]
As mentioned above, although one Example of this invention was described in detail based on drawing, this invention is implemented also in another aspect.
[0031]
For example, in the above-described embodiment, the resinoid grinding wheel 10 which is a cylindrical grinding type disk-shaped grinding wheel has been described. However, the present invention is not limited to this, and the abrasive grains having a particle size of # 800 or more by the synthetic resin binder 18. 16 is widely used for resinoid grinding wheels configured by being coupled to each other. For example, it is suitably used for various resinoid grinding wheels such as a surface grinding type disc-shaped grinding wheel, a cup-type grinding wheel, and an internal grinding wheel. It is what
[0032]
In the above-described embodiment, alumina (Al ₂ O ₃ ) abrasive grains having a particle size of about # 1000 were used, but silicon carbide (SiC) abrasive grains, zirconia-alumina (ZrO ₂ —Al ₂ O ₃ ). The present invention also relates to a resinoid grinding wheel 10 in which other general abrasive grains such as system abrasive grains, superabrasive grains such as cubic boron nitride (CBN) abrasive grains and diamond abrasive grains, or a mixture thereof are used as the abrasive grains 16. Applies as well. Moreover, the particle size of the abrasive grains 16 is appropriately changed.
[0033]
In the above-described embodiment, the entire resinoid grinding wheel 10 is composed of a grindstone structure in which the abrasive grains 16 are bonded by the synthetic resin binder 18, but around the core portion made of synthetic resin, metal, or the like. The present invention is similarly applied to a grinding wheel provided with an outer peripheral grinding wheel portion.
[0034]
In addition, although not illustrated one by one, the present invention is implemented with various modifications without departing from the gist thereof.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the shape of a resinoid grinding wheel according to an embodiment of the present invention.
FIG. 2 is an enlarged view showing a configuration of a resinoid grinding wheel according to an embodiment of the present invention.
FIG. 3 is a diagram showing a relative positional relationship between a resinoid grinding wheel and a work material in a grinding test performed by the present inventor.
FIG. 4 is a graph showing the transition of the power consumption value of the grinding machine spindle with respect to the number of workpieces obtained as a result of the grinding test conducted by the present inventor.
[Explanation of symbols]
10: Resinoid grinding wheel 16: Abrasive grain 18: Synthetic resin binder

Claims (3)

A resinoid grinding wheel constructed by combining abrasive grains having a particle size of # 800 or more with a synthetic resin binder,
The synthetic resin binder, resinoid grinding wheel, characterized in that the hydrogenated bisphenol A all SANYO to use base resin as a main raw material, the glass transition temperature of a single post-curing is made of a 100 ° C. or higher .   The resinoid grinding wheel according to claim 1, wherein the synthetic resin binder has a viscosity of 1 Pa · s or less when the main agent and the curing agent are mixed. The resinoid grinding wheel according to claim 1 or 2 , wherein the synthetic resin binder has a flexural modulus of a simple substance after curing of 2 GPa or less.

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