JPS6325915B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a rotary grinding and polishing tool that is made of a resinoid grindstone and coated abrasive paper and can be used for both grinding and polishing. (Prior Art) Resinoid grindstones have been used in various ways since they have high strength and safety. For example, there are a wide variety of grindstones, such as general flat types, offset types, thin ones for cutting, and flexible grindstones, all of which have strong grinding power and can grind a large amount of workpiece material per unit time. Those who can do it are given prizes. However, on the other hand, the ground surface after grinding is rough, making it unsuitable for finishing purposes even with a flexible grindstone. Therefore, as polishing tools for finishing, coated abrasive paper, which is made by bonding abrasive grains to the surface of cloth or paper, has traditionally been widely used, and in order to obtain a particularly beautiful surface, highly flexible sponges are often used. A whetstone (vinyl whetstone) is used. Therefore, the reality is that resinoid grinding wheels are used when a large cutting allowance is required for the work material, and coated abrasive paper is used when finishing. In this case, two grinding machines such as grinders were required. Additionally, it is not uncommon for the part of the workpiece to be ground and the part to be polished to be processed in adjacent processes, requiring two grinders to be replaced each time, and the time loss cannot be ignored. It was hot. Therefore, multiple sheets of coated abrasive paper are placed on the surface of a disc-shaped substrate made of thermoplastic resin, fiber material, metal such as aluminum, etc., to prevent large escaping when the coated abrasive paper is pressed against the workpiece. By narrowing the spacing between the coated abrasive papers on the substrate and gluing them radially with the coated abrasive paper tilted backwards in the direction of rotation relative to the substrate, the part of each coated abrasive paper in contact with the substrate can be bonded to the adjacent abrasive cloth. A rotary grinding and abrasive tool can be considered that can be used for both grinding and polishing by covering it with paper for protection and suppressing the relief of the coated abrasive paper to a level that exhibits appropriate elasticity. However, such rotary grinding and polishing tools have the following problems. That is, it is difficult to bond the substrate and the coated abrasive paper with high strength, and therefore, the coated abrasive paper is likely to peel off during use. Also, substrates (especially substrates made of fiber material)
Because the strength of the grinding wheel is relatively weak, it is dangerous to increase the rotation speed to the peripheral speed of 4,300 m/min, which is generally achieved with grinding wheels, and the peripheral speed is approximately 3,000 m/min.
is the limit and cannot be used safely at high speeds. Furthermore, as the coated abrasive paper wears out and the substrate comes into contact with the workpiece, it becomes possible to continue using it by reducing the angle between the abrasive tool and the workpiece, but in reality it is not possible to use it. hard. Further, once the coated abrasive paper is safely consumed, it becomes unusable, but it is difficult to use the coated abrasive paper until it is completely consumed because the substrate becomes an obstacle, and the usable limit is narrow. Furthermore, as mentioned above, it is necessary to maintain high strength of the substrate, so it is expensive. (Object of the Invention) The present invention has been made in view of the above points, and its purpose is to provide excellent safety and high-speed usability by using a resinoid grinding wheel instead of the above-mentioned disc-shaped substrate. The object of the present invention is to provide a rotary grinding and polishing tool that has a wide range of usability, is inexpensive, and can be used for both grinding and polishing. (Structure of the Invention) In order to achieve the above object, the structure of the present invention uses a disc-shaped resinoid grinding wheel as a substrate, and a plurality of sheets of coated abrasive paper having an appropriate shape such as a strip shape are attached to the grinding surface of the resinoid grinding wheel. , the back surface of each coated abrasive paper is radially bonded to the polishing surface of the coated abrasive paper on the rear side in the direction of rotation of the whetstone in a manner that is partially polymerized and arranged in the circumferential direction. The grain size is set to be finer than the grain size of the coated abrasive paper mentioned above, and when used while maintaining a large angle with the workpiece, the grinding wheel mainly comes into contact with the workpiece and grinds, and the angle When used with a small abrasive paper, only the coated abrasive paper comes into contact with the workpiece to perform polishing. By doing this, the adhesive for bonding the coated abrasive paper penetrates into the inside of the used side of the resinoid grinding wheel, and this penetration makes the coated abrasive paper adhere to the whetstone like an anchor, making it difficult to peel off, and also increases the strength of the whetstone itself. Also high,
Coupled with the reinforcement with glass cloth, which is usually done with resinoid grinding wheels, this increases the strength of the entire rotary grinding tool and allows it to be used at peripheral speeds of 4,300 m/min. Furthermore, the grinding wheel wears out as the coated abrasive paper wears out, and the grain size of the whetstone is set to be finer than the coated abrasive paper, which has an adverse effect on the abrasiveness of the coated abrasive paper (the polished surface of the workpiece becomes coarser). Since the coated abrasive paper can be used until it is completely used up, the usable limit can be expanded, and the amount of polishing that can be performed on the workpiece can be increased compared to conventional methods. Furthermore, by appropriately selecting the material of the resinoid grindstone, it is possible to reduce the cost without causing any change in strength. (Effects of the Invention) Therefore, according to the present invention, a plurality of appropriately shaped abrasive coated papers are arranged in a predetermined state and bonded together on the use surface of a disc-shaped resinoid grindstone. The unique effects of the whetstone and coated abrasive paper are synergistically and organically exhibited, and it is safe, has excellent high-speed usability, has a wide usable range, is inexpensive, and is suitable for both grinding and polishing. It is possible to provide a highly practical rotary grinding and polishing tool, and by using this rotary polishing tool, the workability of grinding and polishing work can be greatly improved. (Example) Hereinafter, an example of the present invention will be described in detail based on the drawings. 1 and 2 show a rotary grinding and polishing tool A according to an embodiment of the present invention, in which 1 is an offset type resinoid grindstone having a predetermined grain size;
has a mounting hole 1a at its center for mounting on the rotating shaft of a rotary motor (for example, a disc grinder).
and an offset portion 1 that is offset toward the back surface side from other portions around the mounting hole 1a.
It has b. Further, a predetermined number (two in the figure) of reinforcing glass cloths 2, 2 are integrally embedded in the grindstone 1 so as to be parallel to the front and back surfaces. On the surface where the grinding wheel 1 is used, a plurality of strip-shaped coated abrasive papers 3, 3, etc. are arranged on the outer periphery (other than the offset portion 1b), each consisting of two overlapping sheets of abrasive paper 3, 3, etc. , are bonded together at one long side via an adhesive 4 such as room temperature curing type or heat curing type epoxy resin or resorcinol resin. As shown in an enlarged view in FIG. 3, each set of coated abrasive papers 3, 3, . . . Direction shown) Tilt to the rear side, and the tip of the back surface 3b of the coated abrasive paper 3 on the rear side in the grindstone rotation direction of each set of coated abrasive papers 3, 3 is adjacent to the rear side in the grindstone rotation direction from each set. They are arranged at equal intervals in the circumferential direction so as to overlap with the base of the polishing surface 3a of the coated abrasive paper 3 located on the front side in the rotational direction of the grindstone among the coated abrasive papers 3, 3 of the set. Furthermore, since grinding with the whetstone 1 of this rotary grinding and polishing tool A tends to make the ground surface of the workpiece rougher due to an increase in cutting pressure compared to grinding with the coated abrasive paper 3, 3, ..., the resin The grain size of the grinding wheel 1 is set to be finer than the grain size of the coated abrasive papers 3, 3,... to prevent an adverse effect on the polishing properties of the coated abrasive papers 3, 3, etc. (the polished surface of the workpiece becomes coarse). I try not to give it. In addition, if an appropriate amount of abrasive grains (preferably about the same or three times the weight percentage) that are finer than the grindstone 1 and the coated abrasive papers 3, 3, etc. are mixed into the adhesive 4 such as epoxy resin, the grinding tool When the 4 layers of adhesive are exposed due to the wear of A, there is no slipping and good grinding performance is maintained, and the coated abrasive paper 3, 3, ... and the grinding wheel 1
This is preferable because it also increases the adhesive strength with. Now, to explain the manufacturing method of the rotary grinding and polishing tool A, the grindstone 1 is manufactured by a normal offset grindstone manufacturing method. That is, for example, a predetermined amount of abrasive grains coated with 20 to 25% phenolic resin as a binder is placed in an offset mold and smoothed, and then glass cloth 2 is impregnated with 20 to 40% phenolic resin as a binder. After putting in the coated abrasive grains and glass cloth 2 alternately, a laminate in which two glass cloths 2, 2 are embedded between three layers of abrasive grains is formed, The grindstone 1 is manufactured by compression molding this laminate using a press and then heating and firing it to a maximum of 180° C. in an electric furnace for about 20 hours. On the other hand, the coated abrasive papers 3, 3, ... are used by punching out ordinary commercially available products into a predetermined shape, and the coated abrasive papers 3, 3, ... are placed in a predetermined state and glued to the grinding wheel with an adhesive 4. The rotary grinding and polishing tool A is manufactured by adhering it to the surface to be used. Therefore, in the rotary grinding and polishing tool A, when performing grinding work, the angle θ between the grinding and polishing tool A and the workpiece B is increased, as shown in FIG. 4a. Mainly the outer peripheral portion of the grindstone 1 of the tool A comes into contact with the workpiece B, and the workpiece B can be ground by the grinding action of the grindstone 1. On the other hand, when performing polishing work, as shown in Fig. 4b, by reducing the angle θ between the grinding tool A and the workpiece B, the outer circumference of the grinding wheel 1 does not hit the workpiece B. Only the abrasive surfaces 3a, 3a,... of the abrasive coated papers 3, 3,... come into contact with the workpiece B due to the abrasive action of the abrasive coated papers 3, 3,...
can be polished. That is, by simply changing the pressing angle θ of the grinding and polishing tool A against the workpiece B, it is possible to easily switch between grinding and polishing with a single touch. Both can be performed, and the work efficiency of grinding and polishing work can be improved. In addition, since the adhesive 4 for bonding the coated abrasive papers 3, 3, ... penetrates into the inside of the whetstone 1 from the surface where it is used, the coated abrasive papers 3, 3,... are firmly attached to the whetstone 1 in an anchored state. Glue it to the abrasive cloth paper 3, during use.
3, ... becomes difficult to peel off from the grindstone 1, and stable grinding and polishing can be performed. In addition, the abrasive bonding effect due to the penetration of the adhesive 4 into the grinding wheel 1 and the glass cloth 2, 2 in the grinding wheel 1
As the strength of the grinding wheel 1 increases due to the synergistic reinforcement effect of the
It is safe even when used at min, thus improving safety and high-speed usability. In addition, with use, the grindstone 1 and the abrasive cloth paper 3,
3, . . . are worn out in a well-balanced manner while maintaining the original arrangement, so that the coated abrasive paper is not obstructed by the substrate and becomes unusable, unlike in cases where a substrate made of thermoplastic resin or the like is used. Furthermore, by setting the grain size of the resinoid whetstone 1 to be finer than that of the coated abrasive paper 3, even if the whetstone 1 is exposed due to wear during polishing with the coated abrasive paper 3, the grinding surface will be There is no rough texture,
Good polishability can be maintained. Therefore, the coated abrasive papers 3, 3, . . . can be used until they are completely consumed, and the usable limit can be expanded and the amount of abrasive polishing applied to the workpiece B can be increased. Furthermore, since the resinoid grindstone 1 is used as a substrate to which the coated abrasive papers 3, 3, ... are bonded, the grindstone 1
By appropriately selecting the material within a range that allows variation in the grinding ability of the grinding tool A, costs can be reduced without reducing strength, and the grinding tool A can be made inexpensive. Furthermore, coated abrasive paper 3,
Since the coated abrasive papers 3, 3,... are bonded together, the softness of the coated abrasive papers 3, 3,... can be fully utilized during polishing work, thereby reducing operator fatigue. In the above embodiment, the resinoid grindstone 1 to which the coated abrasive papers 3, 3, .
However, considering that it is easier to use if the tightening flange of the rotary motor does not protrude outward from the use surface of the grindstone 1, an offset type as in the above embodiment is most suitable. Further, in the above embodiment, the coated abrasive papers 3, 3, . . . have a rectangular shape, but it goes without saying that they may be changed to other shapes. Finally, a specific example will be explained. By the manufacturing method described in the above embodiment of the present invention, abrasive grains with a particle size of #60 were coated with 20% resin for grinding wheels as a binder, and glass cloth with a mesh size of #430 was coated with resin for a cloth as a binder. Using a 30% coated material, two sheets of glass cloth were embedded between three layers of abrasive grains, outer diameter 100 mm, thickness 6
We manufactured an offset type resinoid grindstone with a diameter of 15 mm and a mounting hole of 15 mm. In addition, the amount of coated abrasive grain used in each abrasive grain layer above is the same for the surface layer, middle layer, and back layer.
37≒, 37≒ and 26≒. Next, on the use side (surface) of this whetstone, two 72 pieces of trapezoidally punched polishing cloth with grain size #40 were layered and arranged radially with an angular interval of 10 degrees, and epoxy resin was used. A rotary grinding and polishing tool (an example of the present invention) was prototyped by bonding them together. In addition, as a comparative example, an offset type resinoid grindstone (first comparative example) before the above-mentioned polishing cloth was bonded was used.
A prototype was prepared in which polishing cloths were adhered to the surface of a disk substrate made of fiber material in the same arrangement and number as in the above-mentioned example of the present invention (second comparative example).
The dimensions such as the outer diameter of this second comparative example are the same as those of the present invention example. Then, each of the above three prototypes was
Attached to 100mm electric grinder, rotation speed
6mm width general steel (steel type SS-41) approximately 50 at 12000rpm
When the surface was ground for a minute, the test results shown in Table 1 below were obtained.

[Table] In addition, under the same conditions as the surface grinding test above, 12 mm wide general steel (SS-41) was subjected to corner grinding within the effective usage amount range until each prototype became unusable. The test results shown in the figure were obtained.

[Table] Finally, when determining the destructive rotational speed of the example of the present invention,
It was destroyed at a rotation speed of 27,500 rpm. From the above results, it can be seen that the example of the present invention is particularly suitable for the second
Compared to the comparative example, although it has the same grinding performance in surface grinding, it takes longer to reach a usable state in corner grinding, and the amount of grinding for the work material increases, so it is difficult to use. It turns out that the possible limits can be expanded. In addition, the example of the present invention has a circumferential speed of 4300 m/min.
It can be used up to a rotation speed of more than twice that (27388rpm or more for a 100mm outer diameter), which fully satisfies the structural standards for normal speed disc grinders.
It can be seen that safety and high-speed usability can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall perspective view, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG.
Figure 3 is an enlarged sectional view taken along the line - in Figure 1, and Figure 4 a.
and b are explanatory diagrams each showing a state of use. A...Rotary grinding polishing tool, 1...Resinoid grindstone, 3
...Abrasive coated paper, 3a...Abrasive surface, 3b...Back surface, 4...Adhesive, B...Work material.

Claims (1)

[Scope of Claims] 1. A plurality of appropriately shaped coated abrasive papers are arranged radially on the use surface of a disc-shaped resinoid grindstone, and the back surface of each coated abrasive paper is placed on the polishing surface of the coated abrasive paper on the rear side in the direction of rotation of the grindstone. rotary grinding and polishing, characterized in that the resinoid grindstone is partially polymerized and bonded together in a circumferentially aligned state, and the grain size of the resinoid grindstone is set to be finer than the grain size of the coated abrasive paper. Ingredients. 2. The rotary grinding and polishing tool according to claim 1, wherein the resinoid grindstone and each coated abrasive paper are bonded with an adhesive mixed with abrasive grains having a finer particle size than both of them.