JP2003103461A - Sharpness evaluation method and sharpness management method for grinding wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To directly and objectively evaluate sharpness of a grinding wheel without measuring surface roughness of a ground object. SOLUTION: Surface roughness of the grinding wheel 1 is detected by a pickup 2 provided with a stylus, and the sharpness of the grinding wheel is evaluated from an initial wear height calculated by a computer 4 on the basis of a detection result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sharpness evaluation method and a sharpness management method for a grinding wheel, such as a solid rubber roll and a soft roll such as a sponge roll. The sharpness of the grindstone, which has a great influence on the surface roughness of the soft roll, can be grasped directly and objectively, and the sharpness can be managed based on it.

[0002]

2. Description of the Related Art When grinding the surface of a soft roll using a grindstone, there is no regeneration of cutting edges due to the dropping or missing of abrasive grains as in the case of grinding hard materials such as metals Since the surface is only worn away, the sharpness decreases over time as the wear progresses, and as a result,
The surface roughness of the soft roll that is the object to be ground gradually becomes rough. However, conventionally, there is no method of directly and objectively evaluating the sharpness of the grinding wheel, and therefore, by measuring the surface roughness of the soft roll after grinding, it is possible to estimate the sharpness of the grinding wheel. Had to be forced.

[0003]

SUMMARY OF THE INVENTION Therefore, according to the present invention, the sharpness of a grinding wheel can be directly and objectively evaluated without the need to measure the surface roughness of a ground object to be ground. A method and a sharpness management method using the method are provided.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to the smoothness of the surface of a soft ground object that has been ground and the surface roughness of a grindstone.
Consequently, various tests were performed on the relative relationship with the sharpness, which has a high correlation with the smoothness of the surface of the object to be ground, and was made by finding a method for measuring the surface roughness of the grindstone. The method for evaluating the sharpness of the grinding wheel is to detect the surface roughness of the grinding wheel with a pickup equipped with a stylus and to evaluate the sharpness of the grindstone with the initial wear height calculated from the detection result.

Here, "initial wear height" means ISO13.
The term "Rpk" (The reduced peak height) defined by the 565-1 standard (and DIN 4776-1990) is used. This standard is a standard for evaluating lubricity by dividing a load curve into an initial worn portion, a substantial contact portion, and an oil reservoir portion. Here, Rpk is a special roughness curve from which undulation is removed as an extraction curve. , From now on evaluation length method and μm
In the load curve as shown in FIG. 6, which corresponds to the cumulative probability density function statistically obtained by the method, a width of 40% is taken in the direction of the load length ratio (tp value), and the height of both ends is increased. The position where the difference in height is the minimum is searched for, the intersection a between the straight line passing through the two points (minimum inclination straight line) and the limit line of tp = 0% is obtained, and the horizontal line and the load curve from this intersection a The intersection point is determined as c (ac is the load length ratio after initial wear), and the side ac is equal to the area surrounded by the 0% limit line, the side ac, and the load curve. It shows the height on the limit line of tp = 0% forming a right triangle.

In this case, the height of the oil sump is equal to the area enclosed by the 100% limit line, the side bd, and the load curve, and the height on the 100% limit line is a right triangle having the side bd as one side. The depth of the valley (Rvk), c obtained above,
The difference in height between d is defined as effective load roughness (Rk). This will represent the height at which the surface will wear before it becomes unusable due to long term wear.

As described above, in the sharpness evaluation method according to the present invention, attention is paid particularly to the evaluation standard of lubricity, and the initial wear height (Rpk) of the grinding wheel is used as the sharpness evaluation standard of the grinding wheel with a specific numerical value. By expressing, the sharpness of the grinding wheel, in other words, the degree of wear of the grinding wheel can be directly and objectively and accurately grasped, and in particular, by evaluating the sharpness with the initial wear height (Rpk),
A high correlation can be given to the smoothness of the surface of the object to be ground, and the smoothness of the surface can be predicted with high accuracy by evaluating the sharpness.

Further, according to this method, the sharpness can be evaluated simply and quickly without removing the grindstone from the grinder by simply bringing the stylus of the pickup into contact with the surface of the grindstone. It is also possible to accurately predict the number of objects to be ground or the number of objects to be ground by that time.

The sharpness management method according to the present invention using this evaluation method detects the surface roughness of the grindstone with a pickup equipped with a stylus in order to secure the sharpness of the grinding grindstone. The initial wear height (Rpk) obtained by calculating the result is a predetermined value, more preferably 10
The dressing of the grinding wheel is performed with the limit when it becomes less than μm. According to this, the dressing time of the grinding wheel can also be grasped concretely and objectively and the sharpness of the grinding wheel can be always maintained constant, and the surface of the object to be ground ground by the grinding wheel can be sufficiently smoothed. Can be kept at

This becomes more remarkable by dressing the grindstone every time the initial wear height (Rpk) becomes less than a predetermined value. Above all, the initial wear height (Rpk) is 1 or less.
When dressing is performed with the limit being less than 0 μm, the required smooth surface of the object to be ground can be realized in a short time.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram illustrating an apparatus used for carrying out the sharpness evaluation method according to the present invention, in which 1 denotes a grinding wheel.

Here, the pickup 2 is connected to the computer 4 which analyzes and calculates the roughness detection result by the pickup 2 through the roughness measuring machine body 3, and preferably displays the result on the display. Configure the device.
In such an apparatus, the pickup 2 is positioned and held with respect to the surface of the grindstone by, for example, a magnet stand 5, and as shown in FIG.
Is pressed against the surface of the grindstone with the required force, and in this state, the stylus 6
And the grindstone surface 7 are subjected to relative displacement over a predetermined measurement length, and the surface roughness is detected by the pickup 2.
The initial wear height (Rpk) is calculated by fetching the detection data at this time into the roughness measuring machine main body 3, amplifying the same, and further fetching the upper and lower position data at every 0.6 μm by the computer 4, for example. By doing so, the sharpness of the grinding wheel is evaluated.

By the way, at each of three places of the wide type grinding wheel of GC80 porous type after grinding 1500 urethane rubber rolls having a diameter of 20 mm, the measurement length was 2.5 mm, and the roughness about 4167 points was set between them. The special roughness curves as computer output when the measurement is performed are shown in FIGS. 3 (a), 3 (b) and 3 (c), respectively.
It became as shown in the graph.

Further, when the respective initial wear heights ( _RPK ) are calculated from the special roughness curves shown in FIGS. 3 (a), 3 (b) and 3 (c), respectively, the results are shown in FIG. 3 (a). It is 7.5 μm, and in FIG. 3 (b) is 11.9 μm.
It became 7.3 μm in (c).

On the other hand, similar special roughness curves after dressing the same grinding wheel are shown in FIG.
As shown in (b) and (c), the initial wear height (Rp) calculated based on these respective curves
k) are 14.9 μm, 9.6 μm and 14.5 μm, respectively.
became μm.

[0016]

[Example] In the evaluation of the sharpness of such a grinding wheel,
When the relative relationship between the initial wear value of the grinding wheel and the surface roughness of the soft roll after grinding was verified, it was as follows.
The surface roughness of the GC80 porous type wide grinding wheel is
Measurements were made at the time of wear and after dressing, and the rubber hardness (J
The surface roughness (R _Z μm) of the rubber roll having an ISA of 40 ° was ground as shown in Table 1. Here, the dressing speed is 40
The cutting was performed at 0 (mm / min) and a cut of 0.02 (mm). The surface roughness required for this type of roll is usually in the range of 7 to 9 (μm) as a ten-point average value R _Z.

This ten-point average value R _Z is based on JIS B060
1 to 1994 means a ten-point average value of the amplitude of roughness, and R _Z is an extraction curve,
That is, from the roughness curve, extract the part of the reference length, measure from the average line of the extracted part in the direction of vertical magnification, and measure the average absolute value of the altitudes of the 5th to the highest peaks, and It is the sum of the absolute value of the average of the elevations from the lowest to the fifth. In addition, here, a value obtained by calculating for each reference length and then averaging over the entire evaluation length is shown.

[0018]

[Table 1]

From Table 1 above, it is clear that dressing the surface of the grinding wheel can greatly reduce the surface roughness of the roll as compared with that when the wheel is worn.

Next, when the change in the surface roughness of the rubber roll was determined when the dressing degree of the grinding wheel was variously changed, the results shown in FIG. 5 were obtained. According to this, the initial wear height (R _PK ) of the grinding wheel is 10
The average value of ten points (R _Z ) on the surface of the rubber roll can be sharply reduced by setting the thickness to be equal to or more than 10 μm, and the initial wear height (R _PK ) is 10 μm. It can be seen that _{Z 1} ) can be reduced to almost 8 μm. Therefore, the sharpness of the grindstone has an initial wear height of 10 μm.
If it is less than 10 μm, the sharpness is significantly reduced, and the sharpness can be controlled by dressing with the limit when the initial wear height is less than 10 μm.

[0021]

As is apparent from the above description, according to the present invention, the sharpness of the grinding wheel can be evaluated specifically by the initial wear height, so that the sharpness can be grasped concretely and objectively. Therefore, by maintaining the sharpness above a certain level, it is possible to reliably maintain the surface quality of the object to be ground within a predetermined range without actually measuring the surface roughness of the object to be ground. Further, according to this sharpness management method, dressing of the grinding wheel can always be performed at an appropriate timing.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a device for carrying out a measuring method according to the present invention.

FIG. 2 is an enlarged side view of a pickup.

FIG. 3 is a graph showing a special surface roughness curve and the like of a grindstone after grinding a rubber roll.

FIG. 4 is a graph showing a special surface roughness curve of a grindstone after dressing.

FIG. 5 is a graph showing the relationship between initial wear height and ten-point average value.

FIG. 6 is a diagram showing how to determine an initial wear height.

[Explanation of symbols]

1 grinding wheel 2 pickups 3 Roughness measuring machine body 4 computers 5 magnet stand 6 stylus 7 Wheel surface

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Claims (3)

[Claims] 1. A method for evaluating the sharpness of a grinding wheel, wherein the surface roughness of the grinding wheel is detected by a pickup equipped with a stylus, and the sharpness of the grinding wheel is evaluated based on the initial wear height calculated from the detection result. 2. In order to secure the sharpness of the grinding stone, the surface roughness of the grinding stone is detected by a pickup equipped with a stylus, and the initial wear height obtained by calculating the detection result is less than a predetermined value. A method for controlling the sharpness of a grinding wheel that performs dressing of the grinding wheel when it reaches the limit. 3. The sharpness control method for a grinding wheel according to claim 2, wherein the predetermined value of the initial wear height is 10 μm.