KR20090131268A - Polishing apparatus of substrate end face and polishing determining method - Google Patents

Abstract

PURPOSE: A substrate edge polishing device and a polishing determining method are provided, which judge polishing state accurately by setting upper and lower limits of load current. CONSTITUTION: A substrate edge polishing device comprises a polishing wheel(10), a rotation driving unit(20) of the polishing wheel, and a cutting edge transfer unit of the polishing wheel. The polishing wheel polishes cross section(1a) of a substrate. The rotation driving unit of the polishing wheel has a load current correcting unit and load current detection unit. The load current detection unit detects the load current by contact with the cross section of the substrate. The correcting unit corrects the load current which is generated since the side of the worn groove(14) of the polishing wheel comes into contact with the substrate.

Description

Polishing Apparatus and Polishing Method of Substrate Cross Section {POLISHING APPARATUS OF SUBSTRATE END FACE AND POLISHING DETERMINING METHOD}

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to a polishing apparatus for polishing a cross section of a glass substrate such as a liquid crystal substrate and a method for determining the quality of polishing finish.

In glass substrates used for liquid crystal substrates and the like, minute irregularities and cracks exist in the cut end surface, so that the end surface is mirror-finished in addition to the chamfer, thereby suppressing the oscillation and improving the cross-sectional strength. For the purpose of polishing.

Diamond abrasive grains, silicon carbide abrasive grains, CBN (cubic boron nitride) abrasive grains, or cerium oxide abrasive grains are used for the polishing wheels used to polish the cross section of a hard brittle material such as a glass substrate to a mirror surface shape. In order to prevent cracks, chips, and the like, a polishing wheel having abundant elasticity is preferable.

For example, as a grinding wheel, resin is filled in the fiber, and what disperse | distributed the abrasive grain to this resin is used.

However, when the end surface of the glass substrate is polished with such a highly abrasive polishing wheel, it has an intimacy when cutting the end surface of the substrate and finishes in a mirror surface shape that suppresses micro cracks, etc. Wear grooves occur in the

When the wear groove is formed on the outer circumferential surface of the polishing wheel, the range of the polishing wheel in contact with the end face of the glass substrate is not only the end face of the glass substrate, but also, for example, as shown in 1c and 1d of FIG. 2 (b). It extends to cover the front and back surfaces.

That is, since the contact range (contact area) with the polishing wheel is extended by the contacting surface of the groove side of the wear groove formed in the polishing wheel to cover the front and back surfaces of the substrate, the contact resistance is increased.

Conventionally, in the polishing process by the polishing wheel of the glass substrate cross section, the polishing current of the glass substrate cross section by the load current value of the polishing wheel drive motor and the preset load current value when the polishing wheel is in contact with the glass substrate cross section. Was controlled.

For example, as shown schematically in FIG. 7, before the start of production of the glass substrate, the load current value is divided into a lower load limit value: LL, an appropriate load area value: L to H, and an upper load limit value: HH, and measured. The feed length of the polishing wheel in contact with the end face of the glass substrate was controlled according to which set area the loaded load current value corresponds to.

In this control method, if the load current value measured during polishing is L to H, for example, as shown in (a), polishing is performed normally and it is determined that the contact pressure of the polishing wheel is also appropriate. Thus, the feed amount to the glass substrate cross section of the polishing wheel was maintained.

In addition, when the load current value was in the range of H to HH, the contact pressure with respect to the end face of the glass substrate of the polishing wheel was determined to be excessive, and the position of the polishing wheel was retracted (away from the end face of the glass substrate) in the next polishing process. Further, if the load current value was in the L to LL region, it was determined that the contact pressure of the polishing wheel was insufficient, and in the next polishing, the position of the polishing wheel was advanced (approached to the end surface of the glass substrate). In addition, when the load current value was higher than HH or lower than LL, it was determined that polishing was excessive or insufficient, and polishing processing was stopped.

However, in the above conventional method, only the value out of the first L to H region is fed back in the polishing operation of the glass substrate cross section immediately before determining the feeding amount of the polishing wheel, so that the feeding amount of the polishing wheel matches the actual polishing situation. There was a problem that does not. For example, when the load current value deviates from the L to H range by one or several abnormal values, even if the polishing is actually performed normally, one or more initial values are fed back first. Discarded, the abrasive wheel was unnecessarily advanced or retracted. For example, as shown in (b), when the load current value is in the HH to H region immediately after the start of polishing, and the load current value is in the LL to L region immediately before the end of polishing, actually, the polishing wheel Although the contact pressure was low, the values of the first HH to H region were fed back first, causing the polishing wheel to retreat.

In the conventional control method, the setting of HH, L to H, and LL is set on the basis of the state of the polishing wheel before starting the production of the glass substrate in advance, so that the groove of the polishing wheel is deepened by continuous operation. There was a problem inconsistent with the load current value in the state. For example, in a polishing wheel that has undergone a certain amount of polishing of the glass plate, the grooves are deeper than at the start of production, and the load current is also increased by increasing the contact area between the groove-shaped surface and the glass plate.

Therefore, in reality, even if the contact pressure of the polishing wheel is insufficient, there is a problem in that the feeding amount is maintained or the polishing wheel is retracted, so that the glass substrate having insufficient cross-sectional polishing or not being completely polished is supplied to the next step.

Further, for example, even when the load current is determined to be an abnormal value (in this case, exceeding the HH value) by increasing the contact area between the covering surface and the glass plate, an alarm is issued to control the polishing line to stop. As a result, there was a problem that the line stopped even if it was not the original abnormal value (in this case, overpolishing).

In order to deal with the problem of the covering surface, whenever the polishing process of the glass plate in a continuous operation | finishes a fixed amount, an operator has no choice but to change a setting value based on each user's experience, and work efficiency may fall.

In addition to the above-described problems, such a conventional method has a problem that a product which is not polished at all or a product having a small polishing amount, on the contrary, has a large polishing amount, abrasion of the polishing wheel, and a short life.

Patent Literatures 1 and 2 disclose techniques for adjusting the cutting speed based on the power value of a grindstone drive motor, and Patent Literature 3 describes a technique for calculating the average value of the processing load at the end of the processing to correct the cutting amount. Although it discloses, neither reflects the depth of the groove formed in a grinding wheel in cutting amount.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2004-122259

[Patent Document 2] Japanese Patent Application Laid-Open No. 7-171742

[Patent Document 3] Japanese Unexamined Patent Publication No. 2003-25149

An object of the present invention is to provide a device for polishing a single-sided surface of a substrate and a method of determining whether the substrate is polished by reliable adaptive control including the wear groove depth of the polishing wheel in the correction element.

A cross-sectional polishing apparatus for a substrate according to the present invention includes a polishing wheel for polishing a cross section of the substrate, a rotation driving means of the polishing wheel, and cutting edge feeding means for polishing the polishing wheel. The rotation driving means of the wheel is provided with load current detection means by contacting the end face of the substrate, and means for correcting the load current generated when the groove side surface of the wear groove generated in the polishing wheel contacts the substrate.

Further, a means for comparing with an appropriate upper and lower limit current is provided on the basis of the load current detected by the load current detecting means, and the cutting edge conveying means of the polishing wheel includes a conveying amount based on a comparison result with the appropriate upper and lower limit current. It may be provided with a feed adjusting means for adjusting the pressure.

Here, a hard brittle substrate is an object, and there is a glass substrate typically.

A grinding wheel is a disk-shaped rotating body and has an abrasive grain at the periphery which comprises the outer periphery.

There are various methods for maintaining the abrasive grains, but the present invention is effective when the peripheral portion is made of a material having elasticity and contains abrasive abrasive grains in the material, particularly the peripheral portion of the abrasive wheel contains abrasive abrasive grains in the fiber. It is preferable to apply to the use of a polishing wheel made by filling one resin.

The present invention employs the above-described configuration of the polishing apparatus, whereby the method of determining the substrate cross-section polishing according to the present invention includes a polishing wheel for polishing the end surface of the substrate, rotation driving means of the polishing wheel, and the polishing. A cutting edge transfer means of the wheel, a rotation driving means of the polishing wheel, and a load current detection means by contacting the end face of the substrate. The determination method according to the present invention is provided in the polishing wheel in accordance with the number of polishing processes. By setting the upper and lower limits of the appropriate load current by correcting the load current due to the contact between the groove side of the wear groove and the covering surface in contact with the substrate, the load current at the time of polishing processing detected by the load current detection means is increased above and below. The board | substrate which exists in the inside is judged as good quality.

In the present invention, with the increase in the amount of abrasive machining, attention is paid to the wear grooves formed on the outer circumferential surface of the polishing wheel, and the groove side surfaces of the wear grooves are in contact with the front and back surfaces of the substrate so that the polishing wheel rotates with respect to the rotary drive motor. By adding the load current increase as a correction value and setting the upper limit and the lower limit of the load current, it is possible to determine whether the polishing is successful or not.

In addition, since the cutting edge feed amount of the polishing wheel is suppressed from being larger than necessary, it contributes to improving the life of the polishing wheel.

In addition, the number of stops of the machining line is reduced, and the productivity is improved.

Embodiment of this invention is described based on the following drawings.

The external perspective view of the grinding | polishing apparatus concerning this invention is shown in FIG. 4, and a grinding | polishing mechanism part is shown in FIG.

6 shows a state in which the cover 14 of the polishing wheel is removed and a cross-sectional view taken along line A-A.

The polishing wheel 10 is detachably attached to the spindle 22 and is rotationally controlled by the rotation driving motor (rotary driving means) 20 of the polishing wheel.

The polishing wheel 10 is connected to the servo motor 30 as the cutting edge transfer means together with the rotation driving motor 20.

In this embodiment, as shown in Fig. 4, a pair of rotary drive motors are provided as 20a and 20b, and the two sides of the glass substrate are controlled by positioning them (X axis, Z axis), (U axis, W axis). The cross section can be simultaneously polished, but is not limited thereto.

In the polishing wheel 10 used in the present embodiment, as shown in FIG. 2, the peripheral portion 11 is filled with a resin in fibers, and silicon carbide abrasive grains are dispersed in the resin.

The polishing wheel 10 is rotationally controlled by the rotation driving motor M1 20 and has a load current detection unit 21.

Here, the feed amount of the polishing wheel is controlled by the cutting edge feed servomotor (M2).

As shown in FIG. 2A, when the outer peripheral surface of the peripheral portion 11 of the polishing wheel 10 is polished by contacting the end face 1a of the glass substrate 1, the load current chart as shown in FIG. 3 is obtained. Is obtained.

3 is a chart showing the polishing processing time on the horizontal axis and the load current value of the rotational drive motor 20 on the vertical axis.

Both sides of the W-axis side and the X-axis side are shown.

When the polishing wheel 10 comes into contact with the end face of the glass substrate, the load current increases, but in general, the peak current tends to occur at the contact start (s) and the contact end (e).

In addition, as the polishing wheel 10 shown in FIG. 2 (a) is new, as shown in FIG. 2 (b), the groove portion 14 caused by abrasion on the outer circumferential surface of the polishing wheel as the number of abrasive machining increases. Is formed, the contact area increases and the load current rises as the groove portion 14 deepens even when polished normally.

When the groove portion 14 is formed on the outer circumferential surface of the polishing wheel 10, the bottom portion 12 of the groove portion contacts the end face 1a of the glass substrate, but the side surface 13 of the groove portion is the surface 1c and the rear surface of the glass substrate. The covering contact is made to cover 1d.

In the example shown in FIG. 2, the chamfer 1b is given in the ridge part of the glass substrate 1, but a chamfer is performed as needed.

In addition, the glass substrate 1 shown in FIG. 2 expresses the thickness larger than the actual size and at the same time expresses the polishing wheel 10 extremely small. In practice, the polishing wheel 10 of FIG. , A plurality of grooves are formed.

The present invention is characterized in that the load current increase due to this covering contact is corrected and processed.

An example of the control and determination system of the present invention will be described based on the flowchart of FIG. 1.

First, the groove depth of the polishing wheel 10 is measured before starting the polishing process.

Although there is no limitation in particular in a measuring means, Non-contact automatic measurement is preferable.

As shown in steps S1 and S2, depending on the degree of groove depth, for example, b is a groove depth of medium, based on the initial setting current of the control current of the motor in the case of a having almost no groove. In this case, whether or not the load current is determined at 120% of the initial set current is corrected, and in the case of a large groove depth, c is corrected to determine whether the load current is at 140% of the initial set current.

In addition, it is necessary to set the determination criteria of both parts appropriately according to the material of the wheel and the size of the substrate. As in this embodiment, not only three levels but also more levels may be used, or even proportional setting corresponding to the groove depth may be used. do.

The polishing process of the glass substrate is started by the control current considering the groove depth (S3), and the motor load current is measured n times in proportion to the time elapsed from the start of polishing to the end (S4), and the average value (S5). ), And the lower limit of the load current for performing polishing processing appropriately from the deviation (S6), and similarly, the upper limit of the load current value when the cutting edge feed amount of the polishing wheel 10 is strong (S7).

In this way, the setting accuracy is improved by setting the average of n pieces of data.

In this way, the lower limit and the upper limit of the load current can be set according to the depth of the groove, and if there is a load current in the range, automatic polishing of the next glass substrate is continuously continued (S8).

If the load current value exceeds the upper limit of management, the feed amount of the cutting edge feed servo motor 30 of the next glass substrate can be reduced to prevent abnormal wear of the polishing wheel.

On the other hand, when the load current value is lower than the lower limit of the proper current value, it is determined that the polishing amount is small, and the upper limit and the lower limit of the load current are set based on the regrinding set current value (S10), and based on this determination Regrind processing (S11).

If the load current value is smaller than the reprocessing set value, the feed amount is adjusted to control the pressurization for the next glass substrate according to the degree (S12).

In addition, when the rework is three or more times, a warning alarm sounds, and when the alarm sounds, the setting of the device is changed (S13).

In this case, instead of giving an alarm warning, the polishing wheel may be moved to automatically switch control so that a new polishing groove is formed.

By using such a polishing apparatus, by detecting the quantity and the conveying amount of the polishing process, the automatic stop of the processing line is reduced, and the yield rate is improved.

1 is a diagram showing an example of a flowchart of control according to the present invention.

2 is a diagram showing changes in the control system and wear of the polishing wheel;

3 is a diagram illustrating an example of a load current chart.

4 shows an external perspective view of a polishing apparatus;

5 shows a drive of the polishing wheel.

FIG. 6 is a view showing a drive section of the polishing wheel and a sectional view thereof; FIG.

7 is a diagram illustrating a method for determining the quality of a conventional polishing process.

Explanation of symbols on the main parts of the drawings

10: polishing wheel 14: groove

Claims (5)

A polishing wheel for polishing the end surface of the substrate, a rotation driving means of the polishing wheel, and cutting edge feeding means of the polishing wheel, The rotating drive means of the polishing wheel includes a load current detecting means by contacting the end face of the substrate, and a load current correcting means generated by contacting the substrate with the groove side of the wear groove generated in the polishing wheel. Single side polishing device. The method of claim 1, And a comparison means with an appropriate upper and lower limit current on the basis of the load current detected by the load current detecting means, and the cutting edge conveying means of the polishing wheel has a feed length based on a comparison result with the appropriate upper and lower limit currents. And a feed adjusting means for adjusting the substrate. A polishing wheel for polishing the end surface of the substrate, a rotation driving means of the polishing wheel, and a cutting edge transfer means of the polishing wheel, The rotary drive means of the polishing wheel has a load current detection means by contacting the end face of the substrate, The load current is adjusted by setting the upper and lower limits of the appropriate load current by correcting the load current due to the groove-shaped surface contact between the groove side of the wear groove formed on the polishing wheel and the substrate in contact with the grinding wheel. A determination method of substrate cross-sectional polishing, wherein the substrate in which the load current at the time of polishing processing detected by the current detecting means is within the upper and lower limits is regarded as good quality. The method of claim 3, wherein A grinding wheel is a method for determining a substrate cross-section polishing, wherein the peripheral edge is made of a material having elasticity, and the abrasive grain is contained in the material. The method of claim 3, wherein The grinding wheel is a method for determining the substrate cross-sectional polishing, characterized in that the peripheral edge is made by filling the fiber with a resin containing abrasive grains.

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