Double-sided surface grinding process and double-sided surface grinder

Abstract

Double-sided surface grinding method, comprising, when both surfaces of the workpiece (W) are ground by rotating a pair of grinding wheels (3, 4) pointing towards a grinding wheel shaft, while a thin, plate-shaped workpiece (W) is rotated, supported by a static pressure by a static pressure fluid between a pair of static pressure pads (1, 2) in a state in which the pair of static pressure pads (1, 2) point towards the grinding wheel shaft: during pre-machining prior to a grinding step using the grinding wheels (3, 4), detecting a position of the workpiece (W) towards the grinding wheel shaft by means of a workpiece position detection means, while the workpiece is rotated by the grinding wheels (3, 4) towards the grinding wheel shaft to a center between the two static pressure pads (1, 2) from each side of the pads (1, 2).2) of the static pressure, which are arranged at support positions of the static pressure; setting, as grinding feed end positions, of positions of the grinding wheels (3, 4) in the direction of the grinding wheel shaft, when the workpiece position detection means detects that the workpiece (W) is separated by a certain distance in the direction of the grinding wheel shaft from the corresponding pads (1, 2) of the static pressure, and in the subsequent grinding step advancing both grinding wheels (3, 4) at the same speed from the grinding feed end positions in the direction of the grinding wheel shaft in the direction of the workpiece (W) in order to grind the workpiece (W).

Description

TECHNICAL AREA

[0001] The present invention relates to a double-sided surface grinding method and a double-sided surface grinder. STATE OF THE ART

[0002] When both side surfaces of a thin disk-shaped workpiece, such as a silicon wafer, are ground by means of a horizontal double-sided surface grinder in a state in which a workpiece is held by means of static pressure from both sides in a disk thickness direction by means of a pair of right and left rest pressure cushions or pads of static pressure, the two surfaces of the workpiece are ground to a certain thickness by means of a pair of right and left grinding wheels while the workpiece is rotated by a carrier (Patent document 1).

[0003] With such a horizontal double-sided surface grinder, it is very important for improving grinding precision that a workpiece is held in the central position between the static pressure pads during grinding. Various conventional measures have been considered, for example, moving both static pressure pads to the right and left by the same amount by applying a movement mechanism while grinding a workpiece (Patent Document 1).

[0004] The horizontal double-sided surface grinder in patent document 1 includes a movement mechanism that moves both static pressure pads synchronously to the right and left during grinding, wherein a workpiece attachment reference position is set to the center, and wherein the two static pressure pads are moved synchronously at the same speed and by the same amount during grinding of the workpiece with reference to this position.

[0005] In addition to such a horizontal double-sided surface grinder, which incorporates a movement mechanism, a horizontal double-sided surface grinder was considered that performs the following adjustment procedure. First, a workpiece is placed in a carrier and held in contactless position above the static pressure pad by means of the two static pressure pads on the right and left. The carrier is then actuated to rotate around its center, thereby rotating the workpiece and stabilizing it between the two static pressure pads. Subsequently, when the workpiece is in a stable position, its position is measured by air sensors embedded in the two static pressure pads to perform a zero adjustment, and the zero position is stored.Next, after the rotation of the carrier has stopped, both grinding wheels are pushed forward to the right and left to sandwich the workpiece, which continues to be held by static pressure from the two static pressure pads, from both sides to the right and left of the two grinding wheels, and the positions of the two grinding wheels are adjusted so that there is a correspondence with the stored zero position, and a thickness of the sandwiched workpiece is entered to perform an alignment of a grinding position.

[0006] Furthermore, it was considered that the positions of both static pressure pads and the positions of both surfaces of the workpiece on the right and left could be measured using a pair of right and left contact-type measuring devices that have access to a static pressure pad and a workpiece in order to calculate the mean position between the static pressure pads. STATE OF THE TECHNOLOGY PATENT DOCUMENT

[0007] Patent document 1: Japanese published unexamined patent application no. 2003-236746 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0008] The conventional horizontal double-sided surface grinder, which has a movement mechanism, has a problem in that it becomes mechanically complicated, and even if a workpiece mounting reference position is set to the center and the two static pressure pads are moved synchronously at the same speed and by the same amount with respect to the position during grinding of a workpiece, it cannot be guaranteed that the mounting reference position is located at the middle position between the two grinding wheels.

[0009] Furthermore, the first horizontal double-sided surface grinder, which employs an adjustment procedure, has the problem that it requires time to restart grinding and a trial grinding of workpieces in the event of a change in settings or setup. Since the workpiece shapes are not necessarily constant, the shapes are inconsistent depending on the workpiece. Additionally, depending on the state of the settings, the perpendicularity between the grinding wheel shafts of both grinding wheels and the workpiece support surfaces of the two static pressure pads, or similar components, is not necessarily set to zero.Consequently, even if a workpiece is held by the static pressure above the water level by the two static pressure pads, the workpiece will rotate at an angle, depending on its shape, the settings, or similar factors. This means it is difficult to rotate the workpiece stably in the center position between the two static pressure pads, and the neutral position can deviate significantly from this center position. As a result, problems arise in such cases, including the need for a lengthy grinding cycle and the waste of many workpieces through trial grinding.

[0010] Furthermore, with the latter horizontal double-sided surface grinder, which uses the contact-type measuring device, it is possible to calculate the mean position between the two pads of the static pressure more reliably and accurately. However, problems remain, such as the time and effort required for the calculation, the need for a highly qualified operator, and similar issues.

[0011] The present invention was made with these conventional problems in mind, and one object of the present invention is to provide a double-sided surface grinding method and a double-sided surface grinder with which it is possible to easily and safely align a grinding position of a thin disc- or plate-shaped workpiece at a central position between the two pads of static pressure, and to carry out grinding with a certain grinding precision with respect to an original product immediately after the setup or adjustment. MEANS TO SOLVE THE PROBLEM

[0012] A double-sided surface grinding method according to the present invention comprises, when both surfaces of the workpiece are ground by means of a pair of grinding wheels, while a thin plate-shaped orA disc-shaped workpiece is rotated, supported by a static pressure from a pair of static pressure pads; a workpiece position detection device is used to detect the position of the workpiece while the workpiece is moved towards a central side between the two static pressure pads at static pressure support positions by the grinding wheels; the positions of the grinding wheels are tentatively determined when the workpiece position detection device detects that the workpiece is separated by a certain distance from the corresponding static pressure pads, as grinding feed end positions; and the two grinding wheels are advanced at the same speed from the grinding feed end positions to grind the workpiece.

[0013] A preferred procedure involves, after the workpiece has been pressed or pushed against one of the static pressure pads at the static pressure support positions, the workpiece is levitated or suspended by a certain distance or amount from the grinding wheel, whose rotation is stopped, while the grinding wheel is advanced on the side of the static pressure pad, and a preliminary determination of the grinding wheel's position when the workpiece is levitated by the certain amount is performed as the grinding feed end position on each side, and subsequently the workpiece is supported by static pressure through the two static pressure pads.

[0014] A fluid under static pressure can be supplied from the other static pressure pad to press the workpiece against the side of one static pressure pad. Preferably, a displacement amount for both grinding wheels is predetermined, and the two grinding wheels are adjusted so that they do not advance by the displacement distance during grinding of the workpiece.

[0015] A double-sided surface grinder according to the present invention, which grinds both surfaces of the workpiece by means of a pair of grinding wheels, while a thin plate-shaped orA disc-shaped workpiece is rotated, supported by static pressure through a pair of static pressure pads, the double-sided surface grinder comprising: a pair of workpiece position detection means for detecting a position where the workpiece is separated by a certain distance from both static pressure support positions, a grinding feed end position determiner for preliminary determination of grinding wheel positions when the corresponding workpiece position detection means detect the positions where there is a separation by the certain distance as grinding feed end positions, and a grinding cycle control means for advancing the two grinding wheels at the same speed from the grinding feed end positions preliminaryly determined by the grinding feed end position determiners to perform a grinding cycle or grinding operation. IMPACT OF THE INVENTION

[0016] According to the present invention, advantages include the fact that it is possible to align a grinding position of a thin disc-shaped or plate-shaped workpiece at a central position between both pads of static pressure simply and safely, and to perform a grinding process with a specific grinding precision with respect to an original product immediately after the adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Fig. Figure 1 is a schematic cross-sectional view of a horizontal double-sided surface grinder, showing an embodiment of the present invention.

[0018] Fig. Figure 2 is a side view of the same.

[0019] Fig. Figure 3 is a block diagram of a control system of the same.

[0020] Fig. Figure 4 is an explanatory diagram of the same.

[0021] Fig. Figure 5 is an explanatory diagram of how it works.

[0022] Fig. Figure 6 is an explanatory diagram of how it works.

[0023] Fig. Figure 7 is an explanatory diagram of how it works.

[0024] Fig. Figure 8 is an explanatory diagram of how it works.

[0025] Fig. Figure 9 is a flowchart of the same.

[0026] Fig. Figure 10 is an explanatory diagram of a suspended state of a workpiece of the same. BEST WAY TO IMPLEMENT THE INVENTION

[0027] In the following, embodiments of the present invention are described in detail based on the drawings. The drawings depict a horizontal double-sided surface grinder that applies the present invention. The horizontal double-sided surface grinder includes, as shown in Fig. 1 and Fig. Figure 2 shows a pair of right and left static pressure pads. 1 and 2 , which are arranged on the right and left sides so that they are opposite each other, which hold a thin plate-shaped or disc-shaped workpiece W, such as a silicon wafer, by means of static pressure, a pair of right and left grinding wheels 3 and 4 , which are designed to rotate around the center of the horizontal axis, so that these recessed sections 1a and 2a the corresponding pads of static pressure 1 and 2 correspond to both right and left side surfaces of the workpiece W, which is subjected to the pads of static pressure. 1 and 2 is held, grinds, and a carrier 5 , which rotates the workpiece W, which is subjected to static pressure by the pads 1 and 2is held to essentially be the center of it. The carrier 5 is actuated to rotate essentially around the center of the workpiece W, by means of an actuating or drive means outside the drawing.

[0028] The static pressure pads 1 and 2 are horizontal between support positions of static pressure H1 and H2 (compare Fig. 1) movable in the vicinity of the workpiece W and withdrawn positions (not shown) that are withdrawn from the static pressure support positions H1 and H2, and when a static pressure fluid, such as static pressure water (hereinafter referred to as static pressure water), is applied to the workpiece support surfaces 1b and 2b of the two pads of static pressure 1 and 2When the workpiece W is supplied to the support positions of the static pressure H1 and H2, it is held in a contact-free manner by the static pressure at the middle position between the two pads of the static pressure. 1 and 2 supported by the water of the static pressure, and furthermore, when the water of the static pressure is supplied by one of the pads of the static pressure 1 and 2 When the workpiece W is fed in, it is subjected to static pressure against the other pad. 1 and 2 pressed or squeezed over the water of static pressure.

[0029] On the sides of the workpiece support surfaces 1b and 2b the pads of static pressure 1 and 2In addition to several pockets (not shown) to which water of static pressure is supplied, and drainage grooves (not shown) through which the water of static pressure is discharged from the respective pockets to the outside, there are several (for example, three in the circumferential direction) air sensors. 6 and 7 at specific intervals in the circumferential direction in the vicinity of the recessed sections 1a and 2a arranged. The air sensors 6 and 7 They build a workpiece position detection device that detects the position of the workpiece W, and expel air from its air nozzles to the workpiece W in order to measure distances or gaps between the workpiece W and the workpiece support surfaces. 1b and 2b the pads of static pressure 1 and 2 to be measured according to a change in back pressure at that time.

[0030] Furthermore, the air sensors 6 and7 These are merely examples of workpiece position detection devices; other devices capable of detecting the position of the workpiece W can be used. Furthermore, workpiece position detection devices can be contact-based or non-contact, and any of these can be used.

[0031] The grinding wheels 3 and 4 are bowl-shaped, etc., and are located at the front ends of horizontal grinding wheel shafts. 8 and 9 fixed and are horizontal between feed end positions and retraction end positions according to the movement of the grinding wheel shafts 8 and 9 movable and rotate around the grinding wheel shafts 8 and 9 , in order to grind both surfaces of the workpiece W on the right and left.

[0032] The carrier 5 contains a carrier opening 10, into which the workpiece W is removablely inserted in an essentially concentric manner, and the support 5 is rotatable around essentially the center of the workpiece W by several support rollers 11 supported, which are arranged circumferentially on the outer side, being driven by a drive means (not shown) to rotate substantially around the center of the workpiece W. The support 5 has an intervention area 13 up, which goes into the carrier opening 10 protrudes to accommodate a notched area 12 to intervene in the workpiece W.

[0033] Fig. Figure 3 shows a control unit that controls the horizontal surface grinder. This control unit includes a control mechanism for the static pressure pads. 15 , the supply / stop of water of the static pressure of the pads of static pressure 1 and 2and the movement of the pads of static pressure 1 and 2 controls, a grinding wheel shaft control device 16 , which controls the feed / retraction, rotation / stop, and similar functions of the grinding wheel shafts 8 and 9 controls a pair of right and left air sensors (workpiece position detection means) 6 and 7 , which floating amounts or floating movements C1 and C2 of the workpiece W from the pads of the static pressure 1 and 2 at the holding positions of the static pressure H1 and H2 (distances between the pads of the static pressure) 1 and 2 and of the workpiece W) (compare Fig. 5 and Fig. 7) detect, a floating amount setting device 17 , which causes a certain amount C of the workpiece W to float from the pads of static pressure 1 and 2 sets, a grinding feed end position determining device 18, that the positions of both grinding wheels 8 and 9 as grinding feed end positions F1 and F2 (compare Fig. 5 and Fig. 7) provisionally determined if floating amounts C1 and C2, which are determined by the corresponding air sensors 6 and 7 be detected, reach the specific float level C, which is determined by the float level setting device 17 It was determined that an intermediate space adjustment device was used. 19 , which creates a gap A between the pads of static pressure 1 and 2 at the holding positions of static pressure H1 and H2 (compare Fig. 1) adjusts, an adjusting means of the final thickness 20 , which sets a final thickness B of the workpiece W, and a grinding cycle control device 21 , which is a feed rate F of both grinding wheel shafts 8 and 9 based on the space A between the two pads of static pressure 1 and2 , which is from the gap adjustment device 19 is determined, and the final thickness B of the workpiece W, which is determined by the setting means of the final thickness 20 is set, calculated and both grinding wheels 3 and 4 advances from the grinding feed end positions F1 and F2 at essentially the same speed and by the same distance or amount as determined by the grinding feed end position determiner 18 to be provisionally determined in order to determine a grinding cycle or grinding process for grinding the workpiece W by the two grinding wheels 3 and 4 to be carried out at the front ends of it.

[0034] Furthermore, the feed rates in the case where both grinding wheels 3 and 4The grinding wheels are advanced from the grinding feed end positions F1 and F2, preferably at the same speed on the right and left sides, and the feed rates are preferably the same on the right and left sides. However, the feed rates and feed rates can be essentially the same within a permissible range of the grinding accuracy or grinding precision of the workpiece W. Furthermore, in the case where the feed rates of the corresponding grinding wheels 3 and 4 The grinding wheels can be accelerated or decelerated in several stages, and the grinding wheels on the right and left can be accelerated or decelerated to be essentially synchronized. Consequently, there is no need to adjust the corresponding grinding wheels. 3 and 4 to always advance at a constant speed.

[0035] The control device for the static pressure pads 15is able to control the supply / stop of static pressure water to the static pressure pads. 1 and 2 to control individually, and is able to hold the workpiece W in the carrier by means of static pressure. 5 by supplying water of static pressure simultaneously to both pads of static pressure 1 and 2 to maintain through the control system, and is able to draw water of static pressure from one of the static pressure pads. 1 and 2 to supply the workpiece W in the carrier 5 against the other pad of static pressure 1 and 2 to press. Furthermore, water of static pressure can be supplied as required at the time of insertion and removal of the workpiece W.

[0036] The grinding feed end position determining device 18This results in a function of pressing the workpiece W against one of the pads of static pressure. 1 and 2 at the support positions of the static pressure H1 and H2 and then a function of the feed of a grinding wheel shaft 8 or 9 on the same side of one of the static pressure pads 1 or 2 out, to measure the workpiece W with respect to the pads of static pressure 1 and 2 to keep in suspension, accordingly by the grinding wheels 3 and 4 at the front ends of the corresponding grinding wheel shafts 8 and 9 on the right and left sides, through the control mechanism for the static pressure pads 15 , the grinding wheel shaft control device 19 and the like, to determine the positions of the grinding wheels 3 and 4, when the floating amounts C1 and C2 of the workpiece W on the right and left sides reach the determined floating amount C, then the right and left grinding feed end positions F1 and F2 are provisionally determined.

[0037] At the time of determining a grinding position of the workpiece W, the workpiece W is first pressed against one of the pads of static pressure. 1 and 2 pressed. Next, in this state, a grinding wheel shaft will be... 8 or 9 advanced to engage one grinding wheel 3 or 4 to bring the workpiece W into contact with the grinding wheel. Then the workpiece W is moved through the grinding wheel. 3 or 4 , whose rotation was stopped, pressed or pushed to remove the workpiece W from the one pad of static pressure 1 or 2to lift or suspend the workpiece. Subsequently, the position when the suspension amount C1 or C2 of the workpiece W reaches the specified suspension amount C is defined as the grinding feed end position F1 and F2 of one grinding wheel shaft. 8 or 9 determined. This function is executed accordingly on the right and left sides in this way.

[0038] This places the middle position between the right and left grinding wheels. 3 and 4 essentially in the middle between the two static pressure pads 1 and 2 Consequently, it is possible, provided that both surfaces of the workpiece W are in this state through the two grinding wheels. 3 and 4 The workpiece W is ground at essentially the middle position between the two pads of static pressure. 1 and 2to grind. Consequently, advantages lie in the fact that it is possible to position the grinding position of the thin plate-shaped or disc-shaped workpiece W at an essentially central position between the two pads of static pressure. 1 and 2 to align easily and safely and to perform grinding with a specific grinding accuracy with respect to an original product immediately after adjustment or setup.

[0039] Furthermore, the middle position between the two grinding wheels 3 and 4 preferably the middle position between the two pads of static pressure 1 and 2 However, as long as the effect of the grinding accuracy of the workpiece W is within a permissible range, a small deviation or decentering between the center position between the two grinding wheels is acceptable. 3 and 4and the middle position between the two pads of static pressure 1 and 2 are present. Consequently, the middle position between the two grinding wheels can be... 3 and 4 essentially in the middle between the two static pressure pads 1 and 2 lie within the permissible range of the grinding accuracy of the workpiece W.

[0040] This horizontal surface grinder is preset so that the right and left grinding wheel shafts 8 and 9 are positioned coaxially, the workpiece support surfaces 1b and 2b both pads of static pressure 1 and 2 to the right and left at a right angle to both grinding wheel shafts 8 and 9 are located and the workpiece support surfaces 1b and 2b both pads of static pressure 1 and 2They lie parallel to each other. Furthermore, the space A between the two pads is subject to static pressure. 1 and 2 determined according to the thickness of the workpiece W, grinding conditions for it and the like.

[0041] Next, a description with reference to a flowchart of the Fig. 9. Next, the workpiece W is placed in the carrier. 5 (Step S1) introduced. The insertion of the workpiece W can be carried out directly manually, and in the case where an insertion / removal device is provided, the insertion can be carried out automatically using the insertion / removal device.

[0042] For example, in the case where the workpiece W is automatically inserted into the carrier 5 The right pad of the static pressure is located where the material is introduced by means of the application / distribution agent. 2 in advance at the support position of the static pressure H2 in the vicinity of the carrier 5, and the workpiece W is brought into this state in the carrier from the left side by means of the insertion / removal device. 5 introduced to apply pressure to the workpiece W using the insertion / removal agent and the right pad of the static pressure 2 to pick up in a sandwich-like manner, and then the workpiece W is applied by means of a vacuum to the side of the right pad of the static pressure 2 It is sucked in. Subsequently, after the application / discharge agent has been drawn back outwards, the left pad of the static pressure is applied. 1 moved to the support position of the static pressure H1 to clamp the workpiece W from both sides so that the workpiece W does not come out of the carrier 5 falls out. Furthermore, the support positions of the static pressure H1 and H2 correspond to the two static pressure pads. 1 and 2 the gap A, which is controlled by the gap adjusting device 19 is being discontinued.

[0043] Next, the water will be subjected to static pressure. 2c for example in the direction of the arrows in Fig. 4 of the right static pressure pad 2 both pads of static pressure 1 and 2 right and left, positioned at the support positions of the static pressure H1 and H2, are supplied (step S3), and as described in Fig. As shown in section 4, the workpiece W is placed against the workpiece support surface. 1b of the left pad of static pressure 1 , which is positioned at the support position of the static pressure H1, by means of the water of the static pressure 2c pressed (step S4).

[0044] Then the left grinding wheel shaft 8 in the direction of arrow X in Fig. 5 pushed forward at a constant speed in a state in which the rotation of the grinding wheel 3is stopped (step S5). Then, after the left grinding wheel 3 with the workpiece support surface 1b of the left pad of static pressure 1 Once aligned to come into contact with the workpiece W, the workpiece W is moved in the right direction (direction of arrow X) into the area of ​​influence (in the teeth) of the water supply of the static pressure. 2c pressed to lift the workpiece W from the workpiece support surface 1b of the left pad of static pressure 1 to lift off or to put into suspension, as in Fig. 5 is shown (step S6). The floating amount C1 of the workpiece W at this time is then determined using the air sensor. 7 of the right pad of static pressure 2 measured (step S7).

[0045] If the air sensor 7The amount of suspension C1 of the workpiece W is measured in the grinding feed end position determining device. 18 an output value of the floating amount C1 by the air sensor 7 and a setting value of the specific float amount C, which is determined by the float amount setting device 17 The set value is compared to determine whether or not the workpiece W has lifted off the left pad of the static pressure by the specified amount C (step S8). Subsequently, if the workpiece W has lifted off by the specified amount C, the output value from the air sensor is determined. 7 is brought into agreement with the set value of the determined floating amount C, and consequently the feed of the left grinding wheel shaft is 8 stopped simultaneously with the assessment or determination of the specific suspended amount C (step S9), and as it is in Fig. As shown in section 5, the position of the left grinding wheel shaft is shown. 8at this point the left grinding feed end position F1 is provisionally determined (step S10).

[0046] Furthermore, the specific floating amount C of the workpiece W can be set as desired. However, C < (A – D) / 2 must hold true, where A is the space between the two pads of the static pressure. 1 and 2 is and D is the thickness of the workpiece W before grinding.

[0047] If the workpiece W is suspended by a certain amount C from the left pad of the static pressure 1 Once lifted, the left grinding wheel shaft 8 withdrawn to the retraction position by a certain amount (step S11), and the supply of water under static pressure 2c from the right pad of static pressure 2 is stopped (step S12).

[0048] Next, how it works in Fig. 6 is shown after the water is under static pressure. 1cin the direction of the arrows from the left static pressure pad 1 is supplied to press the workpiece W against the right pad of the static pressure. 2 to press, which is positioned at the support position of the static pressure H2, using the water of the static pressure 1c (Steps S13 and S14), as described in Fig. As shown in Figure 7, by performing a function of advancing the right grinding wheel shaft 9 , whose rotation in the direction of arrow Y in Fig. 7 is stopped, at a constant speed, and so on, the grinding feed end position F2 of the right grinding wheel shaft is reached. 9 The right grinding wheel shaft is then determined provisionally using the same procedure (steps S15 to S20). 9 by the same amount as the left grinding wheel shaft 8 withdrawn (step S21). Furthermore, to equalize the movement paths, until the corresponding grinding wheel shafts 8and 9 be stopped after the air sensors 6 and 7 Once the specific floating amount C has been detected, the feed rates of both grinding wheel shafts will be adjusted. 8 and 9 set to the same speed.

[0049] Next, how it works in Fig. As shown in section 8, the water is subject to static pressure. 2c from the right pad of static pressure 2 supplied (step S22), the workpiece W is subjected to the static pressure via the water of the static pressure. 1c and 2c through the two pads of static pressure 1 and 2 The two grinding wheels are supported at the support positions of the static pressure H1 and H2. 3 and 4in a rotational state from the rotary feed end positions F1 and F2 to the side of the workpiece W, in order to initiate a grinding cycle for grinding the workpiece W through the two grinding wheels 3 and 4 to be performed (step S23). The feed rates of the two grinding wheel shafts 8 and 9 and the rotational speeds of the two grinding wheels 3 and 4 are the same.

[0050] Since the space A between the two pads is subject to static pressure 1 and 2 right and left according to the setting by the gap adjusting device 19 is determined and the final thickness B of the workpiece W is determined according to a setting by the setting means of the final thickness 20 is determined while the grinding cycle control means 21 the feed rate F of the grinding wheel shafts 8 and 9based on the space A between the pads of static pressure 1 and 2 and the final thickness B of the workpiece W is calculated in advance, the two grinding wheel shafts 8 and 9 pushed forward at the same speed from the right and left grinding feed end positions F1 and F2 to move the workpiece W through the two grinding wheels 3 and 4 to grind the front ends of them.

[0051] At that time, assuming that the feed rate S during the feed of the grinding wheel shafts 8 and 9 If the ratio of the right and left grinding feed end positions F1 and F2 is equal to (A – B) / 2, then the gap between the right and left grinding feed end positions F1 and F2, which are provisionally determined, is smaller than the gap A between the two static pressure pads by an amount equal to the right or left float amount C1 or C2.1 and 2 right and left. Consequently, the two grinding wheels grind. 3 and 4 The workpiece W is too thick, resulting in the production of defective products that are thinner than the specified final thickness B.

[0052] To prevent the production of such defective products, a displacement amount or displacement path G is incorporated into the grinding cycle control unit. 21 Entered, both grinding wheel shafts 8 and 9 advanced at a constant speed, while the feed rate S, when the right and left grinding wheel shafts 8 and 9 from the grinding feed end positions F1 and F2, is calculated by S = (A – B – G) / 2 so that the two grinding wheel shafts 8 and 9 not be advanced by the displacement path G.

[0053] This displacement path G is preferably equal to the predetermined floating amount C of the workpiece W. However, since the determined floating amount C of the workpiece W depends on the feed rates of the grinding wheel shafts 8 and 9 , the use of air sensors 6 and 7 and similar variations occur, the displacement amount G is actually fixed to be greater than the determined floating amount C of the workpiece W for safety reasons. Furthermore, provided that the determined floating amount C of the workpiece W is determined according to the feed rate of the grinding wheel shafts. 8 and 9 and every condition of the air sensors 6 and 7 and the like are entered into a database and the displacement amount G is determined based on the database, it is possible to determine a more precise displacement amount G.

[0054] After grinding the workpiece W in such a grinding cycle or grinding operation, it is assessed whether the ground workpiece W has been completed with the specified grinding accuracy (step S24). If it has been completed with the specified grinding accuracy, the grinding process is continued continuously (step S25). Furthermore, if the grinding accuracy is low, a specific adjustment operation is performed, such as adjusting the grinding position by recalculating the grinding feed end positions F1 and F2 of the grinding wheel shafts. 8 and 9 or a tilting adjustment of the grinding wheel shafts 8 and 9 executed (step S26) to obtain the specified grinding accuracy.

[0055] Provided that the grinding position of the workpiece W is determined in this way, a function is used in which, after the workpiece W is placed in the carrier 5The workpiece W is placed against one of the pads of static pressure. 1 and 2 When pressed, a grinding wheel shaft 8 or 9 pushed forward on the same side to remove the workpiece W from the static pressure pad 1 or 2 through one of the grinding wheels 3 and 4 to lift or suspend, implemented accordingly on the right and left sides, making it possible to position the workpiece W in the middle position between the right and left pads of the static pressure. 1 and 2 to align. Consequently, it is possible to perform an alignment easily and accurately regardless of the operator's skill level, and it is possible to reproduce essentially the same grinding position every time, thus making it possible to reduce the production of defective products as much as possible.

[0056] Furthermore, since it is possible to move the workpiece W through the two grinding wheels 3 and 4 at the middle position between the two static pressure pads 1 and 2 One advantage of grinding is that no trial grinding is required, thus reducing the number of test workpieces W. Consequently, since the workpiece W can be aligned without rotating the grinding wheels, 3 and 4 When the process is carried out, the workpiece W is not damaged, and the workpieces W can be used directly as products.

[0057] Furthermore, even if the workpiece W warps or becomes wavy, due to the water's static pressure 1c or 2c from a static pressure pad 1 or 2 is applied to apply static pressure to the entire surface of the workpiece W against the other pad. 1 or 2To apply pressure, it is possible to achieve precise alignment without being influenced by the shape of the workpiece W. Even if the thickness of the workpiece W is unknown, it is possible to position the workpiece W at the midpoint between the two pads of static pressure. 1 and 2 to align. Since an existing equipment used to support static pressure is for supplying the water under static pressure 1c and 2c from the static pressure pads 1 and 2 As it can be used, there are no problems regarding an increase in production costs for a complete horizontal surface grinder.

[0058] Furthermore, in the case where the grinding wheels 3 and 4 to be advanced in order to lift or suspend the workpiece W when the grinding wheels 3 and 4If the wheels are in a rotating state, wind pressure or similar factors can become disruptive due to the rotation, and additionally the grinding wheels can 3 and 4 grinding the workpiece W, whereby or when the grinding wheel shafts 8 and 9 being pushed too far forward, and so on. However, it is possible to push the grinding wheel shafts forward. 8 and 9 in a state in which the rotation of the grinding wheels 3 and 4 has stopped, while problems such as a malfunction due to the rotation of the grinding wheels 3 and 4 to be released, and grinding of the workpiece W takes place, it is possible to remove the workpiece W from the pads of static pressure. 1 and 2 to lift off by using the grinding wheels 3 and 4 .

[0059] Multiple air sensors 6 and 7For example, there are three locations in the circumferential direction in the vicinity of the recessed section. 2a arranged, making it possible to determine the floating amount C1 or C2 of the workpiece W using a sum or an average of the output values ​​of the three air sensors. 6 and 7 , an edition of the air sensors 6 and 7 , which first reaches a specified value, output values ​​from one or two or the three air sensors 7 to detect. However, since one of the air sensors 6 and 7 , which is arranged on the end side in the circumferential direction, in this embodiment, an advantage is that it is possible to easily measure the floating amount C1 or C2 of the workpiece W.

[0060] That is, in the case where one grinding wheel 3When pushed forward to press the workpiece W, the workpiece W is subjected to the water of static pressure. 2c , which is from the other pad of static pressure 2 The water is supplied and counter-pressured. Meanwhile, the workpiece W receives the water under static pressure. 2c essentially across its entire surface, and on the other side is the grinding wheel. 3 in the omitted section 1a of the static pressure pad 1 , in order to press or compress the lower half of the workpiece W. Consequently, as described in Fig. As shown in 10, the workpiece W is being examined by the grinding wheel. 3 is pressed or squeezed by the pad of static pressure 1The workpiece is lifted while its upper side tilts around a pivot point P, maximizing the lift of the lower side W, which is furthest from the pivot point P. Consequently, an advantage is that it is easy to detect changes in the lift or float amount C1 or C2 of the workpiece W by simply measuring it with a single air sensor. 7 to measure on the end side of the workpiece W, which is arranged to correspond to the bottom side, the lifting of which is large.

[0061] Furthermore, in the case where the floating amount C1 or C2 of the workpiece W is determined by the air sensor 6 or 7 The air sensor measures 6 or 7 , which is attached to the static pressure pad 1 or 2 on the same side of the grinding wheel 3 or 4 , which lifts the workpiece W, is intended to be used, or the air sensor6 or 7 , which is attached to the static pressure pad 1 or 2 It can be used if it is provided on the opposite side.

[0062] In this case, assuming that the air sensor 6 or 7 On the opposite side, one advantage is that even a sensor whose measuring range contains no values ​​close to zero can be used. For example, if the specified levitation amount C is a small amount close to zero that lies outside the measuring range, it is possible, in the case where the air sensor 6 or 7 of the static pressure pad 1 or 2is used on the same page, even if the floating amount C1 or C2 of the workpiece W reaches the specified floating amount C, it is not measured because the amount is outside the measuring range. However, in the case where the amount is measured by the air sensor 6 or 7 of the static pressure pad 1 or 2 on the opposite side of the grinding wheel 3 or 4 Even when a sensor is used where values ​​of approximately zero are outside the measuring range, there is a gap between the static pressure pad and the surface. 1 or 2 on the opposite side and the workpiece W within the measuring range, in contrast to values ​​that are approximately zero. Consequently, it is possible to detect the small floating amount C1 or C2 of the workpiece W using the air sensors. 6 or 7 to eat.

[0063] The embodiments of the present invention have been described in detail above; however, the present invention is not limited to these embodiments and can be modified in various ways within the subject matter, which does not deviate from the idea of ​​the present invention. For example, in the embodiment the grinding wheels 3 and 4 In a stopped state, they are pushed forward to press or squeeze the workpiece W. However, the grinding wheels can 3 and 4 The grinding wheels are rotated at speeds corresponding to a level at which the workpiece W is not ground. Consequently, the grinding wheels exert pressure. 3 and 4 The workpiece W is preferably in a stopped state, but is not necessarily in a state in which the rotations are completely stopped.

[0064] Furthermore, in the case where an existing horizontal surface grinder is used, provided that a program of an alignment procedure as in this embodiment is entered into the control device, it is possible, after a grinding wheel replacement operation that occurs periodically in the manufacturing process, to automatically perform the operation of inserting the workpiece W until removing the workpiece W after completion of the grinding by combining the insertion / removal means of the workpiece W, and it is possible for an operator to perform other work away from the machine during this time.

[0065] Furthermore, a workpiece W of normal dimensions can be used before the grinding process begins and both grinding wheel shafts 8 and 9 Both the right and left wheels can be moved forward by the same distance, aligning both grinding wheels. 3 and 4The workpiece W can be manually calibrated to begin the grinding cycle. Provided that a grinding cycle utilizing an in-process calibration device is used, it is possible to omit steps such as setting a displacement path, thus simplifying the grinding of workpiece W to standard dimensions.

[0066] In the grinding cycle, which uses an in-process calibration device, even if there is no gap between the two pads of static pressure 1 and 2 If the right and left pads are found, it is possible to find the middle position between the two pads of static pressure. 1 and 2 to determine, and it is possible to obtain the normal dimensions of the workpiece W. Furthermore, the middle position between both pads of static pressure is determined. 1 and 2not through the space A between the two static pressure pads on the right and left. 1 and 2 The right and left sides are affected, as the positions of the two grinding wheels 3 and 4 with reference to the workpiece support surfaces 1b and 2b the two pads of static pressure 1 and 2 be determined.

[0067] It is possible to reproduce the grinding position prior to adjustment by simultaneously using a technology in which, at the same time as a zero-point signal is received by the process-internal calibration device at the time when the workpiece W reaches the final dimensions, output values ​​are obtained from the air sensors. 6 and 7 the pads of static pressure 1 and 2The data is obtained and monitored to determine whether or not there is a difference between the right and left sides in the output values ​​of the air sensors. 6 and 7 is available to correct a grinding position resulting from a material removal difference between the two grinding wheels. 3 and 4 originates from the air sensors. 6 and 7 at the time of the test grinding and the output values ​​from the air sensors 6 and 7 The values ​​should be compared before adjustment (before replacing the grinding wheels and the like) to correct any discrepancies between the output values ​​from the air sensors. 6 and 7 This is before the adjustment or setup. Consequently, it is possible to restart production without manufacturing defective products, thus making it possible to stabilize the grinding precision over a long period of time.

[0068] Furthermore, by using a technology to correct a faulty alignment of the grinding positions before trial grinding, it is possible to check the grinding accuracy until the next setup by comparing it with the output values ​​from the air sensors. 6 and 7 to stabilize in real time during the trial grinding before the setup in order to correct the faulty alignment.

[0069] In the present embodiment, the air sensors 6 and 7 , which are in the pads of static pressure 1 and 2 Included are used as workpiece position detection devices. Provided that an in-process calibration device is used during the grinding of the workpiece W, it is possible to determine the midpoint between the two pads of static pressure. 1 and 2To obtain right and left. Any position detection means capable of measuring distances between the pads of static pressure. 1 and 2 and to measure the workpiece W (floating amounts C1 and C2), can be used.

[0070] The grinder is preferably a horizontal double-sided surface grinder in which both pads are subject to static pressure. 1 and 2 and both grinding wheels 3 and 4 are arranged on the right and left. However, since water of static pressure from both pads of static pressure 1 and 2 is supplied to press the workpiece W so that the workpiece W is removed from the grinding wheels. 3 and 4 The present invention can be achieved equally by means of a vertical double-sided surface grinder, in which the two pads of the static pressure 1 and 2 and the two grinding wheels3 and 4 are arranged at the top and bottom. Reference symbol list W workpiece 1, 2 Static pressure pad 3, 4 grinding wheel 7 carriers 8, 9 grinding wheel shaft 17 Levitation amount setting means 18 Grinding feed end position determining devices 19 gap adjusting devices 20 Adjustment devices for final thickness 21 Grinding cycle control device C Predetermined levitation amount F1, F2 Grinding feed end position S feed amount QUOTES INCLUDED IN THE DESCRIPTION

[0071] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0072] JP 2003-236746

[0007]

Claims

[1] Double-sided surface grinding process comprising, when both surfaces of the workpiece are ground by means of a pair of grinding wheels, while a thin plate-shaped workpiece, supported by a static pressure by means of a pair of static pressure pads, is rotated: Detecting the position of the workpiece using a workpiece position detection device while the workpiece is moved to a central side between the two static pressure pads at static pressure support positions by the grinding wheels; Preliminary determination of grinding wheel positions when the workpiece position detection means detects that the workpiece is separated from the corresponding static pressure pads by a certain distance, as grinding feed end positions, and Advance both grinding wheels at the same speed from the grinding feed end positions to grind the workpiece. [2] Double-sided surface grinding method according to claim 1, wherein a function is performed on each side in which, after the workpiece is pressed against one of the static pressure pads at the static pressure support positions, the workpiece is lifted by a certain amount from one static pressure pad by the grinding wheel, the rotation of which is stopped, while the grinding wheel is advanced on the side of one static pressure pad, and a position of the grinding wheel when the workpiece has been lifted by the certain amount is provisionally determined as grinding feed end positions, and thereafter the workpiece is supported by the static pressure from the two static pressure pads. [3] Double-sided surface grinding method according to claim 2, wherein a static pressure fluid is supplied from the other static pressure pad to press the workpiece against the side of one static pressure pad. [4] Double-sided surface grinding method according to one of claims 1 to 3, wherein a displacement amount of both grinding wheels is determined in advance and both grinding wheels are adjusted so that they are not advanced by the displacement amount during grinding of the workpiece. [5] Double-sided surface grinder grinding both surfaces of the workpiece with a pair of grinding wheels while a thin, plate-shaped workpiece is rotated, supported by a static pressure from a pair of static pressure pads, wherein the double-sided surface grinder has: two workpiece position detection means for detecting a position where the workpiece is separated by a certain distance from the two static pressure pads at static pressure support positions; a grinding feed end position determining device for the preliminary determination of the positions of the grinding wheels, if the corresponding workpiece position detection device detects the position at which a separation of the determined distance exists as the grinding feed end position; and A grinding cycle control device for advancing both grinding wheels at the same speed from the grinding feed end positions, which have been provisionally determined by the grinding feed end position determining device, in order to perform a grinding cycle.

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