Cylindrical grinding machine

Abstract

To provide a cylindrical grinder which can suppress occurrence of breakage of an end part of a crystal rod and mechanical misalignment of a support unit, can reduce a required process time, and can reduce the need for maintenance of a part detecting a positional relationship between the crystal rod and a main spindle or the like in a loading process.SOLUTION: A cylindrical grinder has: first and second detection means which detect proximity between one end or the other end of a crystal rod and a main shaft or a countershaft without contact; and a drive mechanism which can change and adjust a movement speed of a second support unit on the countershaft side. In contact support between one end of the crystal rod and the countershaft, a movement speed B of the second support unit from detection of proximity between one end and the countershaft by the second detection means to the contact support is adjusted to a speed lower than a movement speed A until the detection of proximity, and in contact support between the other end of the crystal rod and the main spindle, a movement speed D from the detection of proximity between the other end and the main spindle by the first detection means to the contact support is adjusted to a speed lower than a movement speed C until the detection of proximity.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cylindrical grinding machine that can safely and quickly perform the operation of clamping and supporting a crystal rod (such as a silicon single crystal ingot) in the axial direction between a main shaft and a sub-shaft by detecting both ends of the crystal rod (the conical cone portion and the tail portion) in the preparation process (loading process) for traverse grinding the crystal rod. [Background technology]

[0002] In recent years, semiconductor devices have become larger in diameter due to improvements in performance and reductions in manufacturing costs. The wafers used in semiconductor device manufacturing are produced by using a method such as the Czochralski method to create a crystal ingot with a cylindrical body and a conical cone and tail at the front and rear. The outer periphery of the crystal ingot is then ground using a cylindrical grinder, after which it is sliced ​​perpendicular to the axial direction into plates, which are then polished. As a result, as the number of wafers obtained from a single crystal ingot increases and the diameter of the wafers increases, the diameter and weight of the resulting crystal ingots also increase.

[0003] When cylindrically grinding such crystal rods, a typical cylindrical grinding machine is composed of a transport unit for transporting the crystal rod inside and outside the machine, a support unit for supporting the crystal rod inside the machine, and a grinding unit for traverse grinding the outer periphery of the crystal rod. FIG. 8 shows a preparation step (loading step) in which the crystal bar is sandwiched in the crystal axis direction by the transport unit 38 and the support units 34a and 34b. (Carrying in crystal rods) The conveying unit 38, which holds the crystal bar 7 in the diametrical direction, moves to align the crystal axis center 10 with the rotation center 9 of the main shaft 33a and the sub-shaft 33b (Step 1 in FIG. 8).

[0004] (Crystal rod support) Next, the crystal rod 7 is clamped between support units 34a and 34b. In a cylindrical grinding machine, the support unit 34a on the main shaft side is generally fixed, and the support unit 34b on the counter shaft side is moved by a drive mechanism such as a servo motor (Step 2 in Figure 8). The holding portion (support device) 32b of the support unit 34b on the counter-spindle side, which is continuously moved toward the main spindle side by a drive mechanism such as a servo motor, contacts the conical tail portion 12 of the crystal rod 7 and continues to move toward the main spindle side together with the conveying unit 38, which holds the crystal rod 7 in the diametrical direction (step 3 in Figure 8). This continuous movement also brings the holding portion 32a of the support unit 34a on the main shaft into contact with the conical cone 11 of the crystal rod 7. The crystal rod 7 is supported by being sandwiched between the holding portion 32a on the main shaft and the holding portion 32b on the countershaft. However, during the subsequent cylindrical grinding process, when the cylindrical surface of the crystal rod 7 is ground by a grinding wheel in the grinding unit, it is necessary to prevent the holding portions 32a and 32b from slipping on the cone 11 and tail 12 due to grinding resistance. Therefore, after the crystal rod 7 is supported by being sandwiched between the holding portions 32a and 32b, the support unit 34b on the countershaft continues to move toward the main shaft, increasing the frictional forces between the cone 11 of the crystal rod 7 and the holding portion 32a, and between the tail 12 and the holding portion 32b (step 4 in Figure 8).

[0005] (Transport unit evacuation) After the crystal bar 7 is sandwiched between the support units 34a and 34b in the crystal axis direction in the above step, the transport unit 38 releases the crystal bar 7 and retreats (step 5 in FIG. 8). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-221393 Summary of the Invention [Problem to be solved by the invention]

[0007] During the loading process described above, the operation of the countershaft support unit 34b causes the conical cone 11 and tail 12 of the crystal rod 7 to come into contact with the holders 32a and 32b, which can result in damage to the conical cone 11 and tail 12 of the crystal rod 7. In this case, during the cylindrical grinding process, when the cylindrical surface of the crystal rod 7 is ground with the grinding wheel of the grinding unit, the grinding resistance can cause the crystal rod to slip or become misaligned, which can have a negative impact on quality, such as poor cylindrical surface quality and poor diameter accuracy, so the countershaft support unit 34b must be operated at a slow speed. On the other hand, if the support unit 34b on the countershaft side is operated at a low speed to prevent damage due to the above-mentioned impact, the loading process will take a long time.

[0008] Patent Document 1 also discloses a technology that uses an ingot detection rod that can contact the end (cone and tail) of an ingot (crystal rod) through an engagement hole in a holder (support device). Figure 9 shows a conventional contact-type detection technology that detects the position of a crystal rod 7 just before it comes into contact with a holder 45. The crystal rod 7 is clamped diametrically by a conveying unit and moved to align the center of the crystal axis with the center of rotation of the main shaft and secondary shaft (upper view of Figure 9: secondary shaft side shown here). Then, the end (tail portion 12) of the crystal rod 7 comes into contact with the ingot detection rod 46 (movable by ingot detection rod moving device 50) held in the sliding portion 47 through an engagement hole in the holder 45 on the secondary shaft side, which is continuously moved toward the main shaft by a drive mechanism such as a servo motor. When this happens, the end detection dog 49 moves from the position of sensor 48a, causing sensor 48b to enter a detection state. It is easy to imagine that the position just before the end comes into contact with the holder 45 can be grasped (lower view of Figure 9).

[0009] Although the contact-type detection technology including the ingot detection rod 46 described in Patent Document 1 is an effective means for detecting the position of the ends (the conical cone and tail) of a crystal rod, there are concerns about component failure and deterioration. Specifically, the ingot detection rod 46 is held by a sliding part 47, and it is conceivable that the intrusion of mist-like grinding powder produced by grinding the outer peripheral surface of the cylinder during the cylindrical grinding process could cause wear on the sliding part 47 and result in sliding malfunction (malfunction), necessitating periodic maintenance.

[0010] Therefore, the present invention has been made to solve the above problems, and its object is to provide a cylindrical grinding machine that can prevent damage to the end of the crystal rod and mechanical misalignment of the support unit due to impact from contact with the main shaft or sub-shaft during the loading process, can shorten the time spent on the loading process, and can reduce the need for maintenance of components that detect the positional relationship between the crystal rod and the main shaft or sub-shaft. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a crystal rod grinding apparatus comprising: a conveying unit for holding and conveying a crystal rod; a pair of support units for sandwiching the crystal rod held by the conveying unit in the axial direction and enabling it to rotate around the axis; and a grinding unit for traverse-grinding the outer periphery of the crystal rod while moving along the axial direction of the crystal rod supported by the pair of support units, the pair of support units includes a first support unit having a main shaft and a second support unit having a sub-shaft, and a drive mechanism capable of moving the second support unit toward the first support unit; In a cylindrical grinding machine, when the second support unit is moved toward the first support unit by the driving mechanism, one end of the crystal rod held by the transport unit approaches the secondary shaft of the second support unit and is supported by contacting it, and then the other end of the crystal rod approaches the primary shaft of the first support unit and is supported by contacting it, so that the crystal rod is sandwiched and supported between the primary shaft and the secondary shaft, The crystal rod further includes a first detection means for detecting the proximity of the other end of the crystal rod to the main axis in a non-contact manner, and a second detection means for detecting the proximity of the one end of the crystal rod to the sub-axis in a non-contact manner, The drive mechanism includes: The moving speed of the second support unit is changeable and adjustable, In the contact support between one end of the crystal rod and the secondary shaft, the moving speed B of the second support unit from the detection of the proximity of the one end of the crystal rod and the secondary shaft by the second detection means to the contact support is adjusted to be slower than the moving speed A of the second support unit until the detection of the proximity; A cylindrical grinding machine is provided, characterized in that, in contact support between the other end of the crystal rod and the main spindle, the movement speed D of the second support unit from the detection of the proximity of the other end of the crystal rod and the main spindle by the first detection means to the contact support is adjusted to be slower than the movement speed C of the second support unit until the detection of the proximity.

[0012] In the cylindrical grinding machine of the present invention, the drive mechanism slows the movement speed of the second support unit during the loading process when it detects the proximity of the tail (one end) or cone (the other end) of the crystal rod to the main shaft or sub-shaft. This reduces the impact when the end of the crystal rod comes into contact with the main shaft or sub-shaft, ensuring safe contact. This reduces damage to the end of the crystal rod and prevents mechanical misalignment of the support units. Therefore, in the subsequent cylindrical grinding process, the crystal rod does not slip or become misaligned due to grinding resistance, preventing adverse effects on quality, such as poor cylindrical surface condition and poor diameter accuracy. Furthermore, because the second support unit moves at a higher speed until the proximity detection, the process time can be significantly reduced compared to conventional cylindrical grinding machines, which move at a slower speed from start to finish of the loading process. This results in a cylindrical grinding machine with improved processing capacity, which can improve productivity. Furthermore, since the proximity detection means is non-contact rather than contact-type as in the past, defects due to wear of the detection components do not occur, and the frequency of maintenance can be reduced.

[0013] In this case, the main shaft and the sub-shaft each have a holding portion with which the crystal bar is supported by contacting the holding portion, the first detecting means and the second detecting means are each a sensor, the sensor is disposed in a direction perpendicular to the main shaft and the sub-shaft inside each of the holding portions of the main shaft and the sub-shaft, and a detection line is provided by the sensor; the first detection means detects the proximity of the other end of the crystal rod to the main axis when the other end of the crystal rod passes through the detection line; The second detection means may detect the proximity of one end of the crystal rod to the secondary axis when the one end of the crystal rod passes through the detection line.

[0014] Alternatively, the main shaft and the sub-shaft each have a holding portion with which the crystal bar is supported by contacting the holding portion, the first detecting means and the second detecting means are each a sensor, the sensors are connected to the first support unit and the second support unit via brackets, and are disposed outside the respective holding portions of the main shaft and the sub-shaft, with detection lines for the sensors being provided at the outsides; the first detection means detects the proximity of the other end of the crystal rod to the main axis when the other end of the crystal rod passes through the detection line; The second detection means may detect the proximity of one end of the crystal rod to the secondary axis when the one end of the crystal rod passes through the detection line.

[0015] In this way, by using a sensor disposed inside or outside the holder, it is possible to more easily detect the proximity of the end of the crystal rod to the main axis or the sub axis.

[0016] The sensor may be a photoelectric sensor having a light emitter and a light receiver, or an image sensor.

[0017] Such a sensor makes it possible to more reliably detect the proximity of the end of the crystal rod to the main axis or the sub-axis.

[0018] Furthermore, the moving speed A and the moving speed C of the second support unit are 3,000 to 4,000 mm / min, The moving speeds B and D of the second supporting unit may be set to 50 to 200 mm / min.

[0019] This makes it possible to more reliably shorten the time required for the loading step and more reliably prevent damage to the end of the crystal ingot. [Effects of the Invention]

[0020] The cylindrical grinding machine of the present invention can prevent breakage or misalignment of the end of the crystal ingot during the loading process. It can also significantly shorten the time required for the loading process. Furthermore, it can reduce the need for maintenance. Consequently, it can improve the quality of the crystal ingot after cylindrical grinding and its productivity. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is an explanatory diagram showing an example of a cylindrical grinding machine of the present invention. [Figure 2] FIG. 10 is a flowchart showing the functions and cooperation of the detection means and the drive means in the loading process (first half). [Figure 3] FIG. 10 is a flowchart showing the functions and cooperation of the detection means and the drive means in the loading process (second half). [Figure 4] FIG. 2 is an explanatory diagram showing an example (internal arrangement) of a detection means in the first embodiment. [Figure 5] 1 is an explanatory diagram showing an example of the state before and after detection of the proximity of the end of the crystal rod to the secondary shaft (holding part) in the first embodiment. FIG. [Figure 6] FIG. 10 is an explanatory diagram showing an example (external arrangement) of a detection means in embodiment 2. [Figure 7] 10 is an explanatory diagram showing an example of the state before and after detection of the proximity of the end of the crystal rod to the secondary shaft (holding part) in the second embodiment. FIG. [Figure 8] FIG. 1 is a flow chart showing an example of a conventional loading process. [Figure 9] FIG. 1 is a flow chart showing a conventional contact detection technique for detecting the position of a crystal rod just before it comes into contact with a holder. [Figure 10] FIG. 10 is an explanatory diagram showing the relationship between the shape of the end of the ingot detection rod and the crystal rod in a conventional machine. BEST MODE FOR CARRYING OUT THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. An overall view of a cylindrical grinding machine 1 of the present invention is shown in Figure 1. As shown in Figure 1, the cylindrical grinding machine 1 first has a transfer unit 8, a pair of support units 4, and a grinding unit 5. It also has a non-contact detection means 14. First, the transport unit 8 may be any unit capable of holding and transporting the crystal rod 7. The grinding unit 5 may have a grinding wheel 6 and may be any unit capable of traverse grinding the outer periphery of the crystal rod 7 while moving along the axial direction of the crystal rod 7 supported by the pair of support units 4. The transport unit 8 and grinding unit 5 are equipped with a drive mechanism (not shown) and are movable, and may be, for example, the same as conventional units.

[0023] Next, the pair of support units 4 will be described. The pair of support units 4 sandwich the crystal rod 7 held by the transport unit 8 in the axial direction, allowing it to rotate around its axis, and include a first support unit 4a and a second support unit 4b. The first support unit 4a has a main shaft 3a, and the second support unit 4b has a sub-shaft 3b. The main shaft 3a has a holder 2a at its tip, and the sub-shaft 3b has a holder 2b at its tip. Therefore, the crystal rod 7 is supported by being sandwiched between the holder 2a of the main shaft 3a and the holder 2b of the sub-shaft 3b. Here, an example is shown in which the tail portion (one end) 12 of the crystal rod 7 is supported on the side of the secondary shaft 3b and the cone portion (the other end) 11 is supported on the side of the primary shaft 3a, but this is not limited to this, and the orientation of the crystal rod 7 may be reversed.

[0024] The pair of support units 4 also have a drive mechanism 13. For simplicity, the drive mechanism 13 is only shown in FIG. 1. This drive mechanism 13 has, for example, a motor (such as a servo motor) and can move the second support unit 4b toward the first support unit 4a. Of course, it can also move in the opposite direction to the first support unit 4a. By adjusting the number of rotations and direction of rotation of the motor, the movement speed and movement direction of the second support unit 4b can be freely changed and adjusted. In addition, the drive mechanism 13 can also be equipped with a computer or the like, and in particular, can be configured to automatically adjust the movement speed of the second support unit 4b in conjunction with a detection signal from the detection means 14.

[0025] The detection means 14 detects the proximity of the crystal rod 7 to the pair of support units 4 without contact. More specifically, it comprises a first detection means 14a that detects the proximity of the other end 11 of the crystal rod 7 to the main shaft 3a, and a second detection means 14b that detects the proximity of the one end 12 of the crystal rod 7 to the sub-shaft 3b.

[0026] Here, the detection means 14 and the driving mechanism The 13 functions and their linkages will be explained together with an explanation of the loading process (Figure 2: first half, Figure 3: second half). First, the basic flow of the loading process is the same as that of the general example described above (Figure 8). That is, after the crystal rod 7 is loaded, the second support unit 4b is moved toward the first support unit 4a by the drive mechanism 13, so that one end 12 of the crystal rod 7 held by the transport unit 8 approaches and contacts the secondary shaft 3b (more specifically, the holding part 2b) of the second support unit 4b and is supported; then, the other end 11 of the crystal rod 7 approaches and contacts the primary shaft 3a (more specifically, the holding part 2a) of the first support unit 4a and is supported, so that the crystal rod 7 is sandwiched and supported between the primary shaft 3a (holding part 2a) and the secondary shaft 3b (holding part 2b). Thereafter, Transport Unit 8 evacuates. However, in the cylindrical grinding machine 1 of the present invention, the contact support between one end 12 of the crystal rod 7 and the countershaft 3b and the contact support between the other end 11 of the crystal rod 7 and the main shaft 3a are performed by cooperation between the second detection means 14b and the drive mechanism 13, and the first detection means 14a and the drive mechanism 13, respectively.

[0027] Each flow will be explained. (Carrying in crystal rods) The conveying unit 8, which holds the crystal rod 7 in the diameter direction, moves to align the crystal axis center 10 with the rotation center 9 of the main shaft 3a and the sub-shaft 3b (Step 1 in FIG. 2).

[0028] (Crystal rod support) Next, in order to sandwich the crystal rod 7 between the first support unit 4a and the second support unit 4b, the second support unit 4b is moved toward the first support unit 4a by the drive mechanism 13. At this time, the second detection means 14b is adjusted to move at a moving speed A until it detects that one end 12 of the crystal rod 7 is close to the secondary shaft 3b (steps 2 and 3 in FIG. 2).

[0029] When the second detection means 14b detects the proximity, the drive mechanism 13 automatically adjusts the movement from that point until the one end 12 and the countershaft 3b come into contact and support, so that the movement is at a movement speed B, which is slower than the movement speed A (steps 3 and 4 in FIG. 2).

[0030] After the end 12 of the crystal rod 7 contacts and supports the countershaft 3b, the second support unit 4b is moved further toward the first support unit 4a by the drive mechanism 13. At this time, the crystal rod 7, the transport unit 8, and the second support unit 4b move together. The movement is then adjusted to a moving speed C until the first detection means 14a detects the proximity of the other end 11 of the crystal rod 7 to the main shaft 3a (steps 4 in FIG. 2 and 5 in FIG. 3). Moving speed C can be faster than moving speed B, for example, it can be the same as moving speed A. Note that the change from moving speed B to moving speed C can be manually performed by an operator, for example, by visually confirming the start of movement of the crystal rod 7 or the transport unit 8. Alternatively, the position control mechanism of the transport unit 8 can transmit the start of movement to the drive mechanism 13, and the change can be automatically adjusted.

[0031] When the first detection means 14a detects the proximity, the drive mechanism 13 automatically adjusts the movement from that point until the other end 11 comes into contact with the main shaft 3a at a movement speed D slower than the movement speed C (steps 5 and 6 in FIG. 3) based on the detection signal. The movement speed D can be set to the same speed as the movement speed B, for example. As a result, the crystal bar 7 is sandwiched and supported between the main shaft 3a and the sub-shaft 3b. To prevent the main shaft 3a and the sub-shaft 3b from slipping on the other end 11 and one end 12 of the crystal bar 7 due to grinding resistance when the cylindrical surface of the crystal bar 7 is ground by the grindstone of the grinding unit in the subsequent cylindrical grinding process, the second support unit 4b continues to move (push) toward the first support unit 4a, increasing the friction between the other end 11 and one end 12 of the crystal bar 7 and the main shaft 3a and the sub-shaft 3b that are in contact with them (step 6 in Figure 3). In this way, the crystal bar 7 is sandwiched between the first support unit 4a and the second support unit 4b in the crystal axis direction. The timing of completion of this sandwiching can be determined, for example, by visually confirming that the crystal bar 7 or the transport unit 8 has stopped moving, or by confirming that the transport unit 8 has stopped moving using the position control mechanism of the transport unit 8.

[0032] (Transport unit evacuation) After the crystal rod 7 is clamped in the above step, the transport unit 8 releases the crystal rod 7 and retreats (step 7 in FIG. 3).

[0033] With the cylindrical grinding machine 1 of the present invention, which is equipped with such a combination of detection means 14 and drive mechanism 13, the movement speed of the second support unit 4b is slowed down when the end of the crystal rod 7 approaches the main shaft 3a or the sub-shaft 3b, thereby preventing damage to the end of the crystal rod 7 or mechanical displacement of the support unit 4 due to the impact at the time of contact. Furthermore, since the second supporting unit 4b can be moved at high speed until it approaches the substrate, the time required for the loading step can be shortened. Furthermore, as mentioned above, contact-type detection means such as that in Patent Document 1 tend to cause wear on parts related to detection, making maintenance necessary, but non-contact detection means 14 such as that of the present invention does not cause wear on parts, reducing the need for maintenance. These excellent effects make it possible to obtain high quality cylindrically ground products, and also improve productivity.

[0034] Although the specific set values ​​of the moving speed AD of the second support unit 4b are not particularly limited, moving speed A and moving speed C can be set to, for example, 3,000 to 4,000 mm / min, and moving speed B and moving speed D can be set to, for example, 50 to 200 mm / min. Setting values ​​selected from these numerical ranges can more reliably shorten the loading process and prevent damage to the end of the crystal rod 7.

[0035] Examples of the detection means 14 (first detection means 14a, second detection means 14b) include various sensors, such as photoelectric sensors and image sensors. Photoelectric sensors can be equipped with a light projector and a light receiver. Image sensors can also be equipped with an image processor (such as a computer) for processing the acquired image. These sensors can more reliably detect the proximity of the crystal rod to the major and minor axes.

[0036] Specific embodiments of the detection means 14 will be described below (embodiments 1 and 2). Note that, although the second detection means 14b and the countershaft 3b (holding portion 2b) will be used as an example for description, the same configuration can also be used for the first detection means 14a and the main shaft 3a (holding portion 2a).

[0037] (Detection Means Embodiment 1: Internal Arrangement) An example of the detection means 14 (second detection means 14b) is shown in Figure 4. This is a case where the detection means 14 is disposed in a direction perpendicular to the secondary axis 3b inside the holder 2b. Figure 5 shows an example of the state before and after detection of the proximity of the end of the crystal rod 7 to the secondary axis 3b (holder 2b). The holder 2b at the tip of the countershaft 3b, which contacts and supports the crystal rod 7, has a through-hole that combines a conical recess and a hole of a specified diameter. The end of the crystal rod 7 is inserted into this through-hole to be supported. The holder 2b is provided with a sensor installation hole 21, in which a cone portion detection sensor 22 is disposed as the second detection means 14b, and a detection line 23 is provided by the cone portion detection sensor 22. When the one end 12 of the crystal rod 7 passes through the detection line 23, the proximity of the one end 12 to the secondary shaft 3b (holder 2b) is detected. This configuration makes it easier to detect proximity.

[0038] In addition, by providing a mechanism for flowing compressed air 24 into the sensor installation hole 21, it is possible to prevent the cone portion detection sensor 22 from becoming dirty due to the intrusion of mist-like grinding powder generated when the cylindrical outer surface of the crystal rod 7 is ground during the cylindrical grinding process, thereby minimizing maintenance.

[0039] In this case, since there is no contact area when detecting the end of the crystal rod 7 (because the detection means 14 is non-contact), there is no restriction on the distance that can be inserted into the holding portion 2b, and there is no restriction on the shape of the end. The first detection means 14a may also have a similar configuration.

[0040] Regarding the shape restrictions on the end of the crystal rod, let us consider the example of the contact type described in Patent Document 1. Figure 10 shows the relationship between the ingot detection rod 46 and the shape of the end of the crystal rod 7, with the top row showing an example in which the ingot detection rod is extended, the middle row showing an example in which the end of the crystal rod is short, and the bottom row showing an example in which the end of the crystal rod is long. Since the end of the crystal rod 7 (the conical cone portion and the tail portion) is supported by the holder 45, the distance that the end penetrates into the holder 45 must be smaller than the allowable stroke (a) of the ingot detection rod 46 and the ingot detection rod moving device 50. In the middle part of Figure 10, the penetration distance (b) is less than the allowable stroke (a), and the conical end of the crystal rod 7 is supported by the holder 45 without any problems. However, in the bottom part of Figure 10, the penetration distance (c) is greater than the allowable stroke (a), and the end of the crystal rod 7 is not properly supported by the holder 45. In other words, in the case of contact-type detection means, this means that there are limitations due to the shape of the end of the crystal rod 7, and this is considered to be one of the disadvantages.

[0041] As such, contact-type detection means may obstruct the entry of the end of the crystal rod 7, so the shape of the end of the crystal rod 7 must also be taken into consideration, but a non-contact type like the present invention does not require such considerations and is simple.

[0042] (Detection Means Embodiment 2: External Arrangement) 6 shows another example of the detection means 14 (second detection means 14b). This is a case where the detection means 14 is disposed outside the holder 2b. By installing an end detection sensor 25 as the second detection means 14b outside the holder 2b, it becomes possible to detect the end of the crystal rod 7 before it enters the holder 2b. Because the relative position of end detection sensor 25 and holding portion 2b needs to be constant, the easiest installation method is to completely fix end detection sensor 25 by connecting it to second support unit 4b (for example, base portion 27b of the second support unit) via bracket 28. This makes it possible to move end detection sensor 25 in synchronization with second support unit 4b on the countershaft side, which moves to the main shaft side by a drive mechanism such as a servo motor. In addition, a detection line 26 is provided by an end detection sensor 25. When one end 12 of the crystal rod 7 passes through the detection line 26, the proximity between the one end 12 and the secondary shaft 3b (holding part 2b) is detected. With this configuration, proximity detection can be performed more easily. The first detection means 14a may also have a similar configuration.

[0043] Furthermore, in embodiment 1 of Figure 5, the conical end of the crystal rod 7 must enter the inside of the holding portion 2b, so if the end of the crystal rod 7 does not have a conical end, it cannot be detected.However, in the case of external placement, as shown in Figure 7, the end of the crystal rod 7 may be conical, but detection is possible even if it is flat.

[0044] The detection means 14 for detecting the proximity of the end of the crystal rod to the main axis or sub-axis does not require a structure in which components for contact with the crystal rod or for detection come into contact with each other, as in Patent Document 1, but is not particularly limited as long as it can detect without contact and can cooperate with the drive mechanism 13 as described above. In order to prevent damage to the end of the crystal rod, etc., it is necessary to detect the position where the support unit 4 and the end of the crystal rod 7 approach each other in order to move the second support unit 4b at a slow speed just before the support unit 4 comes into contact with the end of the crystal rod 7.A mechanism such as that described in embodiment 1 or embodiment 2 above makes it easier to detect the proximity. [Example]

[0045] The present invention will be explained in more detail below by showing examples and comparative examples, but the present invention is not limited to these examples. A conventional automatic cylindrical grinding machine (comparison example) that does not detect the ends of the crystal rod (the conical cone and tail) was prepared, and an automatic cylindrical grinding machine (Figure 1) (example) of the present invention in which end detection sensors 25 (Figure 6), which are non-contact detection means, are installed outside the holding parts on the main shaft side and the sub-shaft side, respectively, and the time required for the loading process was compared using each machine. (Example) End detection sensor 25 is a general photoelectric sensor with a separate light emitter and receiver, and on the countershaft 3b side, it was completely fixed to base portion 27b of second support unit 4b via bracket 28 so that distance 29 between the optical axis of the photoelectric sensor and the end face of holder 2b was 100 mm, and spacing 30 between the light emitter and receiver was 450 mm. The main shaft 3a side was also set to have the same conditions. The crystal rod 7 used had a diameter of 300 mm, a cone length of 150 mm, a straight body length of 1,000 mm, and a tail length of 250 mm.

[0046] The loading process was carried out as shown in Figures 2 and 3. First, the crystal rod 7 was moved and carried in by the transport unit 8 so that the crystal axis center 10 was aligned with the rotation center 9 of the main shaft 3a and the sub-shaft 3b (step 1 in Figure 2). The time required was 30 seconds. After this carrying in, the distance between the end face on the sub-shaft 3b side and the tail portion (one end) 12, and the distance between the end face on the main shaft 3a side and the cone portion (other end) 11 were both 1,000 mm. The second support unit 4b was continuously moved toward the main shaft 3a by the drive mechanism 13 until the tail portion 12 was detected (steps 2 and 3 in FIG. 2). The movement speed until the end detection sensor (second detection means 14b) on the counter shaft 3b side detected it was 4,000 mm / min (hereinafter referred to as high speed), and the time required was approximately 15 seconds. Next, the conical tail portion 12 of the crystal rod 7 entered and contacted the inside of the holding portion 2b (steps 3 and 4 in FIG. 2). The moving speed until contact was 100 mm / min (hereinafter referred to as low speed), and the time required was approximately 48 seconds.

[0047] The holding portion 2a on the spindle 3a side and the conical cone portion 11 of the crystal rod 7 also operate in the same manner. The second support unit 4b was moved at high speed (step 4 in FIG. 2 to step 5 in FIG. 3) until the end detection sensor (first detection means 14a) on the spindle 3a side detected the cone portion 11. The time required was approximately 18 seconds. The cone 11 of the crystal rod 7 moved slowly into and contacted the inside of the holder 2a, and the crystal rod 7 was sandwiched and supported between the holders 2a and 2b. The second support unit 4b then continued to move toward the first support unit 4a, increasing the friction between the cone 11 of the crystal rod 7 and the holder 2a, and between the tail 12 and the holder 2b, completing the sandwiching (steps 5 and 6 in Figure 3). The entire process took 78 seconds. Thereafter, the transport unit 8 was moved away from the crystal rod 7. The time required was 30 seconds.

[0048] (Comparative Example) The crystal rod used was the same as in the example. The loading process was carried out as shown in FIG. The crystal rod is carried in (step 1 in Figure 8) and transported by the transport unit. 38 The evacuation (step 5 in FIG. 8) was the same as in the example, and the time required was also 30 seconds for each, similar to the example. In addition, the support unit on the countershaft side 34b The tail portion 12 of the crystal rod 7 is moved by a driving mechanism, and the tail portion 12 is supported by the supporting unit 34b The cone portion 11 of the crystal rod 7 is brought into contact with the supporting unit of the main shaft (steps 2 and 3 in FIG. 8), and the cone portion 11 of the crystal rod 7 is brought into contact with the supporting unit of the main shaft. 34a of main shaft The crystal rod 7 was then brought into contact with the holding portion of the support unit 10, and the clamping of the crystal rod 7 was completed (steps 3 and 4 in FIG. 8). 34b The movement speed was a low speed of 100 mm / min in all cases, and the times required for steps 2 to 3 and steps 3 to 4 were 630 seconds and 663 seconds, respectively.

[0049] Table 1 shows the time required for each step in the loading process in the examples and comparative examples. The total time required for the loading process was 1,353 seconds in the comparative example, while it was 219 seconds in the example. In this way, the example required about 16% of the time required for the comparative example, and a significant time reduction of about 84% was confirmed. In an automatic cylindrical grinding machine, the time required for cylindrical grinding accounts for the majority of the time, and considering that it takes about 2 to 4 hours per crystal rod (depending on the length of the crystal rod, etc.), the present invention makes it possible to reduce the processing time for the entire cylindrical grinding process, including the loading process, by about 11 to 5%, thereby improving productivity. Furthermore, even when cylindrical grinding was performed while supporting the crystal rod under the conditions of the example, no misalignment occurred, just as when cylindrical grinding was performed while supporting the crystal rod under the conditions of the comparative example, and the ground surface had a surface condition similar to that of the comparative example.

[0050] [Table 1]

[0051] The present specification includes the following aspects. [1]: A method for manufacturing a crystal rod, comprising: a conveying unit for holding and conveying a crystal rod; a pair of support units for axially sandwiching the crystal rod held by the conveying unit so that the crystal rod can be rotated around the axis; and a grinding unit for traverse-grinding the outer periphery of the crystal rod while moving along the axial direction of the crystal rod supported by the pair of support units; the pair of support units includes a first support unit having a main shaft and a second support unit having a sub-shaft, and a drive mechanism capable of moving the second support unit toward the first support unit; In a cylindrical grinding machine, when the second support unit is moved toward the first support unit by the driving mechanism, one end of the crystal rod held by the transport unit approaches the secondary shaft of the second support unit and is supported by contacting it, and then the other end of the crystal rod approaches the primary shaft of the first support unit and is supported by contacting it, so that the crystal rod is sandwiched and supported between the primary shaft and the secondary shaft, The crystal rod further includes a first detection means for detecting the proximity of the other end of the crystal rod to the main axis in a non-contact manner, and a second detection means for detecting the proximity of the one end of the crystal rod to the sub-axis in a non-contact manner, The drive mechanism includes: The moving speed of the second support unit is changeable and adjustable, In the contact support between one end of the crystal rod and the secondary shaft, the moving speed B of the second support unit from the detection of the proximity of the one end of the crystal rod and the secondary shaft by the second detection means to the contact support is adjusted to be slower than the moving speed A of the second support unit until the detection of the proximity; A cylindrical grinding machine in which, during contact support between the other end of the crystal rod and the main spindle, the movement speed D of the second support unit from the detection of the proximity of the other end of the crystal rod and the main spindle by the first detection means to the contact support is adjusted to be slower than the movement speed C of the second support unit until the detection of the proximity. [2]: the main shaft and the sub-shaft each have a holding portion with which the crystal rod is supported in contact; the first detecting means and the second detecting means are each a sensor, the sensor is disposed in a direction perpendicular to the main shaft and the sub-shaft inside each of the holding portions of the main shaft and the sub-shaft, and a detection line is provided by the sensor; the first detection means detects the proximity of the other end of the crystal rod to the main axis when the other end of the crystal rod passes through the detection line; The cylindrical grinding machine according to [1] above, wherein the second detection means detects the proximity of one end of the crystal rod to the counter shaft when the one end of the crystal rod passes through the detection line. [3]: the main shaft and the sub-shaft each have a holding portion with which the crystal rod is supported in contact; the first detecting means and the second detecting means are each a sensor, the sensors are connected to the first support unit and the second support unit via brackets, and are disposed outside the respective holding portions of the main shaft and the sub-shaft, with detection lines for the sensors being provided at the outsides; the first detection means detects the proximity of the other end of the crystal rod to the main axis when the other end of the crystal rod passes through the detection line; The cylindrical grinding machine according to [1] above, wherein the second detection means detects the proximity of one end of the crystal rod to the counter shaft when the one end of the crystal rod passes through the detection line. [4]: The cylindrical grinding machine according to [2] or [3], wherein the sensor is a photoelectric sensor having a light emitter and a light receiver, or an image sensor. [5]: the moving speed A and the moving speed C of the second support unit are 3,000 to 4,000 mm / min; The cylindrical grinding machine according to any one of the above [1] to [4], wherein the moving speed B and the moving speed D of the second support unit are 50 to 200 mm / min.

[0052] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0053] 1... cylindrical grinding machine of the present invention, 2a, 2b... holding unit, 3a...Main shaft, 3b...Sub-shaft, 4...pair of support units, 4a...first support unit, 4b...second support unit, 5...grinding unit, 6...grinding stone, 7...crystal rod, 8...transport unit, 9...rotation center of the main axis and secondary axis, 10...crystal axis center, 11... cone portion (other end), 12... tail portion (one end), 13... drive mechanism, 14...detection means, 14a...first detection means, 14b...second detection means, 21...sensor installation hole, 22...cone portion detection sensor, 23...detection line, 24...compressed air, 25...end detection sensor, 26...detection line, 27b...base portion of second support unit; 28...bracket; 29...Distance between the optical axis of the photoelectric sensor and the end face of the holding part, 30...Distance between the emitter and receiver.

Claims

1. The apparatus comprises a conveying unit that holds and conveys a crystal rod, a pair of support units that sandwich the crystal rod held by the conveying unit in the axial direction and allow it to rotate around the axis, and a grinding unit that moves along the axial direction of the crystal rod supported by the pair of support units and traverse-grinds the outer periphery of the crystal rod, the pair of support units includes a first support unit having a main shaft and a second support unit having a sub-shaft, and a drive mechanism capable of moving the second support unit toward the first support unit; a driving mechanism for moving the second support unit toward the first support unit, so that one end of the crystal rod held by the transport unit approaches the secondary shaft of the second support unit and is supported by the secondary shaft; and then the second support unit, which supports one end of the crystal rod with the secondary shaft, further moves toward the first support unit by the driving mechanism, so that the other end of the crystal rod approaches the primary shaft of the first support unit and is supported by the secondary shaft; and the crystal rod is sandwiched and supported between the primary shaft and the secondary shaft, and then the transport unit releases the crystal rod and retreats; The crystal rod further includes a first detection means for detecting the proximity of the other end of the crystal rod to the main axis in a non-contact manner, and a second detection means for detecting the proximity of the one end of the crystal rod to the sub-axis in a non-contact manner, The drive mechanism includes: The moving speed of the second support unit is changeable and adjustable, In the contact support between one end of the crystal rod and the secondary shaft, a moving speed B of the second support unit from the detection of the proximity of the one end of the crystal rod and the secondary shaft by the second detection means to the contact support is adjusted to be slower than a moving speed A of the second support unit until the detection of the proximity; A cylindrical grinding machine characterized in that, in contact support between the other end of the crystal rod and the main spindle, the movement speed D of the second support unit from the detection of the proximity of the other end of the crystal rod and the main spindle by the first detection means to the contact support is adjusted to be slower than the movement speed C of the second support unit until the detection of the proximity.

2. the main shaft and the sub-shaft each have a holding portion with which the crystal bar is supported in contact with the holding portion; the first detecting means and the second detecting means are each a sensor; the sensor is disposed in a direction perpendicular to the main shaft and the sub-shaft inside each of the holding portions of the main shaft and the sub-shaft, and a detection line is provided by the sensor; the first detection means detects the proximity of the other end of the crystal rod to the main axis when the other end of the crystal rod passes through the detection line; 2. The cylindrical grinding machine according to claim 1, wherein the second detection means detects the proximity of one end of the crystal rod to the countershaft by the one end of the crystal rod passing through the detection line.

3. the main shaft and the sub-shaft each have a holding portion with which the crystal bar is supported in contact with the holding portion; the first detecting means and the second detecting means are each a sensor; the sensors are connected to the first support unit and the second support unit via brackets, and are disposed outside the respective holding portions of the main shaft and the sub-shaft, and detection lines for the sensors are provided at the outsides; the first detection means detects the proximity of the other end of the crystal rod to the main axis when the other end of the crystal rod passes through the detection line; 2. The cylindrical grinding machine according to claim 1, wherein the second detection means detects the proximity of one end of the crystal rod to the countershaft by the one end of the crystal rod passing through the detection line.

4. 3. The cylindrical grinding machine according to claim 2, wherein the sensor is a photoelectric sensor having a light emitter and a light receiver, or an image sensor.

5. 4. The cylindrical grinding machine according to claim 3, wherein the sensor is a photoelectric sensor having a light emitter and a light receiver, or an image sensor.

6. the moving speed A and the moving speed C of the second support unit are 3,000 to 4,000 mm / min; 6. The cylindrical grinding machine according to claim 1, wherein the moving speeds B and D of the second support unit are 50 to 200 mm / min.

Images