JP2018024051A - Dressing method and grinding method for workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and easy method for preventing occurrence of variation in dressing to a grind stone caused by the grinding margin of a workpiece exceeding an assumption amount, abrasion of the grind stone and the like.SOLUTION: A dressing method includes: calculating the diameter of a grind stone on the bases of the positions of a grind stone shaft 3 and a dressing unit 11; obtaining a contact location B1 of a grind stone 2 and a workpiece 6 by the load power of a grind stone shaft rotation mechanism 4; and obtaining the positional deviation of the grind stone shaft 3 by comparing the position of the shaft 3 at the time point of grinding completion obtained based on the actual dimension of the workpiece 6 measured by an in-line sizing device 10 with the position of the shaft 3 at the time point of planned grinding completion calculated based on the grind stone diameter. In the case where the number of times of contact of the grind stone 2 with the workpiece 6 faster than setting pluralizes at a dressing interval, dressing of the grind stone 2 is performed.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a grinding wheel dressing method and a workpiece grinding method used in a grinding machine.

  When grinding a large amount of workpieces in grinding metal or the like, the grinding accuracy decreases due to clogging or wear of the grindstone. Therefore, conventionally, when the preset number of workpieces have been ground, the dressing device is fed toward the grindstone, the dress diamond held by the dressing device is cut into the grinding surface of the grindstone, and dressing is performed. In general, a process for recovering the sharpness of the food has been performed.

  By the way, in an internal grinder or the like, a disc-shaped or cylindrical grindstone rotates around a grindstone axis to perform grinding. As the accumulated grinding amount of the workpiece increases, the outer peripheral surface, which is a grinding surface, retreats inward in the radial direction due to wear, and the grindstone diameter decreases. In order to secure a sufficient dressing amount when dressing the grindstone, it is necessary to adjust the cutting amount of the dress diamond in consideration of a decrease in the grindstone diameter.

  As an example of a dressing method in consideration of the reduction of the grindstone diameter, Patent Document 1 describes the actual radius of the grindstone based on the workpiece processing surface position after grinding and the feed amount of the grindstone at that time. A technique for dressing a grindstone every time the amount exceeds a predetermined value is disclosed.

  Patent Document 2 obtains the maximum load Wmax of the grinding wheel shaft rotation motor, the time T0 until reaching the maximum load, and the workpiece diameter D0 at the time of trial grinding before workpiece grinding, and actual grinding. A technique is disclosed in which the dress start time is determined by comparing the maximum load at the time, the processing time, the workpiece diameter and the values at the time of trial grinding.

Japanese Patent Laid-Open No. 3-60971 JP-A-3-228574

  When the grinding allowance greatly varies due to the dimensional variation of the workpiece before grinding, there is a problem that the grinding wheel wear exceeds the assumption and the grinding accuracy cannot be maintained even if dressing is performed at a predetermined dressing interval.

  Further, when the wear amount of the grindstone is large, there is a possibility that the grindstone and the dress diamond do not contact during dressing.

  In order to optimally adjust the dressing amount of the grindstone, it is necessary to consider not only the grindstone diameter but also the wear of the dress diamond. As the wear of the dress diamond progresses, the actual cut amount of the dress diamond with respect to the grinding surface of the grindstone becomes smaller than the set value even if the dressing device is sent toward the grindstone by the set amount. Also in this case, there is a possibility that the grinding stone dress is insufficient and the grinding accuracy cannot be maintained.

  The present invention has been made in view of such points, and an object thereof is to stabilize the grindstone dress by a simple method and to maintain the grinding accuracy of the workpiece.

  In order to solve the above problems, the dressing method of the present invention performs contact detection between a workpiece and a grindstone, obtains a difference between the contact position and a position corresponding to a planned grinding allowance, When grinding a workpiece whose difference from the position corresponding to is over the set range, the grinding wheel is dressed.

  Specifically, the dressing method of the present invention is a dressing method for dressing a grindstone using a dressing device in a grinding machine having a grindstone that is held by a grindstone shaft and grinds a workpiece, the position of the grindstone shaft and the dressing device. Calculating the grinding wheel diameter based on the position of the grinding wheel, calculating the grinding wheel shaft position when the grinding is scheduled to be completed based on the grinding wheel diameter and the finishing target dimension of the workpiece, feeding the grinding stone toward the workpiece, Detecting the contact between the workpiece and the workpiece, storing the contact position, and the grinding wheel shaft at the completion of grinding obtained based on the workpiece dimensions at the completion of grinding measured by an in-line sizing device provided in the grinding machine. Stores the position, compares the wheel axis position when grinding is completed with the wheel axis position when grinding is scheduled, and calculates the wheel axis position deviation, and whether the contact position exceeds the set range And determining out if, when the contact position is beyond the set range is characterized by comprising the steps of: performing a dress using dresser.

  According to this method, it is determined whether or not the contact position between the workpiece and the grindstone exceeds the set range. If the position is outside the set range, the grinding amount with the grindstone becomes larger than expected by dressing the grindstone. In this case, an appropriate amount of dressing can be reliably performed on the grindstone, and the grinding accuracy is stabilized.

  If the contact position exceeds the set range, the method further includes a step of determining whether the number of times the contact position exceeds the set range is N times (N ≧ 2) in one dress interval, and the contact position is within the set range. It is preferable to perform dressing if the number of times exceeds N times or more.

  According to this method, the timing of whether or not to perform dressing can be more appropriately determined by determining the grinding amount of the workpiece in one dressing interval. Thereby, grinding accuracy can be maintained and productivity can be improved.

  When the contact position exceeds the set range, it is determined whether or not the position deviation is within a predetermined range. When the position deviation exceeds the predetermined range, a preset is performed using a dressing device. It is preferable to perform correction according to the position deviation with respect to the dress thus formed.

  According to this method, based on the contact position between the workpiece and the grindstone, it is determined whether the grinding allowance exceeds the set range, and further, the position of the grindstone shaft when the grinding is scheduled to be completed and the position of the grindstone shaft when the grinding is completed Based on the difference, it is possible to decide whether or not to perform dress correction of the grindstone. As a result, it is possible to grasp how much the grinding amount of the workpiece is larger than the set range, and when the allowable value is exceeded, the fluctuation amount of the grinding wheel diameter is obtained, and an appropriate amount of dressing is applied to the grinding wheel based on that value. It can be performed reliably and the grinding accuracy is stabilized during grinding of the workpiece.

  In the dressing, it is preferable to feed the grindstone shaft to the dressing device in a plurality of times.

  According to this method, the feeding amount of one dressing device can be reduced, and even if there is an error in grasping the position of the grindstone and the dressing device, the grindstone and the dress diamond suddenly collide, either or both Both can be prevented from being damaged.

  Grinding wheel controller, grinding wheel diameter, workpiece finish dimensions, contact position between grinding wheel and workpiece, grinding wheel shaft position when grinding is scheduled, grinding wheel shaft position when grinding is completed It is preferable to store them in the respective storage units and use them for calculating the position deviation.

  According to this method, various data can be calculated reliably and quickly.

  The workpiece grinding method of the present invention includes a step of dressing a grindstone by any one of the above dressing methods and a step of grinding the workpiece using the dressed grindstone.

  According to this method, based on the contact position between the workpiece and the grindstone, it is determined whether the grinding allowance exceeds the set range, and further, the position of the grindstone shaft when the grinding is scheduled to complete and the position of the grindstone shaft when the grinding is completed are determined. Based on the difference, an appropriate amount of dress correction can be determined. Thus, an appropriate amount of dressing can be reliably performed on the grindstone, and the workpiece can be ground with stable grinding accuracy.

  According to the above configuration, even when a large number of workpieces having a grinding allowance larger than the schedule are ground, it is possible to appropriately correct the influence of grinding wheel wear during dressing of the grinding wheel and maintain grinding accuracy.

It is the schematic of the internal grinding machine in Embodiment 1 of this invention. It is a schematic diagram which shows the positional relationship of the workpiece | work and grinding stone before grinding. It is a schematic diagram which shows the positional relationship of the workpiece | work and grindstone after grinding. It is another example of the schematic diagram which shows the positional relationship of the workpiece | work and grindstone after grinding. It is a schematic diagram which shows the positional relationship of the grindstone and dressing apparatus in the dress of a grindstone. It is a grinding flowchart of a work in Embodiment 1 of the present invention. It is a grinding flowchart of a work in Embodiment 2 of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description of the preferred embodiment is merely illustrative in nature.

  In this specification, a period between a dress and the next dress is referred to as a dress interval.

Embodiment 1 of the Invention
FIG. 1 is a schematic view of an internal grinding machine in the present embodiment.

  The internal grinding machine 1 moves the grindstone shaft 3 in the XY directions shown in FIG. 1, the grindstone shaft 3 that fixes and holds the grindstone 2, the grindstone shaft rotation mechanism 4 that rotates the grindstone shaft 3 around its central axis. And a grindstone shaft feed mechanism 5 to be operated.

  Further, the internal grinding machine 1 includes a chuck device 7 that fixes and holds the workpiece 6, a workpiece spindle 8 that rotates the workpiece 6, and a workpiece spindle rotating mechanism 9 that rotates the workpiece spindle 8 around its central axis. ing. The in-line sizing device 10 is set so that the inner diameter of the workpiece 6 before and during grinding is measured in-line, and the output becomes zero when the inner diameter of the workpiece 6 reaches the target dimension. Details of the inline sizing device 10 are not shown.

  The dressing device 11 has a dress diamond 12 made of single stone diamond or the like at the tip. When performing dressing, the grindstone shaft 3 moves in the XY directions and comes into contact with the outer peripheral surface of the grindstone 2 and the dress diamond 12. A feed mechanism (not shown) for moving the dress diamond 12 is provided.

  The grindstone shaft 3, the grindstone shaft rotation mechanism 4, the grindstone shaft feed mechanism 5, the chuck device 7, the work spindle 8, the work spindle rotation mechanism 9, the in-line sizing device 10, and the dressing device 11 Both are arranged on a bed (not shown).

  The grinder control device 13 controls the operation of the grinding wheel shaft rotating mechanism 4, the grinding wheel shaft feeding mechanism 5, the work spindle rotating mechanism 9, and the feeding mechanism of the dressing device 11, and the grinding wheel 2 and the grinding wheel shaft 3. In order to calculate the respective positions of the workpiece 6, the workpiece spindle 8, and the dressing device 11, an input unit 14, an arithmetic processing unit 15, a storage unit 16, a drive control unit 17, an operation panel 18, A display unit (informing unit) 19 is provided.

  Signals relating to these positions and operation states are input to the input unit 14 from the grindstone shaft rotation mechanism 4, the grindstone shaft feed mechanism 5, the work spindle rotation mechanism 9, and the feed mechanism of the dressing device 11. An output signal from the inline sizing device 10 is also input. Moreover, it has the electric power monitoring part (not shown) which detects and monitors the electric power of the grindstone shaft rotating mechanism 4.

  The arithmetic processing unit 15 receives the signal from the input unit 14 or the signal held in the storage unit 16 to calculate the position of the grindstone shaft 3, the dressing device 11, and the like, and outputs the signal from the inline sizing device 10. Based on this, an operation control signal for the grindstone shaft 3 and the dressing device 11 is output.

  The storage unit 16 stores a signal from the input unit 14 or an output signal from the arithmetic processing unit 15, and outputs data necessary for the arithmetic processing to the arithmetic processing unit 15 in response to a request from the arithmetic processing unit 15.

  The drive control unit 17 receives a signal from the arithmetic processing unit 15 and sends a control signal to a drive circuit (not shown), the grindstone shaft rotation mechanism 4, the grindstone shaft feed mechanism 5, the work spindle rotation mechanism 9, and the dressing device. The operation with 11 feeding mechanisms is controlled.

  The operation unit 18 is used, for example, to directly input the position coordinates of the grindstone shaft 3, the workpiece 6, the dressing device 11, the target dimension of the workpiece, and the like. The grinding program is called and entered through the operation unit 18.

  The display unit 19 displays input data and the called program, the operating state of each mechanism during grinding, the position of the grindstone shaft 3, the dimensions of the workpiece 6 during grinding, and the like on the screen. It also functions as a notification unit that notifies the operator of the status of the device through a display screen, alarm lamp, audio output, or buzzer sound when workpiece lot processing ends, device abnormality, program error, etc. To do.

  When the data input / output of the grinding machine is managed on the system, a signal notifying the system of the end of processing or abnormality is transmitted.

  Next, in the present embodiment, changes in the positional relationship between the grindstone, the grindstone shaft, and the workpiece before and after grinding the workpiece will be described.

  FIG. 2 is a schematic diagram showing the positional relationship between the grindstone before grinding, the grindstone shaft, and the workpiece in the present embodiment. 2 is a view of the grindstone 2 and the workpiece 6 as seen from the Y-axis direction in FIG.

  The workpiece 6 and the grindstone shaft 3 are aligned so that their central axes coincide.

Assuming that the radius of the grindstone 2 is D0, a radius R0 calculated from the inner diameter of the workpiece 6 before grinding measured by the inline sizing device 10, and a radius R1 calculated from the planned inner diameter of the workpiece 6 to be ground, the grinding wheel shaft 3 at the time of grinding completion The feed amount S in the workpiece radial direction is S = R1-D0 (Formula 1)
It is represented by

  FIG. 3 is a schematic diagram showing the positional relationship between the grindstone after grinding, the grindstone shaft, and the workpiece in the present embodiment, and FIG. 4 is another example of the schematic diagram shown in FIG. 3. FIG. 5 is a schematic diagram showing the positional relationship between the grindstone before and after dressing, the grindstone shaft, and the dressing device in this embodiment, and FIG. 5A is a schematic diagram shown in the lower side of FIG. b) corresponds to the schematic diagram shown on the lower side of FIG. 3 and 4 are views of the grindstone 2 and the workpiece 6 viewed from the Y-axis direction in FIG.

  The upper diagram in FIG. 3 shows the positional relationship among the grindstone 2, the grindstone shaft 3, and the workpiece 6 when the grindstone diameter before grinding and the actual grindstone diameter after grinding are the same.

  In this case, the feed amount S in the workpiece radial direction of the grindstone shaft 3 coincides with the above (Formula 1).

3 shows the positional relationship among the grindstone 2, the grindstone shaft 3, and the workpiece 6 when the grindstone 2 is worn and the grindstone diameter is reduced by ΔD from the grindstone diameter D0 before grinding. Show. In this case, the feed amount S in the workpiece radial direction of the grindstone shaft 3 is S = R1−D0 + ΔD (Formula 2)
It is represented by Note that the direction toward the outer periphery in the radial direction of the workpiece is positive.

  In this case, if the dress start time has arrived, as shown in FIG. 5A, the actual grindstone diameter decreases by ΔD from the grindstone diameter stored in the storage unit 15 of the grinding machine control device 12. Yes. Therefore, even if the grinding wheel shaft 3 is fed toward the dress diamond 12 by the optimum cutting amount D1 for dressing the grinding wheel, the actual cutting amount is (D1-ΔD), and the dressing is not sufficiently performed. There is a fear. In particular, when abnormal wear or the like of the grindstone occurs during grinding, the grindstone may not be dressed in relation to the dress interval.

  Usually, the dress start time is preset based on the grinding amount of the workpiece. The grinding amount of the workpiece is derived from the processing amount and the grinding allowance by estimating the grinding allowance per workpiece from the dimensions of the workpiece before grinding and the finish target dimension.

  However, if the workpiece needs to be ground more than the planned grinding allowance due to dimensional variation of the workpiece before grinding, there are many such situations, especially in workpiece grinding between the dress start time and the next dress start time. When this occurs, the wear amount of the grindstone greatly exceeds the assumption. In such a case, there is a possibility that the grindstone may not be dressed in relation to the wear amount of the grindstone.

  Therefore, it is possible to perform an appropriate dressing on the grinding surface of the grindstone by calculating the deviation of the grindstone of the workpiece and the diameter of the grindstone before and after grinding the workpiece, and changing the dressing interval and correcting the dressing amount under predetermined conditions. The inventor has found a method.

  Hereinafter, the dressing method and the workpiece grinding method of the present invention will be described in detail with reference to flowcharts.

  FIG. 6 is a workpiece grinding flowchart in the embodiment of the present invention.

  First, when the first machine is started up, the grindstone 2 and the workpiece 6 are manually positioned. Similarly, manual positioning is performed when trial grinding is performed before the start of lot processing. The grindstone diameter is measured with a gauge or the like. When exchanging the grindstone, it is calculated based on the position coordinates as follows.

  The grinding wheel diameter and the finish target dimension of the workpiece 6 are respectively input to the input unit 14 via the operation unit 18 and stored in the storage unit 16. Similarly, the position of the grindstone shaft 3 determined by the positioning, the position of the workpiece 6, and the position of the dress diamond 12 are also input to the input unit 14 via the operation unit 18 and stored in the storage unit 16. At this time, the position of the grindstone shaft 3, the position of the workpiece 6, and the position of the dress diamond 12 are determined based on the position coordinates of the dressing device 11. Various positions appearing thereafter are also calculated based on the position coordinates of the dressing device 11. The position coordinates at the time of initial positioning can also be used as a reference.

  After the first dressing, the grindstone diameter is calculated based on the position of the grindstone shaft 3 and the position of the dressing device 11 (step S1).

  Next, based on the finish target inner diameter of the workpiece 6 inputted in advance and the grindstone diameter calculated in step S1, the position A0 of the grindstone shaft 3 at the time of completion of grinding is calculated, and the position A0 of the grindstone shaft 3 is stored. It memorize | stores in the part 16 (step S2).

  The inner diameter of the workpiece 6 before grinding is measured by the inline sizing device 10 (step S3). Based on the measurement result, it is determined whether the machining allowance of the workpiece 6 is normal (step S4).

  If the machining allowance is too small, grinding may not be performed sufficiently and the workpiece may become a defective product.

  If the machining allowance is excessive, the grindstone may come into contact with the workpiece when the grindstone is fast-forwarded, and the grindstone may break or the grinding machine may break down.

  In step S4, the workpiece whose machining allowance is determined to be abnormal is discharged as a defective product, or the display unit (notification unit) 19 notifies a nearby worker to see if an appropriate workpiece is set. Ask for confirmation.

  Next, the grindstone 2 is fast-forwarded toward the inner surface of the workpiece 6. After the rapid feed, the feed speed of the grindstone 2 is decreased and the grindstone 2 is continuously fed toward the inner surface of the workpiece 6. In the present embodiment, the period from the end of rapid feed to the contact between the grindstone and the workpiece, which will be described later, is called “quasi-rapid feed”. When the grindstone 2 and the workpiece 6 come into contact with each other, the load power of the grindstone shaft rotating mechanism 4 rapidly increases. This change is monitored by a power monitoring unit (not shown) in the input unit 14, and when the load power increase value is a predetermined value or more, it is determined that the grindstone 2 and the workpiece 6 are in contact with each other. The contact position B1 on the outer peripheral surface of the grindstone 2 is stored in the storage unit 16 (step S5).

  After the contact between the grindstone 2 and the workpiece 6, the workpiece is ground by changing the feed speed of the grindstone 2. Grinding is performed in the order of grinding (hereinafter referred to as “black skin grinding”) for removing the surface modified portion of the workpiece, rough grinding, finish grinding, and spark out. This switching is a dimension measured by the in-line sizing apparatus 10. Determine based on. The feed speed of the grindstone 2 is in the order of (rapid feed)> (semi-rapid feed)> (black skin grinding)> (rough grinding)> (finish grinding). In the spark-out, the grindstone 2 is not cut into the workpiece 6 (step S6).

  The position B1 at which it is determined that the grindstone 2 and the workpiece 6 are in contact is obtained by detecting the position of the grindstone shaft 3 with reference to the position coordinates of the dressing device 11.

  When the inline sizing device 10 outputs a zero point, the grinding of the workpiece is completed. The position A1 of the grindstone shaft 3 at this time is stored in the storage unit 16 (step S7).

  When the workpiece grinding is completed, it is determined whether the lot processing has been completed based on the number of grinding processes counted so far (step S8). If the lot processing has been completed, the process is ended. If not, it is determined whether or not the dress start time has been reached (step S9).

  If the dress start time has been reached, the grindstone shaft 3 is fed to the dress diamond 12 by a predetermined feed amount, and the dress diamond 12 is cut into the outer peripheral surface of the grindstone 2 to perform dressing (step S10).

  In the present embodiment, the feed amount of the grindstone shaft 3 is 10 μm.

  In addition, this value is an example and it cannot be overemphasized that it changes suitably according to a grindstone diameter, the grinding number of a workpiece | work, machining allowances, etc.

  The dress start timing depends on the material of the grindstone, the grindstone diameter, the number of workpieces to be processed, the cumulative amount of workpiece grinding, and the like, and is determined in consideration of these factors.

  If the dress start time has not been reached, it is determined whether or not the contact position B1 exceeds the set range (step S11). In step S5, since the contact position B1 is stored in the storage unit 16, it is determined using this value whether the process proceeds to step S12 or step S3.

  In the present embodiment, the stored contact position B1 is within 30 μm in the direction in which the stored contact position B1 advances in the radial direction and the center of the workpiece 6 on the basis of the planned contact position of the grindstone outer peripheral surface calculated from the finish target dimension and the planned grinding allowance. Is within the set range, and if it exceeds 30 μm, it is determined that the set range has been exceeded. That is, it corresponds to the case where the grindstone 2 and the workpiece 6 come in contact with each other earlier than planned.

  The set range is determined based on the grinding allowance derived from the dimensional specifications of the workpiece.

  However, in this embodiment, setting the setting range to 30 μm is merely an example, and this range is appropriately changed depending on the number of workpieces to be ground, the grinding allowance, and the like.

  If the contact position B1 is within 30 μm, the ground workpiece is removed, the next workpiece is set, and the process proceeds to dimension measurement before grinding (step S3).

  If the contact position B1 exceeds 30 μm, the position deviation R (hereinafter referred to as deviation R) is calculated based on the position A0 of the grinding wheel shaft 3 when grinding is scheduled and the position A1 of the grinding wheel shaft 3 when grinding is completed. (Step S12).

In particular,
R = A1-A0 (Formula 3)
It is.

  That is, when the position A1 of the grindstone shaft 3 at the time of completion of grinding is located on the outer peripheral side of the work 6 relative to the position A0 of the grindstone shaft 3 at the time of completion of grinding as viewed from the center of the work 6, the deviation R becomes positive. .

  In the present embodiment, the number of processing is counted when grinding is completed.

  Next, it is determined whether or not the calculated deviation R is within a predetermined range (step S13).

  If the deviation R is within a predetermined range, the ground workpiece is removed, the next workpiece is set, and the process proceeds to dimension measurement before grinding (step S3).

  If the deviation R exceeds the predetermined range, the number of times that the contact position B1 exceeds the set range is detected in the workpiece processed from the most recent dress to the present (step S14).

  If the number of times is less than 2, for example, once, the ground workpiece is removed, the next workpiece is set, and the process proceeds to dimension measurement before grinding (step S3).

  The above number of times is an example, and may be changed as appropriate depending on the number of workpieces to be ground and the grinding allowance.

  If the number of times that the contact position B1 exceeds the set range is two times or more, the feed amount of the grinding wheel shaft 3 by the correction dress, that is, the amount corresponding to the deviation R calculated in step S12 with respect to the predetermined feed amount. The dress diamond 12 is cut into the outer peripheral surface of the grindstone 2 to perform dressing (step S15).

  The amount corresponding to the deviation R may not be the same as the absolute value of the deviation R, and may be a smaller value.

  The main cause of position deviation is wear of the grinding wheel and dress diamond, but there are various other factors such as changes in the sharpness of the grinding wheel, displacement (elongation) of the grinding wheel shaft and workpiece spindle due to heat, and poor teaching on the grinding machine. There is something.

  If the deviation R is directly used as the correction amount at the time of the correction dress, there is a possibility that the grindstone and the workpiece collide with each other.

  Therefore, when a correction dress having a value smaller than the absolute value of the deviation R is performed, the influence of the deviation caused by other than the wear of the grindstone and the dress diamond can be reduced.

  When step S10 or step S15 is completed, the process returns to step S1, and the grindstone diameter is recalculated based on the position of the grindstone shaft 3 and the position of the dressing device 11. The recalculated grindstone diameter is stored in the storage unit 16. Further, the position of the grindstone shaft 3 is corrected using the recalculated grindstone diameter.

  If the calculated grindstone diameter is approaching the grindstone replacement limit, the operator or system in the vicinity of the grinding machine 1 is informed via the display unit (notification unit) 19.

  According to the present embodiment, the contact position between the grindstone and the workpiece is detected, the deviation from the planned grinding allowance is estimated to estimate the degree of wear of the grindstone, and the deviation is calculated based on the position of the grindstone axis before and after grinding. By finding and correcting the amount corresponding to the deviation, it is possible to perform an appropriate amount of dressing on the grinding surface of the grindstone regardless of fluctuations in the grindstone diameter caused by wear of the grindstone during workpiece grinding. It becomes. As a result, the grinding accuracy can be maintained, the wheel life can be appropriately managed, and the productivity can be improved and the production cost can be reduced.

  Further, since the contact position between the grindstone and the work is obtained using the load power of the grindstone shaft rotating mechanism, the contact detection mechanism between the grindstone and the work becomes unnecessary. Furthermore, since the grindstone diameter is calculated based on the position coordinates of the grindstone axis and the dressing device, a contact detection mechanism between the grindstone and the dressing diamond is not required, and the device can be downsized and the equipment cost can be reduced. In addition, since the grindstone diameter is recalculated for each dress, it is possible to correctly notify the time for exchanging the grindstone and to prevent the grindstone and the workpiece from colliding during rapid feed during grinding immediately after dressing.

(Embodiment 2)
FIG. 7 is a workpiece grinding flowchart according to the second embodiment of the present invention.

  The difference between the first embodiment and this embodiment is that when the contact position B1 exceeds the set range for a predetermined number of times (for example, two times or more) (step S12), the process immediately proceeds to step S10 and is set in advance. The point is to do dress.

  According to this embodiment, when the grinding amount of the workpiece exceeds the assumption, an appropriate amount of dressing can be immediately performed on the grindstone, and the grinding accuracy is stabilized.

  In addition, since the dress amount is not corrected for the fluctuation of the grindstone diameter, it is assumed that the frequency at which the contact position B1 exceeds the set range increases and the dress interval is shortened. However, the correction dress amount based on the deviation R is calculated. Is not required, and the process is simplified.

  In the grinding flow shown in FIG. 7, between step S11 and step S12, step S12 and step S13 shown in FIG. 6, that is, deviation R is calculated, and it is determined whether or not this is within a predetermined range. When the deviation R exceeds a predetermined range, a preset dress may be added.

  Although the process is slightly complicated, since dressing is not performed when the deviation R is within a predetermined range, the number of dresses is reduced and the life of the grindstone is reduced as compared with a case where it is not determined whether the deviation R is within the predetermined range. Can be extended.

(Embodiment 3 of the invention)
As described above, the actual radius of the grindstone, the actual position of the dress diamond, etc. before dressing the grindstone are easily affected by the grinding process and the dressing process. In addition, if the feed amount of the grindstone shaft necessary for proper dressing is large, the amount of cutting into the grindstone at a time becomes large, and either or both of them are damaged due to excessive contact between the grindstone and the dress diamond. There is a risk.

  Therefore, in the present embodiment, the above-mentioned problem is solved by performing the necessary grinding wheel shaft feeding in a plurality of times.

  The present embodiment is applicable to both the dress (step S10) and the correction dress (step S15) in the first and second embodiments.

  First, application to the dress shown in step S10 of FIGS. 6 and 7 will be described.

  For example, it is assumed that the cutting amount D1 of the dress diamond 12 required for dressing an appropriate grindstone is 10 μm. At this time, at the time of dressing in step S12, the grindstone shaft 3 is not fed 10 μm at a time, but is fed in 5 times by 2 μm.

  In this case, it is possible to perform dressing of a grindstone sufficient to maintain grinding accuracy. Moreover, the excessive contact with the dress grindstone 2 and the dress diamond 12 is suppressed, and both damages are suppressed.

  Next, application to the correction dress shown in step S15 of FIG. 6 will be described.

  For example, it is assumed that the cutting amount D1 of the dress diamond 12 necessary for dressing an appropriate grindstone is 10 μm and the correction amount corresponding to the deviation R is 3 μm. At this time, when performing the correction dressing in step S15 in FIG. 6, the grindstone shaft 3 is not fed 13 μm at a time, but is fed 7 times by 2 μm.

  In this case, although the actual dressing amount with respect to the grindstone 2 is 14 μm, which is larger than the set value, it is possible to perform dressing of the grindstone sufficient to maintain the grinding accuracy. Moreover, the excessive contact with the dress grindstone 2 and the dress diamond 12 is suppressed, and both damages are suppressed.

  As described above, according to the present embodiment, the predetermined dressing amount is divided into a plurality of times in the dress of the grindstone, so that the preset dress (step S12) and correction shown in the first and second embodiments are corrected. Even when performing dressing (step S14), excessive contact between the grindstone and the dress diamond or excessive dressing on the grindstone can be suppressed. As a result, breakage of the grindstone or dress diamond can be prevented, and the life of the apparatus can be extended, the productivity can be improved, and the production cost can be reduced without reducing the frequency of replacement.

  In the first to third embodiments, the dress interval may be constant, but may be changed, for example, by shortening the dress interval in accordance with a decrease in the grindstone diameter.

  In the first to third embodiments, the number of times that the contact position B1 between the grindstone and the workpiece exceeds the set range is counted, and it is determined whether to perform dressing based on this number of times. For example, when the set value is exceeded N (N ≧ 2) times continuously or when the set value is exceeded even once, the process may proceed to a dressing step.

  Further, in the first to third embodiments, the position of the wheel shaft is corrected every time the dressing of the wheel is completed, but each time one workpiece is ground, the position of the wheel shaft at the time of completion of grinding and the wheel at the time of scheduled grinding completion. The position of the grinding wheel shaft may be corrected based on the deviation from the shaft position.

  In the first to third embodiments, the structure of the inline sizing device is not limited to the gauge, and other configurations such as an optical measurement system may be used.

  Moreover, although the example which dresses a grindstone using a dress diamond was shown, you may use a disk shaped or cylindrical rotary diamond instead of a dress diamond.

  In the case of using a rotary diamond, the difference between the outer peripheral surface of the rotary diamond corresponding to the tip of the dress diamond and the position reference of the dressing device, in this case, the radius of the rotary diamond, this value is input in advance and the storage unit 16 is stored. Further, the radius of the rotary diamond also varies due to wear or the like. For example, the radius is corrected again by measuring or recalculating the radius at the end of dressing, and the corrected radius value is stored in the storage unit 16. This can prevent erroneous recognition of the grindstone diameter.

  In the first to third embodiments, an example of an internal grinding machine has been described. However, the present invention is a grinding machine having a structure in which a grindstone rotates around a rotation axis and an outer peripheral side surface of the grindstone serves as a grinding surface, for example, a cylindrical shape. The present invention can also be applied to an outer peripheral grinding machine that grinds the outer peripheral surface of the workpiece.

  The present invention is suitable for grinding a grindstone and a workpiece in a grinder equipped with a dressing device.

DESCRIPTION OF SYMBOLS 1 Internal grinding machine 2 Grinding wheel 3 Grinding wheel axis 4 Grinding wheel axis rotation mechanism 5 Grinding wheel axis feed mechanism 6 Work piece 7 Chuck device 8 Work spindle 9 Work spindle rotation mechanism 10 Inline sizing device 11 Dressing device 12 Dress diagram 13 Grinding machine control device 14 Input Unit 15 Arithmetic processing unit 16 Storage unit 17 Drive control unit 18 Operation unit 19 Display unit (notification unit)

Claims (6)

A dressing method for dressing the grindstone using a dressing device in a grinder having a grindstone that is held by a grindstone shaft and grinds a workpiece,
Calculating a grindstone diameter based on the position of the grindstone shaft and the position of the dressing device;
Calculating a position of the grindstone shaft at the time of completion of grinding based on the grindstone diameter and a finishing target dimension of the workpiece;
Sending the grindstone toward the workpiece, detecting contact between the grindstone and the workpiece, and storing a contact position;
Storing the position of the grinding wheel shaft at the completion of grinding obtained based on the dimensions of the workpiece at the time of grinding completion measured by an inline sizing device provided in the grinding machine; Comparing the position of the wheel axis at the time of completion of grinding to calculate the position deviation of the wheel axis;
Determining whether the contact position exceeds a set range;
Dressing using the dressing device when the contact position exceeds the set range. If the contact position exceeds the set range, the method further comprises determining whether the number of times the contact position exceeds the set range is N times (N ≧ 2) in one dress interval;
The dressing method according to claim 1, wherein if the number of times the contact position exceeds the set range is N or more, dressing is performed using the dressing device.   When the contact position exceeds the set range, it is determined whether the position deviation is within a predetermined range, and when the position deviation exceeds the predetermined range, the dressing device is used. The dress method according to claim 1, further comprising a step of performing correction according to the position deviation with respect to a preset dress.   The dressing method according to any one of claims 1 to 3, wherein in the dressing, the grindstone shaft is fed into the dressing device in a plurality of times.   The grinding wheel diameter, the finishing target dimension of the workpiece, the contact position between the grinding wheel and the workpiece, the position of the grinding wheel shaft when the grinding is scheduled to be completed, and the position of the grinding wheel shaft when the grinding is completed. The dressing method according to any one of claims 1 to 4, wherein the dressing method is stored in a storage unit provided in a control device of a grinding machine and used for calculating the positional deviation. A workpiece grinding method,
Dressing the grindstone by the dressing method according to claim 1;
Grinding the workpiece using the dressed grindstone, and a workpiece grinding method.

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