Processing apparatus

Abstract

There is used a processing apparatus comprising: a main spindle capable of gripping a material to be processed, the main spindle being capable of conveying the material in a conveyance direction by gripping and moving the material; a supply unit that supplies the material to the main spindle by sending out the material in the conveyance direction; a control unit capable of controlling the conveyance of the material by the main spindle and controlling the conveyance of the material by the supply unit; and a detection unit that detects the distance along which the material has been conveyed by the supply unit and outputs the result of detection as a supply-side detected conveyance amount, the control unit synchronously controlling a first control for controlling the spindle so as to convey the material by a prescribed conveyance amount and a second control for controlling the supply unit so as to convey the material to be supplied to the spindle, and, on the basis of the prescribed conveyance amount and the supply-side detected conveyance amount, correcting a control value related to the conveyance amount when the supply unit conveys the material.

Description

Machining apparatus

[0001] The present invention relates to a machining apparatus.

[0002] Conventionally, as a machining apparatus that machines a material, an apparatus that performs machining while conveying the material is known. As an example, there is a machining apparatus that machines a material having an axial direction, such as a bar, by moving the material in the same conveyance direction as the axial direction. Such a machining apparatus generally includes a supply unit that supplies the material and a machining unit such as a spindle that machines the material, and has a configuration in which the material fed from the supply unit is gripped by the machining unit to perform machining.

[0003] For example, Patent Document 1 discloses a machining apparatus including a supply unit that supplies a bar material, and a bar material machining unit having a spindle and a gripping means. In this apparatus, a first detection means for detecting a conveyance amount of the bar material by the conveyance means and a second detection means for detecting a movement amount of the spindle are provided, and the presence or absence of conveyance abnormality is determined based on detection results of the two. Specifically, when a difference between the conveyance amount of the bar material by the conveyance means and the movement amount of the spindle exceeds a predetermined value, it is determined that a conveyance abnormality occurs.

[0004] Japanese Patent Application Laid-Open No. 10-71504

[0005] However, although the machining apparatus described in Patent Document 1 can detect conveyance abnormality, it does not disclose control for improving conveyance accuracy. For this reason, there has been a demand for a control mechanism that prevents conveyance abnormality in advance and realizes high-precision conveyance.

[0006] The present invention has been made in view of the above problems. An object of the present invention is to provide a technique for improving conveyance accuracy in a machining apparatus that grips and machines a material conveyed from a supply unit with a spindle.

[0007] The processing apparatus of the present invention employs the following configuration: a spindle capable of gripping a material to be processed, and capable of transporting the material in a transport direction by gripping and moving the material; a supply unit that supplies the material to the spindle by feeding it in the transport direction; a control unit capable of controlling the transport of the material by the spindle and the transport of the material by the supply unit; and a detection unit that detects the distance the material has been transported by the supply unit and outputs it as a supply-side detected transport amount. The processing apparatus is characterized in that the control unit synchronously controls the spindle to transport the material by a predetermined amount, and the supply unit to transport the material for supply to the spindle, and corrects the control value relating to the transport amount when the supply unit transports the material based on the predetermined transport amount and the supply-side detected transport amount.

[0008] According to the present invention, it is possible to provide a technology for improving the transport accuracy in a processing apparatus that grips and processes material transported from a supply unit with a main spindle.

[0009] Schematic diagram showing the overall appearance of the processing apparatus. Schematic diagram showing the internal configuration of the processing apparatus. Block diagram showing the functional configuration of the processing apparatus. Flowchart showing calibration and processing. Block diagram illustrating the control of Example 2.

[0010] The embodiments for carrying out this invention will be described in detail below with reference to the drawings, based on examples. Note that the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments should be appropriately modified depending on the configuration and various conditions of the device to which the invention is applied. In other words, the scope of this invention is not intended to be limited to the following embodiments.

[0011] The present invention is suitable for processing equipment that performs processing on a material (workpiece). The present invention can also be considered as a control device or information processing device installed in or capable of communicating with the processing equipment. The present invention can also be considered as a control method for processing equipment. The present invention can also be considered as a program that causes the control device or information processing device to execute a control method for processing equipment, or as a storage medium for storing the program. The storage medium may be a non-temporary storage medium readable by the information processing device.

[0012] [Example 1] (Device Configuration) The schematic configuration of the processing device 10 of this embodiment will be explained using Figures 1 and 2. Figure 1 is a schematic diagram showing the overall external configuration of the processing device 10. The processing device 10 comprises a processing unit 100 and a supply unit 200. The processing unit 100 is a device that performs various processing on the material W (workpiece), for example, a cutting machine that performs cutting. However, the processing unit 100 is not limited to this, and any device such as a lathe that performs turning, a milling machine that performs milling, or a grinding machine that performs grinding can be applied. In addition, multiple types of processing may be performed, such as cutting after grinding or polishing. In this embodiment, the material W is a bar with an axial direction.

[0013] The supply unit 200 is a bar material supply device that feeds and supplies material W to the processing unit 100. Preferably, the supply unit 200 includes a holding unit (stocker) for holding multiple bar materials and an exchange device for replacing bar materials.

[0014] The processing unit 100 has a housing 101 and an operation panel 102 provided on its upper part. The supply unit 200 also has a housing 201 and an operation panel 202 provided on its upper part. The processing unit 100 and the supply unit 200 have independent housing structures and are each installed on separate bases. However, the processing unit 100 and the supply unit 200 may be configured as an integrated unit.

[0015] Figure 2 is a schematic diagram showing the internal configuration of the processing apparatus 10. The processing unit 100 includes a spindle 110 capable of gripping the material W to be processed, a spindle chuck 111 provided on the spindle 110, and a cutting blade 112 for cutting the material W. The spindle 110 can be precisely moved in the direction of the spindle-side transport axis B by a servo motor driving a ball screw, and the cutting blade 112 can move in the direction C.

[0016] The supply unit 200 includes a pusher 211, which is a pressing unit for feeding out the material W, and a pusher chuck 210 provided at its tip. The pusher 211 is connected to the chain 212 via a connecting member 216. The pusher 211 is made of a rigid member that transmits the driving force of the chain 212 to the material W. The pusher chuck 210 employs a configuration that grips the end of the material W using an elastic member such as a spring. Alternatively, the pusher chuck 210 may be omitted, and a fitting portion may be provided at the end of the pusher 211 to allow insertion of the material W.

[0017] The chain 212 is stretched between a drive-side sprocket 213 and a driven-side sprocket 214, both of which are rotationally driven by a drive motor 215. The chain 212 moves in the direction of the supply-side conveying axis A as the drive motor 215 is driven. As the chain moves in direction A, the pusher 211 connected to the connecting member 216 moves, and the material W is conveyed. The drive motor 215 is also equipped with an encoder 217, which acts as a detection unit to detect and output the amount of drive and rotation angle.

[0018] The material W is positioned so that its central axis WA coincides with the conveying direction on the supply side and the conveying direction on the main spindle side, and is conveyed while being gripped by the push arrow chuck 210. In this way, the conveying mechanism using the chain 212 allows the push arrow 211 to move while being guided in the direction of the supply side conveying axis A. The operation of the main spindle 110 of the processing unit 100 to process the material W gripped by the main spindle chuck 111 while conveying it in direction B, and the operation of the push arrow 211 of the supply unit 200 to convey the material W gripped by the push arrow chuck 210 in direction A are linked, thereby realizing coordinated operation of the entire processing device 10. Note that the drive mechanism of the push arrow 211 is not limited to a chain-sprocket combination. A conveying mechanism using a belt may also be used, as well as a ball screw or a rack and pinion mechanism.

[0019] (Control Configuration) Figure 3 is a block diagram showing the control system of the processing apparatus 10. The processing apparatus 10 is equipped with a control unit 300 as a control device that provides overall control. The control unit 300 includes a CPU 301, a memory 302, and a communication I / F 303, and is connected to the processing unit 100 and the supply unit 200 in a communicative manner. As a means of realizing the control unit 300, a PLC (Programmable Logic Controller) or a computer can be used. As the control unit 300, an industrial PC is preferred that has high-speed computation processing capability, highly reliable real-time control performance, and high-precision synchronous control and positioning control capabilities, and that can perform the various controls required in this embodiment. For communication between the control unit 300 and the processing unit 100 and the supply unit 200, it is preferable to use an industrial communication standard such as Ethernet® or Profinet®, which has high real-time capabilities and can transmit large amounts of data such as positioning data at high speed.

[0020] The machining unit 100 is equipped with a control unit 120. The control unit 120 can be implemented using a custom-designed processing circuit board or a small microcontroller board. Alternatively, a distributed small PLC module or a control board using an FPGA (Field-Programmable Gate Array) can also be used. The control unit 120 has communication capabilities with the higher-level control unit 300, while also being equipped with input / output interfaces necessary for direct control of each device. The control unit 120 includes a spindle control 130 and a cutting control 135 as functional control blocks. These are conceptual blocks corresponding to program modules and the like that realize predetermined functions.

[0021] The spindle control 130 fixes the material W via the spindle chuck 111 based on commands from the control unit 300 and inputs from the operation panel 102, drives the servo motor 137 to move in direction B, and controls the positioning. The spindle control 130 applies multi-loop control including position loops, speed loops, current loops, etc., enabling highly accurate positioning control. Furthermore, a high-resolution, high-precision encoder built into the servo motor 137 enables fine position control. The cutting control 135 controls the operation of the cutting blade 112.

[0022] The supply unit 200 is equipped with a control unit 220, which can be configured similarly to the control unit 120 of the processing unit 100. The control unit 220 includes a pusher control 230 as a functional control block. The pusher control 230 controls the fixing and release of the material W via the pusher chuck 210 based on commands from the control unit 300 and inputs from the operation panel 202. The pusher control 230 also controls the transport operation of the pusher 211 by the drive motor 215. The control unit 220 detects the position of the pusher 211 by converting the rotation angle detected by the encoder 217 into a transport distance in direction A. The encoder 217 has a predetermined resolution per rotation and, when combined with the pitch spacing of the chain 212, can detect the position of the pusher 211. The detected position information is fed back to the control unit 300 and used for coordinated operation with the spindle control 130.

[0023] In this way, smooth transport and processing operations are achieved by the coordinated operation of the processing unit 100 and the supply unit 200 under the overall control of the control unit 300. Note that the above description is merely an example and is not limited to this configuration. For example, instead of providing an independent control unit 300, a control circuit provided in at least one of the processing unit 100 and the supply unit 200 may perform overall control.

[0024] The spindle 110 and the supply unit 200 are affected by precision errors, deterioration, and wear over time due to their configuration, which can cause errors between the amount of movement recognized by the control system and the actual amount of movement. When the machining unit 100 and the supply unit 200 work together to transport the material W, if either or each has an error, it can cause malfunctions in the machining apparatus 10. Therefore, the control unit 300 calibrates the amount of movement of the pusher 211 in relation to the amount of movement of the spindle 110. In a typical machining apparatus 10, the machining unit 100 is often more precise than the supply unit 200. This is because the machining unit 100 employs a high-precision mechanism to ensure machining quality. Therefore, in this embodiment, as described above, the amount of movement of the pusher 211 is calibrated in relation to the amount of movement of the spindle 110.

[0025] In this embodiment, a calibration mode is performed separately from the normal processing mode (actual operation mode) in order to understand the characteristics of the transport distance detection of the supply unit 200 and correct the control values ​​given to the supply unit 200. Calibration is performed at predetermined timings such as when the device is started up, during periodic maintenance, or after the replacement of mechanical elements.

[0026] During calibration, the control unit 300 switches to calibration mode. In this mode, with the material W being held, the spindle 110 and the pusher 211 are moved synchronously by a predetermined distance (for example, 100 mm). The transport control on the spindle side is designated as the first control, and the transport control on the pusher side is designated as the second control. At this time, the actual transport amount Psa on the spindle side, which is the actual amount of movement of the spindle 110, and the detected transport amount Pfe on the supply side, which is the amount of movement of the pusher 211 detected by the encoder 217, are measured. Note that the actual transport amount Psa on the spindle side may be the detected value of the high-precision encoder of the machining unit 100, or, assuming that the feed mechanism of the machining unit 100 is high-precision, the commanded transport amount Psc on the spindle side, which is the target amount of movement commanded to the spindle 110, may be used as is.

[0027] The control unit 300 then calculates a correction coefficient Cf representing the transport characteristics of the supply unit 200 from the ratio of the actual transport amount Psa on the spindle side to the detected transport amount Pfe on the supply side. For example, if the actual transport amount Psa on the spindle side is 100 mm and the detected transport amount Pfe on the supply side is 98 mm, the correction coefficient Cf is set to 102 / 100.

[0028] In normal machining mode, the supply-side command transport amount Pfc, which is the target movement commanded to the pusher 211, is calculated using this correction coefficient Cf. Specifically, the supply-side command transport amount Pfc is obtained by multiplying the spindle-side command transport amount Psc by the correction coefficient Cf. For example, if the spindle-side command transport amount Psc = 100 mm, then the supply-side command transport amount Pfc = 100 × 1.02 = 102 mm. This enables synchronous control that reflects the actual transport characteristics of the material W.

[0029] In the flowchart of Figure 4, steps S1 to S6 represent the calibration mode processing (dashed line C). Steps S10 to S15 represent the normal machining mode processing (dashed line M). The correction coefficient Cf calculated in the calibration mode is stored in the non-volatile memory 302 of the control unit 300 and is read out and used in the normal machining mode.

[0030] First, let's explain the calibration mode. In principle, each of the following steps is performed by the CPU 301 of the control unit 300 controlling each component of the processing apparatus 10. In step S1, the user operates the control unit 300 to select the calibration mode. Alternatively, the calibration mode may be started when the predetermined timing described above arrives.

[0031] In step S2, the material W is gripped by the spindle chuck 111 on the spindle side and the pusher chuck 210 on the pusher side. In step S3, the gripped material is moved synchronously over a predetermined distance (for example, 100 mm).

[0032] In step S4, the actual conveying amount Psa on the spindle side and the detected conveying amount Pfe on the supply side are measured. In step S5, a correction coefficient Cf is calculated from these measured values ​​and stored in the memory 302 in step S6.

[0033] Next, the normal machining mode will be described. When machining is started in step S10, in step S11 the user sets the spindle-side command transport amount Psc based on the desired machining content. In step S12 the stored correction coefficient Cf is read out, and in step S13 the supply-side command transport amount Pfc is calculated.

[0034] In step S14, the spindle 110 and the supply unit 200 are synchronized based on the calculated supply-side command transport amount Pfc. In step S15, it is determined whether the machining is complete, and if not, the process returns to step S11.

[0035] According to this embodiment, the following effects can be obtained. First, in calibration mode, the actual conveying amount Psa on the spindle side and the detected conveying amount Pfe on the supply side are measured using the actual material W, and a correction coefficient Cf is calculated from the ratio thereof. This correction coefficient Cf is a value that reflects the change in characteristics due to wear and deterioration of the mechanical elements of the supply unit 200.

[0036] In normal machining mode, the supply-side commanded transport amount Pfc is calculated by multiplying the spindle-side commanded transport amount Psc by a correction coefficient Cf. This makes it possible to issue transport commands that correspond to the actual characteristics of the supply unit 200. For example, by setting the spindle-side commanded transport amount Psc = 100 mm and the supply-side commanded transport amount Pfc = 102 mm, the actual transport amounts can be made to match 100 mm for both.

[0037] In conventional technology, the spindle-side command transport amount Psc and the supply-side command transport amount Pfc were set to the same value. As a result, depending on the characteristics of the supply unit 200, differences in the actual transport amount occurred, putting undue stress on the control system. In contrast, in this embodiment, the characteristics of the supply unit 200 are known in advance as a correction coefficient Cf, and the supply-side command transport amount Pfc is appropriately set based on this value, thereby achieving smooth synchronous control and improved transport accuracy.

[0038] Furthermore, the calibration method of the present invention does not require the addition of mechanical elements to the processing apparatus 10. Therefore, processing accuracy can be improved without increasing costs.

[0039] [Example 2] Next, Example 2 will be described. This example is characterized by the specific configuration of the mechanism that causes the pusher 211 of the supply unit 200 to be driven by the main spindle 110 of the processing unit 100 during calibration. The same configuration and functions as in Example 1 will not be described.

[0040] Figure 5 is a block diagram showing the control flow in Embodiment 2. The control unit 300 is communicatively connected to the control unit 120 of the machining unit 100 and the control unit 220 of the supply unit 200, and synchronously controls both. The control unit 120 outputs a movement command value, a speed command value, and a torque command value to the servo motor 137 that drives the spindle 110, and the control unit 220 outputs a movement command value, a speed command value, and a torque command value to the drive motor 215 that drives the pusher 211, respectively.

[0041] In the calibration mode, a material W is connected to a pusher 211, and the tip end of the material W is gripped by a main spindle 110. In this state, a control unit 120 outputs command values of a predetermined main spindle movement amount, a predetermined main spindle speed, and a predetermined main spindle torque to a servo motor 137. In response, a control unit 220 outputs command values of a pusher movement amount, a pusher speed, and a pusher torque to a drive motor 215. ・Pusher movement amount command value: 1.2 times the main spindle movement amount (for example, 120 mm for 100 mm of main spindle movement) ・Pusher speed command value: 1.2 times the main spindle speed ・Pusher torque command value: approximately 0.3 times the main spindle torque

[0042] With this setting, the pusher 211 can follow the movement of the main spindle 110 without excess or deficiency. That is, by setting the pusher movement amount command value and the pusher speed command value to be larger than those on the main spindle side, the operation of the pusher 211 is prevented from being delayed with respect to the main spindle 110.

[0043] Furthermore, by setting the torque command value of the pusher 211 to be appropriately smaller than that of the main spindle 110, an excessive pressing force is prevented from being applied to the material W. That is, even if the supply unit 200 side has a characteristic that causes the pusher to move a distance larger than the pusher movement amount command value, it is possible to prevent an excessive pressing force from being applied via the material W and an excessive load from being applied to the main spindle 110. Furthermore, with the pusher torque command value of the present embodiment, it is possible to prevent damage to the connecting member 216 and an increase in backlash of the chain 212 when an excessive load is applied to the pusher 211 side.

[0044] With this configuration, when the main spindle 110 moves a commanded distance (for example, 100 mm), the actual movement amount of the pusher 211 reliably matches the movement amount of the main spindle 110. On the other hand, if there is deterioration of a mechanical element, the movement amount of the pusher 211 detected by the encoder 217 is different from the movement amount of the main spindle 110. The correction coefficient Cf described in the first embodiment is calculated from the ratio between the movement amount of the pusher 211 and the movement amount of the main spindle 110.

[0045] In this embodiment, it is preferable that the servo motor 137 and the drive motor 215 operate in a torque control mode, which maintains a constant force generated by the motors and allows the position and speed to change in accordance with load conditions. For example, in the position control mode, since the motor attempts to forcibly reach a commanded position, there is a possibility that an excessive force is applied to the material W. In addition, in the speed control mode, a similar problem may occur because the motor excessively attempts to maintain the commanded speed. In contrast, in the torque control mode, the position and speed are adjusted in accordance with the state of the material while maintaining a constant force applied to the material W.

[0046] During normal machining operations, it is preferable that the control unit 120 operates the servo motor 137 in the position control mode to perform high-precision positioning. In addition, during normal machining operations, it is preferable, on the premise that calibration has been completed, that the movement speed and movement amount are matched between the machining side and the supply side.

[0047] The numerical values shown in this embodiment, such as the commanded values for the spindle movement amount, plunger movement amount, spindle speed, plunger speed, spindle torque, and plunger torque, are merely examples, and are not limited to these as long as the plunger 211 can be appropriately caused to follow the spindle 110 during calibration.

[0048] <Modification 1> In Embodiment 2, the control values of the servo motor 137 and the drive motor 215 are adjusted so that the plunger 211 can follow the spindle 110 without excess or deficiency. In particular, by setting the drive motor 215 to a constant torque smaller than that of the servo motor 137 and continuously pressing the plunger 211, the play of the chain 212 is biased in one direction, thereby reducing measurement error.

[0049] However, the configuration for causing the plunger 211 to follow the spindle 110 is not limited to this, and the following configuration can be adopted. First, in a state where both ends of the material W are respectively gripped by the spindle chuck 111 and the plunger chuck 210, the control unit 220 of the supply unit 200 controls the current to turn off the excitation of the drive motor 215. In this state, the motor shaft becomes rotatable, and the plunger 211 is brought into a state of following the movement of the spindle 110 via the material W.

[0050] In this state, when the spindle 110 is fed, the push arrow 211 is also moved. Even when the drive current of the drive motor 215 is turned off, the power to the encoder 217 is maintained, and the rotation of the motor shaft accompanying the movement of the push arrow 211 is continuously detected. When the spindle 110 is moved, it is preferable to always move it forward towards the target position and to take care not to overshoot the target position. By performing positioning from the same direction in this way, the slack in the chain 212 can be concentrated in a certain direction, and measurement errors can be reduced. This method reduces the power consumption of the drive motor 215 and saves energy.

[0051] <Modification 2> Furthermore, in a configuration where the drive current of the drive motor 215 is turned off in principle, as in Modification 1, the drive current can also be turned on for a short period of time corresponding to the start point and end point of the measurement of the movement of the push arrow 211. As a result, excitation is turned on during the period when the drive current is on, and torque is applied to the chain 212. By applying torque for only a short time in this way, measurement accuracy can be improved without compromising energy efficiency.

[0052] The configurations of each embodiment of the present invention can contribute to the preservation of the global environment in the following ways: (1) Reduction of material loss and defective products: By optimizing material feeding control, unnecessary cutting and damage of material W are prevented, and product quality is stabilized. This reduces the amount of raw materials used and waste, contributing to the effective use of resources. (2) Energy saving effect: By appropriately controlling torque, unnecessary load on the motor is reduced, and power consumption can be reduced. As a result, this contributes to the reduction of greenhouse gas emissions during product processing. (3) Extended equipment life and smarter operation: Optimal control extends the life of equipment, and the automation and efficiency of the entire factory are promoted. As a result, the frequency of replacement of manufacturing equipment decreases, leading to reduced energy consumption and effective use of resources.

[0053] 10: Processing device, 100: Processing section, 110: Main spindle, 200: Supply section, 300: Control section, W: Material

Claims

1. A processing apparatus comprising: a spindle capable of gripping a material to be processed, and capable of transporting the material in a transport direction by gripping and moving the material; a supply unit that supplies the material to the spindle by feeding it in the transport direction; a control unit capable of controlling the transport of the material by the spindle and the transport of the material by the supply unit; and a detection unit that detects the distance the material has been transported by the supply unit and outputs it as a supply-side detected transport amount, wherein the control unit synchronously controls: a first control that controls the spindle to transport the material by a predetermined transport amount; a second control that controls the supply unit to transport the material for supply to the spindle; and corrects a control value relating to the transport amount when the supply unit transports the material based on the predetermined transport amount and the supply-side detected transport amount.

2. The processing apparatus according to claim 1, wherein the material is a member having an axial direction, and is arranged from the supply unit to the main spindle such that the axial direction is along the conveying direction, and the supply unit feeds the material to the main spindle by pressing the material in the conveying direction with a pressing unit.

3. The processing apparatus according to claim 2, wherein the control unit has a calibration mode for performing the correction, and in the calibration mode, the control unit makes the supply-side command transport amount used to command the transport amount by the supply unit during the second control greater than the predetermined transport amount, thereby controlling the transport of the material by the supply unit to be carried out in accordance with the transport of the material by the spindle.

4. The processing apparatus according to any one of claims 1 to 3, wherein the control unit controls the transport by the supply unit using a supply-side command transport amount for commanding the transport amount by the supply unit during the second control, and calculates a correction coefficient to be applied to the supply-side command transport amount based on the predetermined transport amount and the supply-side detected transport amount.

5. The processing apparatus according to claim 4, wherein the control unit has a calibration mode for performing the correction, and in the calibration mode, the control unit calculates the correction coefficient based on the ratio of the predetermined transport amount to the supply-side detected transport amount, and in the actual operation mode, corrects the supply-side command transport amount using the correction coefficient to make the predetermined transport amount and the supply-side detected transport amount match.

6. The processing apparatus according to claim 5, characterized in that the control unit acquires the supply-side detected transport amount based on the output from an encoder that detects the amount of drive of a motor used to move a pressing part that presses the material, which is provided in the supply unit.

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