Control method, device and system for synchronization of spindle and feed Z axis during rigid tapping

Abstract

The present invention relates to a control method, device, and system for synchronizing a spindle and a feed Z-axis during rigid tapping, and relates to the technical field of CNC machine tools. The control method includes: determining a first mapping relationship between a first target speed of the spindle and a first delay time, and a second mapping relationship between a second target speed of the feed Z-axis and a second delay time; determining the first target speed of the spindle and the second target speed of the feed Z-axis; determining a first delay time based on the first target speed and the first mapping relationship, and determining a second delay time based on the second target speed and the second mapping relationship; determining a relative delay time between the spindle and the feed Z-axis based on the first delay time and the second delay time; after sending the first target speed to the spindle, sending the second target speed to the feed Z-axis after a relative delay time. The present invention achieves synchronization between the spindle and the feed Z-axis, improving the precision and processing efficiency of rigid tapping.

Description

Technical Field

[0001] The present invention relates to the technical field of numerically controlled machine tools, and in particular to a control method, device and system for synchronizing a spindle and a feed Z axis during rigid tapping. Background Art

[0002] Rigid tapping is to install the tap on the spindle of the CNC machine tool, position it on the processing coordinate through the cooperation between the spindle and the feed Z axis, and then rotate the tap into the pre-machined hole in the workpiece. After reaching the bottom of the hole, it pauses for a while, then rotates in the opposite direction and exits the workpiece to produce an internal thread in the hole of the workpiece.

[0003] Because the spindle's delay time is longer than the Z-axis's, related techniques attempt to reduce machining errors caused by the lack of synchronization between the spindle and the Z-axis by controlling the Z-axis to follow the spindle's motion. However, this control method results in complete desynchronization between the spindle and the Z-axis, resulting in large thread errors after tapping and a high risk of tool breakage and workpiece damage. Summary of the Invention

[0004] In order to overcome the problems existing in the related art, the present invention proposes a control method, device and system for synchronizing the spindle and the feed Z axis during rigid tapping.

[0005] A first aspect of the present invention provides a method for controlling synchronization between a spindle and a feed Z axis during rigid tapping, the method comprising:

[0006] Determine a first mapping relationship between a first target speed of the spindle and a first delay time, and a second mapping relationship between a second target speed of the feed Z axis and a second delay time;

[0007] Determining a first target speed of the spindle and a second target speed of the feed Z axis;

[0008] Determine the first delay time according to the first target speed and the first mapping relationship, and determine the second delay time according to the second target speed and the second mapping relationship;

[0009] Determine the relative delay time between the spindle and the feed Z axis according to the first delay time and the second delay time;

[0010] After sending the first target speed to the spindle, the second target speed is sent to the feed Z axis after a relative delay time.

[0011] Further optionally, determining a first mapping relationship between a first target speed of the spindle and a first delay time, and a second mapping relationship between a second target speed of the feed Z axis and a second delay time includes:

[0012] Determining, through autonomous learning of the spindle and the feed Z-axis, a first mapping relationship corresponding to different maximum spindle speeds and a second mapping relationship corresponding to different maximum feed Z-axis speeds;

[0013] Determine the maximum speed of the spindle and the maximum speed of the feed Z axis;

[0014] The first mapping relationship is determined according to the maximum speed of the main shaft, and the second mapping relationship is determined according to the maximum speed of the feed Z axis.

[0015] Further optionally, determining the maximum speed of the spindle and the maximum speed of the feed Z axis includes:

[0016] Obtaining pre-stored maximum speed and tapping characteristic parameters of the spindle;

[0017] The maximum speed of the feed Z axis is determined according to the maximum speed of the spindle and the characteristic parameters.

[0018] Further optionally, the characteristic parameter includes a tapping pitch.

[0019] Further optionally, the maximum speed of the feed Z axis is a function of the maximum speed of the spindle and the pitch; and / or,

[0020] The maximum speed of the feed Z axis satisfies: Vz = Vs × M;

[0021] Wherein: Vz is the maximum speed of the feed Z axis, Vs is the maximum speed of the spindle, and M is the tapping pitch.

[0022] Further optionally, determining the first target speed of the main shaft and the second target speed of the feed Z axis includes:

[0023] Obtaining a pre-stored first target speed of the spindle;

[0024] A second target speed of the feed Z axis is determined according to the first target speed, the maximum speed of the main shaft, and the maximum speed of the feed Z axis.

[0025] Further optionally, determining the second target speed of the feed Z axis according to the first target speed, the maximum speed of the spindle, and the maximum speed of the feed Z axis includes:

[0026] Determining a speed ratio of the maximum speed of the spindle to the maximum speed of the feed Z axis;

[0027] A second target speed of the feed Z axis is determined according to the first target speed and the speed ratio.

[0028] Further optionally, the speed ratio satisfies: k=Vs / Vz; wherein Vs is the maximum speed of the spindle, Vz is the maximum speed of the feed Z axis, and k is the speed ratio;

[0029] The second target speed=first target speed / nk, where n is a coefficient and n is greater than 0.

[0030] Further optionally, the relative delay time is the difference between the first delay time and the second delay time.

[0031] The second aspect of the present invention proposes a control device, which includes one or more processors and a non-temporary computer-readable storage medium storing program instructions. When the one or more processors execute the program instructions, the one or more processors are used to implement the control method proposed in the first aspect of the present invention.

[0032] The third aspect of the present invention provides a numerical control system, which adopts the control method provided in the second aspect of the present invention, or includes the control device provided in the third aspect of the present invention.

[0033] The technical solution of the present invention can include the following beneficial effects: the present invention determines the relative delay time of the spindle and the feed Z axis by determining the delay time of the spindle and the delay time of the feed Z axis, and sends the target speed to the feed Z axis after delaying the target speed to the spindle for the relative delay time, so as to achieve synchronization between the spindle and the feed Z axis, thereby improving the accuracy and processing efficiency of rigid tapping, while improving the qualified rate of workpieces and reducing tool breakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0035] Figure 1 is a flowchart of a control method according to an exemplary embodiment.

[0036] Figure 2 is a flowchart of a control method according to an exemplary embodiment.

[0037] Figure 3 is a flowchart of a control method according to an exemplary embodiment.

[0038] Figure 4 is a flowchart of a control method according to an exemplary embodiment.

[0039] Figure 5 is a flowchart of a control method according to an exemplary embodiment.

[0040] Figure 6 is a speed-time curve diagram according to an exemplary embodiment.

[0041] Figure 7 is a speed-time curve diagram according to an exemplary embodiment. DETAILED DESCRIPTION

[0042] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0043] In the related art, the feed Z axis is controlled to follow the movement of the spindle to reduce the processing error caused by the asynchronous movement of the spindle and the feed Z axis. The distance or angle of the feed Z axis movement is calculated by obtaining the characteristic parameters of the tapping feedback when the spindle rotates. For example, according to the feedback of the tapping thread pitch, the feed Z axis moves the length of one pitch for each rotation of the spindle. Since the spindle moves in advance, the feedback data obtained has a large delay. At the same time, when driving the feed Z axis to move, the feed Z axis will also experience a delay in actual movement under the action of the load. Under the influence of multiple delay factors, it is easy to cause the movement between the spindle and the feed Z axis to be completely out of sync, resulting in a large thread error after tapping. It is also easy to cause tool breakage, damage to the workpiece, etc.

[0044] In order to solve the above technical problems, this embodiment proposes a control method for synchronizing the spindle and the feed Z axis during rigid tapping. The control method of this embodiment includes:

[0045] Determine a first mapping relationship between a first target speed of the spindle and a first delay time, and a second mapping relationship between a second target speed of the feed Z axis and a second delay time;

[0046] Determine a first target speed of the spindle and a second target speed of the feed Z axis;

[0047] Determine a first delay time according to the first target speed and the first mapping relationship, and determine a second delay time according to the second target speed and the second mapping relationship;

[0048] Determine the relative delay time between the spindle and the feed Z axis according to the first delay time and the second delay time;

[0049] The spindle is controlled to move at the first target speed, and the feed Z axis is controlled to move at the second target speed after a relative delay time.

[0050] This embodiment determines the relative delay time of the spindle and the feed Z axis by determining the delay time of the spindle and the delay time of the feed Z axis, and sends the target speed to the feed Z axis after delaying the target speed to the spindle for the relative delay time, so as to achieve synchronization between the spindle and the feed Z axis, improve the accuracy and processing efficiency of rigid tapping, and at the same time improve the qualified rate of the workpiece and reduce the breakage of the tool.

[0051] Figure 1 is a flow chart of a control method according to an exemplary embodiment, referring to Figure 1 , the control method of this embodiment includes the following steps:

[0052] S11, determining a first mapping relationship between a first target speed of the spindle and a first delay time, and a second mapping relationship between a second target speed of the feed Z axis and a second delay time;

[0053] S12, determining a first target speed of the main spindle and a second target speed of the feed Z axis;

[0054] S13, determining a first delay time according to the first target speed and the first mapping relationship, and determining a second delay time according to the second target speed and the second mapping relationship;

[0055] S14, determining a relative delay time between the main shaft and the feed Z axis according to the first delay time and the second delay time;

[0056] S15, after sending the first target speed to the main axis, sending the second target speed to the feed Z axis after a relative delay time.

[0057] In this embodiment, there is a corresponding relationship between the first target speed of the spindle and the first delay time of the spindle. Different first target speeds of the spindle correspond to different first delay times. After determining a first mapping relationship between the first target speed of the spindle and the first delay time, if the first target speed of the spindle is known, the first delay time corresponding to the first target speed can be determined according to the first mapping relationship. Similarly, there is a corresponding relationship between the second target speed of the feed Z axis and the second delay time of the feed Z axis. Different second target speeds of the feed Z axis correspond to different second delay times. After determining a second mapping relationship between the second target speed of the feed Z axis and the second delay time, if the second target speed of the feed Z axis is known, the second delay time corresponding to the second target speed can be determined according to the second mapping relationship. The first mapping relationship and the second mapping relationship of this embodiment can be pre-stored in the system or obtained through autonomous learning of the spindle and the feed Z axis. After determining the first delay time of the spindle and the second delay time of the feed Z axis, the relative delay time of the spindle and the feed Z axis can be determined. In one example, the relative delay time is the difference between the first delay time and the second delay time.

[0058] This embodiment determines the movement order of the spindle and the feed Z axis based on the size of the initial delay time of the spindle and the feed Z axis. Generally, the initial delay time of the spindle is relatively large, so the spindle needs to move first. During the rigid tapping process, the spindle moves at the first target speed, and the first delay time of the spindle is queried through the first mapping relationship. According to the second target speed of the feed Z axis, the second delay time of the feed Z axis is queried. In order to ensure the consistency of the first delay time and the second delay time, the delay times of the two are at the same time point. Figure 6 The speed-time curve is used to make the starting positions of the first delay time and the second delay time coincide with the same time point of the synchronization delay line of the spindle and the feed Z axis. The synchronization delay line of the spindle and the feed Z axis is obtained by tapping tests on a CNC machine tool. Td1 is the first delay time of the spindle, and Td2 is the second delay time of the feed Z axis. The relative delay time Te can be obtained based on the first delay time Td1 and the second delay time Td2. It can then be determined that after the first target speed is issued to the spindle, the second target speed is issued to the feed Z axis after the relative delay time, and then the calculation of the next cycle is performed. The movement of the spindle and the feed Z axis is dynamically adjusted to achieve synchronous movement of the spindle and the feed Z axis.

[0059] Figure 2 is a flow chart of a control method according to an exemplary embodiment, referring to Figure 2 In this embodiment, determining a first mapping relationship between a first target speed of the spindle and a first delay time, and a second mapping relationship between a second target speed of the feed Z axis and a second delay time includes the following steps:

[0060] S21, determining, through autonomous learning of the spindle and the feed Z-axis, a first mapping relationship corresponding to different maximum spindle speeds, and a second mapping relationship corresponding to different maximum feed Z-axis speeds;

[0061] S22, determining the maximum speed of the main spindle and the maximum speed of the feed Z axis;

[0062] S23, determining a first mapping relationship according to the maximum speed of the main shaft, and determining a second mapping relationship according to the maximum speed of the feed Z axis.

[0063] In this embodiment, after the numerical control system sends the target speed to the controlled object, the controlled object feeds back the speed to the control system. There is a time difference Td between the control system sending the target speed and the speed feedback received from the controlled object. The change trend of the target speed Vt, the time difference Td and the feedback speed is referenced. Figure 5The speed-time curve shown in Figure 1 is shown in Figure 2. The time difference Td is related to the acceleration, maximum speed, and target speed Vt of the controlled object. Typically, the acceleration is fixed. Different maximum speeds produce different mappings between the target speed Vt and the time difference Td. That is, at different maximum speeds, each Vt value corresponds to a Td value. For CNC machine tool motion, autonomous learning can generate multiple sets of Vt and Td data at different maximum speeds.

[0064] Similarly, through autonomous learning of the spindle and feed Z-axis, a first mapping relationship of the first target speed-first delay time corresponding to different spindle maximum speeds, and a second mapping relationship of the second target speed-second delay time corresponding to different feed Z-axis maximum speeds can be obtained. Before entering the rigid tapping mode, the spindle and feed Z-axis first conduct autonomous learning to obtain multiple sets of first mapping relationships corresponding to different spindle maximum speeds, and multiple sets of second mapping relationships corresponding to different feed Z-axis maximum speeds. After entering the rigid tapping mode, the first mapping relationship corresponding to the spindle maximum speed and the second mapping relationship corresponding to the feed Z-axis maximum speed can be determined by determining the maximum spindle speed and the maximum feed Z-axis speed.

[0065] It should be noted that since the data for different maximum spindle speeds and different maximum feed Z-axis speeds stored in the CNC system is discrete, the data sets for the first mapping relationship and the second mapping relationship are also limited. If no first mapping relationship that exactly corresponds to the determined maximum spindle speed is found, a query analysis is performed to find the first mapping relationship that is closest to the maximum spindle speed. Similarly, if no second mapping relationship that exactly corresponds to the determined maximum feed Z-axis speed is found, a query analysis is performed to find the second mapping relationship that is closest to the determined maximum feed Z-axis speed.

[0066] Figure 3 is a flow chart of a control method according to an exemplary embodiment, referring to Figure 3 , determining the maximum speed of the spindle and the maximum speed of the feed Z axis includes the following steps:

[0067] S31, obtaining the pre-stored maximum speed of the spindle and characteristic parameters of tapping;

[0068] S32, determine the maximum speed of the feed Z axis according to the maximum speed and characteristic parameters of the spindle.

[0069] In this embodiment, the maximum speed of the spindle is pre-stored in the CNC system. Before entering the rigid tapping mode, the pre-stored maximum speed of the spindle can be directly obtained. At the same time, the characteristic parameters of the tapping need to be obtained. The characteristic parameters of the tapping can be the length of the tapping and / or the pitch of the tapping. After obtaining the characteristic parameters of the tapping, the maximum speed of the feed Z axis can be determined based on the maximum speed of the spindle and the characteristic parameters of the tapping. In one example, the maximum speed of the feed Z axis is a function of the maximum speed and pitch of the spindle. For example, the maximum speed of the feed Z axis satisfies: Vz=Vs×M, where Vz is the maximum speed of the feed Z axis, Vs is the maximum speed of the spindle, and M is the pitch of the tapping. After determining the maximum speed of the spindle and the maximum speed of the feed Z axis, the first mapping relationship corresponding to the maximum speed of the spindle and the second mapping relationship corresponding to the maximum speed of the feed Z axis can be determined.

[0070] Figure 4 is a flow chart of a control method according to an exemplary embodiment, referring to Figure 4 In this embodiment, determining the first target speed of the spindle and the second target speed of the feed Z axis includes the following steps:

[0071] S41, obtaining a pre-stored first target speed of the spindle;

[0072] S42: Determine a second target speed for the feed Z axis based on the first target speed, the maximum speed of the spindle, and the maximum speed of the feed Z axis.

[0073] In this embodiment, the CNC system pre-stores the first target speed of the spindle. Before entering rigid tapping, the pre-stored first target speed of the spindle can be directly obtained. Since the second target speed of the feed Z axis is related to the first target speed of the spindle, the maximum speed of the spindle, and the maximum speed of the feed Z axis, the second target speed of the feed Z axis can be determined after determining the first target speed of the spindle, the maximum speed of the spindle, and the maximum speed of the feed Z axis.

[0074] Figure 5 is a flow chart of a control method according to an exemplary embodiment, referring to Figure 5 In this embodiment, determining the second target speed of the feed Z axis according to the first target speed, the maximum speed of the spindle, and the maximum speed of the feed Z axis includes the following steps:

[0075] S51, determining the speed ratio of the maximum speed of the main spindle to the maximum speed of the feed Z axis;

[0076] S52: Determine a second target speed for feeding the Z axis according to the first target speed and the speed ratio.

[0077] In this embodiment, since the proportional relationship between the maximum speed of the spindle and the maximum speed of the feed Z-axis, as well as the proportional relationship between the first target speed of the spindle and the second target speed of the feed Z-axis, is related, after determining the speed ratio between the maximum speed of the spindle and the maximum speed of the feed Z-axis, the second target speed of the feed Z-axis can be determined based on the first target speed and the speed ratio. In one example, k = Vs / Vz, where Vs is the maximum speed of the spindle, Vz is the maximum speed of the feed Z-axis, and k is the speed ratio; the second target speed = first target speed / nk, where n is a coefficient, n is greater than 0, and illustratively, n = 1.

[0078] This embodiment also provides a control device, which includes one or more processors and a non-temporary computer-readable storage medium storing program instructions. When the one or more processors execute the program instructions, the one or more processors are used to implement the control method proposed in the above embodiment.

[0079] This embodiment proposes a numerical control system, which adopts the control method proposed in the above embodiment, or includes the control device proposed in the above embodiment.

[0080] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow from the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0081] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0082] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow from the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0083] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A control method for synchronizing the spindle and the feed Z axis during rigid tapping, characterized in that: The control method includes: Determine a first mapping relationship between a first target speed of the spindle and a first delay time, and a second mapping relationship between a second target speed of the feed Z axis and a second delay time; Determining a first target speed of the spindle and a second target speed of the feed Z axis; Determine the first delay time according to the first target speed and the first mapping relationship, and determine the second delay time according to the second target speed and the second mapping relationship; Determine the relative delay time between the spindle and the feed Z axis according to the first delay time and the second delay time; After sending the first target speed to the spindle, the second target speed is sent to the feed Z axis after a relative delay time; The determining of a first mapping relationship between a first target speed of the spindle and a first delay time, and a second mapping relationship between a second target speed of the feed Z axis and a second delay time, includes: Determining, through autonomous learning of the spindle and the feed Z-axis, a first mapping relationship corresponding to different maximum spindle speeds and a second mapping relationship corresponding to different maximum feed Z-axis speeds; Determine the maximum speed of the spindle and the maximum speed of the feed Z axis; Determine the first mapping relationship according to the maximum speed of the spindle, and determine the second mapping relationship according to the maximum speed of the feed Z axis; Determining the first target speed of the main shaft and the second target speed of the feed Z axis includes: Obtaining a pre-stored first target speed of the spindle; Determine a second target speed of the feed Z axis according to the first target speed, the maximum speed of the spindle, and the maximum speed of the feed Z axis; Determining the second target speed of the feed Z axis according to the first target speed, the maximum speed of the spindle, and the maximum speed of the feed Z axis includes: Determining a speed ratio of the maximum speed of the spindle to the maximum speed of the feed Z axis; A second target speed of the feed Z axis is determined according to the first target speed and the speed ratio.

2. The method for controlling synchronization between the spindle and the feed Z axis during rigid tapping according to claim 1, characterized in that: Determining the maximum speed of the spindle and the maximum speed of the feed Z axis includes: Obtaining pre-stored maximum speed and tapping characteristic parameters of the spindle; The maximum speed of the feed Z axis is determined according to the maximum speed of the spindle and the characteristic parameters.

3. The method for controlling synchronization between the spindle and the feed Z axis during rigid tapping according to claim 2, wherein: The characteristic parameters include the pitch of the tapping.

4. The method for controlling synchronization between the spindle and the feed Z axis during rigid tapping according to claim 3, wherein: The maximum speed of the feed Z axis is a function of the maximum speed of the spindle and the pitch; and / or, The maximum speed of the feed Z axis satisfies: Vz = Vs × M; Wherein: Vz is the maximum speed of the feed Z axis, Vs is the maximum speed of the spindle, and M is the tapping pitch.

5. The method for controlling synchronization between the spindle and the feed Z axis during rigid tapping according to claim 1, wherein: The speed ratio satisfies: k=Vs / Vz; wherein Vs is the maximum speed of the spindle, Vz is the maximum speed of the feed Z axis, and k is the speed ratio; The second target speed=the first target speed / nk; wherein n is a coefficient, and n is greater than 0.

6. The method for controlling synchronization between the spindle and the feed Z axis during rigid tapping according to claim 1, characterized in that: The relative delay time is the difference between the first delay time and the second delay time.

7. A control device, characterized in that: It includes one or more processors and a non-transitory computer-readable storage medium storing program instructions. When the one or more processors execute the program instructions, the one or more processors are used to implement the control method according to any one of claims 1 to 6.

8. A numerical control system, characterized in that: It adopts the control method according to any one of claims 1 to 6, or includes the control device according to claim 7.

Images