Anti-collision protection method based on PLC double-tool-rest machine tool

Abstract

The invention belongs to the field of numerical control safety protection of double-knife-rest machine tools, and provides an anti-collision protection method based on a PLC (programmable logic controller) double-knife-rest machine tool. The numerical control machine tool is provided with a position measurement feedback encoder or a grating ruler, so that the real-time position of a numerical control shaft of the machine tool can be known, and a knife rest moving shaft is also a numerical control servo shaft; the position of a coordinate axis of a machine tool can be read through the PLC, the distance between the two tool rests is calculated through a formula and then compared with the allowable minimum distance and the allowable maximum distance between the two tool rests, when the distance exceeds the minimum distance or the maximum distance, movement of the tool rest shafts is stopped, and the system gives an alarm to prompt a user. According to the anti-collision protection method, hardware protection and software protection are conducted on the double-tool-rest numerical control machine tool, even if hardware protection fails, software protection also takes effect, and the safety and reliability of the machine tool are effectively enhanced.

Description

Technical Field

[0001] The invention belongs to the field of digital control safety protection of double-tool-post machine tools, and in particular relates to an anti-collision protection method of a double-tool-post machine tool based on a PLC. Background Art

[0002] The double tool holder CNC machine tool has its own tool holder slide moving linearly on the same guide rail. The two tool holders may collide due to mechanical interference, so hardware mutual collision limit switches are installed on the two tool holders to prevent the two tool holders from colliding. When the two tool holders approach each other, they will first collide with the mutual collision limit switch, and then stop the movement of the two axes in the approaching direction to prevent the tool holders from colliding. However, when the switch is damaged or the anti-collision bracket is damaged, the protection will not take effect, so the tool holders may collide, thereby damaging the mechanical parts and affecting the accuracy of the machine tool, which will take a lot of time to repair and adjust. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to propose an anti-collision protection method for a PLC double-turret machine tool, which performs dual protection of hardware and software on the double-turret CNC machine tool. Even if the hardware protection fails, the software protection is still effective, thereby enhancing the safety and reliability of the machine tool.

[0004] In order to achieve the above technical objectives, the protection scheme provided by the present invention is as follows.

[0005] The CNC machine tool involved in the present invention is equipped with a position measurement feedback encoder or grating ruler, which can know the real-time position of the CNC axis of the machine tool. The tool holder moving axis adopts a CNC servo axis, so that the position of the coordinate axis of the machine tool can be read by PLC, the spacing between the two tool holders is calculated by formula, and then compared with the minimum and maximum spacing allowed between the two tool holders. When the minimum or maximum spacing is exceeded, the movement of the tool holder axis is stopped, and the system sends an alarm to prompt the user; at the same time, in order to adapt to different types of machine tools and facilitate the installation personnel to debug, a software protection setting interface is developed in the operating software interface of the CNC system.

[0006] CNC machine tool turret type settings, the types are as follows:

[0007] Ⅰ. Tool holder 1 in the same direction is in the positive direction of tool holder 2:

[0008] The positive and negative movement directions of the two tool holders are consistent, and tool holder 1 is in the positive direction of tool holder 2. It is mostly used for the Y axis of double tool holder milling machines and the Z axis of double tool holder horizontal lathes.

[0009] Ⅱ. Tool holder 1 in the same direction is in the negative direction of tool holder 2:

[0010] The positive and negative movement directions of the two tool holders are consistent, and tool holder 1 is in the negative direction of tool holder 2. It is mostly used for the Y axis of double tool holder milling machines and the Z axis of double tool holder horizontal lathes.

[0011] III. Reverse zero point is at the center:

[0012] The two tool rests move in opposite directions, and the zero points of the two tool rest axes are set at the center. It is mostly used in double tool rest turning and milling compound milling lathes or ZH series.

[0013] IV. Reverse zero point at both ends:

[0014] The two tool rests move in opposite directions, and the zero points of the two tool rest axes are set at the end points on the edges of their respective workbenches.

[0015] Specifically, the anti-collision protection method of the PLC double-tool-post machine tool of the present invention comprises the following steps:

[0016] (1) Data measurement of tool holder 1 in the negative direction of tool holder 2

[0017] (1-1) First, move the two tool holders of the machine tool to the positions where the zero points are to be set. The coordinates displayed by the machine tool coordinate system are 0.000.

[0018] (1-2) Mark the lower reference point of tool holder 1;

[0019] (1-3) Tool holder 1 is moved away from the reference point mark in the negative direction, and then tool holder 2 is moved in the negative direction to the mark made by tool holder 1. At this time, the coordinate value P2 of tool holder 2 in the machine tool coordinate system is the zero point distance P0=P2 between the two tool holders;

[0020] (1-4) Stop tool holder 2 at the zero point, and then open tool holder 1 to the minimum spacing position allowed by the two tool holders. At this time, record the coordinate value P of tool holder 1 in the machine tool coordinate system. 1min , then the minimum allowable spacing between the two tool holders is P min =ABS(P 1min )+P0;

[0021] (1-5) Open tool holder 1 in the negative direction and tool holder 2 in the positive direction to the maximum position allowed by the two tool holders. At this time, record the coordinate values ​​P of the two tool holders in the machine tool coordinate system. 1max and P 2max , then the maximum allowable distance between the two tool holders is

[0022] P max =ABS(P 1max )+ABS(P 2max )+P0;

[0023] (1-6) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =ABS(PT2 -P T1 )+P0, and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max ;

[0024] When P T ≤P min Trigger the alarm of the minimum allowable distance between the two tool holders and lock the corresponding moving directions of the two axes;

[0025] When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked;

[0026] (2) Data measurement of tool holder 1 in the positive direction of tool holder 2

[0027] (2-1) First, move the two tool holders of the machine tool to the positions where the zero points are to be set. The coordinates displayed by the machine tool coordinate system are 0.000.

[0028] (2-2) Mark the lower reference point of tool holder 2;

[0029] (2-3) Tool rest 2 moves away from the reference point mark in the negative direction, and then tool rest 1 moves negatively to the mark made by tool rest 2. At this time, the coordinate value P1 of tool rest 1 in the machine tool coordinate system is the zero point distance P0=P1 between the two tool rests;

[0030] (2-4) Stop tool holder 1 at the zero point, and then open tool holder 2 to the minimum spacing position allowed by the two tool holders. At this time, record the coordinate value P of tool holder 2 in the machine tool coordinate system. 2min , then the minimum allowable spacing between the two tool holders is P min =ABS(P 2min )+P0;

[0031] (2-5) Open tool holder 1 in the positive direction and tool holder 2 in the negative direction to the maximum position allowed by the two tool holders. At this time, record the coordinate values ​​P of the two tool holders in the machine tool coordinate system. 1max and P 2max , then the maximum allowable distance between the two tool holders is

[0032] P max =ABS(P 1max )+ABS(P 2max )+P0;

[0033] (2-6) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =ABS(PT1 -P T2 )+P0, and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max ;

[0034] When P T ≤P min Trigger the alarm of the minimum allowable distance between the two tool holders and lock the corresponding moving directions of the two axes;

[0035] When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked;

[0036] (3) Data measurement with reverse zero point at the center

[0037] (3-1) Move the two tool rests of the machine tool to the center point and set the zero point. The coordinate displayed by the machine tool coordinate system is 0.000, and the zero point distance between the two tool rests is P0 = 0;

[0038] (3-2) Open tool holder 1 to the zero position, and then open tool holder 2 to tool holder 1 to the minimum position allowed by the machine. At this time, record the coordinate P of tool holder 2 in the machine tool coordinate system. 2min , then the minimum allowable spacing between the two tool holders is P min =ABS(P 2min );

[0039] (3-3) Open the two tool holders to their limit positions at both ends. At this time, record the coordinates P of tool holder 1 and tool holder 2 in the machine tool coordinate system. 1max and P 2max , then the maximum allowable spacing between the two tool holders is P max =ABS(P 1max +P 2max );

[0040] (3-4) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =ABS(P T1 +P T2 ), and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max ;

[0041] When P T ≤P min Trigger the alarm of the minimum allowable distance between the two tool holders and lock the corresponding moving directions of the two axes;

[0042] When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked;

[0043] (4) Data measurement with reverse zero point at both ends

[0044] (4-1) First, move the two tool holders of the machine tool to the positions where the zero points are to be set. The coordinates displayed by the machine tool coordinate system are 0.000.

[0045] (4-2) Mark the reference point at the center;

[0046] (4-3) Open tool rest 1 and tool rest 2 to the reference point mark respectively, and record the coordinate value P1 of tool rest 1 and the coordinate value P2 of tool rest 2 in the machine tool coordinate system respectively. The zero point distance P0 of the two tool rests is ABS(P1+P2);

[0047] (4-3) Open tool holder 1 and tool holder 2 to the minimum position allowed by the machine, and record the coordinate value P of tool holder 1 in the machine tool coordinate system. 1min and the coordinate value P of tool holder 2 2min , then the minimum allowable spacing between the two tool holders is

[0048] P min =P0-ABS(P 1min +P 2min );

[0049] (4-4) Open the two tool holders to their limit positions at both ends. At this time, record the coordinates P of tool holder 1 and tool holder 2 in the machine tool coordinate system. 1max and P 2max , then the maximum allowable spacing between the two tool holders is P max =P0+ABS(P 1max +P 2max );

[0050] (4-5) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =P0+P T1 +P T2 , and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max

[0051] When P T ≤P minTrigger the alarm of the minimum allowable distance between the two tool holders and lock the corresponding moving directions of the two axes;

[0052] When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding movement directions of the two axes are locked.

[0053] In the above technical solution, the movement mode of the servo motor of the tool holder shaft is a linear axis.

[0054] The invention is based on the anti-collision protection method of the PLC double-turret machine tool, is simple to use and low in cost, utilizes the machine tool's own measurement system and PLC to perform real-time calculation and comparison, and performs double protection on the double-turret machine tool against collision through the method of the invention, thereby greatly improving the reliability and safety of the machine tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram of the method of the present invention in which the two tool holders move in the same direction and tool holder 1 is in the negative direction of tool holder 2.

[0056] Figure 2 This is a schematic diagram of the method of the present invention in which the two tool holders move in the same direction and tool holder 1 is in the positive direction of tool holder 2.

[0057] Figure 3 This is a schematic diagram of the method of the present invention in which the double tool holders move in opposite directions and the zero points of tool holders 1 and 2 are at the center.

[0058] Figure 4 This is a schematic diagram showing that the double tool holders move in opposite directions in the method of the present invention, and the zero points of tool holder 1 and tool holder 2 are at both ends. DETAILED DESCRIPTION

[0059] In order to facilitate the understanding of the present invention, the following further describes the implementation of the present invention in conjunction with the accompanying drawings and examples. An implementation of the present invention is shown in the accompanying drawings. It should be understood that this embodiment is only used to explain the present invention and is not intended to limit the present invention. The purpose of providing this embodiment is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0060] The embodiment of the present invention provides an anti-collision protection method for a PLC double-tool-post machine tool. The method involves a CNC machine tool with a position measurement feedback encoder or a grating ruler for obtaining the real-time position of a CNC axis of the machine tool. The tool post moving axis adopts a CNC servo axis, and the motion mode of the servo motor of the tool post axis is a linear axis. The method comprises the following steps:

[0061] (1) Data measurement of tool holder 1 in the negative direction of tool holder 2, such as Figure 1 Shown

[0062] (1-1) First, move the two tool holders of the machine tool to the positions where the zero points are to be set. The coordinates displayed by the machine tool coordinate system are 0.000.

[0063] (1-2) Mark the lower reference point of tool holder 1;

[0064] (1-3) Tool holder 1 is moved away from the reference point mark in the negative direction, and then tool holder 2 is moved in the negative direction to the mark made by tool holder 1. At this time, the coordinate value P2 of tool holder 2 in the machine tool coordinate system is the zero point distance P0=P2 between the two tool holders;

[0065] (1-4) Stop tool holder 2 at the zero point, and then open tool holder 1 to the minimum spacing position allowed by the two tool holders. At this time, record the coordinate value P of tool holder 1 in the machine tool coordinate system. 1min , then the minimum allowable spacing between the two tool holders is P min =ABS(P 1min )+P0;

[0066] (1-5) Open tool holder 1 in the negative direction and tool holder 2 in the positive direction to the maximum position allowed by the two tool holders. At this time, record the coordinate values ​​P of the two tool holders in the machine tool coordinate system. 1max and P 2max , then the maximum allowable distance between the two tool holders is

[0067] P max =ABS(P 1max )+ABS(P 2max )+P0;

[0068] (1-6) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =ABS(P T2 -P T1 )+P0, and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max ;

[0069] When P T ≤P min Trigger the alarm of the minimum allowable distance between the two tool holders and lock the corresponding moving directions of the two axes;

[0070] When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked;

[0071] (2) Data measurement of tool holder 1 in the positive direction of tool holder 2, such as Figure 2 Shown

[0072] (2-1) First, move the two tool holders of the machine tool to the positions where the zero points are to be set. The coordinates displayed by the machine tool coordinate system are 0.000.

[0073] (2-2) Mark the lower reference point of tool holder 2;

[0074] (2-3) Tool rest 2 moves away from the reference point mark in the negative direction, and then tool rest 1 moves negatively to the mark made by tool rest 2. At this time, the coordinate value P1 of tool rest 1 in the machine tool coordinate system is the zero point distance P0=P1 between the two tool rests;

[0075] (2-4) Stop tool holder 1 at the zero point, and then open tool holder 2 to the minimum spacing position allowed by the two tool holders. At this time, record the coordinate value P of tool holder 2 in the machine tool coordinate system. 2min , then the minimum allowable spacing between the two tool holders is P min =ABS(P 2min )+P0;

[0076] (2-5) Open tool holder 1 in the positive direction and tool holder 2 in the negative direction to the maximum position allowed by the two tool holders. At this time, record the coordinate values ​​P of the two tool holders in the machine tool coordinate system. 1max and P 2max , then the maximum allowable distance between the two tool holders is

[0077] P max =ABS(P 1max )+ABS(P 2max )+P0;

[0078] (2-6) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =ABS(P T1 -P T2 )+P0, and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max ;

[0079] When P T ≤P min Trigger the alarm of the minimum allowable distance between the two tool holders and lock the corresponding moving directions of the two axes;

[0080] When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked;

[0081] (3) Data measurement with reverse zero point at the center, such as Figure 3 Shown

[0082] (3-1) Move the two tool rests of the machine tool to the center point and set the zero point. The coordinate displayed by the machine tool coordinate system is 0.000, and the zero point distance between the two tool rests is P0 = 0;

[0083] (3-2) Open tool holder 1 to the zero position, and then open tool holder 2 to tool holder 1 to the minimum position allowed by the machine. At this time, record the coordinate P of tool holder 2 in the machine tool coordinate system. 2min , then the minimum allowable spacing between the two tool holders is P min =ABS(P 2min );

[0084] (3-3) Open the two tool holders to their limit positions at both ends. At this time, record the coordinates P of tool holder 1 and tool holder 2 in the machine tool coordinate system. 1max and P 2max , then the maximum allowable spacing between the two tool holders is P max =ABS(P 1max +P 2max );

[0085] (3-4) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =ABS(P T1 +P T2 ), and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max ;

[0086] When P T ≤P min Trigger the alarm of the minimum allowable distance between the two tool holders and lock the corresponding moving directions of the two axes;

[0087] When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked;

[0088] (4) Data measurement with reverse zero points at both ends, such as Figure 4 Shown

[0089] (4-1) First, move the two tool holders of the machine tool to the positions where the zero points are to be set. The coordinates displayed by the machine tool coordinate system are 0.000.

[0090] (4-2) Mark the reference point at the center;

[0091] (4-3) Open tool rest 1 and tool rest 2 to the reference point mark respectively, and record the coordinate value P1 of tool rest 1 and the coordinate value P2 of tool rest 2 in the machine tool coordinate system respectively. The zero point distance P0 of the two tool rests is ABS(P1+P2);

[0092] (4-3) Open tool holder 1 and tool holder 2 to the minimum position allowed by the machine, and record the coordinate value P of tool holder 1 in the machine tool coordinate system. 1min and the coordinate value P of tool holder 2 2min , then the minimum allowable spacing between the two tool holders is

[0093] P min =P0-ABS(P 1min +P 2min );

[0094] (4-4) Open the two tool holders to their limit positions at both ends. At this time, record the coordinates P of tool holder 1 and tool holder 2 in the machine tool coordinate system. 1max and P 2max , then the maximum allowable spacing between the two tool holders is P max =P0+ABS(P 1max +P 2max );

[0095] (4-5) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =P0+P T1 +P T2 , and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max

[0096] When P T ≤P min Trigger the alarm of the minimum allowable distance between the two tool holders and lock the corresponding moving directions of the two axes;

[0097] When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding movement directions of the two axes are locked.

[0098] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0099] Finally, it should be pointed out that the above embodiments are only representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention should be considered to belong to the protection scope of the present invention.

Claims

1. A collision protection method based on a PLC double-turret machine tool, characterized in that The method involves a CNC machine tool with a position measurement feedback encoder or a grating ruler for obtaining the real-time position of the CNC axis of the machine tool. The tool holder moving axis adopts a CNC servo axis. The method includes the following steps: (1) Data measurement of tool holder 1 in the negative direction of tool holder 2 (1-1) First, move the two tool holders of the machine tool to the positions where the zero points are to be set. The coordinates displayed by the machine tool coordinate system are 0.

000. (1-2) Mark the lower reference point of tool holder 1; (1-3) Tool holder 1 is opened in the negative direction away from the reference point mark, and then tool holder 2 is opened in the negative direction to the mark made by tool holder 1. At this time, the coordinate value P2 of tool holder 2 in the machine tool coordinate system is the zero point distance P0=P2 between the two tool holders; (1-4) Stop tool holder 2 at the zero point, and then open tool holder 1 to the minimum spacing position allowed by the two tool holders. At this time, record the coordinate value P of tool holder 1 in the machine tool coordinate system. 1min , then the minimum allowable spacing between the two tool holders is P min =ABS(P 1min )+P0; (1-5) Open tool holder 1 in the negative direction and tool holder 2 in the positive direction to the maximum position allowed by the two tool holders. At this time, record the coordinate values ​​P of the two tool holders in the machine tool coordinate system. 1max and P 2max , then the maximum allowable distance between the two tool holders is P max =ABS(P 1max )+ABS(P 2max )+P0; (1-6) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =ABS(P T2 -P T1 )+P0, and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max ; When P T ≤P min The alarm of the minimum allowable distance between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked; When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked; (2) Data measurement of tool holder 1 in the positive direction of tool holder 2 (2-1) First, move the two tool holders of the machine tool to the positions where the zero points are to be set. The coordinates displayed by the machine tool coordinate system are 0.

000. (2-2) Mark the lower reference point of tool holder 2; (2-3) Tool rest 2 moves away from the reference point mark in the negative direction, and then tool rest 1 moves negatively to the mark made by tool rest 2. At this time, the coordinate value P1 of tool rest 1 in the machine tool coordinate system is the zero point distance P0=P1 between the two tool rests; (2-4) Stop tool holder 1 at the zero point, and then open tool holder 2 to the minimum spacing position allowed by the two tool holders. At this time, record the coordinate value P of tool holder 2 in the machine tool coordinate system. 2min , then the minimum allowable spacing between the two tool holders is P min =ABS(P 2min )+P0; (2-5) Open tool holder 1 in the positive direction and tool holder 2 in the negative direction to the maximum position allowed by the two tool holders. At this time, record the coordinate values ​​P of the two tool holders in the machine tool coordinate system. 1max and P 2max , then the maximum allowable distance between the two tool holders is P max =ABS(P 1max )+ABS(P 2max )+P0; (2-6) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =ABS(P T1 -P T2 )+P0, and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max ; When P T ≤P min The alarm of the minimum allowable distance between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked; When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked; (3) Data measurement with reverse zero point at the center (3-1) Move the two tool rests of the machine tool to the center point and set the zero point. The coordinate displayed by the machine tool coordinate system is 0.000, and the zero point distance between the two tool rests is P0 = 0; (3-2) Open tool holder 1 to the zero position, and then open tool holder 2 to tool holder 1 to the minimum position allowed by the machine. At this time, record the coordinate P of tool holder 2 in the machine tool coordinate system. 2min , then the minimum allowable spacing between the two tool holders is P min =ABS(P 2min ); (3-3) Open the two tool holders to their limit positions at both ends. At this time, record the coordinates P of tool holder 1 and tool holder 2 in the machine tool coordinate system. 1max and P 2max , then the maximum allowable spacing between the two tool holders is P max =ABS(P 1max +P 2max ); (3-4) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =ABS(P T1 +P T2 ), and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max ; When P T ≤P min The alarm of the minimum allowable distance between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked; When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked; (4) Data measurement with reverse zero point at both ends (4-1) First, move the two tool holders of the machine tool to the positions where the zero points are to be set. The coordinates displayed by the machine tool coordinate system are 0.

000. (4-2) Mark the reference point at the center; (4-3) Open tool rest 1 and tool rest 2 to the reference point mark respectively, and record the coordinate value P1 of tool rest 1 and the coordinate value P2 of tool rest 2 in the machine tool coordinate system respectively. The zero point distance P0 of the two tool rests is ABS(P1+P2); (4-3) Open tool holder 1 and tool holder 2 to the minimum position allowed by the machine, and record the coordinate value P of tool holder 1 in the machine tool coordinate system. 1min and the coordinate value P of tool holder 2 2min , then the minimum allowable spacing between the two tool holders is P min =P0-ABS(P 1min +P 2min ); (4-4) Open the two tool holders to their limit positions at both ends. At this time, record the coordinates P of tool holder 1 and tool holder 2 in the machine tool coordinate system. 1max and P 2max , then the maximum allowable spacing between the two tool holders is P max =P0+ABS(P 1max +P 2max ); (4-5) Use PLC to read the real-time coordinate values ​​P of tool holder 1 and tool holder 2 respectively T1 and P T2 , PLC automatically calculates the real-time spacing between the two tool holders as P T =P0+P T1 +P T2 , and then use PLC to compare the real-time spacing P T and minimum spacing P min and the maximum spacing P max When P T ≤P min The alarm of the minimum allowable distance between the two tool holders is triggered, and the corresponding moving directions of the two axes are locked; When P T ≥P max The maximum allowable spacing alarm between the two tool holders is triggered, and the corresponding movement directions of the two axes are locked.

2. The anti-collision protection method for a PLC double-tool-post machine tool according to claim 1 is characterized in that: The servo motor of the tool holder axis moves in a linear axis.

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