CN108838563A - RTCP precision compensation method for five-axis laser processing equipment - Google Patents

Abstract

The invention particularly relates to an RTCP precision compensation method for five-axis laser processing equipment, which solves the problems that the precision compensation method for the existing mechanical five-axis processing equipment is not suitable for the five-axis laser processing equipment and cannot ensure the processing precision of the laser processing equipment. The method comprises the following steps: 1) respectively acquiring a Z-direction vector from a laser processing point to an A rotation axis, a vector from a laser beam central axis to the A rotation axis and a vector from the laser beam central axis to a C rotation axis; 2) and inputting each group of parameters into a control system to complete the precision compensation of the RTCP function.

Description

A RTCP accuracy compensation method for five-axis laser processing equipment

technical field

The invention relates to the field of five-axis laser processing equipment, in particular to an RTCP precision compensation method for five-axis laser processing equipment.

Background technique

With the wide application of laser processing technology, the advantages of laser processing are gradually reflected. Compared with other processing technologies, its main features are: 1. Non-contact processing. Laser processing does not require tools, and there is no mechanical stress in edge trimming, and there are no problems such as tool wear, replacement and disassembly, which greatly shortens the processing time; 2. The thermal impact on the processed materials is small. The surface of the object irradiated by the laser beam is a local area, and its heat-affected area is very small, which has almost no effect on the non-irradiated area, so the workpiece will basically not be deformed; 3. The processing is flexible. The laser beam is easy to focus, diverge and guide, and it is convenient to obtain light spots of different sizes and different powers to meet different processing requirements; 4. Wide range of processing materials. Laser processing can be used for the processing of composite materials, glass, metal, wood and other materials. Based on the above characteristics of laser processing, it has been widely used in aerospace, automobile, electronics and other industries.

As a typical representative of the combination of laser processing and traditional five-axis linkage, five-axis laser processing equipment has both the technical advantages of laser processing and five-axis interpolation, and has been widely used in the field of high-end processing. The existing five-axis processing equipment is basically composed of three linear axes + two rotating axes. Based on the structure of the rotating axes of each equipment, it can be divided into the following three types: a. Tool rotation type, that is, double swing head structure, two Two rotary shafts drive the tool to rotate; b, tool rotation + workpiece rotation type, one rotary shaft drives the tool to rotate, and the other rotary shaft drives the workpiece to rotate; c, workpiece rotation type, both rotary shafts drive the workpiece to rotate.

In the process of laser processing, the additional movement of the tool tip point is generated due to the rotary motion, so the control point of the control system usually does not coincide with the tool tip point, and the control system must automatically correct the control point to ensure that the tool tip point follows the prescribed trajectory. sports. Among the above three types of processing equipment, when the RTCP function is applied to the double swing head structure, the center point of the swing head rotation is used for compensation. Its full name is Rotated Tool Center Point, and its structure is shown in Figure 1. .

In the field of mechanical processing, the RTCP accuracy compensation measurement of five-axis linkage processing equipment is usually detected by the combination tool of "standard gauge + dial indicator". , use a dial gauge to measure the error for compensation. However, the structure of five-axis laser processing equipment is quite different from that of ordinary mechanical five-axis processing equipment. First, it does not have a spindle. Secondly, because the focused beam is usually invisible (such as infrared light and ultraviolet light), it does not have the same shape as the focused beam. "Gauge sticks" of similar dimensions. To sum up, the RTCP accuracy compensation method for mechanical five-axis processing equipment is not suitable for five-axis laser processing equipment, and cannot guarantee the processing accuracy of laser processing equipment.

Contents of the invention

The purpose of the present invention is to solve the problem that the accuracy compensation method of existing mechanical five-axis processing equipment is not suitable for five-axis laser processing equipment, and cannot guarantee the processing accuracy of laser processing equipment, and proposes an RTCP accuracy compensation method for five-axis laser processing equipment . This method fills in the gaps in this field. By using this method, the processing accuracy of the five-axis linkage of laser processing equipment is guaranteed, and because this method has certain versatility, it can be used for reference by other forms of laser processing equipment, such as laser engraving etching, laser drilling, laser cleaning, etc.

Technical scheme of the present invention is:

A five-axis laser processing equipment RTCP accuracy compensation method, the five-axis laser processing equipment includes three linear axes XYZ, A rotation axis, and C rotation axis, and the A rotation axis and C rotation axis respectively surround the X axis and the Z axis The axis of rotation is performed, including the following steps:

1) Obtain the Z-direction vector from the laser processing point to the A rotation axis, the vector from the laser beam center axis to the A rotation axis, and the vector from the laser beam center axis to the C rotation axis;

2) Input each group of parameters into the control system to complete the precision compensation of the RTCP function.

Further, obtaining the Z-direction vector from the laser processing point to the A rotation axis in step 1) specifically includes the following steps,

1.11) A standard flat plate is set on the equipment workbench, the length, width and height of the standard flat plate are respectively parallel to the X-axis, Y-axis and Z-axis of the processing equipment;

1.12) Rotate the C rotation axis to 90°, and the A rotation axis to 90°;

1.13) Move the laser processing point to the right side of the standard plate, and record the X-axis coordinates;

1.14) Rotate the C rotation axis to 270°, move the X axis to move the laser processing point to the left side of the standard plate, and record the △X value of the X axis relative to step 1.13);

1.15) Half of the difference between △X and h is the Z-direction vector from the laser processing point to the A rotation axis, and h is the length of the standard plate.

Further, in step 1.13), a displacement sensor is provided on the laser processing head, and the X-axis coordinate value is obtained by reading the value of the displacement sensor.

Further, obtaining the vector from the central axis of the laser beam to the A rotation axis in step 1) specifically includes the following steps,

1.21) Fix the standard plate on the equipment table;

1.22) Rotate the C rotation axis to 0°, the A rotation axis to 90° position, process the first marking point on the front surface of the standard plate through the laser processing point, and record the Z-axis coordinates of the equipment;

1.23) Rotate the C rotation axis 180°, A rotation axis to -90° position, move the laser processing point to the first mark point in step 1.22), and record the Z-axis coordinate at this time;

1.24) Half of the Z-axis coordinate difference in step 1.22) and step 1.23) is used as the Y-direction component of the laser beam central axis to the A rotation axis vector;

1.25) Rotate the C rotation axis to 90°, the A rotation axis to 90°, use the laser processing point to process the second marking point on the left side of the standard plate, and record the Z-axis coordinates at this time;

1.26) Rotate the C rotation axis to 270°, the A rotation axis to -90°, move the laser processing point to the second mark point in step 1.25), and record the Z-axis coordinate at this time;

1.27) Half of the Z-axis coordinate difference in step 1.25) and step 1.26) is used as the X-direction component of the laser beam central axis to the A rotation axis vector;

1.28) through the Y component of the laser beam central axis obtained in step 1.24) to the A rotation axis vector and the X component of the laser beam central axis obtained in step 1.27) to the A rotation axis vector, obtain the laser beam central axis to the A rotation axis vector.

Further, obtaining the vector from the central axis of the laser beam to the C rotation axis in step 1) specifically includes the following steps,

1.31) Fix the standard plate on the equipment table;

1.32) Rotate the C rotation axis to 0°, the A rotation axis to the 0° position, use the laser processing points to process the third marking point on the upper surface of the standard plate, and record the X-axis coordinates of the equipment at this time;

1.33) Rotate the C rotation axis to 180°, keep the 0° position of the A rotation axis unchanged, move the laser processing point to the third mark point in step 1.32), and record the X-axis coordinates of the equipment at this time;

1.34) Half of the X-axis coordinate difference in step 1.32) and step 1.33) is used as the X-direction component of the laser beam central axis to the C rotation axis vector;

1.35) Rotate the C rotation axis to 90°, keep the 0° position of the A rotation axis unchanged, use the laser processing point to process the fourth mark point on the upper surface of the standard plate, and record the Y-axis coordinates of the equipment at this time;

1.36) Rotate the C rotation axis to 270°, keep the 0° position of the A rotation axis unchanged, move the laser processing point to the fourth mark point in step 1.35), and record the Y-axis coordinates of the equipment at this time;

1.37) Half of the Y-axis coordinate difference in step 1.35) and step 1.36) is used as the Y-direction component of the laser beam central axis to the C rotation axis vector;

1.38) through the X-direction component of the laser beam central axis obtained in step 1.34) to the C rotation axis vector and the Y-direction component of the laser beam central axis obtained in step 1.37) to the C rotation axis vector, obtain the laser beam central axis to the C rotation axis vector.

Compared with the prior art, the present invention has the following technical effects:

The present invention proposes an accuracy compensation method using five-axis linkage RTCP function processing equipment, through which the five-axis interpolation accuracy of laser processing equipment can be improved, and the blank of RTCP accuracy compensation related to laser processing five-axis equipment is filled.

Description of drawings

Fig. 1 is the structural diagram of existing double-swing head five-axis laser processing equipment;

Fig. 2 is a vector closed-loop schematic diagram of the compensation method of the present invention.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the content of the present invention is described in further detail:

As shown in Figure 1, the five-axis laser processing equipment of the present invention is an existing tool rotation type, that is, a processing equipment with a double swing head structure. The equipment includes five axes of XYZAC, wherein the A rotation axis and the C rotation axis are double swing axes , can drive the laser processing head to achieve rotation and yaw motion; XYZ axis is a linear axis, which can drive the processed parts to achieve linear motion. The positive direction of the Cartesian coordinate system formed by the above-mentioned XYZ axes conforms to the right-hand rule, the movement directions of the A rotation axis and the C rotation axis respectively rotate around the axes of the X axis and the Z axis, and the positive direction of rotation conforms to the right-hand spiral Rule (the thumb points to the positive direction of the axis, and the direction of the four fingers is the positive direction of the rotation axis).

As shown in Figure 2, the present invention provides an RTCP accuracy compensation method for five-axis laser processing equipment, which mainly includes the measurement of three groups of parameters, namely the Z-direction vector from the laser processing point to the A rotation axis, the laser beam The vector from the central axis to the A rotation axis and the vector from the laser beam center axis to the C rotation axis, the accuracy compensation of each group of parameters includes the following steps:

1) The Z-direction vector of the laser processing point P to the rotation axis of A;

1.1) Fix a standard flat plate with known thickness on the equipment workbench. The length, width and height of the standard flat plate are parallel to the X-axis, Y-axis and Z-axis of the processing equipment respectively. The surface of the standard flat plate parallel to the X-axis is the front surface. The surface of the standard plate parallel to the Y axis is the left side, and the surface of the standard plate parallel to the XY plane is the upper surface; define the C rotation axis as 0° in the negative X axis direction, and define the A rotation axis as 0° in the negative Z axis direction ;

1.2) Rotate the C rotation axis to 90°, and the A rotation axis to 90°;

1.3) Move the laser processing point to the right side of the standard plate, and record the X-axis coordinates;

1.4) Rotate the C rotation axis to 270°, move the X axis to move the laser processing point to the left side of the standard plate, and record the △X value of the X axis relative to step 1.3);

1.5) (△X-standard plate length)/2 is the vertical distance from the laser processing point to the A rotation axis;

2) The vector from the central axis of the laser beam to the rotation axis of A;

2.1) Fix the standard plate on the equipment table;

2.2) Rotate the C rotation axis to 0°, the A rotation axis to 90°, use the laser processing point to process the first marking point on the front surface of the standard plate, and record the Z-axis coordinates of the equipment at this time;

2.3) Rotate the C rotation axis by 180°, then adjust the A rotation axis to -90°, move the laser processing point to the first mark point in step 2.2), and record the Z-axis coordinate at this time;

2.4) Half of the Z-axis coordinate difference in step 2.2) and step 2.3) is used as the Y-direction component of the laser beam central axis to the A rotation axis vector;

2.5) Rotate the C rotation axis to 90°, the A rotation axis to 90°, use the laser processing point to process the second marking point on the left side of the standard plate, and record the Z-axis coordinates at this time;

2.6) Rotate the C rotation axis to 270°, the A rotation axis to -90°, move the laser processing point to the second mark point in step 2.5), and record the Z-axis coordinate at this time;

2.7) Half of the Z-axis coordinate difference in step 2.5) and step 2.6) is used as the X-direction component of the laser beam central axis to the A rotation axis vector;

2.8) through the Y-direction component of the laser beam center axis obtained in step 2.4) to the A rotation axis vector and the X-direction component of the laser beam center axis obtained in step 2.7) to the A rotation axis vector, obtain the laser beam center axis to the A rotation axis the vector;

3) The vector from the central axis of the laser beam to the C rotation axis;

3.1) Fix the standard plate on the equipment table;

3.2) Rotate the C rotation axis to 0°, the A rotation axis to the 0° position, use the laser processing points to process the third marking point on the upper surface of the standard plate, and record the X-axis coordinates at this time;

3.3) Rotate the C rotation axis to 180°, keep the 0° position of the A rotation axis unchanged, move the laser processing point to the third mark point in step 2, and record the X-axis coordinates at this time;

3.4) Half of the X-axis coordinate difference in step 3.2) and step 3.3) is used as the X-direction component of the laser beam central axis to the C rotation axis vector;

3.5) Rotate the C rotation axis to 90°, keep the 0° position of the A rotation axis unchanged, use the laser processing point to process the fourth mark point on the upper surface of the standard plate, and record the Y-axis coordinates of the equipment at this time;

3.6) Rotate the C rotation axis to 270°, keep the 0° position of the A rotation axis unchanged, move the laser processing point to the fourth mark point in step 5, and record the Y-axis coordinates of the equipment at this time;

3.7) Half of the Y-axis coordinate difference in step 3.5) and step 3.6) is used as the Y-direction component of the laser beam central axis to the C rotation axis vector;

3.8) through the X-direction component of the laser beam center axis obtained in step 3.4) to the C rotation axis vector and the Y-direction component of the laser beam center axis obtained in step 3.7) to the C rotation axis vector, obtain the laser beam center axis to the C rotation axis the vector;

4) After the three groups of parameters are detected by the above method, each group of parameters is input into the control system to complete the precision compensation of the RTCP function;

During the CNC multi-axis interpolation process, the CNC system first calculates the position of each interpolation point on the machining path (including the coordinates of the interpolation point and the direction vector), and then converts the position of the interpolation point into the coordinates of the XYZAC five-axis motion position. In each interpolation cycle, the offset generated by the movement of the AC rotary axis must be compensated by the XYZ axis. Therefore, after the CNC system obtains the above compensation data, according to the relative positional relationship between the AC rotary axes in the XYZ direction, Calculate the offset compensation amount of the XYZ axis of the machine tool during the interpolation process of the AC rotary axis, so as to realize the RTCP function and greatly improve the machining efficiency and machining accuracy.

Wherein, the sequence of above-mentioned step 1), step 2) and step 3) is not required by the present invention, as long as the three groups of parameters of the present invention can be obtained, that is, the sequence of step 1), step 2) and step 3) can be exchange.

The specific embodiment that adopts the method of the present invention is as follows:

The accuracy compensation parameters of RTCP include several vectors, and each vector forms a vector closed loop. This method is aimed at these vectors (the Z-direction vector from the laser processing point to the A rotation axis, the vector from the laser beam center axis to the C rotation axis, and the laser beam center axis to the first rotation axis) provides a calibration method, and then realizes the accuracy compensation of RTCP;

1) The Z-direction vector from the laser processing point to the A rotation axis;

1.1) Fix a standard plate with a length of 10mm on the workbench;

1.2) Rotate the C rotation axis to 90°, and the A rotation axis to 90°;

1.3) Install a displacement sensor on the laser processing head, then move the laser processing point to the right side of the standard plate, and read the value F of the displacement sensor at this time (this value represents the displacement when the laser processing point falls on the standard plate. The distance from the sensor to the standard plate), and record the X-axis coordinates;

1.4) Rotate the C rotation axis to 270°, move the X axis to move the laser processing point to the left side of the standard plate (make sure the displacement sensor indicates F at this time), and record the △X of the X axis relative to step 1.3);

1.5) (△X-10)/2 is the Z-direction vector from the laser processing point to the A rotation axis;

2) The vector from the central axis of the laser beam to the rotation axis of A;

2.1) Fix the standard plate on the equipment table;

2.2) Rotate the C rotation axis to 0°, the A rotation axis to 90°, use the displacement sensor to ensure that the processing point is located on the front surface of the standard plate, and ensure that the displacement sensor indicates F, and use the beam quality analyzer to read this The position of the light spot on the beam quality analyzer (the position of the laser processing point can be more accurately measured by the beam quality analyzer), and record the Z-axis coordinates of the equipment at this time;

2.3) Rotate the C rotation axis 180°, then adjust the A rotation axis to -90° position, move the laser processing point through the Y axis of the equipment until the displacement sensor shows F, then move the X axis and Z axis to translate the laser processing point to Step 2.2) At the position measured by the beam quality analyzer, and record the Z-axis coordinate at this time;

2.4) Half of the Z-axis coordinate difference in step 2.2) and step 2.3) is used as the Y-direction component of the laser beam central axis to the A rotation axis vector;

2.5) Rotate the C rotation axis to 90°, the A rotation axis to 90°, use the displacement sensor to ensure that the processing point is located on the surface of the standard plate, ensure that the displacement sensor shows F, and use the beam quality analyzer to read the spot at this time At the position of the beam quality analyzer (the position of the laser processing point can be measured more accurately with the beam quality analyzer), record the Z-axis coordinates of the equipment at this time;

2.6) Rotate the C rotation axis to 270°, the A rotation axis to -90°, move the laser processing point through the X axis of the equipment until the displacement sensor indicates F, and then move the Y axis and Z axis to translate the laser processing point to the step 2.5) At the position measured by the beam quality analyzer, and record the Z-axis coordinates at this time;

2.7) Half of the Z-axis coordinate difference in step 2.5) and step 2.6) is used as the X-direction component of the laser beam central axis to the A rotation axis vector;

2.8) Calculate the Y-direction component of the laser beam central axis to A rotation axis vector obtained in step 2.4) and the X-direction component of the laser beam central axis to A rotation axis vector obtained in step 2.7), and obtain the laser beam central axis to A the vector of the axis of rotation;

3) The vector from the central axis of the laser beam to the C rotation axis;

3.1) Fix the standard plate on the equipment table;

3.2) The C rotation axis is rotated to 0°, the A rotation axis is rotated to the 0° position, and the displacement sensor is used to ensure that the processing point is located on the upper surface of the standard flat plate, and the indication value of the displacement sensor is F. Use the beam quality analyzer to read the position of the spot on the beam quality analyzer at this time (the beam quality analyzer can be used to more accurately measure the position of the laser processing point), and record the X-axis coordinates of the equipment at this time;

3.3) Rotate the C rotation axis to 180°, keep the 0° position of the A rotation axis unchanged, move the laser processing point to the position measured by the beam quality analyzer in step 3.2), and record the X-axis coordinates of the equipment at this time;

3.4) Half of the X-axis coordinate difference in step 3.2) and step 3.3) is used as the X-direction component of the laser beam central axis to the C rotation axis vector;

3.5) Rotate the C rotation axis to 90°, and the 0° position of the A rotation axis remains unchanged. Use the beam quality analyzer to read the position of the spot on the beam quality analyzer at this time (the beam quality analyzer can be used to measure the laser beam more accurately. The location of the processing point), record the Y-axis coordinates of the equipment at this time;

3.6) Rotate the C rotation axis to 270°, keep the 0° position of the A rotation axis unchanged, move the laser processing point to the position measured by the beam quality analyzer in step 3.5), and record the Y-axis coordinates of the equipment at this time;

3.7) Half of the Y-axis coordinate difference in step 3.5) and step 3.6) is used as the Y-direction component of the laser beam central axis to the C rotation axis vector;

3.8) Calculate the X-direction component of the laser beam central axis to the C rotation axis vector obtained in step 3.4) and the Y-direction component of the laser beam central axis to the C rotation axis vector obtained in step 3.7), and obtain the laser beam central axis to C the vector of the axis of rotation;

4) After the three groups of parameters are detected by the above method, each group of parameters is input into the control system to complete the precision compensation of the RTCP function.

Claims (5)

1. a kind of five axis laser process equipment RTCP precision compensation methods, the five axis laser process equipment includes XYZ tri- straight Spool, A rotary shaft, C rotary shaft, the A rotary shaft, C rotary shaft surround X-axis respectively, the axis of Z axis is rotated, It is characterized in that, includes the following steps：

1) obtain respectively laser processing point to the Z-direction vector of A rotation axis, laser central beam axis to A rotation axis vector, Vector of the laser central beam axis to C rotation axis；

2) accuracy compensation of RTCP function will be completed in each group parameter input control system.

2. five axis laser process equipment RTCP precision compensation method according to claim 1, it is characterised in that：In step 1) The Z-direction vector for obtaining laser processing point to A rotation axis specifically includes following steps,

1.11) dressing plate is set on equipment workbench, and the length of the dressing plate is respectively parallel to process equipment X-axis, Y-axis, Z axis；

1.12) C rotary shaft is rotated to 90 °, A rotary shaft is rotated to 90 °；

1.13) laser processing point is moved to dressing plate right side, records X axis coordinate；

1.14) C rotary shaft will be rotated to 270 °, mobile X-axis makes laser processing point be moved to dressing plate left side, and record is at this time △ X value of the X-axis relative to step 1.13)；

1.15) half of △ X and h difference is the Z-direction vector for laser machining point and arriving A rotation axis, and h is dressing plate length.

3. five axis laser process equipment RTCP precision compensation method according to claim 2, it is characterised in that：Step 1.13) in, it is provided with displacement sensor on laser Machining head, obtains X axis coordinate value by reading the value of displacement sensor.

4. five axis laser process equipment RTCP precision compensation method according to claim 1, it is characterised in that：In step 1) The vector for obtaining laser central beam axis to A rotation axis specifically includes following steps,

1.21) dressing plate is fixed on equipment workbench；

1.22) C rotary shaft is rotated to 0 °, A rotary shaft is rotated to 90 ° of positions, through laser processing point before dressing plate Surface processes the first mark point, recording equipment Z axis coordinate；

1.23) C rotary shaft is rotated 180 °, A rotary shaft is moved to the of step 1.22) to -90 ° of positions, by laser processing point At one mark point, and record Z axis coordinate at this time；

1.24) step 1.22) is with the half of Z axis coordinate difference in step 1.23) as laser central beam axis to A rotation axis The Y-direction component of vector；

1.25) C rotary shaft is rotated to 90 °, A rotary shaft is rotated to 90 °, is added using laser processing point in dressing plate left side The second mark point of work records Z axis coordinate at this time；

1.26) C rotary shaft is rotated to 270 °, A rotary shaft is rotated to -90 °, and laser processing point is moved to step 1.25) At second mark point, and record Z axis coordinate at this time；

1.27) step 1.25) is with the half of Z axis coordinate difference in step 1.26) as laser central beam axis to A rotation axis The X of vector is to component；

1.28) Y-direction component and step of the laser central beam axis obtained by step 1.24) to A rotation axis vector 1.27) the laser central beam axis obtained obtains laser central beam axis to A rotary shaft to the X of A rotation axis vector to component The vector of line.

5. five axis laser process equipment RTCP precision compensation method according to any one of claims 1 to 4, it is characterised in that： The vector that laser central beam axis to C rotation axis are obtained in step 1) specifically includes following steps,

1.31) dressing plate is fixed on equipment workbench；

1.32) C rotary shaft is rotated to 0 °, A rotary shaft rotates to 0 ° of position, using laser processing point in dressing plate upper surface Third mark point is processed, equipment X axis coordinate at this time is recorded；

1.33) C rotary shaft is rotated to 180 °, 0 ° of position of A rotary shaft is constant, and laser processing point is moved to step 1.32) At third mark point, record equipment X axis coordinate at this time；

1.34) step 1.32) is with the half of X axis coordinate difference in step 1.33) as laser central beam axis to C rotation axis The X of vector is to component；

1.35) C rotary shaft is rotated to 90 °, 0 ° of position of A rotary shaft is constant, using laser processing point in dressing plate upper surface The 4th mark point is processed, equipment Y axis coordinate at this time is recorded；

1.36) C rotary shaft is rotated to 270 °, 0 ° of position of A rotary shaft is constant, and laser processing point is moved to step 1.35) At 4th mark point, equipment Y axis coordinate at this time is recorded；

1.37) step 1.35) is with the half of Y axis coordinate difference in step 1.36) as laser central beam axis to C rotation axis The Y-direction component of vector；

1.38) the laser central beam axis obtained by step 1.34) is to the X of C rotation axis vector to component and step 1.37) the laser central beam axis obtained obtains laser central beam axis to C rotary shaft to the Y-direction component of C rotation axis vector The vector of line.