CN115255609A - Self-adaptive positioning method for complex curved surface femtosecond laser micropore processing - Google Patents

Abstract

The invention discloses a self-adaptive positioning method for complex curved surface femtosecond laser micropore processing, which measures the positions of a plurality of characteristic points on a blade body through a distance measuring sensor, takes the positions as input to carry out iterative approximation with a theoretical model to form a blade body coordinate transformation matrix, and then transforms the air film hole coordinate into a machine tool coordinate to obtain the processing accurate position and direction of the air film hole.

Description

Self-adaptive positioning method for complex curved surface femtosecond laser micropore processing

[ technical field ] A method for producing a semiconductor device

The invention belongs to the technical field of femtosecond laser micropore processing, and particularly relates to a self-adaptive positioning method for complex curved surface femtosecond laser micropore processing.

[ background of the invention ]

The femtosecond laser processing integrates an ultrafast laser technology, an ultrahigh precision positioning technology and a microscopic technology, is a novel CMC-SiC material processing mode, and has the following main advantages compared with the common processing mode: 1. the processing damage is small: the femtosecond ultrashort pulse laser has short pulse duration, the energy finishes the interaction with the substance in a very small time and space, the heat cannot be diffused in time from the beginning to the end of the processing, the energy is only accumulated in a thin layer of a material micro area, and after the processing is finished, the material around the damaged area is still in a cold state, so that a plurality of negative effects brought by the thermal effect in the traditional processing are greatly reduced; 2. the processing precision is high: the femtosecond laser energy is distributed in a Gaussian or quasi-Gaussian form in space and time, so that the intensity of only the central part of a focusing light spot can reach the processing threshold of a material, the energy absorption and action range in processing is limited in a small volume at the central part of a focus, the processing scale is far smaller than the size of the light spot, and the processing scale reaches submicron or even nanoscale.

There are related studies at present, for example, chinese patent application No. CN202110490885.8 is a femtosecond laser rotary type dual-spot beam micropore processing method, which uses a spatial light modulator to load 0-pi phase to perform phase shaping on incident femtosecond laser with gaussian intensity distribution, because different phases are applied to the left and right parts of an incident gaussian light field, in the middle area where the two parts are overlapped, a light field intensity dark area is formed due to phase distortion, so that the original gaussian beam is shaped into a dual-spot beam; in the micropore machining process, the light field dark area at the center of the double-light-spot light beam is beneficial to the generated plasma to be sprayed from the position, so that the influence on the subsequent laser pulse is reduced, the energy deposition efficiency is improved, and the micropore machining depth is increased.

When an aeroengine blade air film hole is machined, the requirements of accurate positioning of the machined hole, no damage to the wall, no recasting layer, no microcrack and the like are required, and the traditional air film hole machining method comprises long pulse laser machining, electric spark machining and electro-hydraulic beam machining. The first two processing methods have larger recast layers; the electro-hydraulic beam machining can be carried out without a recast layer, but the machining efficiency is low and the machining consistency is poor.

The femtosecond laser micromachining technology is a new special machining technology, has the advantages of high machining precision, small heat affected zone, thin recasting layer, no burr, strong material applicability and the like, and is a new method for machining the air film hole of the ultra-precise aero-engine blade. In the traditional air film hole machining, a tool coordinate system is established through tool positioning, then the air film hole is machined under the tool coordinate system, and due to the fact that blade casting errors, machining errors, tool fixture manufacturing errors and the like exist, the method can cause certain deviation between the position and the angle of the air film hole and a design value, and the method has great influence on the cold efficiency performance and the service life of an aircraft engine. The positioning accuracy of the complex curved surface is very high due to the requirements of the air film hole, and the positioning accuracy of the complex curved surface is difficult to realize only depending on the positions of theoretical models of a processing machine tool and a clamp.

[ summary of the invention ]

The invention provides a self-adaptive positioning method for complex curved surface femtosecond laser micropore machining, which aims to solve the problems that the positioning precision of an air film hole in the prior art is extremely high and the required complex curved surface positioning precision is difficult to machine only depending on the positions of a machining machine tool and a theoretical model of a fixture.

The purpose of the invention is realized by the following technical scheme:

a self-adaptive positioning method for complex curved surface femtosecond laser micropore processing comprises the following steps:

1) In a theoretical model coordinate system (O, X, Y, Z)_LIn the method, characteristic points capable of optimally positioning the blade are selected on the blade, and coordinates (X) of a plurality of characteristic points are obtained on a theoretical model by using an optical measuring device_L,Y_L,Z_L,α_L,β_L)_i，i＝1，2……；

2) Establishing machine coordinate system (O, X, Y, Z) on real blade using machine positioning_MAssuming that the machine coordinate system and the theoretical model coordinate coincide, in (O, X, Y, Z)_MObtaining coordinates (X) of a plurality of points on a real blade by the optical measuring device in a coordinate system_M,Y_M,Z_M,α_M,β_M)_iI =1,2 … …; because of the difference between the real blade and the theoretical model, the coordinates of a plurality of points obtained on the real blade are different from the coordinates of a plurality of points obtained on the theoretical model;

3) Maintaining the theoretical model coordinate system (O, X, Y, Z)_LWithout change, the theoretical model of the blade is translated and rotated (Δ X, Δ Y, Δ Z, Δ α, Δ β) using the same measurement method as (O, X, Y, Z)_LMeasuring the rotated theoretical model in the coordinate system to obtain new coordinates (X) of several points_L,Y_L,Z_L,α_L,β_L)_iI =1,2 … …; through repeated iteration, finding an optimal translational rotation amount (Δ X, Δ Y, Δ Z, Δ α, Δ β), under which the difference between the coordinates of the points obtained in the theoretical model and the coordinates of the corresponding points obtained on the real blade is minimal;

4) Using the optimal translation rotation quantity (delta X, delta Y, delta Z, delta alpha, delta beta) obtained in the step 3) to establish a machine tool coordinate system (O, X, Y, Z) on the real blade_MCorrecting to obtain the optimal expression of the blade coordinate system under the machine tool coordinate system, and calculating and outputting machine tool coordinate parameters corresponding to all holes to be machined so as to guide workers to machine the hole positions of the workpiece;

the optical measurement Device comprises a control module (1), an industrial personal computer (2), a stepping motor (3), a Charge-coupled Device (CCD) (4), an imaging Device convex lens I (5), an imaging Device concave lens (6), an imaging Device convex lens II (7), a monitoring reflection light path (8), a light splitting plate (9), a processing light path (10), a focusing light path convex lens I (11), a focusing light path concave lens (12), a focusing light path convex lens II (13), a processed engine blade (14) and a fixed clamp (15) of the processed engine blade;

a beam splitter (9), a focusing light path convex lens I (11), a focusing light path concave lens (12) and a focusing light path convex lens II (13) are sequentially arranged on a straight-going light path output by the femtosecond laser, and finally, light beams reach an engine blade (14) of a processed workpiece; after part of reflected light is reflected from an engine blade (14) of a processed workpiece, an imaging device convex lens II (7), an imaging device concave lens (6), an imaging device convex lens I (5) and a charge coupling device (4) are sequentially arranged on a straight light path of a monitoring reflection light path (8) reflected by a light splitting plate (9); the charge coupling device (4) is fixed on the stepping motor (3) and is connected with the industrial personal computer (2) through a data line;

the actual focal lengths of the imaging device convex lens I (5) and the imaging device convex lens II (7) are different;

the actual focal lengths of the focusing light path convex lens I (11) and the focusing light path convex lens II (13) are different.

Step 4), the hole site processing of the workpiece comprises punching monitoring, and the specific steps are as follows:

(1) When the punching is started, each processing module is initialized, and all systems return to zero;

(2) The processing light path (10) sequentially passes through the light splitting plate (9), the focusing light path convex lens (11), the focusing light path concave lens (12) and the focusing light path convex lens (13) and reaches an engine blade (14) of a processed workpiece, and at the moment, a part of light rays can be reflected;

(3) The reflected light rays sequentially pass through a focusing light path convex lens (13), a focusing light path concave lens (12), a focusing light path convex lens (11) and a light splitting plate (9), are refracted by the light splitting plate (9) and then enter an imaging and control module (1);

(4) The refracted light rays passing through the light splitting plate (9) sequentially enter the imaging device convex lens II (7), the imaging device concave lens (6) and the imaging device convex lens I (5) and then are focused on the charge coupled device (4) of the imaging device;

(5) The charge coupled device (4) enters a master control industrial personal computer (2) after feature extraction, feature analysis and mode recognition;

(6) The stepping motor (3) is moved back and forth to change the gray level image on the charge coupled device (4), the industrial personal computer (2) judges whether the CCD (4) is the maximum gray level value, and if the CCD (4) is the maximum gray level value, the stepping motor (3) stops moving;

(7) The energy of the processing light path (10) is increased, and the industrial personal computer (2) judges whether a hole on an engine blade (14) of a processed workpiece is penetrated;

(8) If the industrial personal computer (2) judges that the penetration signal occurs, the laser energy output returns to zero, and the energy of the processing light path (10) returns to zero;

(9) And (6) forming holes.

And 4) processing hole positions of the workpiece, which comprises measurement and specifically comprises the following steps:

(1) when punching starts, each measuring module is initialized, and all systems return to zero;

(2) the measuring light path (10) sequentially passes through the beam splitter plate (9), the focusing light path convex lens (11), the focusing light path concave lens (12) and the focusing light path convex lens (13) and reaches an engine blade (14) of a processed workpiece, and at the moment, a part of light rays can be reflected;

(3) the reflected light rays sequentially pass through a focusing light path convex lens (13), a focusing light path concave lens (12), a focusing light path convex lens (11) and a light splitting plate (9), are refracted by the light splitting plate (9) and then enter an imaging and control module (1);

(4) the refracted light rays passing through the light splitting plate (9) sequentially enter the imaging device convex lens II (7), the imaging device concave lens (6) and the imaging device convex lens I (5) and then are focused on the charge coupled device (4) of the imaging device;

(5) the charge coupled device (4) is subjected to feature extraction, feature analysis and mode recognition, and sends the measured actual coordinate value to the master control computer (2);

(6) and (5) finishing the measurement.

Compared with the prior art, the invention has the following advantages:

1. the self-adaptive positioning method for complex curved surface femtosecond laser micropore processing solves the positioning problem caused by casting deviation of complex molded surfaces.

2. The self-adaptive positioning method for femtosecond laser micropore processing of the complex curved surface realizes the accurate positioning of 5 mu m without depending on an ultra-precise machine tool.

[ description of the drawings ]

FIG. 1 is a cross-sectional view of an aircraft engine film hole made in accordance with an embodiment of the present invention;

FIG. 2 is a schematic view of an aircraft engine blade and a machining tool thereof according to an embodiment of the invention;

FIG. 3 is a diagram of an aircraft engine blade film hole measurement and machining process according to an embodiment of the invention;

FIG. 4 is a schematic diagram of a conventional film hole process in comparison to the present invention.

Reference numerals:

1. a control module; 2. an industrial personal computer; 3. a stepping motor; 4. a charge coupled device; 5. an imaging device convex lens I; 6. an imaging device concave lens; 7. an imaging device convex lens II; 8. monitoring the reflected light path; 9. a light splitting plate; 10. processing a light path; 11. a focusing light path convex lens I; 12. a focusing optical path concave lens; 13. a focusing light path convex lens II; 14. a machined piece engine blade; 15. a fixing clamp for an engine blade of a workpiece to be processed.

[ detailed description ] embodiments

The following examples are provided to further illustrate the embodiments of the present invention.

Example (b):

a self-adaptive positioning method for complex curved surface femtosecond laser micropore processing comprises the following steps:

1) In a theoretical model coordinate system (O, X, Y, Z)_LIn the method, characteristic points capable of optimally positioning the blade are selected on the blade, and coordinates (X) of a plurality of characteristic points are obtained on a theoretical model by using an optical measuring device_L,Y_L,Z_L,α_L,β_L)_i，i＝1，2……；

2) Establishing machine coordinate system (O, X, Y, Z) on real blade by machine positioning_MAssuming that the machine coordinate system and the theoretical model coordinate coincide in (O, X, Y, Z)_MObtaining coordinates (X) of a plurality of points on a real blade by the optical measuring device in a coordinate system_M,Y_M,Z_M,α_M,β_M)_iI =1,2 … …; because of the difference between the real blade and the theoretical model, the coordinates of a plurality of points obtained on the real blade are different from the coordinates of a plurality of points obtained on the theoretical model;

3) Maintaining the theoretical model coordinate System (O, X, Y, Z)_LThe theoretical model of the blade is subjected to translation and rotation (Δ X, Δ Y, Δ Z, Δ α, Δ β) without change, using the same measurement method in (O, X, Y, Z)_LMeasuring the rotated theoretical model in the coordinate system to obtain new coordinates (X) of several points_L,Y_L,Z_L,α_L,β_L)_iI =1,2 … …; through repeated iteration, an optimal translation rotation amount (Δ X, Δ Y, Δ Z, Δ α, Δ β) is found, under which the coordinates of the points obtained in the theoretical model and the coordinates of the points obtained on the real blade are obtainedThe difference between the coordinates of the corresponding points is minimal;

4) Using the optimal translation rotation quantity (delta X, delta Y, delta Z, delta alpha, delta beta) obtained in the step 3) to establish a machine tool coordinate system (O, X, Y, Z) on the real blade_MCorrecting to obtain the optimal expression of the blade coordinate system under a machine tool coordinate system, calculating and outputting machine tool coordinate parameters corresponding to all holes to be machined, and further guiding workers to machine the hole positions of the workpieces;

the optical measurement device comprises a control module (1), an industrial personal computer (2), a stepping motor (3), a Charge-coupled device (CCD) (4), an imaging device convex lens I (5), an imaging device concave lens (6), an imaging device convex lens II (7), a monitoring reflection light path (8), a light splitting plate (9), a processing light path (10), a focusing light path convex lens I (11), a focusing light path concave lens (12), a focusing light path convex lens II (13), a processed engine blade (14) and a fixed clamp (15) of the processed engine blade;

a beam splitter (9), a focusing light path convex lens I (11), a focusing light path concave lens (12) and a focusing light path convex lens II (13) are sequentially arranged on a straight-going light path output by the femtosecond laser, and finally, light beams reach an engine blade (14) of a processed workpiece; after part of reflected light is reflected from an engine blade (14) of a processed workpiece, an imaging device convex lens II (7), an imaging device concave lens (6), an imaging device convex lens I (5) and a charge coupling device (4) are sequentially arranged on a straight light path of a monitoring reflection light path (8) reflected by a light splitting plate (9); the charge coupling device (4) is fixed on the stepping motor (3) and is connected with the industrial personal computer (2) through a data line;

the actual focal lengths of the imaging device convex lens I (5) and the imaging device convex lens II (7) are different;

the focusing light path convex lens I (11) and the focusing light path convex lens II (13) have different actual focal lengths.

And 4) processing the hole positions of the workpiece, wherein the hole position processing comprises punching monitoring, and the processing comprises the following specific steps:

(1) When the punching is started, each processing module is initialized, and all systems return to zero;

(2) The processing light path (10) sequentially passes through the beam splitter (9), the focusing light path convex lens (11), the focusing light path concave lens (12) and the focusing light path convex lens (13) and reaches an engine blade (14) of a processed workpiece, and at the moment, a part of light rays can be reflected;

(3) The reflected light rays sequentially pass through a focusing light path convex lens (13), a focusing light path concave lens (12), a focusing light path convex lens (11) and a light splitting plate (9), are refracted by the light splitting plate (9) and then enter an imaging and control module (1);

(4) The refracted light rays passing through the light splitting plate (9) sequentially enter the imaging device convex lens II (7), the imaging device concave lens (6) and the imaging device convex lens I (5) and then are focused on the charge coupled device (4) of the imaging device;

(5) The charge coupled device (4) enters a master control industrial personal computer (2) after feature extraction, feature analysis and mode recognition;

(6) The stepping motor (3) is moved back and forth to change the gray level image on the charge coupled device (4), the industrial personal computer (2) judges whether the CCD (4) is the maximum gray level value, and if the CCD (4) is the maximum gray level value, the stepping motor (3) stops moving;

(7) The energy of the processing light path (10) is increased, and the industrial personal computer (2) judges whether a hole on an engine blade (14) of a processed workpiece is penetrated;

(8) If the industrial personal computer (2) judges that the penetration signal occurs, the laser energy output returns to zero, and the energy of the processing light path (10) returns to zero;

(9) And (6) forming holes.

Step 4), the hole site processing of the workpiece comprises measurement, and the specific steps are as follows:

(1) when the punching is started, each measuring module is initialized, and all systems return to zero;

(2) the measuring light path (10) sequentially passes through the beam splitter plate (9), the focusing light path convex lens (11), the focusing light path concave lens (12) and the focusing light path convex lens (13) and reaches an engine blade (14) of a processed workpiece, and at the moment, a part of light rays can be reflected;

(3) the reflected light rays sequentially pass through a focusing light path convex lens (13), a focusing light path concave lens (12), a focusing light path convex lens (11) and a light splitting plate (9), are refracted by the light splitting plate (9) and then enter an imaging and control module (1);

(4) after entering a convex lens II (7) of the imaging device, a concave lens (6) of the imaging device and a convex lens I (5) of the imaging device in sequence through the refracted light of the light splitting plate (9), focusing on a charge coupled device (4) of the imaging device;

(5) the charge coupled device (4) is subjected to feature extraction, feature analysis and mode recognition, and sends the measured actual coordinate value to the master control computer (2);

(6) and (5) finishing the measurement.

Comparative example:

in the traditional air film hole machining, a tool coordinate system is established through tool positioning, and then the air film hole is machined under the tool coordinate system.

As shown in fig. 4, because there are always deviations of casting, milling, tooling, etc. between the real workpiece and the theoretical model, the position of the machining micro-hole inevitably has deviations, and it is difficult to ensure the position precision of batch machining.

Results and summary:

according to the self-adaptive positioning method for femtosecond laser micropore processing of the complex curved surface, disclosed by the invention, an iterative mathematical model with multi-feature fusion is constructed for the first time, the high-precision self-adaptive positioning technology of the complex curved surface is broken through, and the positioning problem caused by casting deviation of the complex curved surface is solved; the accurate positioning of 5um is realized under the condition of not depending on an ultra-precise machine tool.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the inventive concept of the present invention, which falls into the protection scope of the present invention.

Claims (5)

1. A self-adaptive positioning method for complex curved surface femtosecond laser micropore processing is characterized in that: the method comprises the following steps:

1) In the theoretical model coordinate system (O, X, Y, Z)_LIn the method, characteristic points capable of optimally positioning the blade are selected on the blade, and coordinates (X) of a plurality of characteristic points are obtained on a theoretical model by using an optical measuring device_L,Y_L,Z_L,α_L,β_L)_i，i＝1，2……；

2) Establishing machine coordinate system (O, X, Y, Z) on real blade using machine positioning_MAssuming that the machine coordinate system and the theoretical model coordinate coincide, in (O, X, Y, Z)_MObtaining coordinates (X) of a plurality of points on the real blade in a coordinate system by using the optical measuring device_M,Y_M,Z_M,α_M,β_M)_iI =1,2 … …; because of the difference between the real blade and the theoretical model, the coordinates of a plurality of points obtained on the real blade are different from the coordinates of a plurality of points obtained on the theoretical model;

3) Maintaining the theoretical model coordinate System (O, X, Y, Z)_LThe theoretical model of the blade is subjected to translation and rotation (Δ X, Δ Y, Δ Z, Δ α, Δ β) without change, using the same measurement method in (O, X, Y, Z)_LMeasuring the rotated theoretical model in the coordinate system to obtain new coordinates (X) of several points_L,Y_L,Z_L,α_L,β_L)_iI =1,2 … …; through repeated iteration, finding an optimal translational rotation amount (Δ X, Δ Y, Δ Z, Δ α, Δ β), under which the difference between the coordinates of the points obtained in the theoretical model and the coordinates of the corresponding points obtained on the real blade is minimal;

4) Using the optimal translation rotation quantity (delta X, delta Y, delta Z, delta alpha, delta beta) obtained in the step 3) to establish a machine tool coordinate system (O, X, Y, Z) on the real blade_MCorrecting to obtain the optimal expression of the blade coordinate system under the machine tool coordinate system, and calculating and outputting machine tool coordinate parameters corresponding to all holes to be machined so as to guide workers to machine the hole positions of the workpiece;

the optical measurement device comprises a control module (1), an industrial personal computer (2), a stepping motor (3), a charge coupling device (4), an imaging device convex lens I (5), an imaging device concave lens (6), an imaging device convex lens II (7), a monitoring reflection light path (8), a light splitting plate (9), a processing light path (10), a focusing light path convex lens I (11), a focusing light path concave lens (12), a focusing light path convex lens II (13), a processed workpiece engine blade (14) and a fixed clamp (15) of the processed workpiece engine blade;

a beam splitter (9), a focusing light path convex lens I (11), a focusing light path concave lens (12) and a focusing light path convex lens II (13) are sequentially arranged on a straight-going light path output by the femtosecond laser, and finally, light beams reach an engine blade (14) of a processed workpiece; after part of reflected light is reflected from an engine blade (14) of a processed workpiece, an imaging device convex lens II (7), an imaging device concave lens (6), an imaging device convex lens I (5) and a charge coupling device (4) are sequentially arranged on a straight light path of a monitoring reflection light path (8) reflected by a light splitting plate (9); the charge coupling device (4) is fixed on the stepping motor (3) and is connected with the industrial personal computer (2) through a data line.

2. The self-adaptive positioning method for femtosecond laser micropore processing of the complex curved surface as claimed in claim 1, wherein: the actual focal lengths of the imaging device convex lens I (5) and the imaging device convex lens II (7) are different.

3. The self-adaptive positioning method for femtosecond laser micropore processing of the complex curved surface as claimed in claim 1, wherein: the actual focal lengths of the focusing light path convex lens I (11) and the focusing light path convex lens II (13) are different.

4. The self-adaptive positioning method for femtosecond laser micropore processing of the complex curved surface as claimed in claim 1, wherein: and 4) processing the hole positions of the workpiece, wherein the hole position processing comprises punching monitoring, and the processing comprises the following specific steps:

(1) When the punching starts, initializing each processing module, and enabling all systems to return to zero;

(2) The processing light path (10) sequentially passes through the beam splitter (9), the focusing light path convex lens (11), the focusing light path concave lens (12) and the focusing light path convex lens (13) and reaches an engine blade (14) of a processed workpiece, and at the moment, a part of light rays can be reflected;

(3) The reflected light rays sequentially pass through a focusing light path convex lens (13), a focusing light path concave lens (12), a focusing light path convex lens (11) and a light splitting plate (9), are refracted by the light splitting plate (9) and then enter an imaging and control module (1);

(4) The refracted light rays passing through the light splitting plate (9) sequentially enter the imaging device convex lens II (7), the imaging device concave lens (6) and the imaging device convex lens I (5) and then are focused on the charge coupled device (4) of the imaging device;

(5) The charge-coupled device (4) enters a master control industrial personal computer (2) after feature extraction, feature analysis and mode recognition;

(6) The stepping motor (3) is moved back and forth to change the gray level image on the charge coupled device (4), the industrial personal computer (2) judges whether the CCD (4) is the maximum gray level value, and if the CCD (4) is the maximum gray level value, the stepping motor (3) stops moving;

(7) The energy of the processing light path (10) is increased, and the industrial personal computer (2) judges whether a hole on an engine blade (14) of a processed workpiece is penetrated;

(8) If the industrial personal computer (2) judges that the penetration signal occurs, the laser energy output returns to zero, and the energy of the processing light path (10) returns to zero;

(9) And (7) forming holes.

5. The self-adaptive positioning method for femtosecond laser micropore processing of a complex curved surface as claimed in claim 1, wherein: and 4) processing hole positions of the workpiece, which comprises measurement and specifically comprises the following steps:

(1) when punching starts, each measuring module is initialized, and all systems return to zero;

(2) the measuring light path (10) sequentially passes through the light splitting plate (9), the focusing light path convex lens (11), the focusing light path concave lens (12) and the focusing light path convex lens (13) to reach an engine blade (14) of a processed workpiece, and at the moment, a part of light can be reflected;

(3) the reflected light rays sequentially pass through a focusing light path convex lens (13), a focusing light path concave lens (12), a focusing light path convex lens (11) and a light splitting plate (9), are refracted by the light splitting plate (9) and then enter an imaging and control module (1);

(4) the refracted light rays passing through the light splitting plate (9) sequentially enter the imaging device convex lens II (7), the imaging device concave lens (6) and the imaging device convex lens I (5) and then are focused on the charge coupled device (4) of the imaging device;

(5) the charge coupled device (4) is subjected to feature extraction, feature analysis and mode recognition, and sends the measured actual coordinate value to the master control computer (2);

(6) and (5) finishing the measurement.

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