A method for calibrating a laser tool setter using a self-made standard bar

Abstract

The present application belongs to the technical field of laser tool setting, and particularly relates to a method for calibrating a laser tool setting instrument using a self-made standard rod. The present application can adapt to various different calibration scenes by establishing a universal geometric parameter model for the self-made standard rod, and meanwhile, the cost of the equipment is reduced by more than 90%. In the calibration process, according to the triggering principle of the laser tool setting instrument, the installation error of the laser tool setting instrument is considered, the motion chain of the calibration system is constructed, and the mathematical model of the calibration process is further obtained. The coordinates of the center point of the laser axis of the laser tool setting instrument in the machine tool coordinate system can be accurately solved through the mathematical model. The inaccurate calibration caused by the installation error of the laser tool setting instrument in the traditional calibration process is solved. In addition, the calibration cycle time of the present method is also greatly reduced, and the calibration efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of laser tool setting technology, and specifically relates to a method for calibrating a laser tool setting instrument using a self-made standard rod. Background Technology

[0002] A laser tool setter is an instrument installed inside a machine tool to accurately measure the dimensions and status of cutting tools. Due to its advantages such as high precision, strong anti-interference capability, and real-time online operation, it is widely used in CNC machining. Before use, the position of the laser axis center point in the machine tool coordinate system must be obtained; this process is called laser tool setter calibration. If the calibration is inaccurate, the dimensions of every tool measured by the laser tool setter will be incorrect, leading to out-of-tolerance machining of parts or even scrapping. Therefore, accurate calibration of the laser tool setter is a crucial step in achieving high-precision tool measurement and ensuring product manufacturing quality. The standard tool used for calibrating the laser tool setter is called a standard bar. Before calibration, the dimensions and geometric parameters of the standard bar must be known.

[0003] Traditional commercial standard rods are very expensive, and their calibration results are not accurate enough when laser tool setters have installation errors. The installation and adjustment process of laser tool setters is very cumbersome, and the errors are almost impossible to eliminate. Therefore, this invention designs a self-made standard rod, takes installation errors into account based on the working mechanism of the laser tool setter, and proposes a method for high-precision calibration of laser tool setters using a self-made standard rod by establishing a mathematical model of the calibration process. Summary of the Invention

[0004] To address the technical problems raised in the background art, this invention provides a method for calibrating a laser tool setter using a self-made standard rod, comprising:

[0005] The carbide bar is inserted into the collet, the collet is inserted into the tool holder of the machine tool spindle, and the screw cap is tightened into the tool holder while the collet is pressed into the screw cap to obtain the self-made standard bar.

[0006] Establish a tool holder coordinate system with the reference point of the tool holder as the origin, and obtain the parametric equations of the bottom edge curve, side surface, and side surface normal vector of the carbide bar in the tool holder coordinate system.

[0007] Establish a machine tool spindle coordinate system with the reference point of the machine tool spindle as the origin, establish a laser tool setter coordinate system with the center point of the laser beam of the laser tool setter as the origin, and determine the direction vector of the laser beam axis in the laser tool setter coordinate system.

[0008] The parametric equations of the bottom edge curve, side surface, and side surface normal vector of the cemented carbide bar in the tool holder coordinate system are converted into parametric equations in the laser tool setter coordinate system.

[0009] A coordinate system for the laser receiver is established with the intersection of the laser beam axis and the laser tool setter receiver as the origin. Under the coordinate system of the laser tool setter, the contour curve of the side surface of the cemented carbide rod along the direction of the laser beam is solved according to the direction vector of the laser beam axis and the normal vector of the side surface of the cemented carbide rod.

[0010] The contour curve and the bottom edge curve of the carbide rod in the coordinate system of the laser tool setter are projected onto the laser receiver to obtain the first projection curve. The area of ​​the shadow region formed by the self-made standard rod and the laser beam at the laser receiver is determined according to the first projection curve and the second projection curve of the laser beam projected onto the laser receiver.

[0011] In response to the area of ​​the shadow region reaching a preset threshold of the projection area of ​​the laser beam on the laser receiver, the laser tool setter is triggered, the machine tool spindle stops moving, and the position of the reference point of the machine tool spindle in the machine tool coordinate system is recorded at this moment, so as to obtain the calibration value of the laser tool setter in each axis in the machine tool coordinate system.

[0012] Preferably, the tool holder coordinate system (O) th X th Y th Z th The direction of the axis is Z. th The axis, with upward as the positive direction, has the middle plane of the tool holder keyway as X. th The axis, with the positive direction being towards the outside of the tool holder; Y th The axis is determined by Cartesian right-hand rule; the perpendicular distance between the end face of the screw cap and the mating surface between the tool holder and the machine tool spindle is denoted as the tool holder length L. th The distance between the center point of the bottom surface of the cemented carbide rod and the end face of the screw cap along the axis of the cemented carbide rod is denoted as the length L of the cemented carbide rod.

[0013] The parametric equation of the bottom edge curve of the cemented carbide rod 1 in the tool holder coordinate system is as follows:

[0014]

[0015] Where ρ is the offset distance; λ is the offset azimuth angle; and τ is the angle between the axis of the carbide rod 1 and the axis of the tool holder 3, i.e., the tilt angle. The azimuth angle is tilted.

[0016] The parametric equation of the side surface of the cemented carbide rod 1 in the tool holder coordinate system is as follows:

[0017]

[0018] The parametric equation of the side surface normal vector of cemented carbide rod 1 in the tool holder coordinate system is:

[0019]

[0020] As a preferred option, the machine tool spindle coordinate system (O) s X s Y s Z s The origin O is taken as the reference point of the machine tool spindle. s , its X s Y s Z s All axes are aligned with the machine tool coordinate system (O). m X m Y m Z m ) of X m Y m Z m The axes are parallel;

[0021] Laser tool setting coordinate system (O) ts X ts Y ts Z ts Taking the center point of the laser beam as the origin O of the coordinate system ts , its X ts Y ts Z ts All axes are aligned with the machine tool coordinate system (O). m X m Y m Z m ) of X m Y m Z m The axes are parallel;

[0022] Let the axis of the laser beam be relative to the X-axis of the laser tool setter coordinate system. ts Y ts The angle between the planes is β, and the axis of the laser beam is at X. ts Y ts Projection of a plane and X ts The angle formed by the counterclockwise rotation between the axes is α.

[0023] The direction vector of the laser beam axis in the coordinate system of the laser tool setter is expressed as:

[0024]

[0025] Preferably, the homogeneous transformation matrix from the tool holder coordinate system to the machine tool spindle coordinate system is:

[0026]

[0027] Where θ is the X coordinate of the machine tool spindle coordinate system. m The axis rotates counterclockwise relative to the X coordinate system of the tool holder. th The angle formed by the axes;

[0028] Using a self-made standard bar along the Z-axis of the machine tool m When using a laser tool setter for axis calibration, the homogeneous transformation matrix from the machine tool spindle coordinate system to the laser tool setter coordinate system is:

[0029]

[0030] Among them, z d The vertical distance between the center point of the bottom surface of the cemented carbide rod and the center point of the laser beam;

[0031] As a preferred option

[0032] Parametric equations of the bottom edge curve and side surface of the cemented carbide rod in the coordinate system of the laser tool setter:

[0033]

[0034] The parametric equation of the side surface normal vector of the cemented carbide rod in the coordinate system of the laser tool setter is:

[0035]

[0036] Preferably, the contour curve is solved as follows: for l ts ·n ts Solving for 0 and substituting the parametric equations of the side surface in the laser tool setting coordinate system yields the profile curve C of the side surface of the cemented carbide rod along the laser beam direction. ts (h);

[0037] The formula for the first projection curve is:

[0038]

[0039] In the formula, P p (t) and C p (h) The curve encloses the projection curves of the side and bottom surfaces of the cemented carbide rod in the projection plane of the laser receiver, L re This represents the distance from the center point of the laser beam along the laser beam axis to the receiving end of the laser tool setter.

[0040] Preferably, the formula for calculating the projected area of ​​the laser beam at the laser receiver is:

[0041] A s =πR 2

[0042] Where R represents the radius of the laser beam.

[0043] Preferably, the area of ​​the shadow region formed by the self-made standard rod and the laser beam at the laser receiving end is determined based on the projection curve, including:

[0044] For Pp (t) and C p The first projection curve of the cemented carbide rod composed of (h) is used to generate polygon W1 using the convex hull algorithm;

[0045] The second projection curve obtained by projecting the laser beam is represented by polygon W2.

[0046] The polygon intersection algorithm is used to calculate the intersecting polygon W3 of polygons W1 and W2;

[0047] Calculate the area of ​​the intersecting polygon W3 to obtain the size of the shadow region in the projection plane of the laser receiver;

[0048] The vertices (x1, y1), (x2, y2), ..., (x2, y2) of the intersecting polygon W3 arranged in clockwise or counterclockwise order n ,y n Its area is:

[0049]

[0050] Where, x n+1 =x1,y n+1 =y1, the two ends are connected to form a closed loop.

[0051] As a preferred option, the laser tool setter is positioned in the machine tool coordinate system (Z-axis). m The calibration values ​​on the shaft are determined as follows:

[0052] When the laser tool setter is triggered, the reference point Os of the machine tool spindle is recorded in the Z-axis of the machine tool coordinate system. m The axis coordinates are

[0053] Z of the laser tool setter m Axial direction calibration value The formula is:

[0054]

[0055] In the formula, z′ d This indicates the vertical distance between the center point of the bottom surface of the cemented carbide rod 1 and the center point of the laser axis 9.

[0056] As a preferred option, a self-made standard bar is used along the Y-axis of the machine tool. m When using a laser tool setter for axis calibration, the homogeneous transformation matrix from the machine tool spindle coordinate system to the laser tool setter coordinate system is:

[0057]

[0058] Where L s The end face of the screw cap 4 and the center point of the laser beam 9 are along the Z-axis of the machine tool. mThe distance along the axial direction, i.e., the measured height. y d The axis of the machine tool spindle 5 and the center point of the laser beam 9 are located at the measurement height along the Y-axis of the machine tool. m Distance along the axial direction;

[0059] Using a self-made standard bar along the Y-axis of the machine tool m When calibrating a laser tool setter for axis alignment, the homogeneous transformation matrix used to transform the machine tool spindle coordinate system to the laser tool setter coordinate system is used to calculate the parametric equations for the bottom edge curve, side surface, and side surface normal vector of the carbide rod. Replace with

[0060] When the laser tool setter is triggered, record the spindle reference point O. s Y in machine tool coordinate system m The axis coordinates are y d Size is y′ d The Y-axis of the laser tool setter can be obtained. m Axial direction calibration value for:

[0061]

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] This invention establishes a universal geometric parameter model for a self-made standard bar, adaptable to various calibration scenarios, while reducing equipment costs by over 90%. During calibration, based on the triggering principle of the laser tool setter, the installation error of the laser tool setter is taken into account, constructing the kinematic chain of the calibration system and further obtaining a mathematical model of the calibration process. This mathematical model allows for the accurate calculation of the coordinates of the laser axis center point of the laser tool setter in the machine tool coordinate system. This solves the calibration inaccuracies caused by installation errors of the laser tool setter in traditional calibration processes. Furthermore, the calibration cycle time of this method is significantly reduced, improving calibration efficiency. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the composition and structure of the self-made standard bar of this invention;

[0065] Figure 2 This is a schematic diagram of the assembly of the self-made standard rod of the present invention;

[0066] Figure 3 This is a schematic diagram of the eccentricity parameters of the self-made standard bar in this invention;

[0067] Figure 4 This is a schematic diagram of calibrating the laser tool setter using a self-made standard rod in this invention;

[0068] Figure 5 This is a schematic diagram of the laser beam tilt in the laser tool setting device of this invention;

[0069] Figure 6 z' in this invention d Solution flowchart;

[0070] The components are: 1. Carbide rod; 2. Screw cap; 3. Tool holder; 4. Spring collet; 5. Machine tool spindle; 6. Laser tool setter receiver; 7. Laser tool setter bracket; 8. Laser tool setter transmitter; 9. Laser beam. Detailed Implementation

[0071] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0072] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0073] Example 1

[0074] The homemade standard bar consists of a carbide rod 1, a spring collet 4, a tool holder 3, and a screw cap 2. Insert the carbide rod 1 into the spring collet 4, then insert the spring collet 4 into the tool holder 3. Finally, tighten the screw cap 2 onto the tool holder 3 to obtain the homemade standard bar. See [link / reference]. Figure 1 and Figure 2 .

[0075] Due to assembly errors between the carbide rod 1 and the spring collet 4, and between the spring collet 4 and the tool holder 3, the axis of the carbide rod 1 and the axis of the tool holder 3 will inevitably not coincide, forming skew lines. Before calibrating the laser tool setter, the dimensions and degree of eccentricity of the self-made standard rod must be fully known.

[0076] The specific steps are as follows: First, establish the tool holder coordinate system (O). th X th Y th Z th ), with the reference point of tool holder 3 as the origin O of the coordinate system. th The axis direction is Z. th The axis is upward, with the positive direction being upward; the middle plane of the tool holder keyway is X. th The axis, with the positive direction being towards the outside of tool holder 3; Y th The axis is determined using Cartesian right-hand rule. The perpendicular distance between the end face of the screw cap 2 and the mating surfaces between the tool holder 3 and the machine tool spindle 5 is denoted as the tool holder length L. th The distance between the center point of the bottom surface of the cemented carbide rod 1 and the end face of the screw cap 2 along the axis of the cemented carbide rod 1 is denoted as the length L of the cemented carbide rod. See also Figure 2 The plane containing the end face of screw cap 2 intersects with the carbide rod 1, and the intersection curve is an ellipse. The eccentricity parameter of the self-made standard rod is defined within the plane containing the end face of screw cap 2. (See [reference needed]). Figure 3 .

[0077] The parametric equation of the bottom edge curve of the cemented carbide rod 1 in the tool holder coordinate system is as follows:

[0078]

[0079] Where ρ is the offset distance; λ is the offset azimuth angle; τ is the angle between the axis of the carbide rod 1 and the axis of the tool holder 3, i.e., the tilt angle; and φ is the tilt azimuth angle.

[0080] The parametric equation of the side surface of the cemented carbide rod 1 in the tool holder coordinate system is as follows:

[0081]

[0082] The parametric equation of the side surface normal vector of cemented carbide rod 1 in the tool holder coordinate system is:

[0083]

[0084] Further establish the connection between the self-made standard bar and the machine tool spindle. Construct the machine tool spindle coordinate system (O). s X s Y s Z s The origin O is taken as the reference point of the machine tool spindle. s , its Xs Y s Z s All axes are aligned with the machine tool coordinate system (O). m X m Y m Z m ) of X m Y m Z m Axis parallel, see Figure 4 .

[0085] The homogeneous transformation matrix for transforming the tool holder coordinate system to the machine tool spindle coordinate system is:

[0086]

[0087] Where θ is the X coordinate of the machine tool spindle coordinate system. m The axis rotates counterclockwise relative to the X coordinate system of the tool holder. th The angle formed by the axes.

[0088] Ideally, the laser tool setter is mounted on the machine tool's worktable, and the axis of its laser beam 9 should be aligned with the X-axis of the machine tool's coordinate system. m The axes are parallel. However, due to installation errors, the axis of the laser beam 9 will be tilted relative to the ideal state. To quantify this, a coordinate system (O) for the laser tool setter is established. ts X ts Y ts Z ts ), with the center point of the laser beam 9 as the origin O of the coordinate system. ts , its X ts Y ts Z ts All axes are aligned with the machine tool coordinate system (O). m X m Y m Z m ) of X m Y m Z m The axes are parallel, and the X-axis of the laser beam 9 is denoteed as parallel to the coordinate system of the laser tool setter. ts Y ts The angle between the two planes is β, and the axis of the laser beam 9 is at X. ts Y ts Projection of a plane and X ts The angle formed by the counterclockwise rotation between the axes is α, see [reference]. Figure 5 .

[0089] The direction vector of the axis of the laser beam 9 in the coordinate system of the laser tool setter is represented by equation (5), and the direction is along the beam direction.

[0090]

[0091] Using a self-made standard bar along the Z-axis of the machine tool m When using a laser tool setter for axis calibration, the homogeneous transformation matrix from the machine tool spindle coordinate system to the laser tool setter coordinate system is:

[0092]

[0093] Among them, z d It is the vertical distance between the center point of the bottom surface of the cemented carbide rod 1 and the center point of the laser beam 9.

[0094] Combining the above equations, we can obtain the parametric equations for the bottom edge curve and side surface of the cemented carbide rod 1 in the coordinate system of the laser tool setter.

[0095]

[0096] The parametric equation of the side surface normal vector of cemented carbide rod 1 in the coordinate system of the laser tool setter is:

[0097]

[0098] Thus, based on the relationship between the coordinate systems, the parameter model of the self-made standard bar is transformed into the coordinate system of the laser tool setter through the homogeneous coordinate transformation matrix.

[0099] The calibration triggering principle of the laser tool setter is as follows: when the intensity of the laser beam 9 emitted from the laser tool setter transmitter 8 is reduced to 50% of that under unobstructed conditions, the laser tool setter will output a trigger signal to the machine tool controller, and the controller will record the position of the machine tool spindle reference point at this moment.

[0100] The intensity of the laser beam 9 received by the laser tool setter receiver 6 is inversely proportional to the area of ​​the shadow region formed by the blocking of the laser beam 9.

[0101] Furthermore, to determine the area of ​​the shadow region formed by the self-made standard rod and the laser beam 9 at the projection plane of the laser tool setter receiver 6, a coordinate system (O) is established at the laser receiver. re X re Y re Z re The origin O is defined as the intersection of the laser beam axis 9 and the laser tool setter receiver 6. re With the axis of laser beam 9 as X... re The axis, with the beam direction being positive. Z re The axis lies within the projection plane of the receiving end and is perpendicular to X. re Axial direction, Y re The axis is determined by Cartesian right-hand rule, see [link / reference]. Figure 5 .

[0102] Furthermore, in the coordinate system of the laser tool setter, the contour curve of the side surface of the cemented carbide rod 1 along the direction of the laser beam 9 is solved.

[0103] l ts ·n ts =0 (10)

[0104] The result t of equation (10) can be solved numerically, and the result can be substituted into equation (8) to obtain the contour curve of the side surface of the cemented carbide rod 1 along the direction of the laser beam 9 in the coordinate system of the laser tool setter, denoted as C. ts (h).

[0105] The homogeneous transformation matrix from the coordinate system of the laser tool setter to the coordinate system of the laser receiver is:

[0106]

[0107] Among them, L re The distance from the center point of laser beam 9 along the axis of laser beam 9 to the receiving end 6 of the laser tool setter.

[0108] In the coordinate system of the laser receiver, to its Y direction re Z re The homogeneous coordinate transformation matrix of the orthogonal projection of the plane is:

[0109]

[0110] Furthermore, the contour curve C in the laser tool setter coordinate system will be... ts (h) and the bottom edge curve P of the cemented carbide rod 1 ts (t) Projected onto the Y coordinate system of the laser receiver re Z re flat

[0111]

[0112] Therefore, P p (t) and C p (h) curves enclose the projection curves of the side and bottom surfaces of the cemented carbide rod 1 in the projection plane of the laser receiver.

[0113] When the laser beam 9 propagates from the laser tool setter's emitting end 8 to its receiving end 6, neglecting the change in light intensity during propagation, the laser beam 9 can be represented by a cylinder. Therefore, the curve of the laser beam 9 in the projection plane of the laser receiving end is a circle S. p Its parametric equation can be expressed as:

[0114]

[0115] R represents the radius of the laser beam 9, which can be found in the manufacturer's manual for laser tool setting equipment.

[0116] S p Area A s for:

[0117] A s =πR 2 (15)

[0118] To further determine the area of ​​the shadow region produced by the cemented carbide rod 1 and the laser beam 9 on the projection plane of the laser receiver, the projection curve P of the cemented carbide rod 1 is used. p (t) and C p (h) Use the convex hull algorithm to generate polygon W1, for the projection curve S of laser beam 9. p Let polygon W2 represent the intersection of polygons W1 and W2. The polygon W3, which intersects polygon W2, is calculated using the polygon intersection algorithm. The area of ​​polygon W3, i.e., the area of ​​the shadow region in the projection plane of the laser receiver, can be calculated using formula (16).

[0119] If the vertices (x1, y1), (x2, y2), ..., (x...) on the intersecting polygon W3 are arranged in clockwise or counterclockwise order... n ,y n Its area is:

[0120]

[0121] Where, x n+1 =x1,y n+1 =y1, the two ends are connected to form a closed loop.

[0122] The convex hull is a smallest convex polygon on a plane, given a set of points, such that all points lie inside or on the edges of the polygon. The polygon intersection algorithm calculates the overlapping area of ​​two polygons and does not involve other Boolean operations.

[0123] According to the triggering mechanism of the laser tool setter, as the self-made standard rod gradually approaches the laser beam 9 of the laser tool setter, the area of ​​the shadow region on the laser receiving end plane gradually increases. When the area of ​​the shadow region increases to fifty percent of the area of ​​the laser beam 9 end face, that is... At this time, the laser tool setter is triggered, the machine tool spindle stops moving, and the spindle reference point O at this moment is recorded. s Position in the machine tool coordinate system.

[0124] When the laser tool setter is triggered, record the spindle reference point O. s Z in machine tool coordinate system m The axis coordinates are The vertical distance z between the center point of the bottom surface of the cemented carbide rod 1 and the center point of the laser axis 9 d Size is z′ d The Z-axis of the laser tool setter can be obtained. m Axial direction calibration value

[0125]

[0126] Since the dimensions of the tool holder 3 and the carbide rod 1, as well as their eccentricity parameters, can be accurately measured on the tool presetting device, the tilt of the laser beam 9 can also be measured and calculated on a machine tool using a self-made standard rod. To obtain the Z-axis of the laser tool setter... m The axis direction calibration value still needs to be solved for z' d Size.

[0127] z' d See the solution method. Figure 6 First, the length of the tool holder 3, the dimensions and eccentricity parameters of the carbide rod 1, and the tilt angle of the laser beam 9 in the laser tool setter were measured. Then, z was given. d The value is substituted into the homogeneous transformation matrix. Then, calculate the area of ​​the shadowed region within the plane of the laser receiver. Determine if the absolute value of the difference between the calculated area and the target area is less than the tolerance of 0.0001. If the condition is met, output the z-axis at this point. d Value. If not satisfied, determine the current value of z. d If the value is less than the radius r of the cemented carbide rod 1, then z d Increment by 1µm (the positioning accuracy of a typical machine tool) and proceed to the next cycle. If the accuracy is not met, an error message is displayed and the cycle exits.

[0128] By following the steps above, the laser tool setter can be accurately calibrated in the machine tool coordinate system using a self-made standard rod at the Z-axis. m Axial direction calibration value Furthermore, a self-made standard bar was used to calibrate the laser tool setter in the Y-axis of the machine tool coordinate system. m Axial calibration values

[0129] Using a self-made standard bar along the Y-axis of the machine tool m When using a laser tool setter for axis calibration, the homogeneous transformation matrix from the machine tool spindle coordinate system to the laser tool setter coordinate system is:

[0130]

[0131] Where L s The end face of the screw cap 4 and the center point of the laser beam 9 are along the Z-axis of the machine tool. m The distance along the axial direction, i.e., the measured height. y dThe axis of the machine tool spindle 5 and the center point of the laser beam 9 are located at the measurement height along the Y-axis of the machine tool. m The distance along the axial direction, when the self-made standard rod is used to calibrate the laser tool setter in the positive direction (from the machine tool + Y). m To-Y m Directional feed), take +y d Negative calibration (from machine tool - Y) m To +Y m Directional feed), take -y d .

[0132] When the laser tool setter is triggered, record the spindle reference point O. s Y in machine tool coordinate system m The axis coordinates are The distance between the center point of the bottom surface of the cemented carbide rod 1 and the center point of the laser axis 9 is in the Y direction. m Distance y along the axis d Size is y′ d The Y-axis of the laser tool setter can be obtained. m Axial direction calibration value for:

[0133]

[0134] When calibrating positively, a positive sign is used; when calibrating with a sign, a negative sign is used.

[0135] y' d The solution method and z' d The basic principles are the same, so I will not repeat them here. Please refer to the relevant documentation. Figure 6 , and Matrix replacement That's all.

[0136] To verify the feasibility of the method of this invention, simulation experiments were conducted using MATLAB and SolidWorks software. First, a set of parameters for a self-made standard rod and a laser tool setter were given. Then, according to the method of this invention, a program was written in MATLAB software to calculate z'. d or y' d Then, this value is considered in the SolidWorks modeling process. Finally, the area of ​​the shadow region formed by the carbide rod 1 and the laser beam 9 in SolidWorks is measured to see if it is equal to the target area. The geometric parameters used in the SolidWorks model construction must be completely consistent with the parameters used in the MATLAB calculations.

[0137] The following will solve for z' dFor example, the given simulation parameters are shown in Table 1, and the simulation results in MATLAB and the measurement results in SolidWorks are shown in Table 2. The difference between the area values ​​in the simulation results and the measurement results is 0.000012 mm. 2 This slight deviation occurs because the simulation accuracy in MATLAB can theoretically reach the maximum length of variable data types, while SolidWorks can only set the maximum dimensional accuracy to 8 decimal places (in mm). Therefore, SolidWorks cannot fully support the accuracy of the MATLAB algorithm, resulting in this minor deviation. This demonstrates that even with errors in the laser tool setter (α, β ≠ 0), the simulation results maintain a high degree of consistency with the measurement results, verifying the accuracy of the method presented in this invention.

[0138] Table 1 Parameters of the self-made standard rod and laser tool setter

[0139]

[0140]

[0141] Table 2 Simulation and Measurement Results

[0142]

[0143] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for calibrating a laser tool setter using a self-made standard rod, characterized in that, include: The carbide bar is inserted into the collet, the collet is inserted into the tool holder of the machine tool spindle, and the screw cap is tightened into the tool holder while the collet is pressed into the screw cap to obtain the self-made standard bar. Establish a tool holder coordinate system with the reference point of the tool holder as the origin, and obtain the parametric equations of the bottom edge curve, side surface, and side surface normal vector of the carbide bar in the tool holder coordinate system. Establish a machine tool spindle coordinate system with the reference point of the machine tool spindle as the origin, establish a laser tool setter coordinate system with the center point of the laser beam of the laser tool setter as the origin, and determine the direction vector of the laser beam axis in the laser tool setter coordinate system. The parametric equations of the bottom edge curve, side surface, and side surface normal vector of the cemented carbide bar in the tool holder coordinate system are converted into parametric equations in the laser tool setter coordinate system. A coordinate system for the laser receiver is established with the intersection of the laser beam axis and the laser tool setter receiver as the origin. Under the coordinate system of the laser tool setter, the contour curve of the side surface of the cemented carbide rod along the direction of the laser beam is solved according to the direction vector of the laser beam axis and the normal vector of the side surface of the cemented carbide rod. The contour curve and the bottom edge curve of the carbide rod in the coordinate system of the laser tool setter are projected onto the laser receiver to obtain the first projection curve. The area of ​​the shadow region formed by the self-made standard rod and the laser beam at the laser receiver is determined according to the first projection curve and the second projection curve of the laser beam projected onto the laser receiver. In response to the area of ​​the shadow region reaching a preset threshold of the projection area of ​​the laser beam on the laser receiver, the laser tool setter is triggered, the machine tool spindle stops moving, and the position of the reference point of the machine tool spindle in the machine tool coordinate system is recorded at this moment, so as to obtain the calibration value of the laser tool setter in each axis in the machine tool coordinate system.

2. The method for calibrating a laser tool setter using a self-made standard rod according to claim 1, characterized in that, The axis of the tool holder coordinate system is Z. th The axis, with upward as the positive direction, has the middle plane of the tool holder keyway as X. th The axis, with the positive direction being towards the outside of the tool holder; Y th The axis is determined by Cartesian right-hand rule; the perpendicular distance between the end face of the screw cap and the mating surface between the tool holder and the machine tool spindle is denoted as the tool holder length L. th The distance between the center point of the bottom surface of the cemented carbide rod and the end face of the screw cap along the axis of the cemented carbide rod is denoted as the length L of the cemented carbide rod. The parametric equation of the bottom edge curve of the cemented carbide rod (1) in the tool holder coordinate system is: Where ρ is the offset distance; λ is the offset azimuth angle; τ is the angle between the axis of the carbide rod (1) and the axis of the tool holder (3), i.e., the tilt angle; φ is the tilt azimuth angle. The parametric equation of the side surface of the cemented carbide rod (1) in the tool holder coordinate system is as follows: The parametric equation of the side surface normal vector of the cemented carbide rod (1) in the tool holder coordinate system is: 。 3. The method for calibrating a laser tool setter using a self-made standard rod according to claim 2, characterized in that, The machine tool spindle coordinate system takes the reference point of the machine tool spindle as its origin O. s , its X s Y s Z s The axes are all aligned with the X coordinate system of the machine tool. m Y m Z m The axes are parallel; The coordinate system of the laser tool setter has its origin O at the center point of the laser beam. ts , its X ts Y ts Z ts The axes are all aligned with the X coordinate system of the machine tool. m Y m Z m The axes are parallel; Let the axis of the laser beam be relative to the X-axis of the laser tool setter coordinate system. ts Y ts The angle between the planes is β， The axis of the laser beam is in the X-axis. ts Y ts Projection of a plane and X ts The angle formed by the counterclockwise rotation between the axes is α ; The direction vector of the laser beam axis in the coordinate system of the laser tool setter is expressed as: 。 4. The method for calibrating a laser tool setter using a self-made standard rod according to claim 3, characterized in that, The homogeneous transformation matrix from the tool holder coordinate system to the machine tool spindle coordinate system is: in, θ X is the coordinate system of the machine tool spindle. m The axis rotates counterclockwise relative to the X coordinate system of the tool holder. th The angle formed by the axes; Using a self-made standard bar along the Z-axis of the machine tool m When using a laser tool setter for axis calibration, the homogeneous transformation matrix from the machine tool spindle coordinate system to the laser tool setter coordinate system is: in, z d This is the vertical distance between the center point of the bottom surface of the cemented carbide rod and the center point of the laser beam.

5. A method for calibrating a laser tool setter using a self-made standard rod according to claim 4, characterized in that, Parametric equations of the bottom edge curve and side surface of the cemented carbide rod in the coordinate system of the laser tool setter: The parametric equation of the side surface normal vector of the cemented carbide rod in the coordinate system of the laser tool setter is: 。 6. A method for calibrating a laser tool setter using a self-made standard rod according to claim 5, characterized in that, The solution method for the contour curve is as follows: Solving for the parametric equations of the side surface in the laser tool setting coordinate system yields the profile curve of the side surface of the cemented carbide rod along the laser beam direction. C ts ( h ); The formula for the first projection curve is: In the formula, P p ( t ) and C p ( h The curves enclose the projection curves of the side and bottom surfaces of the cemented carbide rod onto the projection plane of the laser receiver. L re This represents the distance from the center point of the laser beam along the laser beam axis to the receiving end of the laser tool setter.

7. A method for calibrating a laser tool setter using a self-made standard rod according to claim 1, characterized in that, The formula for calculating the projected area of ​​the laser beam at the laser receiver is: in, R This represents the radius of the laser beam.

8. A method for calibrating a laser tool setter using a self-made standard rod according to claim 6, characterized in that, The area of ​​the shadow region formed by the self-made standard rod and the laser beam at the laser receiver end, determined based on the projection curve, includes: For P p ( t ) and C p ( h The first projection curve of the cemented carbide rod composed of ) is used to generate polygon W using the convex hull algorithm. 1； The second projection curve obtained by projecting the laser beam is represented by polygon W2; The polygon intersection algorithm is used to calculate the intersecting polygon W1 and polygon W2. 3； Calculate the area of ​​the intersecting polygon W3 to obtain the size of the shadow region in the projection plane of the laser receiver; Vertices of intersecting polygon W3 arranged in clockwise or counterclockwise order ( x 1, y 1),( x 2, y 2)…( x n , y n Its area is: in, x n+1 = x 1, y n+1 = y 1. The two ends are connected to form a closed loop.

9. A method for calibrating a laser tool setter using a self-made standard rod according to claim 8, characterized in that, Laser tool setter in machine tool coordinate system Z m The calibration values ​​on the shaft are determined as follows: When the laser tool setter is triggered, the reference point Os of the machine tool spindle is recorded in the Z-axis of the machine tool coordinate system. m The axis coordinates are ; Z of the laser tool setter m Axial direction calibration value The formula is: In the formula, This indicates the vertical distance between the center point of the bottom surface of the cemented carbide rod and the center point of the laser axis.

10. A method for calibrating a laser tool setter using a self-made standard rod according to claim 9, characterized in that, Using a self-made standard bar along the Y-axis of the machine tool m When using a laser tool setter for axis calibration, the homogeneous transformation matrix from the machine tool spindle coordinate system to the laser tool setter coordinate system is: in L s The distance between the end face of the screw cap and the center point of the laser beam along the Z-axis of the machine tool m The distance along the axial direction, i.e., the measured height; y d The axis of the machine tool spindle and the center point of the laser beam are located at the measurement height along the Y-axis of the machine tool. m Distance along the axial direction; Using a self-made standard bar along the Y-axis of the machine tool m When calibrating a laser tool setter for axis alignment, the homogeneous transformation matrix used to transform the machine tool spindle coordinate system to the laser tool setter coordinate system is used to calculate the parametric equations for the bottom edge curve, side surface, and side surface normal vector of the carbide rod. Replace with ; When the laser tool setter is triggered, record the spindle reference point O. s Y in machine tool coordinate system m The axis coordinates are The distance between the center point of the bottom surface of the cemented carbide rod and the center point of the laser axis is in the Y direction. m Distance y along the axis d Size is The Y-axis of the laser tool setter can be obtained. m Axial direction calibration value for 。

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