RU2279964C1 - Method of positioning of tool in reference system of machine tool in automated engraving complex - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention can be used in machining of workpieces with complex relief of engraving pattern formed on surface of functional layer of blanks on NC machines. Prior to forming reference coordinate system X₁Y₁Z₁, correction of control programs of NC system for deflection from flatness of working surface of functional layer of blank is carried out. For this purpose blank is preliminarily secured on mounting surface of device for spatial orientation and is spatially orientated along plane XY. For this purpose great number of points on numbering section of surface arranged on said surface at preset pitch are numbered according to coordinates "z". Form and area of numbering section are regulated by form and area of engraving pattern formed on said surface. Numbering is started from point farthest from center of section and is continued by scanning of numbering section by measuring devices with provision of registration of values of "z" coordinate in each numbering point and automatic correction of control programs of NC system basing on results of numbering. Reference coordinate system X₁Y₁Z₁ is formed from initial numbering point being functionally zero point of said system whose coordinates are verified before beginning of machining by provision of mechanical contact of top of tool secured on spindle with working surface of functional layer of blank in said point. Positioning and counting of motions of tool in process of forming fragments of three-dimensional pattern of engraving in functional layer of blank are carried out from said zero point of reference system X₁Y₁Z₁ according to control programs of NC system with due account of additional correction introduced basing on results of numbering.

EFFECT: improved quality of engraved patter.

3 cl, 4 dwg

Description

The invention relates to the field of mechanical engineering and can be mainly used in automated mechanical processing of products with a complex spatial profile of fragments of a finished engraving pattern formed by processing by planing (planing cutter) on the working surface of the workpiece functional layer (for example, metallographic model forms) on precision metal-cutting (planing) machines with a numerical control system (CNC).

The prior art methods of positioning a tool (i.e., its top and cutting edge) in the coordinate reference system of a metal cutting machine, namely, that the touch detection sensor (whose movements are tracked by the reading system of the machine) is brought to the cutting edge of the tool (usually to its top) and fix the moment the sensor touches the tool, while the fixed spatial position of the tool tip is functionally a zero point (reference point) in the coordinate system that of the machine (Yu.I. Kuznetsov et al. "Equipment for CNC machines", reference book, M .: Mashinostroenie, 1990, p. 477-487).

The prior art also knows a method of positioning a tool in the coordinate reference system of a CNC machine, which means that the tool is moved to the corresponding initial position, where, with the help of an optical position indexing system, it is recorded that its vertex reaches a predetermined reference point by combining the aforementioned vertex with the reference point of reference system of the machine (autonomously formed in space by an optical position indexing system) and displaying the image of the alignment process on the screen by means of ktivov. After completion of the alignment process described above, the coordinate system of the machine is zeroed (adapted to the coordinate system of the machine) according to the corresponding (in this case, one) coordinate and the reference for further tool movements is carried out from the reference point functionally adapted with a zero reference point of the coordinate system of the machine (SU, 612754, CL 23 Q 15/22, 1978).

The disadvantages of the above methods of positioning the tool top in the coordinate system of the machine should include their limited functionality, due to the fact that the data known from the prior art methods (due to their use only for certain types of processing, in particular - for precision boring holes) are able to provide the necessary accuracy of positioning the top of the cutting edge of the tool in the coordinate frame of the machine in only one coordinate. That is, the considered methods are not acceptable in those cases when, in order to ensure a given processing accuracy, it is necessary to provide a correction of the position of the tool tip in the coordinate reference system of the machine in three coordinates. For example, when machining on precision planing machines metallographic forms with a complex spatial profile of the microrelief (formed in the functional layer of the workpiece) in an orthogonal three-coordinate reference system.

The absence of such a possibility in the known known method of positioning (i.e., the possibility of correcting the spatial position of the tool tip in three coordinates of the orthogonal coordinate system) leads to a significant decrease in machining accuracy due to changes in the geometry of the formed profile (especially in the case of cutting, for example, curved profile grooves on the surface of the product), since the spatial orientation of the vertex and, accordingly, the cutting edge of the tool relative to the original (Zero) point of reference machine coordinate system.

The closest in technical essence to the claimed object of the invention is a method for positioning a tool in a coordinate reference system of a machine tool of an automated engraving complex, which consists in the following. An orthogonal reference coordinate system X ₁ Y ₁ Z _{1 is formed} . Spatial coordinate reference of its zero point to the zero point of the orthogonal coordinate system XYZ of the machine reference, spatially adapted with the original control programs of the numerical program control system (CNC), is used to form fragments of the volumetric picture of the engraving in the functional layer of the workpiece, which is fixed and positioned on the installation surface devices for spatial orientation relative to the XY plane of the XYZ coordinate system. And they also carry out operations of photographing the front surface of the cutting part of the tool, positioning its top in three coordinates relative to the zero point of the formed reference system X ₁ Y ₁ Z ₁ and correcting for the coordinates “x ₁ ” and “y ₁ ” passing through this vertex of the longitudinal axis of the tool relative to parallel to the axis Z ₁ or Z actual spindle rotational axis to visually display results of said photographing operations of positioning and adjustment for screen upravlyayuscheg a mechanism for moving the computer machine and coordinate the adaptation of these results with management software CNC system through electro-optical measuring system. This system includes a television computer microscope, which is stationary mounted on the main table of the machine in such a way that the main optical axis of its lens is oriented in the direction of reciprocating movement of the main table of the machine along the X or X ₁ axes _{of the} corresponding coordinate systems and coordinate adapted with the zero point of the coordinate system X ₁ Y ₁ Z ₁ . For this, the cutting part of the instrument is introduced into the field of view of the lens of the said microscope. Its top is combined with a crosshair of orthogonal axes on the monitor screen, which is located on the main optical axis of the aforementioned lens, and the spindle headstock is rotated by an angle of 360 °. And the positioning and counting of tool movements during the formation of fragments of the volumetric engraving pattern in the functional layer of the workpiece is conducted from the mentioned zero point of the reference system X ₁ Y ₁ Z ₁ according to the control programs of the CNC system, taking into account the correction with respect to the coordinates “x ₁ ” and “y ₁ ” of the aforementioned the longitudinal axis of the tool relative to the actual axis of rotation of the spindle of the machine (RU patent No. 2165348).

The disadvantages of this method known from the prior art include insufficient positioning accuracy to improve the quality and accuracy of processing products with a complex spatial profile of the microrelief of the pattern of the engraving being formed (in the functional layer of the workpiece). This is explained, firstly, by the fact that this known method does not provide for the correction of control programs of the CNC system to deviate from the flatness of the working surface of the workpiece functional layer by digitizing points of this surface on the z coordinates of a set located at a given step digitization plot (the shape and area of which is regulated by the shape and area of the engraving pattern formed on this surface). And, secondly, the fact that the reference coordinate system (in particular, its zero point) is formed in isolation from the working surface of the functional layer of the workpiece.

As a result of this, the positioning and counting of the tool movements during the formation of fragments of the volumetric engraving pattern in the workpiece functional layer are conducted from the formed zero point of the reference system X ₁ Y ₁ Z ₁ according to the control programs of the CNC system without taking into account their additional correction according to the digitization results.

It should be noted that the accuracy of processing is the most important quality criterion, for example, for metallographic model forms used, for example, in the process of manufacturing banknotes and other securities, since due to this processing parameter, as a rule, additional degrees of protection against fakes of the mentioned valuable products.

The claimed method for positioning a tool in the coordinate system of a machine tool of an automated engraving complex was based on the task of providing (using means known from the prior art) the simplification of the technology of precision positioning of the vertex and, accordingly, the cutting part of the tool in a three-coordinate reference system with increasing positioning accuracy for increasing purposes quality and accuracy of processing products with a complex spatial profile of the microrelief of the pattern formed (in the functional layer of the workpiece) engravings.

The problem is achieved due to the fact that in the method of positioning the tool in the coordinate reference system of the machine tool of the automated engraving complex, which consists in the formation of the orthogonal reference coordinate system X ₁ Y ₁ Z ₁ ; carry out spatial coordinate reference of its zero point to the zero point of the machine coordinate XYZ coordinate system, spatially adapted with the original control programs of the numerical program control system (CNC), by means of which fragments of a three-dimensional engraving pattern are formed in the workpiece functional layer, which is fixed and positioned on the installation surface devices for spatial orientation relative to the XY plane of the XYZ coordinate system; and they also carry out operations of photographing the front surface of the cutting part of the tool, positioning its vertices in three coordinates relative to the zero point of the formed reference system X ₁ Y ₁ Z ₁ and correcting for the coordinates “x ₁ ” and “at ₁ ” the longitudinal axis of the tool passing through this vertex relative to parallel to the Z or Z axis _{1 of the} actual axis of rotation of the machine spindle with the visual display of the results of the above-mentioned photographing, positioning and correction operations on the monitor screen on the mechanisms of moving the computer machine and coordinate adaptation of these results with the control programs of the CNC system by means of an optoelectronic measuring system including a television computer microscope, which is stationary mounted on the main table of the machine so that the main optical axis of its lens is oriented in the direction of reciprocating movement the main table of the machine along the X or X ₁ axes _{of the} corresponding coordinate systems and coordinate adapted with zero point ordinate system X ₁ Y ₁ Z ₁ ; for this, the front surface of the cutting part of the tool is introduced into the field of view of the lens of the said microscope, its vertex is combined with a crosshair of the orthogonal axes on the monitor screen, which is located on the main optical axis of the said lens, and the spindle headstock is rotated by an angle of 360 °; at the same time, the positioning and counting of tool movements during the formation of fragments of the volumetric engraving pattern in the workpiece functional layer is conducted from the mentioned zero point of the reference system X ₁ Y ₁ Z ₁ according to the initial control programs of the CNC system taking into account the correction along the coordinates “x ₁ ” and “at ₁ "The said longitudinal axis of the tool relative to the actual axis of rotation of the spindle of the machine, according to the invention before forming the reference coordinate system X ₁ Y ₁ Z ₁ carry out the correction of the control programs of the system we are CNC on a deviation from the flatness of the working surface of the functional layer of the workpiece, which is pre-fixed on the mounting surface of the device for spatial orientation and spatially oriented along the XY plane; why they are digitized at the “z” coordinates of the set of points of this surface located at a given step in the digitizing area, the shape and area of which is regulated by the shape and area of the engraving pattern formed on this surface; digitization starts from the point farthest from the center of the digitizing section and continues by scanning the digitizing section with measuring instruments to ensure registration of the “z” coordinate values at each digitization point and automatic correction of CNC control programs based on the digitization results; the reference coordinate system X ₁ Y ₁ Z _{1 is} formed from the starting digitization point, which is functionally the zero point of this system, the coordinates of which are specified before processing by providing mechanical contact between the top of the tool fixed in the spindle and the working surface of the workpiece functional layer at this point; at the same time, the positioning and counting of the tool movements during the formation of fragments of the volumetric engraving pattern in the workpiece functional layer is conducted from the mentioned zero point of the reference system X ₁ Y ₁ Z ₁ according to the control programs of the CNC system, taking into account their additional correction according to the digitization results.

The optimally mentioned operations of photographing the front surface of the cutting part of the tool, positioning its top in three coordinates relative to the zero point of the formed reference system X ₁ Y ₁ Z ₁ and correcting for the coordinates “x ₁ ” and “at ₁ ” the longitudinal axis of the tool passing through this vertex relative to the parallel axis Z or Z _{1 of the} actual axis of rotation of the machine spindle by means of an optoelectronic measuring system is carried out in direct and shadow light, for which the said measuring system is equipped with a screen Ohm, located in the field of view of the lens of a television computer microscope behind the input zone of the instrument in this field, as well as two illuminators, one of which is installed with the ability to illuminate the screen, and the other - the front surface of the cutting part of the tool.

It is advisable to pre-position the fixed workpiece by means of a device for spatial orientation before digitizing by determining and registering with the appropriate means of measuring the coordinate values “z” of at least three points of the working surface of the workpiece functional layer that do not lie on one straight line and subsequent alignment in the range of acceptable deviations of the values of these values through the adjusting nodes of the device for the spatial orientation of the workpiece OK.

It is obvious that each operation of the patented method individually and means for implementing the corresponding operations of the method under consideration are widely known in the art. However, the task can be solved solely due to the combination of well-known operations (technically implemented by known means) carried out in a strictly defined sequence reflected in the claims.

Therefore, reflected in the claims, the combination of features known from the prior art provides a synergistic result in the patented subject matter due to a certain relationship of these features.

An analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information and identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find an analogue characterized by signs and relationships between them that are identical to all the essential features of the claimed invention, and the prototype selected from the list of identified analogues, as the analogue closest in the set of features, made it possible to identify the set of significant, in relation w applicant sees to the technical result in the distinguishing features of the claimed subject set out in the claims.

Therefore, the claimed invention meets the patentability criterion of NOVELTY under current law.

To check the conformity of the claimed invention to the patentability criterion, the INVENTIVE LEVEL, an additional search was carried out for known technical solutions in order to identify features that match the distinctive features of the claimed invention, the results of which show that the claimed invention does not explicitly follow from the prior art, since from the prior art determined by the applicant, the influence of the essential features and transformations to the claimed invention the technical result achievement sees applicant.

In particular, the claimed invention does not provide for the following transformations of a known prototype object:

- addition of a well-known object by any well-known sign, attached to it according to known rules, to achieve a technical result, in respect of which the influence of such additions is established;

- replacement of any sign of a known object with another well-known sign to achieve a technical result, in respect of which the influence of such a replacement is established;

- the exclusion of any sign of a known object with the simultaneous exclusion due to the presence of this sign of the function and the achievement of the usual result for this exclusion;

- an increase in the number of similar features in a known object to enhance the technical result due to the presence of just such signs in the object;

- the implementation of a known object or part of it from a known material to achieve a technical result due to the known properties of the material;

- the creation of an object that includes known features, the choice of which and the relationship between them are based on known rules and the technical result achieved in this case is due only to the known properties of the features of this object and the relationships between them.

Therefore, the claimed invention meets the requirement of the patentability criterion of INVENTION according to the current legislation.

Thus, the above information indicates the fulfillment of the following set of conditions when using the claimed invention:

- an object embodying the claimed invention in its implementation is intended for use in industry, namely in the field of processing products by cutting on precision metal-cutting machines (for example, planing machines);

- for the claimed subject matter as described in the independent clause of the claims below, the possibility of its implementation using the means and methods described above or known from the prior art on the priority date is confirmed;

- an object embodying the claimed invention in its implementation, is able to ensure the achievement of the technical result perceived by the applicant.

Therefore, the claimed invention meets the requirements of the patentability criterion INDUSTRIAL APPLICABILITY under applicable law.

The invention is illustrated in graphic materials.

Figure 1 is a diagram of the digitization of a fragment of an engraving drawing.

Figure 2 - algorithm for digitizing a portion of the working surface of the workpiece by contact measuring means (i.e., by the contact method) by means of an inductive sensor.

Figure 3 - optoelectronic measuring system.

Figure 4 - conditional correction scheme for the coordinates "x ₁ " and "at ₁ " of the longitudinal axis of the tool (passing through its top) relative to the actual axis of rotation of the spindle of the machine (parallel to the axis Z or Z ₁ ).

The technical essence of the patented method of positioning the tool in the coordinate reference system of the machine (mainly for processing products by planing) of an automated engraving complex is as follows.

Before forming the reference coordinate system X ₁ Y ₁ Z ₁ , the initial control programs of the CNC system (for example, the CNC model type Sinumerik 840Di) are corrected for deviation from the flatness of the working surface of the workpiece functional layer. In this case, the workpiece is pre-fixed on the mounting surface of the device for spatial orientation and oriented along the XY plane of the machine coordinate orthogonal coordinate system XYZ.

To carry out the said correction of the initial control programs, the set of points (located at a given step) of the points of the working surface of the workpiece functional layer is digitized at the z-coordinates in the digitizing section, the shape and area of which is regulated by the shape and area of the engraving pattern formed on this surface. Digitization starts from the point farthest from the center of the digitizing section and continues by scanning the digitizing section with measuring instruments to ensure registration of the “z” coordinate values at each digitizing point (digitization accuracy in the plane of the surface of the workpiece functional layer is ensured within the range of 20 ... 30 μm) and automatic correction of CNC control programs based on the results of digitization.

Digitization of the working surface of the functional layer of the workpiece is a technological operation necessary for the correct formation of an engraving pattern on this surface. As a rule, the surface of the workpiece has a smooth change in geometry (in particular, the height of the bumps relative to the XY plane of the coordinate system of the machine). To account for this change, the aforementioned digitization of the workpiece is performed. For this, various measuring instruments known from the prior art can be used, which are divided into contact and non-contact. For example, the inductive sensor used in this automated engraving complex is a contact. Non-contact measuring instruments include, for example, interferometers and laser meters. The latter have an important advantage over contact ones, since there is no need to raise / lower the sensor above the surface of the workpiece, so as not to damage its mirror working surface during scanning. However, the cost of a laser meter is significantly higher than the cost of a contact sensor.

Another disadvantage of a contact meter is the presence of an inertial element (i.e., a spring) in it, which requires appropriate consideration (in particular, determining the exposure time interval for damping oscillatory processes) when registering the measured value.

The workpiece is digitized using an inductive sensor connected to the inductive transducer installed in the socket of the tool holder (i.e., the spindle of the machine headstock). The inductive converter has an analog output on which an output signal is generated in the form of a voltage level. The output signal is fed to one of the inputs of the analog-to-digital conversion (ADC) board installed in a personal electronic computer (PC) of the CNC system.

To avoid interference, including that generated by a pulsed power source of the inductive converter, the connection is made according to a differential circuit.

At the input of the ADC board, the maximum value (upper limit of the range) corresponds to a voltage of +5 V, and the minimum (lower limit of the range) -5 V. The resolution of the ADC is 12 bits. Thus, with a maximum input range of ± 5 V, the resolution will be 0.0025 V, therefore, with a maximum measurement range of an inductive transducer of ± 100 μm, the measurement resolution will be 0.05 μm (which is two orders of magnitude higher than the positioning accuracy in the Z coordinate provided directly by the machine).

Thus, to organize the digitization process, it is necessary:

- determine the dimensions formed on the working surface of the functional layer of the workpiece drawing engravings;

- assign a step size between adjacent digitization points;

- form a set of frames (teams) for practicing on the machine;

- determine the exposure time required to cancel the oscillatory effects of the inductive sensor spring on the measurement result;

- organize a sequential bypass of each of the points of digitization (i.e., scanning a section of digitization).

The step between adjacent points of digitization is selected based on the density of the elements of the engraving pattern and the quality of the working surface of the functional layer of the workpiece used.

The formation of a set of frames (teams) implies the creation of a sequence of commands for organizing the digitization process. Since contact measuring means (i.e., inductive sensors) are used, there is a need to raise the inductive sensors above the working surface of the workpiece functional layer when it is moved (during scanning) to the next digitizing point.

The algorithm for digitizing the working surface of the functional layer of the workpiece can be represented in the form, as shown in figure 2, of graphic materials.

The scheme for digitizing a fragment of the digitizing portion of the working surface of the workpiece functional layer is shown in Fig. 1 of graphic materials (a fragment of the workpiece with a digitizing grid deposited on it is shown).

Correction of control programs of the CNC system to deviate from the flatness of the working surface of the workpiece functional layer (correction along the Z coordinate) takes into account irregularities of the work surface of the workpiece functional layer (on which the engraving pattern is formed). Based on the results of digitization, appropriate changes are made to the original control program at the coordinate Z.

To calculate the actual coordinate (z0) of an arbitrary current (P0) (located on the digitizing section), triangular planes are formed between the digitizing points, which make it possible to determine the necessary increment (dz) from the Z coordinate.

According to figure 1 graphic materials:

- point P0 - this is the point for which the correction of the control program is performed in the coordinate Z;

- a set of points P1, P2 and P3 determine the nearest plane covering the point P0, for which correction is performed.

To determine the increment (dz) by the Z coordinate, a system of equations is compiled:

Having solved the system of equations, the increment (dz) in the Z coordinate can be calculated by the formula:

dz = A · x0 + B · y0 + C,

thus, the new value (z ′) along the Z coordinate at the point (x0, y0) will be equal to:

z ′ = z0 + dz.

After the digitization operation and the corresponding correction of the initial control programs of the CNC system, an orthogonal reference coordinate system X ₁ Y ₁ Z _{1 is formed} .

The reference coordinate system X ₁ Y ₁ Z _{1 is} formed from the starting point (x ₁ = 0, y ₁ = 0, z ₁ = 0) of digitization (which is functionally the zero point of this system), the coordinates of which (before processing) are specified by providing mechanical the contact of the top of the tool (fixed in the spindle of the machine) with the working surface of the functional layer of the workpiece at this point, followed by adaptation of the reference coordinate system X ₁ Y ₁ Z ₁ with a zero reference point of the original control programs.

The mentioned adaptation is carried out through spatial coordinate reference of the zero point of the coordinate system X ₁ Y ₁ Z ₁ to the zero point of the orthogonal coordinate system XYZ of the machine reference, spatially adapted with a zero point of reference of the original control programs of the numerical program control system (CNC).

The initial control programs are designed to form fragments of a three-dimensional engraving pattern in the functional layer of the workpiece, which (as previously indicated) is pre-fixed and positioned on the installation surface of the device for spatial orientation relative to the XY plane of the XYZ coordinate system. The initial control programs for forming an engraving pattern on the working surface of the product functional layer is compiled (based) from a certain starting point of the engraving pattern being formed, the coordinates of which are programmatically adapted with the aforementioned zero reference point of the reference coordinate system X ₁ Y ₁ Z ₁ .

After completion of the formation and appropriate binding of the reference coordinate system X ₁ Y ₁ Z ₁ to the zero reference point of the control programs, the tool directly positioning the cutting part (in particular, its tip) relative to the zero reference point of the control programs coordinate adapted with the coordinate system XYZ of the machine (t .e. with zero point of this system).

To do this, perform operations of photographing the front surface of the cutting part of the tool, positioning its top in three coordinates relative to the zero point of the formed reference system X ₁ Y ₁ Z ₁ and correcting for the coordinates “x ₁ ” and “at ₁ ” the longitudinal axis of the tool passing through this vertex relative to parallel to the Z axis or Z _{1 of the} actual axis of rotation of the machine spindle. At the same time, they provide a visual display of the results of the above-mentioned photographing, positioning and correction operations on a monitor screen controlling the movement mechanisms of a computer machine, as well as coordinate adaptation of these results with control programs of the CNC system.

To implement these processes, an optical-electronic measuring system is used. This system includes a television computer microscope 1, which is stationary mounted on the main table of the machine in such a way that the main optical axis of its lens 2 is oriented in the direction of the reciprocating movement of the main table of the machine along the axes X (or X ₁ ) of the corresponding coordinate systems and coordinate adapted zero point of the coordinate system X ₁ Y ₁ Z ₁ .

Thus, the front surface of the cutting part of the tool (cutter 3) is introduced into the field of view of the lens 2 of the aforementioned microscope 1, its apex is aligned with the crosshair of the orthogonal axes on the monitor screen, which is located on the main optical axis of the aforementioned lens 2, and the spindle head of the machine is rotated at an angle within 360 °.

The cutter 3 is introduced into the field of view of the lens 2 of the television microscope 1 in manual mode after it is sharpened and installed in the working spindle of the machine. The spindle is rotated around its axis by at least 360 ° to detect the radial displacement in the XY (or X ₁ Y ₁ ) plane of the tip of cutter 3 (or the longitudinal axis passing through this vertex, which is equivalent) relative to the real axis spindle rotation. The correction for the magnitude of the detected offset is introduced into the initial PC program of the CNC system with the corresponding correction of this program in relation to this particular tool (cutter 3).

In other words, in manual mode, the tip of the cutter 3 is adjusted in the center of the optical axes of the objective of the television microscope 1 (visually displayed on a PC monitor on an enlarged scale), the crosshair of which is initially coordinate-adapted with a zero reference point of the original control programs.

During the technological processing cycle (i.e., after a given number of worked out control programs or their files), the tool can be automatically (through the adjusted original PC program) entered into a coordinate-fixed (by the above-described methods) point located in the field of view of a television microscope (i.e. point coinciding with the crosshair of the orthogonal optical axes of the lens) for photographing the cutting part of the tool in order to ensure its quality control and assess the suitability of the tool for further processing. After each photographing, the tool returns (also in automatic mode) to the same point on the work surface of the workpiece on which the processing cycle was interrupted.

Precision processing of products with a complex spatial profile of the machined surface (for example, metallographic forms, the relief of the pattern formed on the working surface of the functional layer of the engraving blanks which is formed by an ordered set of profile grooves of various sizes and geometric shapes, as well as other products with increased requirements for processing accuracy, in functional layers of which it is necessary to provide a picture of a given depth with a submicron resolution of its structures) requires exactly and execution of conjugation sites with different shape and formed relief profile. Since the dimensions of the tool used for this processing can be certified with an error of the same order as the technologically specified tolerances for the production of engravings, and when changing the tool, in addition, additional errors in the position of the tip (and, accordingly, cutting edge) of the tool arise, the need arises after each provide accurate tool change by the actual position of its vertex (cutting edge) relative to the zero point of the reference coordinate system X ₁ Y ₁ Z ₁ of the machine frame subsequent correction of the position of said actual working elements of the tool relative to this coordinate system. A similar situation (regarding the need to correct the actual position of the tool in the coordinate system of the machine) can also occur in a number of other cases (for example, when the value of the accumulated error of movement in the mechanisms of the positioning nodes of the machine is above the maximum permissible). Moreover, when processing products with a complex spatially oriented structure of the formed relief, the correction of the position of the top (cutting edge) of the tool must be carried out in three coordinates X ₁ , Y ₁ and Z _{1 of the} coordinate reference system of the machine.

Due to the fact that, according to the invention, the visual display of the binding to the formed reference system X ₁ Y ₁ Z _{1 of the} machine on the monitor screen is carried out in the form of corresponding axes intersecting at right angles, with the appropriate software in the process of implementing the patented method of positioning the tool, it is possible to measure geometric parameters and electronic photographing of the cutting part of the tool, for example, to create a data bank of tools, etc.

In connection with the foregoing, it is advisable to consider in more detail an embodiment of the positioning method, according to the invention, for the case when the top of the tool (and, accordingly, its longitudinal axis passing through this top) changes its spatial position (in the plane X ₁ Y _{1 of the} reference coordinate system machine) when it is rotated together with the spindle through an angle within 360 °. Such a spatial change in the position of the vertex is possible, for example, in cases where the aforementioned vertex is offset, for example, by a value of "y ₁ " relative to the axis of rotation of the spindle of the machine (oriented along the "Z" axis of the coordinate reference system of the machine). For this case, it is first necessary to determine the value of "y" (or "y ₁ ", which is equivalent) of the aforementioned displacement of the vertex by rotating the tool together with the spindle in the field of view of the lens of a computer television microscope and visually recording the rotation process on the monitor of the control computer. Then it is necessary to carry out the above correction of the control programs in accordance with the calculated offset value.

The scheme for determining the magnitude of the aforementioned displacement of the tool tip (and, accordingly, its longitudinal axis passing through this peak) is shown in Fig. 4 of graphic materials.

According to this scheme, the calculation of new values (X ¹ and Y ¹ ) of the X and Y coordinates of the tip of the cutter (or its longitudinal axis passing through this vertex) in the XY plane is calculated by the following formulas:

where Ku is the correction value in Y. It is defined as the middle of the segment [X1, X1 ¹ ]. The sign is determined by determining the position of the tool relative to the axis of the microscope: if when the tool is rotated from 90 ° to 270 °, the tool is on the right, then the plus sign, otherwise minus;

Kx is the correction value by X. It is defined as the length of the segment [X2, X2 ¹ ]. The mark is determined in accordance with the following rule. If the tool in the 0 ° position deviates from the rotation axis to the right, then the minus sign, otherwise plus;

X ¹ - the new value of the X coordinate, taking into account the correction;

Y ¹ - the new value of the Y coordinate, taking into account the correction;

C is the angle of rotation of the tool.

It should be noted that (according to this scheme) the movement along the XY plane is carried out by moving the table with the workpiece, and the tool (or spindle) can only move around its axis.

Such correction of control programs during the subsequent processing halves the error due to the eccentric location of the tool tip relative to the axis of rotation of the spindle. Thus (according to the claimed method), the positioning and counting of tool movements during the formation of fragments of the volumetric engraving pattern in the workpiece functional layer are conducted from the mentioned zero point of the reference system X ₁ Y ₁ Z ₁ according to the initial control programs of the CNC system taking into account the coordinate correction “x ₁ ”And“ y ₁ ”of the longitudinal axis of the tool (passing through its top) relative to the actual axis of rotation of the machine spindle (parallel to the Z or Z ₁ axis), as well as correction according to the results of digitization.

It should be noted that the above-mentioned operations of photographing the front surface of the cutting part of the tool, positioning its vertex in three coordinates relative to the zero point of the formed reference system X ₁ Y ₁ Z ₁ and correction according to the coordinates “x ₁ ” and “y ₁ ” of the longitudinal axis of the tool relative to the real axis It is advisable to carry out the rotation of the machine spindle by means of an optoelectronic measuring system in direct and shadow light. To do this, the said measuring system is equipped with a reflective screen 4 located in the field of view of the lens 2 of the television computer microscope 1 behind the input zone of the instrument into this field, as well as two illuminators 5 and 6. One of the illuminators 5 in this embodiment of the method must be installed with the possibility of screen illumination, and another illuminator 6 - with the ability to illuminate the front surface of the cutting part of the tool.

This embodiment of the optoelectronic measuring system is shown in figure 3 of the graphic materials of the application.

This system is permanently installed on the main table of the machine (performing reciprocating movement along the axis X / or X ₁ / of the corresponding coordinate systems of the machine).

Extension rings are installed between the television camera and the lens of the television computer microscope. The optoelectronic part of the measuring system is fixed on two racks 8 and 9 with adjustable height. The selected height is fixed by a latch 10. The illuminators 5 and 6 and the screen 4 are mounted on the third rack 11 and are height-adjustable simultaneously with the optoelectronic part.

The television camera 12 is connected to the computer with a television cable by means of a video capture card installed in it, for example, Aver Media's EZ Capture model. As a television camera 12, a black-and-white RC-583C television camera with a built-in power supply can be used, and as illuminators -3, Porta brand white LED illuminators.

The use of a reflecting screen 4 and two illuminators 5 and 6 in the optical-electronic measuring system allows increasing the contrast of the image of the cutting part of the tool (especially its borders, i.e., cutting edges) on the monitor screen, which increases the quality and effectiveness of monitoring its parameters in automatic photographing mode.

The preliminary positioning of the fixed workpiece by means of a device for spatial orientation before digitization is carried out by determining and registering with the appropriate means of measuring the coordinate values “z” of at least three points of the workpiece functional layer that do not lie on one straight point of the working surface and subsequent alignment in the range of permissible deviations of these values through the adjustment nodes of the device for the spatial orientation of the workpieces.

When implementing the inventive method on the basis of adjusted source controls on the machine of the considered automated engraving complex, the following technological operations can be performed:

- planing of grooves of various shapes of constant or variable depth (rectilinear, circular, sinusoidal, complex shapes) and the family of these grooves, including those intersecting with each other;

- drilling holes to a shallow depth (if necessary).

Planing straight grooves of constant depth is performed in the following ways:

- moving the main table along the X coordinate with a preliminary deepening of the cutter along the Z coordinate and turning the turntable around its axis by the required angle;

- the required angle of inclination of the groove to the X axis in the horizontal plane instead of turning the turntable can be provided by interpolating the movement along the X and Y coordinates with the rotation of the spindle along the C coordinate by this required angle.

In the case of a variable groove depth, these movements are supplemented by interpolating the movement of the tool along the Z coordinate.

Planing of grooves of arbitrary shape is carried out by moving along the X and Y coordinates and turning the tool along the C coordinate so that the front edge (surface) of the tool during cutting at each moment of time is oriented normal to the processed arc at the cutting point.

The planing of sinusoidal grooves and grooves of complex geometric shape is carried out in a similar way, namely, by interpolating the displacements along the coordinates X, Y and C, and in the case of their variable depths, additionally along the coordinate Z.

Drilling holes to a shallow depth for deepening the planing cutter or other purposes is done when the table is positioned at the X and Y coordinates, followed by the spindle moving along the Z coordinate during its rotation.

Thus, to perform the above types of work (in addition to technological capabilities directly arising from the technical characteristics of the machine), the following auxiliary technological cycles and techniques provided by the design of the machine and control programs are provided:

- correction of the position of the points of the working surface of the functional layer of the workpiece in the Z coordinate taking into account the microroughness of this surface (digitization);

- determination of the position and coordinate reference of the work surface (i.e., the zero reference point of the reference system X ₁ Y ₁ Z ₁ ) of the functional layer of the workpiece relative to the coordinate reference system of the machine;

- determination of errors of sharpening and installation of the cutter in the machine spindle and correction of control programs based on the data obtained.

During the technological cycle of processing, it is necessary to operate with the following rules for moving the tool in the workpiece material.

First, before starting work with a planing cutter, it is necessary to combine the axis of rotation of the spindle with the front surface of the cutter and the axis of symmetry of its profile on the front surface. This is carried out according to the results of photographing the cutting part of the cutter using an optical-electronic measuring system in manual mode as described above, followed by updating the control program in the presence of radial displacement of the corresponding axes.

It is forbidden to rotate the tool along the “C” coordinate at fixed values of the “X”, “Y” coordinates by an angle of more than 5 degrees without removing the tool. If such a turn is necessary in line shape, then it is advisable to remove the cutter from the workpiece, turn it, and crash into the material again. At large angles of rotation, the procedure must be repeated several times (for example, every 15 ... 30 degrees).

The rotation of the cutter in the material is allowed to be carried out along a circle whose radius is greater than R = (b / 2 + 0.005) mm, where b is the width of the front surface of the cutter at the apex.

It is also advisable to consider the CNC system "Sinumerik-840Di", by means of which the claimed method is realized and, accordingly, the entire processing cycle.

The Sinumerik-840Di CNC system is designed as an OP12A operator panel based on an industrial PCU50 computer using a 19 ″ MCP remote control. The control logic of the machine is implemented using the built-in programmable controller S7-315-2DP. To control feed drives by coordinates, the “Simodrive 611U” drive was used. To ensure the input and output of discrete signals, PP72 / 48 modules are used. All of the listed modules are connected with each other and the Sinumerik-840Di CNC system with the ProfiBus DP field bus.

For the normal functioning of software that implements the claimed method, the following hardware is required:

- IBM-compatible machine;

- CNC system "Sinumerik-840Di";

- ADC card company L-Card L-783;

- inductive meter;

- Video capture card compatible with Video for Windows ™ (VfW) or DirectShow ™.

The following requirements are imposed on information and software compatibility (for implementing the method).

This program should be one or more independent executable modules.

The information system must be implemented in a high-level programming language and run under the operating system Windows ™ 98/2000 / XP.

Thus, the claimed method of positioning a tool in a coordinate reference system of a machine tool of an automated engraving complex can be mainly used in mechanical precision processing (for example, on precision planing machines with CNC system) of products with a complex spatial profile of the machined surface (for example, metallographic forms, relief a pattern of engravings formed on the working surface of which is formed by an ordered set of profile grooves of various sizes and geometrical shapes), as well as other articles with high requirements for precision processing, in which the functional layers necessary to provide a predetermined depth obtain a pattern with submicron resolution of its spatial structure.

Claims (3)

1. A method of positioning a tool in the coordinate system of a machine tool of an automated engraving complex, including the formation of an orthogonal reference coordinate system X ₁ Y ₁ Z ₁ , spatial coordinate reference of its zero point to the zero point of the orthogonal coordinate system XYZ of the machine reference, spatially adapted with the initial control programs of the system numerical program control (CNC), by means of which fragments of a three-dimensional engraving pattern are formed in the functional layer preparations that are fixed and positioned on the installation surface of the device for spatial orientation relative to the XY plane of the XYZ coordinate system, photograph the front surface of the cutting part of the tool, position its vertices in three coordinates relative to the zero point of the formed reference system X ₁ Y ₁ Z ₁ and corrected by coordinates " x ₁ "and" y ₁ "passing through this vertex of the longitudinal axis of the tool relative to the parallel axis Z or Z _{1 of the} actual axis of rotation of the spindle of the machine with visual display of the results of the above-mentioned photographing, positioning and correction operations on the monitor screen controlling the movement mechanisms of the computer machine and coordinate adaptation of these results with the control programs of the CNC system by means of an optical-electronic measuring system including a television computer microscope, which is stationary mounted on the main table of the machine in this way that the main optical axis of his lens is oriented in the direction of the reciprocating the room of the main table of the machine along the axes X or X _{1 of the} corresponding coordinate systems and coordinate adapted with the zero point of the coordinate system X ₁ Y ₁ Z ₁ , for which the front surface of the cutting part of the tool is introduced into the field of view of the lens of the said microscope, its vertex is combined with a crosshair of orthogonal axes on the monitor screen, which is located on the main optical axis of the aforementioned lens, and rotate the spindle of the machine headstock by an angle within 360 °, while positioning and counting movements and strument in the formation of fragments of the bulk pattern engravings in functional layer preform leads from said datum reference system X ₁ Y ₁ Z ₁ according to the initial control program numerical control system taking into account correction coordinates "x _1" and "y _1" to said longitudinal axis of the tool relative to the actual axis of rotation of the machine spindle, characterized in that before the formation of the reference coordinate system X ₁ Y ₁ Z ₁ carry out the correction of the control programs of the CNC system for deviation from the flatness of the working surface the functional layer of the workpiece, which is pre-fixed on the installation surface of the device for spatial orientation and spatially oriented along the XY plane, for which they are digitized by the coordinates “z” of the set of points of this surface located at a given step in the digitizing section, the shape and area of which are governed by the shape and the area of the engraving pattern formed on this surface, the digitization starts from the point farthest from the center of the digitization section and continues by the canalization of the digitization plot with measuring instruments, ensuring the registration of the values of the "z" coordinate at each digitization point and automatic correction of the CNC control programs based on the digitization results, the reference coordinate system X ₁ Y ₁ Z _{1 is} formed from the initial digitization point, which is functionally the zero point of this system, the coordinates which, before starting processing, is specified by providing mechanical contact of the top of the tool fixed in the spindle with the working surface of the workpiece functional layer at this point, while positioning and counting the movements of the tool during the formation of fragments of the volumetric pattern of the engraving in the functional layer of the workpiece, lead from the mentioned zero point of the reference system X ₁ Y ₁ Z ₁ according to the control programs of the CNC system taking into account their additional correction according to the digitization results. 2. The method according to claim 1, characterized in that the said operations of photographing the front surface of the cutting part of the tool, positioning its vertices in three coordinates relative to the zero point of the formed reference system X ₁ Y ₁ Z ₁ and correction for the coordinates "x ₁ " and "y ₁ "passing through this vertex of the longitudinal axis of the tool relative to the parallel axis Z or Z _{1 of the} actual axis of rotation of the machine spindle by means of an optoelectronic measuring system is carried out in direct and shadow light, for which the said measurement The system is equipped with a screen located in the field of view of the television computer microscope lens behind the instrument input zone into this field, as well as two illuminators, one of which is installed with the ability to illuminate the screen, and the other on the front surface of the cutting part of the tool. 3. The method according to claim 1, characterized in that the preliminary positioning of the fixed workpiece by means of a device for spatial orientation before digitization is carried out by determining and registering with the appropriate means of measuring coordinate values "z" of at least three points of the working surface not lying on one straight line the functional layer of the workpiece and subsequent alignment in the range of permissible deviations of the values of these values by means of the adjustment nodes of the device for spatial orientation of the workpieces.

Images