RU2528923C2 - Article adaptive machining at nc machines - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to machining and control over machining at NC machines. Proposed method consists in computer-aided support of measurements at NC machines. It integrates machining and measurement in single control programme by application of proposed programme (CAIT-programme subsystem) integrated with CAD/CAM system. It incorporates the function of isolation or identification of set of engineering and design elements of machined parts.

EFFECT: higher machining precision, lower machining costs, higher machining efficiency, simplified and accelerated process.

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Description

The invention relates to the mechanical processing of materials and control the accuracy of processing products when using CNC machines.

There is a method for adaptive processing of curved surfaces of parts made of ceramic materials by the example of manufacturing the outer contour of an aircraft fairing of an aircraft (see the dissertation: "Automation of the technological process of machining and control of shells of double curvature" from ceramic materials (by the example of the head antenna fairing of an aircraft) ". Korolev D.A. RUDN University, Moscow - 2010, 270 pp., Ill.).

In this case, we use our own simplified CAM system, which solves the problem of only forming the contours of shells, surfaces of a limited type, obtained by one type of processing - grinding an external surface of a ceramic workpiece with an abrasive tool. A special active control device with limited functions is used - only for measuring the radius surfaces of shells. Not a serial, not worked out CNC system with special limited functions is used. Thus created a special expensive machine for adaptive processing has a minimum load due to the small range and number of required ceramic fairings and is not suitable for the manufacture of other types of parts.

A known method of active control and measurement of the actual dimensions of the outer surface of a product such as a shell of rotation (see patent No. 2420712, IPC G01B 5/00, publ. 06/10/2011). Measurements are implemented using the control program. The measuring probe is installed on the surface of the controlled product and is based on the end of the product. The control measurement program automatically binds the coordinate systems of the device and the controlled product. All geometric surface parameters are calculated in the coordinate system of the controlled product. The probe automatically moves along the surface of the controlled product from the end to the bow. The scanning step is set by the user in the program. At each step, information is read. Next, the interface unit of an industrial computer removes information from the corresponding units of the device. The control program contains an algorithm for translating the incoming information into the coordinates of the contour points and then into the actual sizes of the radii in the cross sections of the controlled product.

In this case, for measurements, a stationary non-replaceable sensor is used, which moves on a massive guide mounted on a frame rigidly mounted on the machine bed. A guide with a measuring sensor is located near the surface to be measured, along its generatrix and has an overall length greater than the length of the part. This involves the measurement of only external surfaces with smooth transitions without step elements. It is not possible to measure internal contours and holes. To configure the device to the nominal size, the use of a reference ceramic template (part) is required. The setup process of the measuring system is not integrated into one automatic continuous process with the processes of measurement and manufacturing (processing) of the part.

For the generation of control programs, a narrowly targeted CAM system has been developed for the specified device, which is based on simplified local interpolation functions that support only point, rather than continuous scanning of the processed surface, consisting of a small number of contours interconnected, only as a set of simple functions 1 -2nd order. In general, this CAM system cannot be used to generate control programs for the manufacture of other types of engineering parts with other forms of curved and simple stepped surfaces.

A known method and device for controlling the accuracy of processing parts (patent No. 2379169, IPC B23Q 15/00, publ. 20.01.2010). The invention relates to the field of precision control of machining parts on CNC machines. The current value of the cutting force is received from the load cell sensor. The computer compares it with a cutting force value calculated from a known relationship. If they do not match, the values of the parameters of the cutting conditions are recalculated according to the given formulas.

These inventions are aimed at improving the accuracy and quality of processing, however, they use individual parameters of the cutting processes or individual characteristics of the movement of the tool to improve certain types of processing and do not characterize the method as an integrated integrated system. The same tasks can be solved by using modern serial multifunctional equipment with proven advanced CNC systems and serial certified high-precision small-sized measuring sensors with thin long and L-shaped probes for measuring narrow cavities and holes of small diameter, followed by corrected processing of any surface elements with basic types of machining. In this case, it is enough to create advanced software for generating complex control programs that will provide high-quality automatic adaptive processing of the main types: milling, boring, drilling, turning, etc. (It will allow not only more fully use the capabilities of modern CNC equipment, but also significantly expand its capabilities).

Closest to the proposed invention is a method of processing complex surface contours, namely adaptive processing of the plumage of an Eurofighter Typhoon fighter. The method is based on the use of preliminary contour measurement by hardware measuring tools of a CNC multifunctional machine (editorial article: "Application of adaptive processing technology in the production of Eurofighter Typhoon fighters", journal: CAD and Graphics, No. 11, pp. 88-89, 2010), at which the measurement parameters are set in the NC PartLocator software from a separate computer (laptop) installed next to the CNC machine. The contours of the part are preliminarily measured using the measuring head according to the control program developed in the Delcam Powerlnspect OMV product, after which the resulting array of points is transferred to the NC PartLocator program. According to the measurement results, the parameters of the displacements and rotations of the part are calculated and entered into the control program processed through the rack computer — the machine’s CNC system — developed in a preliminary CAM system (Delkam PowerMill).

The disadvantage of this method is the large amount of calculation information for separate control programs for processing and measurements, performed, in practice, in three separate software systems:

- NCPartLocator;

- Powerlnspect OMV;

- Delcam PowerMILL.

In the process of integrating measurements and processing (adaptive processing), additional computer tools are used that are installed next to the CNC machine. Providing a uniform distribution of the allowance due to the correction of the position of the machining axes with respect to the installed workpiece, the output of the suitable part from each workpiece is ensured, the marriage is eliminated. The process of measurement and processing is not continuous and requires the participation of a person, therefore, the manufacturing productivity remains practically unchanged.

Separate programs for measurements and for processing are not integral and do not provide full automatic interaction between each other. To develop a control measurement program, it is necessary to construct their movements for the measuring head according to the 3D model of the workpiece.

The invention is aimed at improving the accuracy of processing, reducing costs for equipping processing processes, increasing the productivity of manufacturing parts on CNC machines while simplifying and accelerating the technological preparation of production.

The essence of the invention lies in the fact that the method of adaptive processing of products on CNC machines provides automated computer support for measurements on CNC processing equipment with the integration of mechanical processing and measurements in one control program through the application of the proposed program (software subsystem) complexly interconnected and representing a single integer with a CAD / CAM system with the function of highlighting or recognizing complexes of design and technological elements (CTE) machined parts.

The technical result is achieved by the fact that in the method of adaptive processing of products on CNC machines, including the installation of the workpiece on the machine, the measurement of geometric parameters intended for processing, and the base surfaces of the workpiece, the results of which change the parameters of the process and perform processing with tools according to the control program, according to the decision of measuring the geometric dimensions is carried out by means of the machine - measuring sensors after installing the workpiece and, if necessary, between processing operations in a continuous automatic mode in accordance with standard software templates for the movements of the probe of the measuring sensor, while ensuring recognition or selection of design and measuring elements of the 3D model of the workpiece used to form a specific integrated (unified) control program for measurement and processing, program-based, calculating the optimal position of the 3D model relative to the measured surfaces, generate a program of changes in the parameters of the technological process according to the optimal position of the 3D model according to the functions laid down in the control program, and carry out further corrected processing of any kind that can be carried out by a multifunctional CNC machine, if necessary, carry out control measurements of the finish surfaces according to the algorithms previously entered into the same combined control the program, while the sensors for adaptive measurements, along with cutting tools, are located in the tool store and in matic mode on command of the control program is made of a change in the machine spindle.

A machine-readable storage medium with the control program code written on it, developed in a CAD / CAM / CAIT system, based on the allocation or automatic recognition of complexes of design and technological elements (CTE) and augmented design and measurement elements (IE) integrated with the used CAD / CAM-system, provides the combination in a single control program of automatic measurements and processing, and automatic calculation adjustment of technological and dimensional parameters, the position of the workpiece and two tool life, the integrated control program, being run on a CNC machine, implements the method.

The invention is illustrated by drawings, where in figure 1 (one example of the main 12 applied IE) shows the position of the surfaces of the measuring element "circumference (holes / protrusions) on the diameter of the initial circle", figure 2 (one example of the main 19 software movement patterns) illustrates the measurement of the incremental distance between two holes, figure 3 shows a structural diagram of a complex (integrated) ASTPP with the proposed CAIT software subsystem to provide automated technological preparation for production (CCI).

In figure 1, the following notation is adopted: D is the diameter of the circle on which the holes / protrusions are located; d is the diameter of the measured holes / protrusions; α is the angle measured from the X axis to the first element;

Figure 2 positions 1-10 graphically depicts the path of the measuring probe when measuring the typical measuring element shown in figure 1.

The generally accepted designations of the subsystems of the automated system for technological preparation of production (ASTPP):

CAD - Computer-Aided Design - computer-aided design support;

CAM - Computer-Aided Manufacturing - computer support for manufacturing (generation of control processing programs);

САРР - Computer-Aided Process Planning - computer support for the design of technological processes;

CAE - Computer-Aided Engineering - computer support for engineering analysis (provides modeling, numerical calculations, etc.).

The proposed program of computer support for measurements can be denoted by the abbreviation:

CAIT - Computer-Aided Inspector technology - computer support for technological measurements. In this case, the concept of technological measurements is measurements directly on the machine in order to ensure high-quality manufacturing of products with high performance. Unlike control measurements, in which the quality of the manufactured product is monitored for compliance with the permissible deviations specified in the design documentation (CD), technological measurements are carried out to determine the technological parameters of the processing in specific transitions of the technological operation, which provide after processing the permissible deviations of the structural elements specified in the CD products.

A prerequisite for the present invention is the mathematical concept of the integral effect established by the theory of systems as the main property of the system. The invention is based on the integration (integration into a single whole) of actions carried out in various systems and subsystems by both information and technical specialists (engineers, operators and adjusters). At the same time, a positive integral effect gives a multiple increase in the productivity of intellectual work of engineers and technicians and the production actions of operators and adjusters of CNC equipment.

Mathematical calculations about the integral effect in the theory of systems (proven in practice, when testing the provisions of this invention) confirm that, based on fundamental mathematical concepts in both information and technical systems, positive results are inevitably achieved.

The principles for constructing measurements provided by the proposed method are based on the recognition of a certain range of typical design and measuring elements, created by analogy with the range of standard design and technological elements recognized in a well-known basic CAD / CAM system (for example, CAD / CAM FeatureCAM from Delcam pie. ) The nomenclature of typical design and measuring elements ensures the formation of almost any surfaces used in any industrial and household products. To ensure the formation of the proposed CAIT software subsystem (programs to ensure the generation of integrated control programs for measurement and processing) for the purpose of technological measurements, the design and measuring elements (IE) are formed on the principles of the formation of thermal power cells (design and technological elements) (see classification structure ( Fig. 3.4) and images of CHP (Fig. 3.5) in the book: “Modular technology in mechanical engineering” B.M.Bazrova, M .: Mechanical Engineering, 2001, 368 pp., ill.). In total, twelve basic design and measuring elements were originally formed:

- Plane (parallel to one of the coordinate planes).

- Inclined plane (a special case of the inclination of a particular axis).

- Rotate the 4th axis of the elements relative to X or Y.

- Circumference (holes / shaft).

- Cone (cone bore / cone shaft).

- Sphere (surface or 3D point).

- The inner corner.

- Outside corner.

- Groove (notch / protrusion).

- Circumference (holes / protrusions) on the diameter of the initial circumference.

- Structural elements are supplemented by "design elements", introduced to "recognize" the accuracy of surface parameters:

- Workpiece / part tolerance.

- Element-element (parameters of the relationship of elements).

An example of the characteristics and properties of IE. The measuring element "Circle (holes / protrusions) on the diameter of the initial circle" (figure 1) are characterized by the properties for its identification in space with recognition conditions:

- D is the diameter of the circle on which the holes / protrusions are located;

- d is the diameter of the measured holes / protrusions;

- absolute position in Z of the measured circles;

- α is the angle measured from the X axis to the first element;

- the number of elements - circles;

- size deviations;

- allowable size deviations;

- size tolerance;

- coordinate system of the part;

- the number and position of touch points during measurement;

- the search distance of the element, in case of not detecting the element;

- the amount of clearance during measurement;

- direction of the size of the gap;

- number of the tool corrector (in the case of calculating the processing correction);

- speed (feed) during measurement;

- safe approach / departure;

- safety plane.

The value of the element parameters that can be obtained after measurement:

- position along the X axis;

- position along the Y axis;

- position along the Z axis;

- the diameter of the initial circle on which the circles are located;

- the size;

- angle;

- deviations of measurement along the axis X, Y, Z;

- size deviations;

- a warning signal about the exit of the size “out of tolerance”.

In the manufacture of unique products (one of a kind) in which previously unknown combinations of surfaces can be used, the range of typical design and measuring elements used in the proposed measurement program can be supplemented with new elements. Each typical IE corresponds to a pattern-template of programmable movements of the probe probe installed in the spindle of a CNC machine (coordinate, vertical milling and boring boring). When introducing the measurement subsystem, the Renishaw MP700 measuring head was used, therefore, the programmable probe movement patterns were made by analogy with the Renishaw MP700 programmable cycles, but in the codes of the CAM system used to generate processing control programs. The specified sequence of commands in the table provides ways to move the probe tip of the measuring sensor shown in Fig.2. Commands are generated in the table (in G-codes used in the CAM system to ensure processing). There are nineteen originally formed similar basic programmatic patterns for structural and design elements (IE).

The code Description 1.G65P9810X30.Y50.F3000 Safe positioning movement 2. G65P9810Z10. Safe positioning movement 3. G65P9814D20 P1, boring hole 20 mm (0.787 d.). 4. G65P9834 Data storage. 5. G65P9810Z10. Moving with safe positioning. 6. G65P9810X80.Y78.867 Move to a new position 7. G65P9810Z10. Safe positioning movement 8. G65P9814D30. P2, boring hole 30 mm (1.181 d.) 9. G65P834X50.Y28.867M.1 or Incremental distance measurement with 0.1 mm actual position tolerance (0.0039) 9. G65P834A30.D57.735M.1

Based on automated programmed measurement cycles, in accordance with the given patterns of movements of the measuring probe, while ensuring recognition of design and measuring elements of the 3D model of the workpiece (3D part with allowances) cast, welded, forged, etc. it is possible to produce high-quality automatic software based workpiece, in which it does not require preliminary accurate installation of the workpiece in a special device, i.e. the parameters of the displacement and rotation of the processing axes with respect to the true position of the workpiece are calculated automatically according to the algorithms laid down in the measurement program part, and all parameters (sizes) are counted during processing on the machine from these offset axes. Software basing in this case allows not only uniform distribution of stocks, but also basing directly from the design bases of the parts to be manufactured, which eliminates the errors of basing in fixtures, errors from changing bases, errors from the state of unprocessed or processed technological bases, etc.

The proposed software subsystem (CAIT) as an integral part of ASTPP (automated system of technological preparation of production) allows for intermediate technological and final measurements both between manufacturing transitions and before and after final processing, provided for in one control program, according to which, in accordance with those laid down in the subsystem Algorithms make adjustments to the machining axes depending on the position of prefabricated workpiece elements orrektirovka tool position to ensure even distribution of the required accuracy and the allowance receiving center distance between the responsible complex surfaces, including body parts. An application No. 20111660223 dated 12/29/2011 for registering a program called Avanpost Probing was submitted to the Rospatent of the Russian Federation for the proposed program (CAIT subsystem).

Figure 3 shows the structural diagram of the integrated (integrated) ASTPP with the proposed software subsystem to provide automated technological preparation of production (CCI).

In this case, to solve technical problems, a comprehensive (integrated) automatic transmission and control system contains the structural subsystems CAD, CAE, CAM, which is supplemented by the CAIT subsystem for the formation of technological measurements on the machine. All ASTPP subsystems, like CAIT, have the properties of individual systems and provide complete design solutions.

If we use the proposed CAIT subsystem as an autonomous system only for measurements on a processing machine, separately without the CAD, CAE, and CAM subsystems, then the obvious advantages in measurement accuracy compared to, for example, stationary control and measuring machines (CMM) or universal micrometric tools may not to be. But in integration with the indicated subsystems of ASTPP, automated technological measurements are carried out to provide radically improved accuracy to ensure basic and tuning procedures in processing operations without stopping production for low-performance inconvenient and not always reliable manual measurements by a variety of universal tools of complex large-sized parts on the machine table, and also provides a multiple reduction in the complexity of commissioning and tuning works in the manufacture of products on m ogofunktsionalnyh CNC machines.

Each subsystem (figure 3) contains a set of computer aided design (KSAP), which includes:

- software (software);

- information support (IO);

- software (MO)

etc. (methodological, organizational) and technical support, which are integrated into a single ASTPP (CAD / CAE / CAM / CAIT).

All the technical decisions made during the formation of the graphic image of the design and measuring elements (IE) and their technical properties, as well as the generated measurement templates for IE, allow developing independent software for implementing automated measurement processes using the hardware of CNC machines. (The software was developed and tested in conjunction with the Delcam FeatureCAM CAM system in the manufacture of parts on HAAS / VF-5 and Topper TMV-850 CNC multifunction machines).

The formed ASTPP (CAD / CAE / CAM / CAIT) is installed on one workplace of a programmer-technologist (with one computer), which generates in an automated mode a comprehensive work program for controlling the operation of measuring sensors and cutting tools that form the surfaces of machined parts on CNC multifunctional machines . Measurement and processing processes are carried out sequentially in automatic mode. Measuring sensors, along with cutting tools, are located in the tool magazine and automatically enter the spindle of the machine according to the commands of the control program (UE). After a measurement cycle, they return to the store. According to the measurement results, under the conditions laid down in the unitary enterprise, the position of the axes is automatically adjusted relative to the actual location of the workpiece or the movement of the tools is adjusted. The considered process is an automatic adaptive processing and an effective step in spreading unmanned technologies to single and small-scale types of production.

Integration of various types of machining on CNC multifunctional machines and measurements in one control program, which has the functions of calculating corrections and introducing them into the automatic process of further processing, allows us to realize the task of fully providing automatic adaptive control on modern multifunctional CNC machines. To solve this problem, at present, all the technical means are available, both modern CNC equipment and programmable measuring heads (sensors) for these machines. In this case, it is enough to create modern software for the development of integrated integrated control programs, which will provide fully automated adaptive processing on progressive multi-function CNC machines.

The proposed method as a system for ensuring the manufacture of products with computer-assisted technological measurements for CNC processing equipment can significantly improve the adaptive processing processes, increase the accuracy and productivity of manufacturing products, reduce equipment costs, expand the capabilities of multi-function CNC machines. This provides accelerated high-quality technical (technological) preparation of production.

Claims (1)

The method of adaptive processing of products on a multifunctional CNC machine, including installing the workpiece on the machine, measuring the geometrical parameters intended for processing, and the base surfaces of the workpiece, the results of which change the parameters of the process and process with tools using the control program, characterized in that the measurements geometric dimensions is carried out using the means of the machine in the form of a measuring sensor after installing the workpiece and, if necessary, I am waiting for processing transitions in continuous automatic mode in accordance with the movements of the probe of the measuring sensor, while ensuring recognition or highlighting of the design and measuring elements of the 3D model of the workpiece used to form the integrated control program for automatic measurements and processing, and automatic calculation of technological and dimensional adjustments parameters, the position of the workpiece and the movements of the tools produce software basing, calculate the optimal position 3D models with respect to the measured surfaces, set the program for changing the process parameters according to the optimal position of the 3D model according to the functions included in the said control program, and then carry out further corrected processing of any kind on the mentioned multifunctional CNC machine, and carry out control measurements of the surfaces finally processed according to the algorithms previously introduced into the aforementioned integrated control program, while sensors for adaptive and measurements and cutting tools are located in the tool store with the ability to automatically change them in the machine spindle according to the commands of the control program.

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