CN107291045B

CN107291045B - Workshop programming system

Info

Publication number: CN107291045B
Application number: CN201710511864.3A
Authority: CN
Inventors: 惠恩明; 杨建中; 王平; 王宏磊; 王洁; 马腾霄
Original assignee: Huazhong University of Science and Technology; Wuhan Huazhong Numerical Control Co Ltd
Current assignee: Huazhong University of Science and Technology; Wuhan Huazhong Numerical Control Co Ltd
Priority date: 2017-06-27
Filing date: 2017-06-27
Publication date: 2020-08-11
Anticipated expiration: 2037-06-27
Also published as: CN107291045A

Abstract

The invention discloses a workshop programming method, which comprises the following steps: extracting geometric information of the part and displaying a three-dimensional model of the part; identifying the manufacturing characteristics of the part according to the three-dimensional model of the part to generate a manufacturing characteristic list; planning and setting a machining process according to the part manufacturing feature list; and generating a numerical control program according to the part manufacturing characteristics and the machining process. The invention also discloses a corresponding workshop programming module. The method of the technical scheme of the invention can contain all information of parts from blanks to products, so that a numerical control system can obtain complete product information, and intellectualization is really realized; automatic programming can be realized quickly and efficiently, and the working efficiency is greatly improved.

Description

Workshop programming system

Technical Field

The invention belongs to the technical field of numerical control machining, and particularly relates to a workshop programming system.

Background

The numerical control machine tool is used as the basis of equipment manufacturing industry and widely applied to the fields of aerospace, energy equipment, automobile manufacturing, ship manufacturing, 3C processing and the like, so that the processing quality and efficiency are improved. A numerical control machine tool is generally provided with a program control system which is capable of logically processing a program defined by a control code or other symbolic command, decoding the program, expressing the decoded program in a coded digital form, and inputting the coded digital form into a numerical control device via an information carrier, thereby controlling a machining process of the machine tool. After operation, the numerical control system sends out various control signals to control the action of the machine tool, and the parts are automatically machined according to the shape and the size required by the drawing. The numerical control machine tool well solves the problem of machining of complex, precise, small-batch and various parts, is a flexible and high-efficiency automatic machine tool, represents the development direction of the control technology of modern machine tools, and is a typical mechanical and electrical integration product.

At present, the NC program input by the numerical control system still adopts a G/M code text programming mode based on the ISO6983 standard, and the programming mode only comprises a plurality of simple motion instructions and auxiliary instructions, does not comprise the information of the geometry of parts, tool path planning, tool selection and the like, and leaves the information to be considered by a programmer. Essentially, this programming method is to implement the machining by specifying the movement of the machine axes, which is process-oriented and contains no other information about the product data.

In fact, the G/M code only defines the movement and switching of the axes of the machine tool, and does not contain other data information of the part to be machined, so that the numerical control system cannot obtain complete information of the part at all, and the programming mode consumes a lot of time and is inefficient. The conventional ISO6983 standard only performs simple linear or circular interpolation and cannot perform very complex machining tasks, such as spline curve interpolation, in which the tool center point is programmed according to the machine tool axis rather than according to the manufacturing characteristics of the part to be machined. Once the program is generated, the modification in the workshop site environment is difficult, the machining process cannot be adjusted according to the actual conditions of the workshop site, and the visual machining, the collision detection and the modification of the complex numerical control program cannot be realized on the numerical control machine tool. Due to the lack of uniform standards, control instructions of different numerical control system manufacturers are not completely consistent, the compatibility of the whole workshop programming system is poor, and an NC program cannot be reused in different numerical control systems, so that the workshop programming efficiency is not high.

Disclosure of Invention

Aiming at the defects or improvement requirements in the prior art, the invention provides a numerical control workshop programming method which can contain all information of parts from blanks to products, so that a numerical control system can obtain complete product information, the intellectualization is really realized, the automatic programming can be quickly and efficiently realized, and the working efficiency is greatly improved.

To achieve the above object, according to one aspect of the present invention, there is provided a method for programming a plant, characterized by comprising

S1 extracting the geometric information of the part and displaying the three-dimensional model of the part;

s2, identifying the manufacturing characteristics of the part according to the three-dimensional model of the part, and generating a manufacturing characteristic list;

s3, planning and setting a machining process according to the part manufacturing feature list;

s4, generating a numerical control program according to the part manufacturing characteristics and the machining process.

According to the method provided by the technical scheme of the invention, the three-dimensional model of the part can be reconstructed by extracting the geometric information of the part, wherein the three-dimensional model contains the required part information. On the basis of the three-dimensional model, feature extraction can be performed, a plurality of manufacturing features are decomposed from one part, and a manufacturing feature list of the part is formed. According to the method of the technical scheme, various machining processes are provided, the machining process corresponding to the part can be found according to the manufacturing feature list of the part, and therefore the machining process can be planned and set according to the manufacturing feature list of the part. In addition, a complete numerical control program for machining the part is obtained through a numerical control program conversion algorithm according to the manufacturing characteristics of the part and the machining process.

As a preferred embodiment of the present invention, step S1 includes,

s11, establishing a mapping relation between the entity description language and the programming language;

s12 stores model entity objects;

s13, acquiring the geometric information and the topological information of the model entity according to the model entity object;

s14 displays the three-dimensional model of the model entity object according to its geometric information and topological information.

In the technical scheme of the invention, the entity is described by adopting a description language, and the numerical control program design is carried out by adopting a program design language. During operation, the description language is mapped to the programming language, and the geometric information and the topological information of the part entity object are further acquired. The geometric information refers to the position and size in the Euclidean space, including point coordinates, curves, curved surfaces and the like, and the topological information refers to the number and type of vertexes, edges and surfaces of the entity, the connection relationship among the vertexes, edges and surfaces and the like. According to the information, the specific three-dimensional model of the part can be displayed finally.

As a preferred embodiment of the present invention, step S2 includes,

s21 traversing the model entity to obtain the manufacturing characteristics of the part;

s22 determining a base of the manufacturing feature;

s23 matches the manufacturing feature types and generates a feature list.

In the technical scheme of the invention, the entity is traversed for many times to acquire all the characteristics of the part as much as possible, and the technical scheme of the invention is optimized for three times. Through the process of traversing all the entities three times, the necessary characteristic points on the part can be basically determined. On the basis, the base surface of the part manufacturing feature, namely the feature bottom surface, can be determined, and further matching with the features in the feature library can be completed, the feature type name can be determined, and the manufacturing feature list of the entity can be generated.

As a preferred embodiment of the present invention, step S4 includes,

s41, generating numerical control code segments according to the manufacturing characteristics and the processing technology;

and S42, sequentially numbering the numerical control code segments to form a complete numerical control processing program.

And according to the set processing technology, a plurality of regular basic numerical control instructions are represented by an NC program conversion algorithm, namely a fixed format instruction which can be identified by a numerical control system, various process parameters are added, and preparation instructions such as machine tool functions, programming methods and the like are added to obtain NC code segments corresponding to the manufacturing characteristic, and each NC code segment is used as a processing subprogram and numbered. And recombining codes by calling subprograms from the main program, and integrating into a complete NC program.

According to another aspect of the present invention, there is provided a plant programming system, comprising

The information extraction module is used for extracting the geometric information of the part and displaying a three-dimensional model of the part;

the characteristic generating module is used for identifying the manufacturing characteristics of the part according to the three-dimensional model of the part and generating a manufacturing characteristic list;

the process setting module is used for planning and setting a machining process according to the part manufacturing feature list;

and the program generating module is used for generating a numerical control program according to the part manufacturing characteristics and the machining process.

As a preferred technical scheme of the invention, the information extraction module comprises

The mapping module is used for establishing a mapping relation between an entity description language and a programming language;

the storage module is used for storing the model entity object;

the topology module is used for acquiring the geometric information and the topology information of the model entity according to the model entity object;

and the display module is used for displaying the three-dimensional model according to the geometric information and the topological information of the model entity object.

As a preferred technical scheme of the invention, the characteristic generating module comprises

The extraction module is used for traversing the model entity to obtain the manufacturing characteristics of the part;

a base module for determining a base of the manufacturing feature;

and the list module is used for matching the feature types and generating a feature list.

As a preferred technical scheme of the invention, the program generation module comprises

The numerical control code module is used for generating numerical control code segments according to the manufacturing characteristics and the machining process;

and the numbering module is used for sequentially numbering the numerical control code segments to form a complete numerical control machining program.

Generally, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

1) the method of the technical scheme of the invention is based on the programming mode of the STEP-NC standard, and comprises all information of the part from the blank to the product, and the information comprises the geometric information, the cutter information, the manufacturing characteristic information, the process information and the like of the part, so that a numerical control system can obtain complete product information and can really realize intellectualization;

2) according to the method of the technical scheme, the manufacturing characteristic processing type template library is automatically matched according to the manufacturing characteristics of the part, the system adopts a man-machine interaction mode, the operation is simple and visual, the field programming is easier, a user can quickly and efficiently realize automatic programming, and the working efficiency is greatly improved;

3) according to the method of the technical scheme, the whole system is a light system, and occupies less system resources compared with a CAD/CAM system, and the system can be integrated into a numerical control system under the conditions of not increasing the hardware configuration of the numerical control system and not changing the frame structure of the numerical control system, so that the functions of the numerical control system are richer;

4) according to the method provided by the technical scheme of the invention, a technician can generate a customized numerical control machining program for a specific part, can check whether the numerical control program has unobserved defects in advance through a three-dimensional simulation process, and can correct the program before actual machining, so that the machining cost is greatly saved, the machining precision of the part is improved, and the efficiency of a numerical control machining machine tool can be further improved.

Drawings

FIG. 1 is a system flow diagram of an embodiment of the present invention;

fig. 2 is a process planning flow diagram of an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other. The present invention will be described in further detail with reference to specific embodiments.

Aiming at the defects of the traditional standard, the international organization for standardization establishes a new numerical control programming interface standard ISO14649, namely a STEP-NC standard, which is used for replacing the traditional ISO6983 standard. The STEP-NC standard uses an object-oriented concept, describing the machining process rather than the machine tool motion, and includes all the information of the part from blank to product, including the three-dimensional geometry information, tool information, manufacturing characteristics information, and process information of the part. The adoption of the STEP-NC standard programming facilitates field modification and can also provide complex processing functions, such as spline curve interpolation and the like. In addition, the STEP-NC standard is also a neutral data description interface which is relatively independent from a CAD/CAM system, a numerical control system and the like, so that the systems have good compatibility.

The STEP-NC standard not only makes up the defects of the traditional standard, but also enables the numerical control technology to develop towards an open type and a network type, but at present, a programming system supporting the STEP-NC standard is not integrated in a system produced by a mainstream numerical control system manufacturer, and the numerical control system is difficult to integrate a system which consumes a large amount of system resources, such as CAD/CAM and the like, due to the limitation of hardware resources and a software framework, so that the field programming of a workshop is difficult.

In terms of the actual processing process, the manufacturing characteristics of parts such as planes, through holes, cavities, islands, arc grooves, circumferential grooves, bosses, lettering and the like are the most common, and the processing types corresponding to the manufacturing characteristics of the parts are packaged into standard templates to form a manufacturing characteristic processing type template library. The system in the embodiment of the technical scheme of the invention comprises a STEP file information extraction module, an automatic feature identification module, a process planning module and a post-processing module. Extracting geometric information of the part from the STEP file preferably through an information extraction module, and displaying a three-dimensional model of the part by using an OpenGL interface; the feature recognition module automatically recognizes the feature of the part according to the geometric information of the part; the process planning module matches the manufacturing characteristic processing type template base according to the identified characteristic information of the part, automatically selects a proper processing type, and performs process planning by adopting a man-machine interaction mode: the method comprises the information of a processing method, a processing sequence, processing parameters, cutter selection and the like; then, an NC program is obtained through the processing of a post-processing module; checking whether the NC program meets the technological requirements through three-dimensional checking simulation; compared with large systems such as CAD/CAM and the like, the system occupies smaller system resources and is easy to integrate into a numerical control system.

The technical solution of the present invention is further explained with reference to the following examples.

As shown in FIG. 1, the present invention discloses a preferred embodiment of a workshop programming system based on STEP-NC, which comprises the following STEPs:

firstly: and extracting the geometric information of the part from the STEP file through an information extraction module and displaying a three-dimensional model of the part. Which comprises a series of sub-steps: establishing a mapping relation between an EXPRESS entity and a C + + object, storing a model entity object, acquiring model entity topogram information and displaying a three-dimensional model. In a preferred embodiment, entity addresses used to express all the geometric information and topology information of the three-dimensional entity model in the file as STEP are first predefined, and each entity is given an index Value (Key) and an entity type name (Value) and stored in a Map container. Secondly, reading the STEP file into a memory in a character string mode, judging each character string line by line, and adding target entity information in the STEP file into a C + + object set which is mapped one by identifying predefined keywords. And then storing the entity topology information in the dynamic array by using a character string segmentation method for subsequent traversal access. The AP203 protocol followed by the STEP file refers to a B-Rep relational expression model, according to the model, address transmission is carried out through an iterator variable of the entity object set, so that the iterator variable always POINTs to the address of the next layer, layer-by-layer access from the top layer (CLOSED _ SHELL) to the bottom layer information (such as CARTESIAN _ POINT and DIRECTION) can be realized, and the data information in the SHELL-surface-side-vertex-DIRECTION of the entity model is obtained. And finally, displaying the three-dimensional model by preferably utilizing an OpenGL interface according to the entity model information, wherein the model display takes surfaces, edges and points as objects, and part of the objects can be selected to be highlighted and displayed in the steps of feature recognition, process planning and the like, so that the graphic visualization of the numerical control programming process is realized.

It should be particularly noted that, in the embodiment of the technical solution of the present invention, STEP files, EXPRESS language and C + + language are preferably used, but other description languages and programming languages that can implement the above operations are also within the scope of the technical solution of the present invention.

And the second step: the manufacturing features are automatically identified by a feature identification module and a feature list is generated. The generation of the feature list comprises several sub-steps: and traversing all the entities, determining the base planes of the features, matching the feature types and generating a feature list. In a preferred embodiment, because in geometry the ring is a closed boundary on a face comprised of edges, the edges in the ring are end-to-end and cannot intersect to form a closed annular boundary. In the STEP model, the ring is divided into an inner ring (FACE _ BOUND) and an outer ring (OUT _ FACE _ BOUND), the maximum outer boundary of a FACE in the geometric model is called an outer ring, and a ring with characteristics such as an inner hole, a cavity or a boss in the FACE is called an inner ring. Therefore, it is as follows: in the process of traversing all the entities for the first time, judging the existence of a new feature according to a FACE _ BOUND inner ring on the surface of the part; traversing all the entities for the second time, and judging the existence of new characteristics according to the unmarked curved surface of the part; and traversing all the entities for the third time, and judging the existence of the new characteristics according to the unmarked non-convex edge of the part. After three times of traversing all the entities, the necessary characteristic points on the part can be basically determined, and on the basis, the next step can be carried out. Namely, determining a base surface of the part feature, also called a feature bottom surface, and further matching the feature type and generating a feature list. The matching feature is to specifically perform matching judgment on data information such as the number, type, and inner ring of faces included in a feature object according to a predefined feature information matching library to determine a type name of the feature.

A third step: and setting a processing technology in a man-machine interaction mode through a technology planning module. The process planning is actually to match the manufacturing characteristic processing type template base according to the part characteristics and automatically select a proper processing type. And the processing process information is set in a man-machine interaction mode, and comprises the steps of setting part geometric parameters, process method parameters, machine tool parameters, cutter parameters, programming parameters and the like. And after the setting is finished, generating machining steps, storing the machining steps into a step list, and finally sequencing the machining steps according to actual requirements to determine the process sequence of part machining. The process planning flow diagram is shown in fig. 2.

Fourthly: and generating a numerical control program through an NC program conversion algorithm according to the part manufacturing characteristics and the machining process. Specifically, a manufacturing feature represents a machining type, a plurality of regular basic numerical control instructions are represented by an NC program conversion algorithm, namely, a fixed format instruction which can be identified by a numerical control system, according to the set machining process, various process parameters are added, and preparation instructions such as machine tool functions, programming methods and the like are added to obtain NC code segments corresponding to the manufacturing feature, and each NC code segment is used as a machining subprogram and numbered. And recombining codes by calling subprograms from the main program, and integrating into a complete NC program. The processing result corresponding to the numerical control program is the target part. That is, through the programming system of the technical scheme of the invention, technicians can generate a customized numerical control processing program for a specific part, thereby improving the precision of part processing and further improving the efficiency of a numerical control processing machine tool.

Fifthly: and (3) simulating the NC program through three-dimensional checking simulation, checking whether the NC program meets the technological requirements, repeating the step 3 if the NC program does not meet the requirements, and machining the NC program on a machine tool if the NC program meets the requirements. The purpose of the three-dimensional checking simulation is to simulate the machining process of the numerical control machine tool, compare the machining result of the three-dimensional simulated part with the real requirement and determine that the numerical control program generated in the fourth step meets the requirement of the part to be machined. Through three-dimensional simulation, whether the numerical control program has unobserved defects can be checked in advance, so that correction can be performed before actual processing, the processing cost is greatly saved, and the precision of numerical control processing is improved.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A workshop programming method is characterized by comprising

S1 extracting the geometric information of the part from the STEP file, reconstructing and displaying the three-dimensional model;

s4, generating a numerical control program according to the manufacturing characteristics and the machining process;

wherein the step S1 includes the steps of,

s11, establishing a mapping relation between an entity description language and a programming language, specifically including predefining entity addresses used for expressing all geometric information and topological information of a three-dimensional entity model in a STEP file, giving each entity an index value and an entity type name, storing the entity addresses in a Map container, reading the STEP file into a memory in a character string form, judging each character string line by line, and adding target entity information in the STEP file into a one-to-one mapping programming language object set by identifying predefined keywords;

s12 storing the model entity object, specifically including storing the entity topology information in the dynamic array by using a character string segmentation method;

s13, acquiring geometric information and topological information of a model entity from the STEP file according to the model entity object, specifically including transferring addresses through iterator variables of the entity object set, so that the iterator variables always point to the address of the next layer, thereby realizing layer-by-layer access from the top layer to the bottom layer information and acquiring data information of the entity model in the shell-face-side-vertex-direction;

s14, reconstructing and displaying the three-dimensional model according to the geometric information and the topological information of the entity object of the model, including displaying the three-dimensional model according to the entity model information, and realizing the graphic visualization of the numerical control programming process by taking the surface, the edge and the point as objects.

2. The plant programming method of claim 1, wherein step S2 includes,

s22 determining a base of the manufacturing feature;

s23 matches the manufacturing feature types and generates a feature list.

3. The plant programming method according to claim 1 or 2, wherein the step S4 includes,

4. A plant programming system, comprising

The information extraction module is used for extracting the geometric information of the part from the SETP file, reconstructing and displaying a three-dimensional model of the part;

the program generating module is used for generating a numerical control program according to the manufacturing characteristics and the machining process;

wherein the information extraction module comprises

The mapping module is used for establishing a mapping relation between an entity description language and a programming language, and specifically comprises the STEPs of predefining entity addresses used for expressing all geometric information and topological information of a three-dimensional entity model in a STEP file, giving an index value and an entity type name to each entity, storing the entity addresses in a Map container, reading the STEP file into a memory in a character string mode, judging each character string line by line, and adding target entity information in the STEP file into a one-to-one mapping programming language object set by identifying predefined keywords;

the storage module is used for storing the model entity object, and specifically comprises the steps of storing entity topology information in a dynamic array by using a character string segmentation method;

the topology module is used for acquiring geometric information and topological information of a model entity according to a model entity object, and specifically comprises the steps of transmitting an address through an iterator variable of an entity object set, enabling the iterator variable to always point to the address of the next layer, so that the information from the top layer to the bottom layer can be accessed layer by layer, and acquiring data information in the shell-surface-edge-vertex-direction of the entity model;

and the display module is used for displaying the three-dimensional model according to the geometric information and the topological information of the entity object of the model, displaying the three-dimensional model according to the entity model information, and realizing the graphic visualization of the numerical control programming process by taking a surface, an edge and a point as objects.

5. The plant programming system of claim 4, wherein the feature generation module comprises

a base module for determining a base of the manufacturing feature;

6. The plant programming system of claim 4 or 5, wherein the program generation module comprises