Be based on AutoCAD to have APT language automatic process designing

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  • source:SHERBURNE CNC Machining
1 foreword   controls technical development as number, the part that uses treatment of numerical control machine tool is increasing. Although CNC Machining has precision tall, benefit is advanced and a lot of advantage, but the machine program that it must have machine tool of numerical control of a control to move. Current, the method that this kind of machine program weaves has two kinds: One kind is manual process designing; Another kind is have the aid of at computer process designing, namely automatic process designing. Because workload of artificial process designing is big, efficiency is low, personnel of requirement process designing possesses certain mathematical knowledge and skilled computational skill, accordingly, the much that uses now is automatic process designing. Implement automation of machine program work out with numerical control language, it is the main form that the computer assists process designing. The whole world applies actually and system of famouser numerical control language has more than kinds 100, among them the mainest is APT (AutomaticallyProgrammedTools) language system. In the process that writes APT language source program, especially below the case with complex part, the book of geometrical definition statement and statement of cutting tool exercise writes workload big, make mistake easily, and ask process designing personnel masters adroitly to APT language. Be aimed at above problem, the article developed the numerical control that is based on APT language system of automatic process designing, realized the significant link of CAD and NC. The spare parts below environment of 2   AutoCAD is designed in recent years, as the development of personal computer, its function rises ceaselessly, make realize CAD job to become reality on personal computer. The most successful rolls out for American Autodesk company AutoCAD system in CAD software, it is a software package that implements CAD and plot on personal computer. AutoCAD software is wrapped with its plot function is strong, open sex is good, support the characteristic such as personal computer platform, get greeting generally. Home props up software to use AutoCAD mostly in the figure that CAD develops on personal computer. The three-dimensional model of AutoCAD makes it can create really three-dimensional entity on screen of individual personal computer, boer operation, analysis and feature extract implementation such as wait for complex hypostatic modelling function. Use it to be able to construct the three-dimensional model that gives intuitionistic, figure, the axis that can obtain three-dimensional model to fall in different viewpoint measures projection drawing and rendering. Three-dimensional model uses interior piece method, reach from body of box, cubic, columnar, cirque, ball, wedge conic wait for basic substance appearance to begin, also can pass group line drawing or rotate a future life of object of 2 dimension AutoCAD becomes three-dimensional entity. Undertake to a few substance next " and " , " hand in " , or " poor " Boer operation, can make new object. Apply entity to revise implement have a circle to its again horn and pour wine cup, can build the hypostatic model that has sense of reality. AutoCAD has function of powerful graphical input, process designing, the content of part drawing is inputted very easily. AutoCAD still offerred a variety of documents with advanced language interface. Want to accept 2 dimension figure already considering this system, want to accept three-dimensional figure again, chose IGES file to regard data as interface. Pass this document, height of the centre of a circle that can draw linear end points coordinate, circular arc conveniently, end points, tool reference plane. After the architect affirms to part drawing, the IGESOUT command that calls AutoCAD makes graphical file (.

IGS) . Use program of IGES file interface (if the graph is shown 1 times) will extract geometrical element, as the foundation that data delivers between CAD and NC. Graph flow chart of program of interface of file of 1   IGES 3 graphs data processing 3.

IGES of   of structure of data of file of 1   IGES is a kind of data form that plans by specific file structure, cent of its file structure is ASC Ⅱ format and binary format two kinds. ASC Ⅱ format is a kind of format that faces character, the IGES file of this kind of format is outputted with ASC Ⅱ character, the user can be read directly take. Look from total construction, IGES file by 5 paragraph of composition. It is respectively: Begin paragraph, overall situation paragraph, the element indexes paragraph, parameter data paragraph, end paragraph. File every 80 character. Every paragraphs are like dry travel, 72 character are every the 1st ~ this paragraphs content; The 73rd character is paragraph of this paragraphs code; 80 character are the 74th ~ this paragraphs of every serial number. Paragraph the code is such regulations: Character " B " or " C " show sign paragraph; "S " express to begin paragraph; "G " indicate overall situation paragraph; "D " state the project indexes paragraph; "P " represent parameter data paragraph; "T " express to end paragraph. For example: The parameter data of linear, circular arc paragraph data is: 110, 1.

0, 1, 0, 0.

0, 5, 0, 5.

0, 0.

  of   of 7P0000004 of   of   of 0     100, 0.

0, 0.

5, 0.

5, 0.

0, 0.

0, 1.

0, 1.

9P0000005 3 of 0     .

2 files change   IGES file to basically be used at the join between AutoCAD and advanced language program, its data configuration cannot satisfy the requirement of NC, must machine processing afresh, the method of processing is the parameter data in IGES file paragraph in extraction geometry element (be like sharp starting point, terminal coordinate, the arc heart coordinate of circular arc, radius, start, terminal coordinate) , elemental sort (the join order that presses an element is arranged) , the APT file that convenient NC machines is made on this foundation. The transition technological process of graphical file is shown 2 times like the graph. Graph the changeover flow chart of 2 graphs file 3.

The parameter of craft of affirmatory   NC of parameter of craft of 3   NC inputs the computer with man-machine interaction means. Reading the geometry that takes TXT file a future life to become APT source program to define statement of exercise of statement, cutting tool while, law, right to the knife the parameter of knife dot, tolerance, cutting tool, a few parameter such as machine tool instruction are inputted with man-machine interaction means. Create the source program that accords with APT language finally. 4 application example pursues 3 part drawing pursue 3 those who be one model is linear, circular arc spare parts, in this spare parts, have already linear, be linked together point-blank, have again linear, circular arc is linked together, have circular arc again, be linked together point-blank. The source program of spare parts APT that uses this system to generate automatically is as follows: INTOL/0 of   of   of   of   of   of CLPRNT   of   of   of   of   of   of MACHIN/2   of   of   of   of   of PARTNO/TESTPART     .

  of   of   of   of 01     OUTTOL/0.

CUTTER/12L1=LINE/-269 of   of   of   of   of 01     .

641022, 0.

000000, 35.

000000, 0.

000000, 0.

000000, 35.

000000L2=LINE/0.

000000, 0.

000000, 35.

000000, - 0.

000000, 100.

000000, 35.

000000L3=LINE/0.

000000, 100.

000000, 35.

0000, - 235.

000000, 60.

000000, 35.

000000C4=CIRCLE/-235.

000000, 20.

000000, 35.

000000, 40.

000000SETPT=POINT/-320.

000000, - 75.

000000, 0.

000000PT=POINT/-320.

000000, 0.

000000, 0.

000000FEDRAT/50SPINDL/900, CLWFROM/SETPTINDIRP/PTGO/TO, l1COOLNT/FLOODTLRGT, GORGT/L1, PAST, l2GOLEF/L2, PAST, l3GOLEF/L3, TANTO, c4GOLFT/C4, PAST, l1SPINDL/OFFCOOLNT/OFFFEDRAT/200GOTO/-320.

000000, - 75.

000000, 0.

000000GOTO/SETPTPRINT/3, ALLSTOPFINI   analyses above APT source program to be able to see the just the same that writes with artificial book. Use the system that the article weaves, use create APT source program automatically with the form of man-machine interaction, improved process designing efficiency greatly, reduced a mistake. 5 conclusion the article designs part drawing form below AutoCAD environment. Regard data as interface with IGES file, regard changeover as means with data file, developed the CNC Machining that creates APT source program automatically to assist process designing system with C language, realized the join of CAD and NC, raised process designing efficiency and accuracy. Systems of other to development CAD / CAM have extensive applied value. CNC Milling CNC Machining