CNC torna tezgahının PC ile programlanması bir CAD paketi
A CAD application for programming of CNC lathes
- Tez No: 39876
- Danışmanlar: PROF.DR. MURAT DİNÇMEN
- Tez Türü: Yüksek Lisans
- Konular: Endüstri ve Endüstri Mühendisliği, Industrial and Industrial Engineering
- Anahtar Kelimeler: Belirtilmemiş.
- Yıl: 1994
- Dil: Türkçe
- Üniversite: İstanbul Teknik Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Belirtilmemiş.
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: 72
Özet
ÖZET. Bu çalışmada, bir CNC torna tezgahının geliştirilen bilgisayar programı aracılığıyla çalıştırılması hedeflenmiştir. Bilindiği gibi CNC programcıları gerekli programlan oldukça uzun süreli çalışmalar sonucunda gerçekleştirebilmektedirler. Geliştirilen CAD paketi sayesinde işlenecek parçanın teknik resimi bilgisayara çizilmekte ve paket istenilen türdeki tezgaha ait komut kümesini kullanarak gerekli CNC programım üretmektedir. Kullanılan algoritma farklı profilleri tammlayabilen ve bu profillerin birbirlerine göre olan farklı pozisyonlarında farklı çözümler üreterek işlemi gerçekleştirmektedir. Çalışan programın CNC kodu oluşturmadaki toleransı sıfirdır ve sadece tezgahın toleransı etkili olmaktadır. Kullanılan CNC tezgahının özelliklerine bağlı olarak oluşturulan CNC kodu seri yada paralel bilgisayar arabirimi üzerinden tezgaha aktanlabilmektedir.
Özet (Çeviri)
SUMMARY. A CAD APPLICATION FOR PROGRAMING OF CNC LATHES. In this study, the aim is to operate a CNC counter by means of an improved computer program. As it is known, CNC programmers are able to create necessary programs as a result of long term studying. This process requires very difficult operations and very long paper works. A CNC programmer must imagine all of the workpiece in his mind. He must not only interest in the workpiece's profile, but also must take care of the cutting pen's coordinates. If not the pen can be broken by hitting the narrow profiles. The designed program must be controlled again and again in order not to destroy the counter. Making some experiences are not easy. Every experience requires downloading of new updated program. And program consists of hundreds of lines. So, a program that takes care of all these will make happy all CNC programmers. Bu this kind of program must be intelligent and we can count requirements like following: This CNC program generator must recognize most of the lathes. Because there are too many kinds of counter programming languages. Of course it in impossible for programmer to know all these languages well so, a kind on CNC programming standard must be builded. What is this standard, or what it must be.? In fact this is a basic of all systems programming. This means a developed program with this thought can be used in every kind of operating systems in difTerenthardwares. Program only knows basic structures like cutting, rapid traversing, left or right movements, etc. Main body of program generates a code that consists of these simple but basic codes. In our thesis, main code uses only two basic commands: rapid traverse and cutting commands. Of course this is not enough for program to process workpiece with a great sensivity. There are some additional commands but they can be explained by basic commands. As an example, a ecliptic cutting consists of very small flat cuttings in two axises.The other part of this generator program is a implemetation section. This algorithm converts basic commands to CNC counter commands that is used. After that, another code must be generated for sensetive cutting. This code is generated by workpiece's profile structure. For every different profile, there must be a sensetive cutting command and this command will be different for different CNC counters. Another important point about processing work pieces is cutting parameters. These are cutting speed, cutting depth and cutting pen. Pen type is important because there are two different cutting directions: Left and right. Also speed and depth directly effects surface quality. Hard processing can be and also must be done in high speeds and high cutting depths. This increases the time required for operation and of course is important in flowing production. As long as we are designing this CNC code generator for gaining time and saving money, this point must be taken care of. But in the surface processing, speed and cutting depth must be changes according to desired surface quality. These are mean, the cutting system must be completely parametrical. And it is good idea to make CNC commands parametrical. So the only thing that prgram needs to know is basic CNC commands and thir usage formats. User can specify these easyly so main CNC generator programme does not need to know all about all CNCs. With the help of improved CAD package, the CNC program of the workpiece that will be processed can be generated with it's technical drawing. The used algorithm recognizes different profiles and generates CNC program according to these profiles' positions in the workpiece. The tolerance of the operating program in forming CNC code must be zero, and only the tolerance of the counter must be effective. This is obtained by work piece's technical drawing. So, we designed a 'CNC program generator' program. It would be great if this program can transfer hundreds of CNC code to the counter via serial or parallel communication cable depending on the features of the CNC counter. This would make experiences easy. vnThis thesis is a complete CAD package. It includes a complete drawing section and it is the most impertant section in package. Whit this drawing utility, technical drawings of work pieces can be easyly entered to computer. This unit especially designed for using with CNC counter. It's data base structure completely fits into CNC counters' logic. And of course implementation part of package can easyly implement this database structure, combine generated code with defined CNC commands and can transfer code to counter. This program can be used with every CNC counter. At least, if used counter can not be recognized by program, the code that will be generated by program can be used as a controlling list or an alternative code for work piece cutting. Firms that have CNC counters always need CNC programmers in their people. But programmers are not cheap. They take lots of money and they only need process or part changeing times. Because CNC codes are only used for their specific work pieces and only if the work piece design changes then CNC code changing is neccessary. This means most of the CNC programmers time is empty. So this kind of program will save lots of money and time for firms. Of course some peple neccessary to use thet program but they don't need to be professiona CNC programmer. They can even be ordinary computer users and have a small knowledge about technical drawing. The program developed with Borland's Tubo Pascal computer programming language with version of 7.0. This version of pascal gives some powerful loop commands to programmer. And also programmer who uses this version can access all of the computer's memory at once. This is one of the important points in gaphical designs. All windows on screen and drawings of workpiece takes too much memory as they are colourful. As long as we must use colour screens in order to implement workpieces' technical drawing, it is improtant for programmer to use memory in a very efficient way. vmThe developed program uses the same logic with object oriented programming technique. Every profile that workpieces consists of can be implemented as a simple part of circle. Even a flat line horizantal or vertical can be thought in this vay. This kind of line is a complete circle wirh of its' radiius zero. In this way computer or pascal programming language can draw them easily. In the program creating routines, program can recognize workpiece areas that must be cut by counter with their coluors. First of all one painting routune paints workpiece in red. This means 'do not cut this areas'. Other parts of workpiece remain in black. This colour means 'cut this area'. After processing begun, the cut areas will be signed with colour of white. Also this colour means 'this areas cut, you can move as fast as possible in this area'. CNC programmes drawing logic is simple and only mathematical functions of profiles will be used for drawing operations. For flat lines, only starting and ending points needed to know. But for circular profiles there are two ways for user to define that profile. One of them is defining circular profile's center coordinates. In this way, user must calculate fitting horizantal and vertical radiuses in order to draw profile. The second way is only using 'circular profile'. User only needs to define starting and ending point like in drawing of flat lines. Computer programme automaticly calculates center point's coordinates and both of vertical and horizantal radiuses. In this way only one quarter of circle will be drawn. This parts of circle's starting and ending angles will be calculated according to fading direction. Processing direction will be from right to left. There will be no turning back. In fact this kind of turnings shuld not be needed by user and also this cuttings need special cutting tools that are not exists in used CNC counter. Coordinate system of the developed program is identical with usee counter. There are 'X1 and 'Y* axises and center '0' point of this coordinate system stands on workpieces most right side, on the center axis line. According to this kind of coordinate system, going right from left means fading in negative values. And processing from top to bottom means fading in negative values, too. Technical drawings of workpieces must be enteres by user in integer psitive or negative values. This valued would be converted to screen pixels by computer programm and would be drawn. User would not allowed to enter non- integer values because the used CNC counter also do not accepts this kind of numbers. IXIn this counter, all measurements are in 1/100 milimeters. So, 3.5 milimeters means 350 in developed program and also in used CNC counter. Program generator works in 'block processisng' logic. This means program will cut rectangular areas, blocks at once so cutting tool does not need to travel across the whole workpiece again and again. A CNC generator program must have this speciality because of it's efficiency. Otherwise cutting tool would travel accross the workpiece cousing time loss. With taking care of this points, generator routine generates a CNC code. After this code executed the workpieces surface will be in stair seem. In order to make this profiles flat another code needed. This additional code uses CNC counters own cutting commands to cut surface al last. And also hard cutting and soft cutting operations are completely different. Their cutting speeds, cutting tools, cutting depths and turning speeds of counter are different. This parameters can be defined by user according to workpieces' specialities. For example aluminium workpieces need lower cutting speeds then steel. And also smooth operations need softer cutting tool than steel. Also in order to process hard plastique materials this kind of parameters needed. This tool and speed changing commands will be executed in the very beginning of two processes. One of them will be executed at the begining of hard processing, another ones will be executed in the begining of soft cutting operations. The developed program offers some useful features to users. Users can generate programs directly to disk files or screen. And also when redirecting CNC program code to screen, every step of cutting operation can seen on screen. After CNC code will be generated, the way of the cutting tool will be drawn on screen with colour of white. After that the CNC code that would be generated will be printed to scrren. And program waits until user presses any key and do not processes next cutting step. At the end of hard cutting process, soft process will be executed. At this point user does not need to press any key and all soft cutting commands will be generated for workpiece. The usage of program is developed for people who do not knows very much about computer. Entering technical drawing of workpiece is done with cursor keys. Pressing left key means T want to draw a flat üne from the point that I am exist to thepoint that is far away from me'. And the length of the line must be given. Also pressing down key means user wats to draw flat line from the point user on it and has a specified length. In the same way user can press up key to draw another line. Drawing other kinds of line and pars of circles can be done by pressing home key or end key. Home key brings a user menu in order to make drawer to draw lines or profiles from the point that user exists to the point to left and up with given measurements. In the same way pressing end key takes user to left and down. In other words,, computer's cursor movement keys' directions are identical with their line styles. This two keystrokes takes user to another menu that user can choose the desired profile type from. After that the only thing that the program needs to know is drawsng parameters of profile. This kind of menu system makes this program very easy to use. As it is known using complicated Computer Aided Design programs is not simple and user must know much about that programs. The developed package is easy but user sholud remember that this packages is developed for CNC counters. XI
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