One. Foreword rises ceaselessly with what machine precision as productivity, numerical control machine tool had mainer and mainer effect in industrial production, and to raise machine tool utilization rate, show process designing teaching style traditionally to cannot have gotten used to manufacturing need, process designing leaving a line becomes the indispensable one part in be being applied for numerical control machine tool. From line process designing need builds the CAD model of the spare parts first, produce its knife file. Most now business uses CAD/CAM software, be like: CAtia, UG, its numerical control emulates the generated knife that is APT format code, cannot be applied directly by numerical control machine tool, need undertakes to its postposition processing generates the NC code that can have operating to the machine tool directly. After that the precision that the process that buy handles decided NC code directly and stand or fall, had crucial effect to CNC Machining process. General business uses CAD/CAM software, be like: CAtia, also can provide the generation of NC code. The configuration document that they used file of a library to regard postposition as processing generates spendable NC code directly. But as a result of the machine tool not versatility, of the NC code that these software provided a few commonly used machine tool only generate, and generated code too diverse and complicated, do not revise easily. The process of major postposition processing or need achieve on purpose separately. 2. At present the programming language of each machine tool does not have the work out method that postposition handles versatility, even if the machine tool that same manufacturer manufactures, before its later period does not have versatility possibly also. Although ever tried to extend a kind of general machine tool language through standardization on international, but the cause as a result of manufacturer, get extensive promotion hard all the time [1] . Because of machine tool language not versatility, general business offers the NC code of all machine tool to generate according to the need of the user hard with CAD/CAM software, the NC code that provided the machine tool with one commonly used part only is generated, much or the APT document that need him user to arise by its come from a processing to generate NC code. To simple numerical control procedure, the user can undertake an interpreter to APT code directly, implementation APT arrives of NC code change, but to major part, the help of computer of user need have the aid of arrives those who implement code change. The changeover means that uses normally has 3 to plant [2] : 1. Universal language is written use common programming language, be like: Visual C++ , the language such as Java can realize postposition processing, the changeover of file of the APT that finish to NC code. The advantage of this kind of method is, the machine tool that should be familiar with place to need to write only and universal language can undertake operating, do not need to other software are assisted or groom. Defect is, special sex is too strong, need special programmer, and versatility is not had after programming, modification difficulty. 2. Current software uses certain universal code to change software, be like [the M SPOST that mentions in 3] and [the KD-NCtool that development studies in 3] , will realize the APT file changeover to NC code. Its roughly the process is as follows: Graph flow chart of module of 1 postposition processing configures the file that believe buy to have a description to the machine tool through a machine tool, control the module that postposition handles with this description. Use this postposition to handle interpreter module to be able to translate the APT document that produces by CAD/CAM system into executable NC program. The machine tool configures those who believe buy file to obtain is to carry answer user dialog box commonly. This kind of dialog box can need an user to have a description to a few character of the machine tool normally, obtain wants information to form interpreter module with this. The machine tool information that gives out in graph 2[3] configures a dialog box the advantage of this kind of method is, the user needs to understand a machine tool to be able to realize APT to arrive directly only of NC code change. Defect is, as a result of the diversity of the machine tool, a simple dialog box describes all machine tools without method, generate probably invalid or the NC code that is a mistake, and cannot undertake to information configuration file detail is revised, gotten NC code is revised not easily also perfect. 3. Special language is written use postposition of a few appropriative to handle to program language to write postposition transaction file, this kind of language is postposition transaction file technically write a setting, have oneself distinctive grammar, offer a few fixed grand will go to the lavatory of postposition transaction file write. The characteristic of this kind of method is the flexibility that increased block format already, make to program method simpler again. But, need learns the discomfort that a kind of special language is this kind of method. [The POST software package that uses in the GNC that mentions in 2] is this kind of method. 3. The specific process that postposition handles although the work out method that postposition handles has 3 kinds, but roughly the process is consistent, be opposite namely the processing of athletic statement and the processing to blame exercise statement. Athletic statement basically is to use geometrical algorithm to undertake handling to its, statement of exercise of and rather than is the correspondence of encode. Athletic statement basically includes: Sky of 1) cutting tool goes (the idle stroke that does not have cutting) block; Block of 2) cutting tool take the air line (the knife fills or fill without the knife) ; 3) cutting tool takes circular arc block (the knife fills or do not have a knife to fill) ; 4) cutting tool rises (carry knife) block; 5) cutting tool drops (next knives) block. Blame exercise statement basically includes: 1) creates machine program initial magic figures drawn by Taoist priests to invoke or expel spirits and bring good or ill fortune (take stop accord with) ; 2) editor builds block of position of spot removing a knife; 3) editor generates main shaft of the machine tool that start, trade the knife, block such as switch cooling fluid; The editor of block of motion of 4) of all kinds cutting tool; 5) is other and auxiliary function (M dictates) the editor of block. An APT format file that makes automatically by Catia is below: PARTNO NAME: EXAMPLE PPRINT MODEL=CAT_M PPRINTNC SET=CAT_NS MULTAX CUTTER/ 40. 0000, 2.
0000, 18.
0000, 0, 0000, 0, 0000, 0.
0000, 100.
0000FROM/ 0.
0000, 0.
0000, 100, 00000, 0, 000000, 0.
000000, 1.
000000PT 1 MACHIN/BAMTRI, 5, 230.
0SPINDL/300 COOLNT/ON FEDRAT/500.
0000GOTO/ 0.
00000, 0.
000000, 5.
0000, 0.
000000, 0.
034899, 0.
999391PT 2 GOTO/40.
0000, 20, 00000, 5.
0000, 0.
00000, 0.
033965, 0.
9999423PT 3... ... SPINDL/OFF STOP FINI among them CUTTER, SPINDL/300, STOP, FINI to be not athletic statement, the meaning of their place correspondence can be in hind civil mention. GOTO/ 0.
00000, 0.
000000, 5.
0000, 0.
000000, 0.
034899, 0.
999391PT 2 is athletic statement. Among them 0.
00000, 0.
000000, 5.
The 0000 X in be knife head to be fastened in workpiece coordinate, y, z value, 0.
000000, 0.
034899, 0.
The 999391 unit vector direction in be knife head to be fastened in workpiece coordinate. These two groups of data use the dimensional position that describes cutting tool place, this position need changes the descriptive way that accepts into machine tool place in postposition processing. PT 2 states this is the place that after taking a knife, reachs the 2nd of cutting tool. 1. The geometrical algorithm that postposition handles uses what business gets with CAD/CAM software is the file of APT format, what this kind of file uses is workpiece coordinate department, those who give out is the vector direction of the position of knife head and cutting tool. And general 5 axes machine tool is it is reference point with runner shaft center, what what need is the angle A that the position of runner shaft center and cutting tool rotate, b and feed factor E. Reason, need undertakes geometrical operation realizes the changeover that coordinate fastens. To particular computational procedure, in [4] and [5] , [there all is relatively detailed description in 6] . To different machine tool, the element that its require to describe cutting tool position differs possibly also, even coordinate department is decided really abhorrent also. Reason, hard relatively unified algorithm decides the changeover on coordinate. But the mind that coordinate changes is identical, adopt the method of dimensional geometry namely, APT file position of medium head of machine tool knife and change of direction of cutting tool vector are the number that place of particular machine tool wants to measure. 2. The G code that place of common machine tool does not include to use in the coding APT document that postposition handles or it is M code, describe the action of the machine tool however with the statement such as GOTO, STOP, the coding since that postposition handles corrects these run-of-mill statements statement of special machine tool exercise. The meaning that the place of commonly used statement in a few APT represents is below. The reader can come according to the grammar of the machine tool corresponding and corresponding description. Place of statement of APT of meaning of watch APT everyday expressions language is denotive meaning FROM/x, y, z, a, b, c comes without cutting shift the position (state the element is decided by the machine tool) GOTO/x, y, z A, b, c cutting comes the position (state the element is decided by the machine tool) SPINDL/n of cutting tool of FEDRAT/n feed CUTTER, cw(ccw) rotate speed coming back leads suitable hour hand, (anticlockwise) / Off stops to rotate COOLNT On opens cooling fluid Off to shut fast feed of cooling fluid RAPID to stop athletic FINI program to end to STOP 3. The postposition processing process that programming gives out in 3 [4] of block diagram graph pursues this is [the graph of process of processing of a postposition that gives out in 4] , the APT file that its had using software Catia by large trade place arises arrives 5 coordinate of MACS5000 of the postposition transaction file of program of numerical control of numerical control planer-type milling machine write. Look from the process, the postposition processing that postposition handles cent to be athletic statement and the postposition that are not athletic statement treat two shares, the processing of athletic statement basically is the computation of positional element, statement of exercise of and rather than is APT statement to NC code statement change. This flow chart represented the process that general postposition handles. 4. Conclusion is overall for, as a result of the diversity of machine tool program, find a current method very hard to undertake to APT file postposition is handled. Those who use the widest lack still is man-to-man process designing means. In the work out process of the program, to the assurance that machine tool coordinate changes, and the key that the familiar degree of machine tool language is stand or fall of program of decision postposition processing. Basically include to the understanding of the machine tool, cutting tool position describes requires element, the position of coordinate origin, feed, rotate speed the descriptive method that wait, athletic description and a few special grammar. The result that postposition processing gets may be wrong, its reason may be the issue of interpreter process existence that handles because of postposition. Also may be itself of APT knife course has particular problem, need examines through certain measure the accuracy of NC code. Can move directly commonly will examine its validity, also can use proper numerical control to emulate software to undertake imitate is emulated come test and verify its accuracy. The research that postposition handles is language of machine tool program not the child of versatility, inevitable also meeting controls the implementation of versatility as the machine tool and die out. And the tide that robot operation PC turns perhaps can make the pilot versatility of the machine tool becomes reality, in those days, postposition processing also is met less and less attention getting a person. CNC Milling