Electric spark sculpture machines automatic process designing

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  • source:BAGANZ CNC Machining
Treatment of electric spark sculpture is technology of a kind of processing. It draws lessons from numerical control milling to machine means, use simple electrode to be below control of numerical control system, move according to certain contrail, through be in between simple electrode and workpiece the discharge treatment of different and relative position gives place to want workpiece form. Because electric spark machines the electric heat when relying on to discharge and blame,contact the characteristic of treatment, already used the treatment of hard fragile data widely. Because electric spark machines the loss of the electrode in the process, the treatment technology program of its process designing is the same as not completely at general CNC Milling. One, systematic whole plans this system serves as an operating system with Win2000, with VC6.

0 regard development as the tool, openGL technology was used in emulation part. The system is after the graphical information that obtains work and treatment information, through craft analysis, situation of choice cutting tool, certain labor and cutting dosage, make NC code file finally, undertake emulation machining to this code, with test and verify its validity. Because of this system by the input module, before 4 parts comprise buy processing module, postposition processing module and emulation treatment module, systematic flow chart is shown 1 times like the graph. 2, of the DXF graph data in inputting module read taking DXF file is a kind of commonly used level figure in AutoCAD data exchanges a document, apply extensively on industry at the interface between different figure system. The DXF document that this system handles is according to processing of pattern of R14 file standard is in version date, file the Communist Party of China has 6 paragraph of composition, namely caption paragraph (HEADER) , kind paragraph (CLASSES) , form paragraph (TA-BLES) , piece paragraph (BLOCKS) , hypostatic paragraph (ENTITIES) and object paragraph (OBJECTS) , each paragraphs begin with SECTION mark, with END-SEC mark ending, document remaining part has end mark EOF. The graph in the file yuan basically POINT, LINE, CIRCLE, ARC, SPLINE, SOL-ID, POLYLINE and 3DFACE, 3DSOLID, 3DLINE waits, every graph yuan with group code 0 begin, with group code 0 ends, these graphs yuan appear in BLOCKS paragraph with ENTITIES paragraph in area. Because electric spark milling is machined, basically machine plane and the curved surface of all sorts of appearance, workpiece uses three-dimensional and hypostatic model, because this basically handles three-dimensional substance. 3, before processing of the buy before buy is handled basically is the course that gets treatment contrail, for postposition processing generates NC machine program offers necessary knife digit to occupy. Are its main does the task have: ? The precision that the data of Zuo XF handles; ② basis to machine redundantly asks the graphical information to extraction reorganizes ③ of graphical data; to machine craft to choose to machine method certainly according to electric spark, produce cutting tool contrail finally. (The immediateness that in handling CAD model redundantly, the data of 1)DXF uses exterior disperse to change processing to make should machine the curved surface of workpiece or carve a range, it is so in DXF file many triangle or quadrangular graph yuan it is CAD substance all pictures that after model surface disperse is changed, get yuan gather. When forming DXF file, every triangular surface that forms reseau piece or quadrangular face piece all acme should be recorded, the face that because every acme wants to be recorded to be in for many times,differs piece in, the data of the file is redundant the phenomenon is very serious. The data in wanting pair of DXF documents so undertakes handling redundantly, purify repeats the apical data of the record. The method is in storing all acme in array, when reading check the number extraction a top to occupy every time, undertake searching comparative, if should nod existence, return position of this bits, if nonexistent, add this a little bit, the position of reentry point, in every face piece in data division, store acme is in the position in array only. (2) is statified and sectional of the model build and reframe treatment of electric spark sculpture is used statified the treatment method of purify, build storied above all so sectional model. Model antrum is statified and sectional by have close attrib border one or more ichnography form is formed, because of this border data beg taking is the linchpin that builds sectional model, also be to undertake a knife calculative foundation. Change processing through hypostatic exterior disperse, can statified and sectional with hypostatic surface beg those who make plane of brief melt into and plane hand in, farther plane of brief melt into and small node of an edge, if the graph shows drop of A, B, C, D 2 times, attack by its develop to every node next the structure undertakes reframing, can obtain statified and sectional attrib border model. When the hypostatic surface triangle of CAD model changes processing, each are small piece distributing continuously. The physical order that presses its photograph adjacent to point of intersection even after obtaining all every node undertakes reframing handling. Is the method as follows: ? To shirk of take along sth to sb carries place of? of Bin of  of Gui of correct of Qiong of reef of brighting Zou of Ji of distant of soft-shelled turtle bad quiet to show, nodical B belongs to plane of A, B at the same time, c dot belongs to plane of B, C at the same time, two node of photograph adjacent belong to a collective plane at the same time surely, what store while computation is nodical nodical place is belonged to even so is planar, already reframed fully use. To nodical as it happens be many small piece when mutual acme, what should make special number and record next this acme to be in at the same time is all and planar, use afore-mentioned methodological processing next. (3) closes the three-dimensional substance that polygon of sectional outline border concerns to close to, model antrum is statified and sectional outline is formed by closed one or more planar graph, form with a certain number of in-house outline by a series of appearance outline namely. Outline is by a series of geometry substance (be like linear) the ring that makes with the means of end to end. Call the link of the outline outside forming outer shroud normally, form inside the annulus of outline calls core. In reframe after finishing, can produce or a few sectional polygon that close, of the sectional polygon that because this judges these a few even,closes include relation. Judgement closes a few times this what is polygon model of antrum outside outline is attrib border, what is inside outline is attrib border, judge which part with this is part part, which part is want treatment cut makings share. Because each other does not intersect between each annulus, between each annulus include the relation is usable nod and close to include polygonally the relation is affirmatory. (The error of 4) process designing is controlled and cut control to press too reframe the principle is treated point of intersection had made statified and sectional model, but even further processing. When the outline inside treatment, need to in deflection R of an electrode radius and Ce of flank discharge clearance. If the graph is shown 3 times, abcd is inside attrib border dot, for deflection quantity, the included angle of Ab and Bc is α , the included angle of Bc and Cd is β , if chord Bc is very small, and deflection quantity E is compared again big when, can produce the case that the graph shows 3 times, the cutting tool method after deflection turns into, the cutting tool way that brings about generation is wrong and had happened to cut. The relation from inside the graph can produce the smallest chord of this kind of circumstance certainly. When producing this kind of situation, want to choose appropriate electrode radius above all. But electrode radius reduces what can bring about treatment efficiency to reduce. Use batten interpolation 3 times to construct for bowstring Abc next a curve replaces real curve, the Cd in the curve paragraph select a site afresh, replace C dot, recount asks with satisfying the smallest chord, with this the method can remove this kind of condition that has produced to cut. Because this system uses a certain number of straight line segment to approach,give a curve, meeting generation approachs an error, if pursue,4 shown δ are worth. To assure to machine precision requirement, make approach an error to be less than or be equal to process designing to allow an error, considering the influence of craft requirement and computational error, common error δ takes the 1/5 ~ 1/10 of σ of spare parts public errand. The curve of 3 batten interpolation that construction uses here replaces real curve, computation whether does the error of every straight line segment satisfy an error to ask. Be in commonly the midpoint of every line segment, the error is the biggest, if satisfy an error to ask namely, handle this to nod no longer, otherwise, add a new dot C to make its contented. Can use the method that wait for an error or waits for a pace to grow, all recount is bit aller, computation gives a new attrib border and sectional polygon to ask in order to satisfy treatment. (Craft of treatment of 5) electric spark and athletic contrail program to simplify electric spark carves the electrode loss in the process to compensate strategy, realize electrode wait for loss treatment, use means of discharge of electrode end panel, each treatment ply is less than discharge clearance, bottom of electrode of be confined to of discharge process bureau. Loss waits in the electrode that is based on electrode underside discharge statified in treatment of electric spark sculpture, if do not have the compensation of electrode loss, move as scanning continuity, because reduce and appear of electrode length,machine exterior general rake. To reduce machining error, the treatment of the two levels that use photograph adjacent uses the athletic means of move back and forth, walk along a knife to will be returned along former method the next time namely. Assure to machine precision to reduce the leftover height that machines the surface, the athletic contrail of electrode carries fixed jackknife rate, use transverse reduce treatment outline parietal to machine a trace with the means of fore-and-aft union. To assure the precision of treatment and efficiency, use rough machining and precision work respectively, set corresponding treatment craft parameter. 4, postposition module processing is in when generating numerical control code, the set circumstance that should move according to main shaft undertakes the motion of main shaft is controlled, include main shaft to open the control that stops to dictate with feed speed. The file of cutting tool contrail that module of the buy before the basis makes can be changed very easily for file of CNC MachiningNC code. The level of file of code of RS-274 numerical control that uses here, main operation uses a function to handle the parameter that module offers, system of the numerical control that finish is described to the instruction of relevant function taking a knife, output file of NC numerical control. 5, module of emulation treatment emulation treatment is undertaken by the accidence of code and syntactic examination validity is checked, the concerned information of the orbit information that NC code interpreter uses at producing cutting tool and motion of machine tool component. Its trends and static state are emulated use OpenGL technology, the execution that can emulate a process and output show a result. The part drawing that the graph shows 5 times, it is the system is read after taking graphical DXF file, the plan that describes according to the file yuan information is generated afresh and show by OpenGL graph system. Graph the 6 graphs that are emulation process. 6, the NC program that epilogue proves to this system arises in machining practice, satisfied the precision requirement of treatment. The code of generation, treatment efficiency is taller, can advance to be emulated all right in treatment, check the validity of cutting tool contrail very easily, whether had existed to cut, whether does treatment method satisfy treatment requirement. CNC Milling