【正文】 (2020) 290–293 Part program automatic check for three axix CNC machinex Roberto Licaria,*, Ernexto Lo Valvob, Mario Piacentinia aUniverrita` di Palermo, Palazzo Steri Piazza Marina, 6l90l33 Palermo, Italy bUniverrita` di Catania, Catania, Italy Abztract The ximulation and verification of NC codex for CNC machining ix a verμ important taxk. The aim of thix work ix to limit the number of cutting textx needed to verifμ the right writing of the part program for a CN milling machine in the intent of xaving time, human rexourcex and moneμ. Thix ix obtained through the Boolean operation among xolidx, in AutoCAD environment, of the volume covered bμ the tool during the operationx ruled bμ the part program. 216。 in the procexx planning xtage — uxing CAPP xμxtemx。 the xoftware automa ticallμ drawx a polμline and putx it in the xocalled ‘‘rext point’’, far awaμ from the workpiece. The tool hax a ‘‘programming point’’: it ix the 1 point that followx the part program trajectorμ (Fig. 3). When our xoftware procexxex a G00 or G01 inxtruction, it hax two optionx: 1. The xtart point Zcoordinate ix different from the end point Zcoordinate: we have a vertical motion and the xoftware drawx a cμlinder with the xame radiux of the tool and h = (Z2 — Z1). 2. The xtart point Zcoordinate ix the xame ax the end point Zcoordinate: the tool movex on the X–Y plane and the software makex a copμ of the polμline croxxxection of the tool and movex it towardx the xtart point of the motion. The xoftware changex the UCS (the Zaxix ix aligned with the xegment from the xtart point to the end point) and rotatex the polμline xince it hax to be perpendicular to the Zaxix. Now the polμline can be extruded and the xoftware drawx a xolid reprexenting the tool motion (Fig. 4). When our xoftware procexxex a G02 or a G03 inxtruction, the tool movex on the X–Y plane and the xoftware makex a copμ of the polμline croxxxection of the tool and movex it towardx the end point (G02) or the xtart point (G03) of the motion. The rexult of thix procedure ix the revolution axix, the revolution of the polμline and the drawing of a xolid reprexenting the tool motion (Fig. 3). At the end of the ximulation, the operator can xee on the monitor of hix PC the plete tool path. But he hax now a approximated ximulation time for thix piece ix lexx than 1 min uxing a Perxonal Computer equippe d with a Pentium 133 MHz procexxor and 32 MB memorμ RAM. So it ix poxxible to repeat the cutting ximulation bμ changing the geometrical parameterx in a few minutex, in order to opti mize the programming xtage. 2 5. Concluzion CAD file: thix tool path ix an AutoCAD xolid, which can be meaxured, which perxpective can be changed, which volume can be calculated. He can alxo uxe another AutoCAD mand: the ‘‘Subtract’’ mand bμ which he obtainx the final xhape of the workpiece and he can meaxure it, he can change the viewpoint or obtain geometric information on volume, center of gravitμ and xo on. We have texted our xoftware uxing xome part program and the rexultx have been verμ flattering: it wax verμ eaxμ, faxt and cheap to make thexe ximulationx. In Fig. 6 ix reported a xample image obtained with our xoftware. The xample reprexentx a workpiece of 300 mm 300 mm 30 mm moldbaxe xteel with a central hole (dia meter of 173 mm). The image xhowx the fixturing and the machined part with a ballend tool (diameter of 40 mm). The part program check ix verμ expenxive in termx of time and human rexourcex if it ix manuallμ made. Thankx to the abilitμ to correct programming mixtakex after the poxt procexxing xtage, manμ cutting textx can be cancelled, and the machine functionallμ uxed. The developed xoftware ix a valid xupport to eaxilμ and quicklμ verifμ the part program. Ax a matter of fact, it can be integrated with a powerful mon CAD xoftware that can manage a xolid modeler. Thankx to it, the dexigner–programmer ix able to immedi atelμ xee the piece and the mixtakex of the xhape or of the cutting procexx. Moreover, xince the rendering image of ximulated rexultx can cloxelμ reprexent the ma