Highly effective way in five-axis sculptured surfaces machining using flat-end cutter

This paper applied the concept of “contact” in Differential Geometry into the machining of the sculptured surface. I presented the contact principle of the machining of complicated surfaces, using the circumference circle of the cylindrical cutter to sweep the curved surface instead of ball-end mill. This is highly effective method. In this paper an theory for machining complicated surface is presented. By using a flat-end mill instead of ball-end mill, and adjusting the axis relate to the surface, the two surfaces, The swept surface and the required surface, has the same curvature, up to as high as 3th order

Quasistatic deflection analysis of slender ball-end milling cutter

This work was supported by the National Natural Science Foundation of China (Grant No. 51975333), Jinan University and Institute Innovation Team Program (Grant No. 2020GXRC025), and Taishan Scholars Project of Shandong Province (ts201712002).Peer reviewedPostprin

Tool path generation for milling of free form surfaces with feed rate scheduling

Upotreba slobodnih (skulptorskih) površina u procesu projektovanja proizvoda raste po eksponencijalnom nivou kako iz funkcionalnih tako i iz estetskih razloga. U procesu projektovanja i izrade slobodnih površina neizostavna je upotreba CAD/CAM softvera. Dok su geometrijski aspekti projektovanja relativno dobro pokriveni, problemi i dalje ostaju kada je u pitanju stvarna proizvodnja slobodnih površina. Glavni problemi su povezani sa određivanjem odgovarajuće putanje alata koja bi obezbedila zahtevan kvalitet obrađene površine, minimizaciju ukupnog vremena obrade, kontrolu intenziteta sile rezanja itd. U radu je prikazan algoritam za generisanje putanje alata zasnovan na kriterijumu održanja sile rezanja na konstantnu unapred definisanu vrednost za procese 3-osne obrade loptastim glodalom. U tu svrhu je razvijen model za predikciju sile rezanja koji je uključen u algoritam za generisanje putanje alata i softver koji je kompatibilan sa svim CAD/CAM sistemima. Eksperimentalno je potvđeno da predloženi algoritam ima brojne prednosti u odnosu na strategije obrade komercijalnih CAD/CAM softvera.The use of freeform (sculptured) surfaces in the product design process is accelerating at an exponential rate driven by functional as well as esthetics demands. CAD/CAM software is a must in their design and manufacture. While the geometric aspects of the design are relatively wellcovered, issues still remain when it comes to the actual manufacture of freeform surfaces. The major issues are related to the generation of the proper toolpaths that would assure the required surface quality, the minimization of the total maching time, the control of the magnitude of the cutting forces, etc. This paper presents an algotithmic procedure for tool path generation based on the criterion of maintaing the cutting forces at a constant pre-defined level for 3-axis ball end milling processes. To this end, a model for cutting force prediction is formulated and incorporated into the tolpath generation algorithm and software that is compatible with all CAD/CAM systems. It has been experimentally confirmed that the proposed algorithm offers a number advantages over the machining strategies used in commercial CAD/CAM software

Tool path generation for milling of free form surfaces with feed rate scheduling

Upotreba slobodnih (skulptorskih) površina u procesu projektovanja proizvoda raste po eksponencijalnom nivou kako iz funkcionalnih tako i iz estetskih razloga. U procesu projektovanja i izrade slobodnih površina neizostavna je upotreba CAD/CAM softvera. Dok su geometrijski aspekti projektovanja relativno dobro pokriveni, problemi i dalje ostaju kada je u pitanju stvarna proizvodnja slobodnih površina. Glavni problemi su povezani sa određivanjem odgovarajuće putanje alata koja bi obezbedila zahtevan kvalitet obrađene površine, minimizaciju ukupnog vremena obrade, kontrolu intenziteta sile rezanja itd. U radu je prikazan algoritam za generisanje putanje alata zasnovan na kriterijumu održanja sile rezanja na konstantnu unapred definisanu vrednost za procese 3-osne obrade loptastim glodalom. U tu svrhu je razvijen model za predikciju sile rezanja koji je uključen u algoritam za generisanje putanje alata i softver koji je kompatibilan sa svim CAD/CAM sistemima. Eksperimentalno je potvđeno da predloženi algoritam ima brojne prednosti u odnosu na strategije obrade komercijalnih CAD/CAM softvera.The use of freeform (sculptured) surfaces in the product design process is accelerating at an exponential rate driven by functional as well as esthetics demands. CAD/CAM software is a must in their design and manufacture. While the geometric aspects of the design are relatively wellcovered, issues still remain when it comes to the actual manufacture of freeform surfaces. The major issues are related to the generation of the proper toolpaths that would assure the required surface quality, the minimization of the total maching time, the control of the magnitude of the cutting forces, etc. This paper presents an algotithmic procedure for tool path generation based on the criterion of maintaing the cutting forces at a constant pre-defined level for 3-axis ball end milling processes. To this end, a model for cutting force prediction is formulated and incorporated into the tolpath generation algorithm and software that is compatible with all CAD/CAM systems. It has been experimentally confirmed that the proposed algorithm offers a number advantages over the machining strategies used in commercial CAD/CAM software

Discrete modeling of sculptured surface machining for robust automatic feedrate selection

Traditional feedrate selection techniques currently used in three and five-axis CNC machining reduces milling efficiency. Manually estimated feedrates tend to be conservative and constant, greatly increasing mill time. The goal of this research is to develop robust techniques and software tools for automatically generating optimized feedrates for use on three and five-axis CNC mills, to both simplify the feed selection process and to increase the safety and efficiency of the milling operation through milling process simulation. The simulation software estimates milling force vectors for each tool move, and identifies a feedrate that maintains a desired peak force. The desired cutting force value may be selected to prevent cutter breakage, maintain part tolerance, or meet some other criteria. Other conditions are also considered, such as maximum allowable chip thickness and machine constraints. This allows for the generation of variable feedrates that are optimized for each tool move. The software consists of three distinct portions: a discrete mechanistic model, a discrete geometric model, and a CNC machine model. The mechanistic model estimates cutting forces as a function of cut geometry, cutter/stock relative velocity, and material constants. The geometric model keeps track of the changing in-process stock geometry and provides the cut geometry parameters required by the mechanistic model. The CNC machine model calculates the cutter/stock relative velocity based on feed inputs, machine kinematics, and controller behavior. A feed value is calculated in an iterative manner for each tool move based on the force estimates. The results of this research have produced accurate force estimates during sculptured surface machining, and have also demonstrated that this approach at automatic feedrate selection is feasible. Testing of feedrate selection has included the five-axis milling of production turbomachinery in an industrial environment. An average improvement in efficiency of 20% has resulted from the use of the optimized feeds

Automatic tool path generation for numerically controlled machining of sculptured surfaces

This dissertation presents four new tool path generation approaches for numerically controlled machining of sculptured surfaces: TRI\sb-XYINDEX, FINISH, FIVEX\sb-INDEX, FIX\sb-AXIS\sb-INDEX. All of the above systems index the tool across the object surface in the Cartesian space so that evenly distributed tool paths are accomplished. TRI\sb-XYINDEX is a three-axis tool path generation system which uses a surface triangle set (STS) representation of the surface for tool position calculations. Surface edges are detected with local searching algorithms. Quick tool positioning is achieved by selecting candidate elements of polygons. Test results show that TRI\sb-XYINDEX is more efficient when machining surfaces which are relatively flat while the discrete point approach is faster for highly curved surfaces. FINISH was developed for generating three-axis ball-end tool paths for local surface finishing. It was based on the SPS. Given a surface with excess material represented by a set of discrete points, FINISH automatically identifies the undercut areas. Results show that FINISH provides significant improvements in machining efficiency. FIVEX\sb-INDEX is developed for generating five-axis flat-end tool paths. It uses an STS approximation. Contact points on the surface are derived from edge lists obtained from the intersections of vertical cutting planes with the polygon set. The distances between adjacent end points set an initial step-forward increment between surface contact points. To verify tool movements, some intermediate tool positions are interpolated. The key features of FIVEX\sb-INDEX are: (1) a polygon set representing an object which may be composed of multiple surfaces; (2) Surface contact point generation by cutting plane intersection; (3) simple tool incrementing and positioning algorithms; (4) minimal user interaction; (5) user controlled accuracy of resulting tool paths. FIX\sb-AXIS\sb-INDEX is a subsystem of FIVEX\sb-INDEX, generating tool paths for a tool with fixed orientations. Surface contact points are generated similar to FIVEX\sb-INDEX while tool positions are corrected with the highest point technique along the tool axis direction. Linear fitting is applied to output tool positions. FIX\sb-AXIS\sb-INDEX is preferred for machining surfaces curved in one direction, such as ruled surfaces. Test results show that FIX\sb-AXIS\sb-INDEX can serve as a three-axis tool path generation system but a five-axis machine is required to do it. (Abstract shortened by UMI.)