Papers by Keyword: Gear Indexing Cam

Abstract: According to the analysis of engagement between indexing roller and cam contour as gear indexing cam mechanism operating and milling process as contour being machined, three kinds of surfaces, cam’s contour, the surface swept by roller’s axis during engagement and the surface swept by cutter’s axis in milling process, are equidistant surfaces. Based on isometric theory, the approaches to determine tool path and to calculate NC program coordinates for inequi-diameter milling have been developed. The architecture of computer aided programming software for inequi-diameter milling was illustrated. Practical example of inequi-diameter milling NC codes was presented. In inequi-milling process, NC program can be updated to adapt the change of cutter diameter in time. So, cutter’s life can be prolonged, the cost of cutter can be cut down.

Abstract: Geometrical model of virtual machining system was introduced. Based on the analysis of the machining system, it was divided into workpiece subsystem and tool subsystem. Dynamic models of subsystems have been established by means of simplification of machining system. Dynamic analysis and simulation have been done. Model of virtual machining system is the combination of geometrical model and dynamic model. Based on the dynamic analysis and simulation of virtual machining system, conclusion was drawn: (1) In cutting process, as cutter feeds into cutting zone, vibration appears and becomes stronger and stronger. As cutter tends to leave cutting zone, vibration becomes weaker and weaker and disappears finally. The most violent vibration occurs as cutter has engaged into cutting zone and as cutter tends to leave cutting zone. (2) As machining corresponding to dwell of indexing plate, dynamic response is smooth and steady. (3) Vibration will attenuate sharply after cutter leaving cutting zone. The operation of virtual machining system accords with the appearance in real machining process. Properties of product model are very close to those of real machined cam.

Abstract: This paper presents a model to predict the cutting forces for flat end milling as machining gear indexing cam. Rotation feeding makes axial depth of cut and uncut chip thickness change during cutting process. The development of the model is based on the analysis of cutting edge expression. According to the existing the relationship of the local cutting force and chip load and assuming the cutter to be divided into a number of differential elements in the axial direction of the cutter, the model is derived by summarising the cutting forces produced by each differential cutter disc engaged in the cut. The equation for calculating uncut chip thickness of differential disc is educed. In order to avoid the complex computing for axial depth of cut of the entire edge, a unit square window function and its criterion are introduced to estimate whether a segment of edge is in engaging range.