A new class of machine codes for the specification of Pythagorean-hodograph (PH) curve tool paths, and associated feedrate functions, is proposed. The PH curves are a special family of free-form curves, compatible with the Bézier/B-spline representations of CAD systems, that are amenable to real-time interpolation at constant or variable feedrate directly from their exact analytic descriptions....

This paper presents a C Pythagorean-Hodograph (PH) spline curve interpolator for contourfollowing tasks. To generate the C PH quintic spline curve, a uniform knot sequence is employed. The Scurve motion planning architecture with variable feedrate for a planar C PH quintic spline curve is also developed. In particular, C cubic feed acceleration/deceleration is imposed on the first and last PH q...

Micro drilled holes are utilized in many of today's fabrication processes.Precision production processes in industries are trending toward the use of smaller holeswith higher aspect ratios, and higher speed operation for micro deep hole drilling. However,undesirable characteristics related to micro drilling such as small signal-to-noise ratios,wandering drill motion, high aspect ratio, and exce...

The overall goal of the research is the integration of geometric and mechanistic models for cutting process simulation and feedrate optimization. Five-axis milling methods are used in industries such as aerospace, automotive and mold for free-form surface machining. In these process, surface quality and material removal rate are of very important. Conservative cutting parameters have been mostl...

In this paper, the time optimal feedrate planning problem under confined feedrate, axis velocity, axis acceleration, axis jerk, and axis tracking error for a high order CNC servo system is studied. The problem is useful in that the full ability of the CNC machine is used to enhance the machining productivity while keeping the machining precision under a given level. However, the problem is comp...

As high-speed machining and unmanned machining become common, the demand for cutting-load regularization increases, so NC machining can be more ef®cient. To be presented is a simple cutting-load regularization method for pocket machining. As the conventional off-line approaches where cutting-load is predicted and cutting parameters are adjusted before actual cutting, the proposed method require...

In the traditional CNC method, acceleration control is applied after interpolation with a causal (not using future information) low-pass filter. In the earliest CNC controller, this was implemented by applying a large time constant (often several hundred milliseconds) in the analog velocity loop of the servo drives. Now it is more commonly implemented with a dynamically equivalent digital low-p...