A dynamic cutting force and vibration model of the microendmilling process that accounts for the dynamics of the microendmill, influences of the stable built-up-edge, and the effects of minimum chip thickness, elastic recovery, and the elastic-plastic nature in ploughing/rubbing has been developed. Experimental validation has been performed, and the model is shown to predict the cutting force a...

This paper proposes an off-line feedrate scheduling method of CNC machines constrained by chord tolerance, acceleration and jerk limitations. The off-line process for curve scanning and feedrate scheduling is realized as a pre-processor, which releases the computational burden in real-time task. The proposed method first scans a non-uniform rational B-spline (NURBS) curve and finds out the cruc...

There are currently no analytical methods available which determine the exact arc length for NURBS curves and for this reason, a smooth feedrate profilewith desired trajectory cannot be achieved. Numerical methods used to calculate the arc length are time-consuming processeswhichmake generating a feedrate profile with desired accelerations difficult in real-time. This paper introduces a look-ah...

In this paper, the problem of time optimal feedrate generation under confined feedrate, axis accelerations, and axis tracking errors is considered. The main contribution is to reduce the tracking error constraint to constraints about the axis velocities and accelerations, when the tracking error satisfies a second order linear ordinary differential equation. Based on this simplification on the ...

Non-uniform rational B-spline (NURBS) interpolator has been widely used in modern manufacturing systems to machine arbitrary geometries with great relief of the data flow bottleneck and feedrate fluctuation. However, in practice, real-time feedrate does not always meet the computer numerical control (CNC) command exactly subject to the system dynamics. To solve this problem, we present a real-t...

Methodologies for planning motion trajectory of parametric interpolation such as non-uniform rational B-spline (NURBS) curves have been proposed in the past. However, most of the algorithms were developed based on the constraints of feedrate, acceleration/deceleration (acc/dec), jerk, and chord errors. The errors caused by servo dynamics were rarely included in the design process. This paper pr...

In this paper, an efficient algorithm is proposed to generate a smooth near-timeoptimal feedrate function along a parametric tool path for 3-axis CNC machining under a feedrate bound, an acceleration bound for each axis, and a chord error bound. The algorithm first gives a discrete and computationally efficient algorithm to find a sequence of globally optimal velocity points under the feedrate,...

This paper proposes a new feedrate control technique of CNC that can achieve high machining accuracy and high productivity. The proposed adaptive neuro-controller adjusts both components of the feedrate and makes an improved command of contour geometry. This control architecture consists of a neural network identifier (NNI) and an iterative learning algorithm with inversion of the NNI. The NNI ...

To achieve a desired fixed or variable speed (feedrate) along a given curved path, CNC machines employ independent motors to drive each of their axes in a time-coordinated manner. There are physical limits to the torque and power that the motors can supply, and the machine performance is compromised if the demands of overcoming machine inertia, cutting forces, and friction exceed these limits. ...

The goal of this research is to improve the productivity of Numerically Controlled (NC) machine tools by optimization of feedrate settings. In this paper we compare the maximum cutting forces and cutting times using traditional methods with those achieved using the optimization methods developed in our research. Results indicate that significant productivity gains can be realized using the feed...