Mechanistic modelling of 5-axis milling using an adaptive depth buffer
Mechanistic modelling of surface machining with a toroidal end mill is presented in this work for 5-axis machining. A graphical representation of tool movements (using tooth swept sectors or the swept surface of the tool) is rendered using a widely available rendering engine, whereby the in-process chip geometry and tool edge contact length are determined by an adaptive and local depth buffer. Owing to the chip geometry being highly dependent on the feedrate, a detailed derivation of the relative tool-workpiece velocity is presented based on the kinematics of a tilt-rotary table configuration. The mechanistic modelling is verified with experimental results and found to agree to within 7% of the peak-to-peak forces.
Surface swept by a toroidal cutter during 5-axis machining
This paper presents a method of determining the shape of the surface swept by a tool that follows a 5-axis tool path for machining curved surfaces. The method consists of discretising the tool into pseudo-inserts and identifying imprint points using a modified principle of silhouettes. An imprint point exists for each pseudo-insert and the piecewise linear curve connecting them forms an imprint curve for one tool position. A collection of imprint curves is joined to approximate the swept surface. This method is simple to implement and executes rapidly. The method has been verified by comparing predicted results of a 3-axis tool path with analytical results and predicted results of a 5-axis tool path with measurements of a part made with the same tool path.
Relationships Between Food Preferences and Food Acceptance Ratings
A study was conducted to assess relationships between food preference ratings and food acceptability ratings. Acceptability ratings for each of two discriminably different samples of nine food items were obtained using the 9-point hedonic scale. Regression analysis indicated that no linear relationship existed between these ratings and either hedonic or frequency preference ratings of the foods. In addition, the range of acceptability ratings was smaller than the range of corresponding’preference ratings. Panelists’expressed preferences had no effect on their assignment of differential acceptance ratings to different samples of the items. Correlations between preference ratings of laboratory panelists and military field panelists were good, in spite of higher absolute preference ratings assigned by the laboratory panel.