Range Of Feed Rates Research Articles

工作機械テーブル案内面の減衰能測定方法

A new method is presented to measure damping capacity and also stiffness of a machine-tool guide way associated with the vibration in the direction of the guide. The method utilizes a spring element in the driving system as a force detecting member so that the dynamic characteristics of the other driving elements and the prime-mover do not affect the measure-ment. The usefulness of the method is examined theoretically and experimentally. A series of dynamic characteristics measurement were taken for each of the combination of mild steel, fluoric resin-cast iron slide ways and also the hydrostatic guide way. The result shows that the stiffness added to the system by the existence of the guide ways are nearly constant for the range of feedrate from 0 to 4000 mm/min. The damping capacity of hydrostatic guide way indicates constant and relatively low value for the above mentioned range of feedrate. In the case of sliding guide ways, on the other hand, the damping capacity is found to be relatively high and also dependent on the oscillating velocity of the table and the feedrate of the drive. The variation of the damping coefficient of these guide ways are hardly estimated from the variation of the steady state frictional force versus sliding velocity.

Short-Time Acceptance Test for Machine Tools Based on the Random Nature of the Cutting Forces

A short-time dynamic acceptance test for machine tools based on a single measurement of a coefficient of dynamic stiffness (Kd) is proposed. A feature of this test is that it takes into account the random fluctuation of the cutting forces that will be experienced by the machine tool in actual operation. Kd is defined as the inverse of the standard deviation of the steady state translational dynamic response of the machine tool under these cutting forces and is a function of the static stiffness of the machine-tool-workpiece system, the damping in the machine, and the equivalent intensity coefficient of the random cutting forces. The analytical expression for the coefficient Kd is obtained from the stationary solution of the Fokker-Planck equation that describes the probabilistic response of the machine tool. The form of excitation considered in the final results is the equivalent “white-noise” spectral density of the ensemble of the cutting forces experienced by the particular machine over the range of feed rates and cutting speeds during operations such as roughing, finishing, etc.

Foam Fractionation Rates

Abstract An empirical model enables the relation of the batch foam fractionation rate as a power function of the air rate and of the instantaneous residual surfactant concentration, eliminating the bubble size which is difficult to control and to measure. For the cationic surfactant, ethylhexadecyl-dimethylarnmonium bromide, the batch foam fractionation rate is directly proportional to the residual surfactant concentration to the first power, except for dilute (>45 mg/liter) solutions, and including suspensions containing colloidal ferric oxide and polynucleated, complexed cyanider Constants obtained from batch data can be used in the analogue equation for continuous operation to predict accurately the continuous foam fractionation rate, for a single air rate but over a substantial range of feed rates and feed surfactant concentrations. Continuous data from an entirely different column can be fit by a power function equation of the same form, with the power on the effluent or bottoms surfactant concentrat...

High-speed Machining (HSM) Using CircularInterpolation Of Free-cutting Steels

So that the many benefits arising from employing a high-speed machining strategy can be realised on conventional machining centres, companies are utilising 'speed-increasers' to elevate the rotational speed of the tooling into the high-speed range. Although such artificially-induced high peripheral speeds enable milling and drilling operations to be undertaken, this in itself causes considerable indirect problems, particularly in any contouring operation. Circular interpolation is probably the simplest form of contouring when milling, utilised for: partial arcs, blend radii, circular bosses and pockets, etc. This research examines the problems associated with using 'speed-increasers' firstly describing typical interpolation calibration procedures using 'Ballbar' techniques - at different feedrates - and secondly, milling circular features in British Steel's leaded- and tellurium-based free-cutting steels. Cutting force analysis was undertaken during milling interpolation at a range of feedrates and later, machined roundness results were obtained. Circular interpolation via milling, introduces sinusoidal variations in cutting forces which either increase, or decrease at the axis transition points. Other roundness contributing errors resulting from both the high contouring feedrates and machine-induced inaccuracies are; servo-spikes, backlash, servo-mismatch and squareness. The interactions resulting from changes in cutting data and effects of freemachining additives whilst high-speed machining.

The ecology of 0-group plaice and common dabs in Loch Ewe. II. Experimental studies of metabolism

The respiratory rate of 0-group plaice and dabs at different weights and at several temperatures has been measured. The results for resting plaice show they are cold-adapted with a respiratory rate (ml O 2/h) of 0.214 W 0.721 where W is the live weight in g. Feeding experiments show a marked correlation between rate of food intake and metabolism so that conversion efficiency is approximately constant over a range of feeding rates and has a value of 36 % under optimal experimental conditions.

THE SIMULATION OF A PACED SINGLE STAGE WORK TASK

SUMMARY A model of a particular type of conveyor-based single stage working has been developed and programmed for a digital computer. The model has been used to simulate “mechanical effect” (i.e. the effect of specific settings of feed rate and tolerance time) on an operator's natural unpaced performance. It is shown that operator response to pacing can be dimensioned more properly by reference to “mechanical effect” measures. Also, with assumptions of operator response to pacing the model can be used to predict output, misses and delay for selected conveyor settings. Response, shown as increased rates of working in a real study, has been incorporated in the simulation of paced from unpaced performance. This response has been represented grossly by a reduction in service time if the part, when picked up, has reached a particular proportion of the tolerance zone. Selected speed up effects have given reasonable agreement between simulated and actual successes and misses in a range of feed rates up to 13 per...