Economics of Multitool Lathe Operations

1963 ◽  
Vol 85 (4) ◽  
pp. 402-404 ◽  
Author(s):  
E. M. McCullough

The formulas for calculation of tool life for maximum production rate and tool life for minimum cost are expanded to include multitool operations and cases in which the total cycle time controlled by the spindle speed is greater than the cutting time. A modification is made to avoid use of conventional overhead rates, which are shown to be invalid in this instance.

1968 ◽  
Vol 90 (3) ◽  
pp. 455-466 ◽  
Author(s):  
M. Field ◽  
N. Zlatin ◽  
R. Williams ◽  
M. Kronenberg

Two of the most important factors in any machining operation are the cost per piece and the production rate. Equations have been developed which enable one to calculate these two factors for a given machining operation on a given part and machine tool. Generalized equations for cost and production rate are presented for turning, milling, drilling, reaming, and tapping. The items which make up the cost and production rate can be readily evaluated in each of the equations. The generalized cost per piece and production-rate equations for turning are then expanded to cover brazed and throwaway carbide tools and solid HSS tools. In order to use these equations, it is necessary to have available pertinent tool-life data for each of the tools under the actual machining conditions. Typical tool-life data have been generated and are shown here for a variety of alloys. All of the aforementioned equations have been programmed on a computer so that the cost and production rates can be readily calculated for specific parts, operations, and machine-tool combinations. The computer will print out not only the cost and production rate but also a detailed cost breakdown. A visual examination of each of the cost and production-rate factors makes possible a rapid analysis of the significance of each of the items making up the total cost and production rates. In addition, the cost and production-rate equations for turning have also been optimized. Thus calculations can be made to determine the minimum cost per piece and the maximum production rate for the cases where a mathematical expression, such as the Taylor equation, can be applied relating tool life and cutting speeds. Any projection beyond experimental data would have to be verified to serve as a guide for shop use.


1985 ◽  
Vol 107 (4) ◽  
pp. 361-364 ◽  
Author(s):  
S. W. Dharmadhikari ◽  
C. S. Sharma

Based on two models of material removal in ultrasonic machining, developed in an earlier work, conditions for optimum abrasive life for the objective functions of minimum cost per unit volume of material removed, maximum production rate and maximum profit rate are presented. A simple nomogram is designed for the determination of optimum abrasive life. Sensitivity studies of production rate and profit rate functions are presented. An illustrative example highlights the application of the analysis.


2011 ◽  
Vol 17 (2) ◽  
pp. 99-109 ◽  
Author(s):  
Kuan-Chen Cheng ◽  
Ali Demirci ◽  
Jeffrey M. Catchmark

The goal of this study was to enhance pullulan production by evaluating the effects of different fermentation parameters. Various carbon sources and their concentrations, yeast extract (YE) concentrations, fermentation temperatures and various pH profiles were examined. The optimal growth condition for pullulan production by Aureobasidium pullulans has been found as 75 g/L of sucrose as carbon source, 3 g/L of YE and cultivation temperature at 30 °C. Under these conditions with an initial pH at 5, 20.7 g/L of final pullulan concentration and 0.22 g/L/h maximum production rate were obtained. Later on, various pH profiles, agitation speeds, aerations and fed-batch fermentation were evaluated. The results demonstrated that pullulan production was enhanced to 25.8 g/L after 7-day cultivation with a 0.68 -g/L/h maximum production rate. There was no significant improvement of pullulan production from fed-batch fermentation. The optimal kinetics parameters were as follows: initial pH at 2.0, switched to pH 5.0 after 72 h and kept constant; agitation speed at 200 rpm; aeration at 1.5 vvm. The quality analysis demonstrated that the pullulan content produced from optimal conditions was 94.5% and its viscosity was 2.3 centipoise (cP). Fourier transform infrared spectroscopy also suggested that pullulan dominated the produced exopolysaccharide.


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