Tool and Process Design for Semi-dry Drilling of Steel: An Innovation for Green Manufacturing

The current trend in the metal-cutting industry is to find ways to completely eliminate or drastically reduce cutting fluid use in most machining operations. Recent advances in tool and machine technology have made it possible to perform some machining without cutting fluid use or with minimum quantity lubrication (MQL). Drilling takes a key position in the realization of dry or MQL machining. Economical mass machining of common metals (e.g., tool and construction-grade steels) requires knowledge of the work piece characteristics as well as the optimal machining conditions. In this study we investigated the effects of using MQL in drilling 1020 and 4140 steels using HSS tools with different coatings and geometries. The treatments selected for MQL in this study are commonly used by industry under flood cooling for these materials. A full factorial experiment was conducted, and the regression models for both surface finish and hole size were generated. The regression models were then used in a Pareto optimization study, and the trade-off between surface finish and hole size deviation from the nominal size was reported. The results showed a definite increase in tool life and better or very acceptable surface quality and size of holes drilled when usingMQL compared with flood cooling.ISTC Sponsored Research Program ; HWR05-192Ope

Analyzing the Effectiveness of Microlubrication Using a Vegetable Oil-Based Metal Working Fluid during End Milling AISI 1018 Steel

Microlubrication minimizes the exposure of metal working fluids to the machining operators leading to an economical, safer, and healthier workplace environment. In this study, a vegetable oil-based lubricant was used to conduct wear analysis and to analyze the effectiveness of microlubrication during end milling AISI 1018 steel. A solid carbide cutting tool with bright oxide finish was used with varying cutting speed and feed rate having a constant depth of cut. Abrasion was the dominant wear mechanism for all the cutting tools under consideration. Other than abrasion, sliding adhesive wear of the workpiece materials was also observed. The scanning electron microscope investigation of the used cutting tools revealed microfatigue cracks, welded microchips, and unusual built-up edges on the cutting tools flank and rake side. A full factorial experiment was conducted and regression models were generated for both the sides of tool flank wear. The study shows that with a proper selection of the cutting parameters it is possible to obtain higher tool life

EFFECTS OF SOME MACHINING VARIABLES IN LATHE FACING USING A PROFILOMETER AND SPECKLE CONTRAST METHODS TO MEASURE SURFACE ROUGHNESS

A review of literature indicated that the technique that has found general usage and widespread acceptance for the measurement of surface roughness is the use of a profilometer. This instrument has been found to have at least two limitations in measuring surface roughness. First, there is the limitation associated with the radius of the stylus that prevents an accurate profiling of the surface. Second, the instrument tends to distort the real nature of the image of the solid surface because the vertical magnification is greater than the horizontal magnification. Because of these limitations, substantial research has been reported in the literature on optical techniques to replace the profilometer. The main objective of this study was to compare the profilometer results with the results of a surface roughness measuring technique using speckle contrast in the facing of medium carbon steel. The variables whose effect on the resulting surface roughness was investigated were: the cutting speed, the feed rate, the depth of cut and the surface speed per minute. Two different measures of the resulting speckle contrast were used. First the surface roughness was characterized by the arithmetic average of the speckle intensity, resulting from translating the rough sample across a (He-Ne) laser beam. Second, the surface roughness was characterized at each of twenty randomly selected points; across one of its major diameters, by the resulting speckle intensity. The results indicated that neither the profilometer nor the average speckle contrast were adequate techniques to measure surface roughness in the facing of medium carbon steel. The results also indicated that the point-by-point method of characterizing surface roughness using speckle contrast, is a useful method in determining the effects of the machining variables on surface roughness in the facing of medium carbon steel. The study also pointed out the need for developing a better method of measuring surface finish than the profilometer technique

Development of an aggregate indicator to assess the machinability of steels

A methodology for the machinability assessment of steel is proposed based on the direct measurement of cutting forces and surface roughness, along with the development of an aggregate machinability indicator. Experimental work for the verification of the validity of this testing scheme was carried out at different cutting condition combinations using three grades of steel, namely, 1018 (Low Carbon, Cold-Rolled Steel), 304 (Austenitic Stainless Steel), and 4140 (Low-Alloy Steel) and uncoated carbide inserts as the tool material. Mathematical models are developed for predicting the forces acting on the tool for different cutting conditions and materials. The test results show that the developed indicator provides a number of advantages: (1) an adequate estimate of a material’s machinability; (2) a cost effective method for machinability testing

CT/MR imaging: a design tool for custom orthosis

Purpose : Orthotics attempts to correct imperfections of the human body. These deficiencies can be either congenital or due to injury. Orthotic devices have continuously evolved over the years and range in sophistication from simple joint braces to spinal body jackets. Generic orthoses, such as knee braces, come in various sizes and can be purchased over-the-counter. Sophisticated orthoses, such as those used to correct scoliosis, have to be custom made. Each of such orthoses has to be fabricated for one particular patient and requires the patient's exact geometry. The conventional technique to acquire patient geometric information has generally been casting. This latter is a time proven method of capturing the geometry of body sections of interest. However, in certain situations, casting might not always be the best alternative to obtain patient geometric data. Method/Results : This paper presents a new approach to acquire patient geometric information using CT/MR imaging. The proposed approach can help in cases where casting is not the best option. Conclusion : Using CT/MR imaging to acquire patient geometry is shown to be feasible both clinically and economically

Management of Computerintegrated Manufacturing Systems

A methodology of integrating the functions of engineering design and manufacturing in a production environment is described. A hybrid approach using quality function deployment QFD and multiobjective optimisation techniques is developed. The purpose of this methodology is to alleviate the problem of unidirectional flow of information and to eliminate the subjective decision making of the QFD approach

Analyzing the Effectiveness of Microlubrication Using a Vegetable Oil-Based Metal Working Fluid during End Milling AISI 1018 Steel

This article describes a study in which a vegetable oil-based lubricant was used to conduct wear analysis and to analyze the effectiveness of microlubrication during end milling AISI 1018 steel