Tool Life In Machining Research Articles

Fabrication of Ni-W Electroplated Micro Diamond Grinding Tools and Their Application to Grooving in Silicon(M^4 processes and micro-manufacturing for science (continued))

Ni-W electroplated micro diamond grinding tools with cylindrical carbide substrate having a diameter of 100μm were fabricated in ammonium citrate bath. In a fabrication of the Ni-W electroplated micro diamond tools, the effect of stirring the electroplated liquid on the abrasive grain distribution was investigated. Furthermore, the tool life in machining of the single crystalline silicon with the electroplated tools was examined.

Stress Analyses of CBN Insert in Hybrid Machining of RBSN Ceramic

This article investigates the significant improvement in cutting tool life in machining of Reaction Bonded Silicone Nitride (RBSN), using cryogenic coolant. A finite element model is developed to analyze stress distributions in the Cubic Boron Nitride (CBN) cutting inserts used in a hybrid turning process. The analysis reveals that the decrease in cutting tool temperature caused by cryogenic cooling leads to a decrease of stresses in the cutting tool, especially when micro-cracks are present. It is found that a decrease in temperature from 1740 to 788°C leads to approximately 56% stress reduction at the flank face of the cutting tool.

Machining aspects of a high carbon Fe 3Al alloy

Iron aluminide alloys containing both ferrous as well as non-ferrous (aluminum) components form unique materials from machining theory and practice point of view. While the cutting tool materials specifically required for their machining are not available, the mechanism of machining of such materials containing ferrous and non-ferrous components has not been adequately investigated. This paper deals with fundamental aspects of chip formation and tool-life in machining of an iron aluminide, Fe 3Al alloy. Microstructural analysis of chips shows that the interaction of chip and tool in the secondary deformation zone, dependent upon the cutting speed mainly determines the mechanism of chip formation. Results of tool-life testing indicate that thermal softening of tool point combined with abrasion is the predominant tool failure mechanism.

Macroparticle induced corrosion for arc bond sputtering CrN/Nbn superlattice coatings

Transition metal nitride (TMxNy ) coatings prepared by physical vapor deposition (PVD) techniques have proven to be highly wear and corrosion resistant, thanks to the excellent combination of high hardness, electrical and thermal conductivity, and electrochemical nobility. Although a mere monolayer of binary TiNor CrN could have remarkable effect on increasing a machining tool's life in the early days, more complex ternary or higher coatings, with a functional base layer, or consisting of multiple layers, have been explored subsequently for enhanced performances in wear or corrosion. As for the coating techniques, while the traditionally classified evaporation deposition, sputter deposition, and ion plating (using relatively low keV ion beams to assist vapor deposition) have all been enjoying some success in achieving particular coating properties, recent years have seen the emergence of a particular promising sputter deposition technique, namely the arc bond sputtering (ABSTM), which combines the cathodic arc evaporation and unbalanced magnetron sputtering (UBM) in one process [1].

PREDICTION OF TOOL LIFE IN MACHINING WITH RESTRICTED CONTACT TOOLS

A semi-empirical method is described for predicting tool life in orthogonal machining with restricted contact tools. The method uses a well established machining theory to predict cutting forces, tool-chip contact length and cutting temperatures for the corresponding plane face tool i.e. tool having the same cutting edge geometry but no restricted contact. These predicted parameters and a set of empirical relations are then used to calculate the cutting temperatures and tool life for the restricted contact tool. A comparison has been made between predicted and experimental results obtained from the literature and from tests carried out by the authors.

Cutting Temperature and Forces in Machining of High-Performance Materials with Self-Propelled Rotary Tool.

Cutting temperature and forces are two dominant parameters that influence finish quality and tool life in machining. This paper undertakes the evaluation of these two factors in relation to machining by a self-propelled rotary tool, an efficient cutter recently reported to be superior in cutting some new materials. Temperature analysis is based on a model of a heat source movind cyclically along the cutting edge. Both analytical and experimental rtsults indicate that the rotating motion of the cutting edge transfers heat away from the cutting zone with the result being a reduced cutting temperature. Temperature of the cutting edge drops to the neighborhood of the ambient value after it passes the cutting zone. Cutting forces of the rotary tool are found to be smaller, especially the radial thrust component, which is 30-40 % lower, than those of the fixed circular tool.

The effect of nitrogen on the machinability of low-carbon, free-machining steels

Long turning tests on nitrogenized and non-nitrogenized 1214 and plunge forming tests on a range of AISI 12L14 steels with varying nitrogen contents have been carried out. Both tests have revealed an adverse effect of nitrogen on high-speed steel tool life in machining, and this is attributed to static strain aging of the cold-drawn feed stock prior to testing. No compensating beneficial effect of nitrogen on surface roughness was observed in the plunge forming tests, so it is concluded that, overall, nitrogen has a detrimental effect on machinability.

Wear mechanisms that dominate tool-life in machining

The broad concern of the research described in this paper is to identify which of a number of possible tool wear mechanisms have the dominant influence on tool performance for a given toolwork combination. It is proposed that the commercially relevant measure of tool performance is the volume of material worn away from the noseradius region of the tool. A general equation is presented stating that this is affected by adhesion, abrasion, oxidation/adhesion wear, diffusion and plastic deformation of the edge. Micrographs are presented showing these main forms of wear, and the cutting conditions at which they dominate are discussed. The magnitude of the normal stress acting on the cutting edge and the elevated temperature compressive strength of the tool material are shown to limit the maximum rate of metal removal for a particular toolwork combination.

On the machining of aluminum cast alloy AC4D

Aluminum casting alloy AC4 (JIS) has widely been used in the parts of machines and automobiles because of its high castability, weldability, and shock resistance. A new kind of alloy, AC4D in Al-Si-Cu-Mg system, was admitted to JIS (Japan Industrial Standard) aiming at a higher degree of reliability. Its composition is prepared by blending of copper and magnesium with AC4, and it has lower silicon content as compared with the latter for the purpose of obtaining ability for heat treatment. The relation between casting conditions and mechanical properties, mass effects, effects of heat treatment, etc. of AC4D has thoroughly been studied. However, its data on machining (especially, on machinability) have still remained unsolved.In this study, the machinability of AC4D was researched mainly by turning tests. The following results were obtained.(1) The cutting resistance and cutting temperaure of AC4D were lower than those of AC4A and AC4B. Consequently, its tool life in machining was slightly longer.(2) However, when it was machined with a cutting tool of high speed steel, the wear of tool, especially for 4DT6, was not negligible; and the finished surface was made worse with the progress of the tool wear. Whereas, the clips were in finely sheared form, which was not troublesome in treatment. Thus, it was concluded that AC4D has fairly high machinability.