Amount Of Tool Wear Research Articles

粒子強化アルミニウム基複合材料切削時の焼結工具の摩耗と工具および被削材中の粒子硬さとの関連性

Mechanically alloyed ceramic particles (Si, AlN, Al2O3 or SiC; 0.4-1μm in diameter; 15vol%)/aluminum composite were machined by dry turning using sintered tungsten-carbide tools and sintered diamond ones with different contents of Co as a binder. In both kinds of tools, the tool wear was uniquely related to the cutting distance, and its amount did not depend on the content of Co. Despite such an apparent similarity in the wear behavior for both kinds of tools, the amount of wear in the latter tools was much smaller than that in the former ones. The main factor determining the amount of tool wear was not the macroscopic (average) hardness of tools and alloys, but the hardness of ceramic particles involved in them; tool wear and hence cutting resistance decrease remarkably in case that the particle hardness in tools exceeds that in work materials.

Mapping the wear of some cutting-tool materials

In this short paper, a map describing the flank-wear characteristics of uncoated high-speed-steel (HSS) cutting tools during turning operations is presented. In this map, there is a region where the rate of flank wear is lowest, called the safety zone. The presence of this safety zone suggests that it may be possible to select the machining parameters so that a machinist can operate with the lowest amount of tool wear without compromising the level of productivity desired.

The Influence of Temperature Gradient on Cutting Tool's Life

The wear of a cutting tool is the main parameter in defining its life span. The amount of tool wear resulting from a cutting process depends upon a number of parameters. Each of them influences, to a different extend, the amount and rate of wear. Of these, the main parameter is the cutting speed, as it causes the largest changes in the wear process and in the temperature field in the cutting region i.e. thermal failure. The thermal failure of a cutting tool depends on the temperature gradient. This gradient is directly proportional to the shear gradient, from the body surface to its depth. The application of the “Thermal failure” model to cutting tools suggests that by cooling the lower face of the tool it is possible to increase the temperature gradient of the cutting surface, thus decreasing the wear level of the tool and increasing tool life. Experimental results as well as finite elements analysis showed a very good agreement with the calculated theoretical outcome.

The establishment of a tool life equation considering the amount of tool wear

A new tool life equation is proposed: in this equation the cutting conditions and the amount of tool wear are treated as independent variables. The model is constructed so that it fits a process of tool wear which follows three stages, i.e. rapid initial wear followed by gradual or little wear and finally very rapid or catastrophic wear. The model is compared with the multiplication and polynomial models with respect to the accuracy and the applicability to optimization of the cutting process. A sensitivity analysis of the model was carried out by investigating the effect of parameter variation on the accuracy of the model. A convenient technique is suggested for application of the model to practical use.

Control of tool wear during metal cutting using a computer and on line measurements

SUMMARY An adaptive control system is proposed in which a given amount of tool wear is allowed per operation. The objective of the control system is to machine a certain feed distance in the minimum tune using no more than the wear allowed and working within the conventional adaptive control constraints. The average rate at which the operation progresses can thus be regulated by appropriately setting the wear target. The adaptive control system has been applied to the control of a lathe performing a simple bar turning operation. An on-line computer receives transducer responses, calculates and issues feed and speed corrections. The optimization policy requires the tool wear rate to be estimated while cutting and in this work the estimation was made from the cutting process variables including the tool-work thermocouple voltage. Workpiece disturbances in the form of hardness changes were introduced and the experimental responses of the control system to these disturbances are presented. The success of esti...