Metal Machining Processes Research Articles

Software System for Simulation and Control Synthesis of Robots for Metal Machining Processes

Abstract The software system for simulation and synthesis of control of manipulation robots which are intended for metal machining is presented in the paper. The package includes various dynamic models of a robot in the contact with a constraint surface. These models are considered and the problems of application of these models for simulation and synthesis of position/force control for manipulation robots are addressed. The various dynamic models are compared in the paper from standpoints of both computer Simulation and their application within position/force control schemes. Numerical examples of these comparisons are given. The package also includes models of some specific robotic tasks. The special emphasis is given to simulation and control of robotic deburring process.

Vibration Problems in Metal Cutting Systems

This review evaluates and presents an overview of the most significant developments reported on vibration problems in metal machining processes in recent literature. The causes of vibration in metal cutting systems and the various theories of chatter are presented. The influence of vibration and chatter on the machining process is discussed. The developments of on-line condition monitoring and use of intelligent diagnostic systems are pointed out

Advanced Coatings by Vapour Phase Processes

The process of vapour phase deposition such as CVD and PVD are of growing importance for the production of high grade coatings. Single and multilayer coatings with exceptional adhesive, hardness, wear and anti-corrosive properties can be produced in this way. Tools with hard coatings are already widely used on the basis of well developed processes. Coatings for more complex tools used in metal-machining processes as well as for machine tool components are still in the process of development. New variations to these processes and defined process control will significantly extend the application range of vapour phase coatings within the next years.

Further Analysis of Cancer Mortality Patterns Among Workers Exposed to Cutting Oil Mists<xref ref-type="fn" rid="FN1">2</xref>

Workers exposed to cutting oil mists at a single U.S. plant were followed to determine if they experienced unusual death rates for specific cancer sites, which would be indicative of a carcinogenic potential for some or all of the oils used. The study group consisted of 2,485 white males who were employed between 1938 and 1967 and had 5 or more years' employment in jobs exposing them to varying levels of cutting oil mists anytime prior to 1968; 1.137 of these men were engaged in a wide range of metal machining processes that entailed longterm heavy exposure to the mists. Cause-specific mortality patterns among the workers during 1938–67 were compared to death rates in the total U.S. white male population. The usual deficits were seen in mortality for most major disease categories, although total cancer deaths were very close to expectation. Analysis of mortality for each of 15 cancer site categories showed no significant differences between observed and expected deaths for almost all comparisons. However, a twofold risk of cancers of the stomach and large Intestine (combined) was seen after 20 years of follow-up In the subgroup of men with 5 or more years' exposure to cutting oil mists prior to 1938. Deaths from nonmalignant respiratory disease were significantly less than expected. These results suggested that occupational exposure to soluble and nonsoluble cutting oil mists during various metal machining processes does not pose a health hazard in terms of respiratory cancer and fatal nonmalignant respiratory disease but may be associated with certain forms of gastrointestinal cancer.

Some Practical Aspects of Cutting Tool Nomenclature Arising from Recent Research

In recent years a considerable volume of research has been carried out to improve the techniques employed in the most widely used metal machining processes. An essential preliminary to all these experiments in turning, milling, drilling, tapping, etc., was accurate control of tool shapes. This necessitated the development of adequate tool-measuring equipment and a comprehensive nomenclature. The nomenclature has resulted from an analysis of tool geometry, and an examination of applicable tool grinding methods and inspection equipment. The nomenclature has been extended to take account of factors which were proved by research to be of considerable practical significance in the ultimate tool performance. Nomenclatures for the most commonly used types of tool are presented as a basis for discussion together with typical examples of tool geometry, tool grinding methods, and tool inspection equipment which should be taken into account when developing improved nomenclatures. Reference is also made to some of the British, European, and American standards, which have an important place in these discussions. Some of the problems involved in the workshop application of cutting tool nomenclatures are also considered. Recently, significant advances have been made in tool nomenclature as a result of the increasing co-operation between manufacturers and users of tools, but the nomenclature used for development work in research stations, colleges, universities, and industrial research laboratories, needs to be more comprehensive and precise than that at present used in general engineering practice.