The skiving, which is a very efficient machining technology for processing short form surfaces of revolution

1  Common description of the thesis

Evolution of modern machine building is focused mainly on increasing of production flexibility and product quality. These are the basic requirements that are necessary for a competitive output under market conditions.

It is well known that there is a great variety of machining technologies for processing of surfaces of revolution. These technologies are highly beneficial in specified production type providing a high dimensional accuracy and high surface quality.

According to experience of Ukrainian as well as foreign machine building companies the skiving can be viewed as the most efficient mass production technology for processing of short bodies of revolution. Sometimes it can be called turnbroaching or off-centering cutting depending on the real implementation in the machine design.

Nevertheless, this technology has been known for more than half a century but it still has no wide utilization in our industry because of process complexity and unwillingness of our companies to change their current technology. On the other hand, skiving is widely used by an foreign machine building industry especially by an automobile building companies (e. g. RENAULT, FORD etc.) for machining crankshaft journals and bearing rings. Therefore, the application of modern technologies in the Ukrainian industry is the main task for improving an economics of our country. The skiving technology might be one of them.

The substance: Today machining is still staying the most popular technology to process a great variety of different machine parts and according to ASME report it will be at this position for at least half a century. The need to understand and model the metal cutting process is driven by a number of intimately interwoven technological requirements. Chief among them, from the user’s standpoint, are the requirement to archive the required quality of the machined part and to perform the operation under minimum environmental pollution. From the machine tool and cutting tool builder’s standpoint, to ascertain the magnitude of the loads in order to generate appropriate design.

Actually the skiving is very productiveness, much more harmless than conventional technologies with similar capabilities and allows to generate an automate-machine design with a high volume and flexibility simultaneously. Moreover, it seems that the skiving involves features of the main cutting processes too. That is why it suits well for development of the comprehensive cutting model which has to provide a prediction of the cutting variables for all known cutting processes as well as to develop a CAM software for engineering utilization. These are actual problem today, but unfortunately, no reliable skiving simulation methods are known.

The connection with research projects: This work carried out according to research project 67.01.02 97/99 directed by Prof. Zaloga W. A.

The statement: The main object of this work is to develop the reliable method of chip formation and heattransfer process simulation under skiving conditions based on well-known principles of material mechanics. This skiving model must be made taking into account the features of metal deformation and interface contact processes under cutting with a high cutting speed and thin undeformed chip thickness (UCT). It should provide a determination of basic cutting variables by experimentally measured cutting forces and cutting length ratio.

Scientific ideas: In this work a method of unsteady-state skiving simulation which takes into account complex pattern of UCT and cutting angles variation has been given for the first time. Moreover, an experimental methods to determine a tool edge radius by using scanning electron microscope (SEM) and real UCT variation within cutting cycle by using contactless inductive pick-up have been proposed.

The results: The semi-experimental method of skiving simulation has been developed, programmed and validated. The future research activity in this direction seemingly results in elaboration of the computer based optimization method of skiving as well as  any other cutting process.

Author personal contribution: The author of this work has developed the skiving simulation algorithm and the approaches of its implementation. He is also the inventor of the experimental methods to determine a tool edge radius by using SEM and real UCT variation within cutting cycle by using contactless inductive pick-up.

Results application: Obtained results might be a topic of great scientific and practical interest from skiving optimization, new machine designing and simulation software development point of view.

Publications: The main aspects of this work have been published in six articles and in eight abstracts of scientific reports. This study has been also reported on both student and scientific conferences including international scientific conference «Interpartner ‘98” which has been held in Kharkov in 1998.

2  The Overview

This work investigates the skiving, which is a very efficient machining technology for processing  short form surfaces of revolution. It is well known that the up-to-day machine building industry needs a very flexible and high quality machining technologies that provide both ecological compatibility and cheapness. The fact is that the skiving is one of those processes. According to the world experience, this process can be applied to the mass production for processing  crankshafts, bearing rings, gears etc. Therefore, it can be called as skiving, off-centering cutting, tangential turning depending on the application in the lathe. Unfortunately, it is not well studied and that is why it is not widely used in Ukrainian industry. It presently becomes more popular and can compete with milling, former turning, grinding because of its ecological preference and high accuracy which are provided simultaneously.

The thesis consists of introduction, five chapters and conclusion. The nomenclature, abbreviations list and references are included.

Chapter One. The problem state-of-the-art

In this chapter a deep description of the problem has been given.