Sampsa V.A. Laakso

Relationships of Factors in a Manual Assembly Line Environment

This study makes a proposal and then presents the information required to describe operations and human resources management factors in a manual assembly line environment. This information is needed since the purpose of this study is to increase the understanding of the effects of the factors and their interrelationship on system performance. Because of the complex nature of the socio-technical assembly environment the present study focuses on task- and worker-related matters as a basis for conceptual-level analysis and factor connections flow. The study uses the Gephi software for analyzing factor clusters, occurrences, and connections by means of a relationship network. As a result, the software produced four different factor clusters, each characterized by strong mutual relationships between the factors comprising them. Further, the results of this study help to identify the factors that are to be used in more thorough analysis, from assembly environment development up to semi-intelligent decision-making systems.

Surface improvement of shafts by the diamond burnishing and ultrasonic burnishing techniques

The demand for good surface quality and good fatigue resistance of engineering components is becoming ever greater. Mechanical surface treatments are performed to improve the surface properties and quality of cylindrical workpieces. In this article, the surfaces produced by two different surface treatment methods are evaluated in terms of their surface integrity. The processes are diamond burnishing and ultrasonic burnishing. Both diamond burnishing and ultrasonic burnishing are fast, simple and economical cold-working processes that provide good surface quality and hardness. This paper examines the residual stresses, the changes in the surface quality and the changes in the surface hardness of the workpieces that have been finished via diamond burnishing and ultrasonic burnishing processes. It is extremely important to know what effect the methods have on the residual state of the material. The results demonstrate that it is possible to achieve reductions of as much as 78% to 94% in surface roughness (Ra) via the diamond burnishing and ultrasonic burnishing processes.