April 2008

System methodology of risk assessment in machine tools

MM (Modern Machinery) Science Journal, April 2008
Petr BLECHA
Institute of Production Machines, Systems and Robotics,
Faculty of Mechanical Engineering,
Brno University of Technology
Abstract

The contribution deals with the problem of safety assurance in machinery in accordance with the requirements of the Directive 2006/42/EC of the European parliament and of the Council of 17 May 2006 on machinery, and amending Directive 95/16/EC (recast), replacing the Directive 98/37/ES. The existing methods suitable for identification of hazards associated with machinery are reviewed. A new method of risk assessment in machine tools is presented, applying the system approach to hazard identification and to analysis and evaluation of risks associated with machinery, in accordance with the relevant Czech and EU legislation. Further, the contribution discusses a suitable way of documenting the risk assessment process.

Keywords: Risk analysis, Risk assessment, Risk management
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A study of computer assisted analysis of effects of drill point geomerical features on forces and power in dribling with general purpose twisk drills

MM (Modern Machinery) Science Journal, April 2008
Jaromir AUDY
Edith Cowan University,
(ECU-SW),
Bunbury,
Australia
Abstract

This paper presents results of a systematic – computer assisted – study focused on determining, and describing, from a mathematical point of view, the relationship between the drill point geometrical features and predicted performance measures as assessed by the cutting forces (thrust and torque) and cutting power when drilling a Type Bisalloy 360 steel work-piece material with general purpose twist (GPT) drills. The current study presents an innovative predictive strategy for eliminating the need of experimental testing when comparing drilling performance of GPT drills. It employs an advanced computer assisted model to analyse the rake angle distributions along the drill lips and the chisel edge regions when changing the six main individual drill point geometrical features (D, 2W, δO, ψ, ClO, and 2P) in the software input and looking at their effects on the generation of thrust, torque and power in drilling. It is expected that this sort of information may be used to assist in optimisation of the cutting performance of drills via advances through the modification of drill point geometrical features.

Keywords: Computer assisted predictions, general purpose twist drills, geometrical features, drill point, lip region, chisel edge, rake angles, thrust and torque forces, cutting power.
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