Cornel Mihai Nicolescu

Performance analysis of the closed loop supply chain

PurposeThe question of resource scarcity and emerging pressure of environmental legislations has brought a new challenge for the manufacturing industry. On the one hand, there is a huge population that demands a large quantity of commodities; on the other hand, these demands have to be met by minimum resources and pollution. Resource conservative manufacturing (ResCoM) is a proposed holistic concept to manage these challenges. The successful implementation of this concept requires cross functional collaboration among relevant fields, and among them, closed loop supply chain is an essential domain. The paper aims to highlight some misconceptions concerning the closed loop supply chain, to discuss different challenges, and in addition, to show how the proposed concept deals with those challenges through analysis of key performance indicators (KPI).MethodsThe work presented in this paper is mainly based on the literature review. The analysis of performance of the closed loop supply chain is done using system dynamics, and the Stella software has been used to do the simulation.FindingsThe results of the simulation depict that in ResCoM; the performance of the closed loop supply chain is much enhanced in terms of supply, demand, and other uncertainties involved. The results may particularly be interesting for industries involved in remanufacturing, researchers in the field of closed loop supply chain, and other relevant areas.OriginalityThe paper presented a novel research concept called ResCoM which is supported by system dynamics models of the closed loop supply chain to demonstrate the behavior of KPI in the closed loop supply chain.

Investigation of tool wear mechanisms in CGI machining

In this study, the tool wear, including wear mechanisms on coated cemented carbide inserts were investigated in the turning of Compacted Graphite Iron (CGI) materials with varying nodularity. The results showed that increasing nodularity, in the range of 5-62%, affects wear at moderate and high cutting speeds without having the same impact at lower cutting speeds. A small difference in nodularity, in the lower range, such as an increase from 5% to 20%, has a more significant impact on wear than an increase from 20% to 62%.

On-line identification and control of dynamic characteristics of slender workpieces in turning

Abstract Increasing interest has been shown in the design of process control systems for manufacturing. The interest is driven by the rapid development of advanced sensor technology, signal processing and the successful implementation of intelligent control systems. This paper focuses on the practical implementation and experimental test of an original system for identifying and controlling the dynamic characteristics of the cutting process. The theoretical research has primarily been devoted to the investigation of dynamic stability using stochastic modeling. This technique represents an ideal tool for properly describing the dynamic interaction between the dynamics of the cutting process and the machine tool structure. Modeling the dynamic behavior of the cutting process with an adequate stochastic model leads to an increase of the performance of the control system because the time available for control action increases. The control strategy has been developed in a flexible and distributive architecture that provides an effective and robust control of the cutting process. Real time experience of the control system is described.

Performance Evaluation of TiAlN-PVD Coated Inserts for Machining Ti-6Al-4V under Different Cooling Strategies

Titanium alloys are labeled as difficult to materials because of their low machinability rating. This paper presents an experimental study of machining Ti-6Al-4V under turning operation. All machining tests were conducted under dry, mist and flood cooling approaches by using a TiAlN coated carbide cutting inserts. All cutting experiments were conducted using high and low levels of cutting speeds and feed rates. The study compared surface finish of machined surface and flank wear at cutting edge under dry, mist and flood cooling approaches. Scanning electron microscopy was utilized to investigate the flank wear at cutting edge under various cooling approaches and cutting conditions. Investigation revealed that TiAlN coated carbides performed comparatively better at higher cutting speed.

On a Finger Model Actuated With Shape Memory Alloy Artificial Muscles

The simulation of a flexible finger, actuated with the shape memory alloys (SMAs) artificial muscles, is presented in the paper. The finger is modeled as a cylindrically rod with three embedded NiTi wires in a n aluminum matrix. Forces between NiTi wires causes bending in any plane perpendicular to the longitudinal axis of the finger. The NiTi wires are heated above the austenitic start temperature by passing an electrical current, and the deflected wire tends to return to the initial configuration. Using characteristics of SMAs such as high damping capacity, super-elasticity, thermo-mechanical behavior and shape memory, the actuation for the finger is theoretically introduced and discussed.Copyright

A Shape Description Model by Using Sensor Data From Touch

In this paper we consider the problem of recognizing the shape of a 3D object using tactile sensing by a dexterous robot hand. Our approach uses multiple fingers to slide along the surface of the object. From the sensing contact points we extracts a number of 3D points belonging to the surface of the object. The unknown surface Γ of the object is determined by using an “n-ellipsoid” model (Bonnet [1]). The set of parameters that define the surface Γ is determined such that the n-ellipsoid best fits the set of data points.Copyright

Development of Cutting Force Measurement System for Gear Hobbing

Increasing demands for high quality and high performance gear manufacturing are reflected in a need for a model based investigation of gear hobbing process. This paper presents the development of a ...