Publications    

Abstract: The reduction of the overall Life Cycle Costs (LCC) is a key issue in manufacturing sector. Among the various contributions to LCC an important part is due to Reliability and Maintainability (R&M) issues and therefore a substantial reduction in LCC can be achieved by a conscious decisions and planning. Besides the failure and repair characteristics, the R&M related costs vary according to the maintenance strategy and policy selected for each components that form the manufacturing system. The aim of this paper is to describe a mathematical model that takes into account the R&M related fraction of the LCC in order to compare scenarios in which different maintenance strategies and policies are applied on the components of manufacturing systems. The calculations cover three policy possibilities: internal crew, external service (on-demand) and external service (annual contract). Both scheduled (preventive maintenance, inspection-based maintenance) and unscheduled (corrective maintenance, condition monitoring) strategies are considered. On the basis of the proposed formulae, optimization is carried out with a view to find the best solution in economical aspect. Furthermore, the method takes into account the possibility of clustering the scheduled interventions with the intention of reaching a predefined availability constraint while keeping the costs as low as possible. The paper presents the results of the European FP7 research project EASE-R3 where a specific maintenance planning software tool is being developed implementing the methodologies outlined above.

Abstract: In the diamond wire stone cutting process the objective is to remove a chip of material or a layer of uniform thickness from the entire length of the cut. The aim of this study is to correlate the cutting performance to the characteristics of the natural stone and subsequently to propose a method of classification strictly connected to stone workability. This paper studies eight different stones classified according to an “easy-to-cut” scale based on the historical company know-how (HIC - Historical Industrial Classification).  This classification is based upon experience and not on explicit or really scientifically quantified parameters, nonetheless, it describes the stones workability completely.

Abstract: Stone cutting with diamond wires results in the progressive and concurrent wear of the natural stone and the cutting tool (diamond wires - diamond beads). This phenomenon has been investigated since the beginning of stone machining, but there are still several open questions concerning the parameters controlling it. The aim of this study is to establish correlations between the natural stone mineralogical composition and the diamond wires cut performance in terms of efficiency, productivity and diamond beads consumption. This investigation requires a multidisciplinary approach. Microscopic analysis have been done in order to investigate the wear processes of the diamond beads in terms of super-abrasive grains (diamond grits) damage and pull out. Petrographic analysis and mineralogical investigation have been considered in order to correlate the removal rate during the cutting action with the characteristics of the stones. Muds derived from cutting have been characterized for the complete comprehension of the cutting process. The erosion analysis concerned both stone debris and diamond beads, characterizing both the metal powder and super-abrasive grains (diamond) in the cut waste (mud). Moreover, the metal matrix is the core of the diamond wire technology and it drives cutting performance and efficiency.

Abstract: Besides having effect on the capacity through the availability, the maintenance of production machinery also influences the usage of human and material resources. These factors are strongly related to the costs, which makes the determination of the optimal failure handling solutions be an important task for companies concerned with manufacturing. In order to find the best strategy it is essential to investigate the possibility of not only the individual but also the common maintenance schedule for components of the machines which can be carried out by system level optimization. In this paper an expression is proposed for the calculation of the long term cost per unit time which takes into account the system level effect of the maintenance of production machinery characterized by serial reliability, assuming perfect corrective and preventive interventions. The formula can be used as an objective function of which minimum determines the best solution in economical point of view. In order to find this extremum, a semi-discrete firefly algorithm is implemented which provides component clusters and a common prevention interval for each group. The proposed method is illustrated using an example data set. Furthermore, the values of the steady state availability and cost per unit time achieved by the optimization are verified using Monte Carlo simulation.

Abstract: Augmented Reality (AR) has been proved to be an effective tool to improve and enhance the learning experience of students. On the other hand, issues regarding the in flexibility of AR contents can strongly limit the usability of AR applications in education. This paper presents results obtained by using the AR framework designed and developed for the EASE-R3 European project and focused on the generation of maintenance procedures for machine tools. The high system flexibility allows instructors to easily make maintenance procedures suitable for the skill level of technicians to be trained. A case study is presented and results gathered so far analyzed and assessed.

Abstract: Augmented Reality (AR) applications are nowadays largely diffused in many elds of use, especially for entertainment, and the market of AR applications for mobile devices grows faster and faster. Moreover, new and innovative hardware for human-computer interaction has been deployed, such as the Leap Motion Controller. This paper presents some preliminary results in the design and development of a hybrid interface for hand-free augmented reality applications. The paper introduces a framework to interact with AR applications through a speech and gesture recognition-based interface. A Leap Motion Controller is mounted on top of AR glasses and a speech recognition module completes the system. Results have shown that, using the speech or the gesture recognition modules singularly, the robustness of the user interface is strongly dependent on environmental conditions. On the other hand, a combined usage of both modules can provide a more robust input.

Abstract: This paper studies the opportunities coming from the use of consumer devices like smartphones and tablets to perform maintenance and assembly procedures with Augmented Reality (AR). Pros and cons are evaluated by comparing completion times and errors made while executing a maintenance procedure with an AR-based tool and paper-based instructions.

Abstract: Augmented reality (AR) is a well-known technology that can be exploited to provide mass-market users an effective and customizable support in a large spectrum of personal applications, by overlapping computer-generated hints to the real world. Mobile devices, such as smartphones and tablets, are playing a key role in the exponential growth of this kind of solutions. Nonetheless, there exists some application domains that just started to take advantage from the AR systems. Maintenance, repair, and assembly have been considered as strategic fields for the application of the AR technology from the 1990s, but often only specialists using ad hoc hardware were involved in limited experimental tests. Nowadays, AR-based maintenance and repair procedures are available also for end-users on consumer electronics devices. This paper aims to explore new challenges and opportunities of this technology, by also presenting the software framework that is being developed in the EASE-R3 project by exploiting reconfigurable AR procedures and tele-assistance to overcome some of the limitations of current solutions

Abstract: Manufacturing strives to reduce waste and increase Overall Equipment Effectiveness (OEE). When managing machine tool maintenance a manufacturer must apply an appropriate decision technique in order to reveal hidden costs associated with production losses, reduce equipment downtime competently and similarly identify the machines’ performance. Total productive maintenance (TPM) is a maintenance program that involves concepts for maintaining plant and equipment effectively. OEE is a powerful metric of manufacturing performance incorporating measures of the utilisation, yield and efficiency of a given process, machine or manufacturing line. It supports TPM initiatives by accurately tracking progress towards achieving “perfect production.”

Abstract: The widespread adoption of mobile devices is giving everyone access to augmented reality systems, possibly involving a huge number of people in AR-based apps, with a pervasive social impact that cannot be neglected. AR systems are becoming affordable to everyone and especially useful in the maintenance field. This report aims to describe in a clear and accessible way the workflow to design and develop an augmented reality (AR) application for supporting maintenance procedures. The main focus of this paper is the evaluation of markerless tracking systems, as they could provide environment-independent solutions. The tests performed on a real use case outline the robustness of 3D CAD tracking with respect to other solutions