AMST’05 Advanced Manufacturing Systems and Technology

In the last twenty years the increased international competition in the wake of globalization has changed the methods of manufacturing, especially the structure and organization of a factory. More self-similarity among the enterprise, the groups and the employees, self-organization and self-optimization have arisen. For this structure the name Fractal Company has been used. Many companies are following this perception, but it is a long and difficult way to go which needs vision and leadership. Some examples are given here.

Today 5 production paradigms can be identified as actual and with future potential. The advanced machining technologies and the developments of machine tools and tools are already initiated, but must be implemented to a growing extend.

Competition and collaboration are the driving forces for science in general and for production science in specific. Competition is an appropriate mean to focus rare sources. Collaboration enables a holistic approach to production and can be seen as a new paradigm for production research. An example for the new paradigm of process chain development is given: the decreased process chain for the production of gears for the automotive industry. Material scientists, metal forming engineers, grinding experts and automation specialists work together with industrial partners.

The existing industrial production structures for various products are based on A.W. Taylor principles of the division of work and operations, developed almost a hundred years ago. The previous century introduced into manufacturing technology, systems and their control a large number of innovations, based on fundamental and applied research in various fields of interest. The contribution presents a new approach to the structuring of an Adaptable Network Manufacturing System (ANMS) for the production of various HT-products. The ANMS is based on a competent selection of Elementary Work Systems (EWS). Some structures and characteristics of their elements and units are explained in detail. The second part of the contribution presents the procedure for the structuring of an optimal ANMS. The role of innovation management and marketing research is analyzed. The active cooperation with a team of researchers, dealing with advanced investigations related to the new product, and the team of product designers is explained. Special attention is focused on the subjects S and their competence, as well as on the methods of how to increase the necessary knowledge, needed by the subjects operating an ANMS.

The paper discusses some approaches in machining research. Development of empirical technology, as well as of science-based (predictive) technology, and development of computer-based technology are presented. The application of mathematics of statistics and design of experiments, simulation of machining processes such as analytical simulation, geometrical simulation, finite element simulation, and supervision systems in machining are discussed. Also, the importance of machining research for computer integrated manufacturing enterprise in global market conditions is discussed.

Numerical analysis of metal cutting operations is increasingly relied upon in computer experiments, in order to clarify mechanical, thermal and tribological aspects in view of process optimization. The acid question is, however, whether impressive color displays and detailed figures describe what is actually taking place, or if some results might more properly belong to virtual reality. A classic experimental design for second order response surface work, concerning a simple cutting operation on mild steel, was run both in the metal cutting laboratory and on dedicated software, and results compared also in the light of classic models. Agreement concerning responses such as forces, temperature, and cutting ratio, was found to range from definitely fair to quite poor, underlining that reliance on numerical model may not always be fully justified. Analysis of deviations throws some light on a complex situation.

A wide experimental investigation on the friction stir welding of AA6082-T6 sheets is presented. In particular the influence of some of the most relevant process parameters was taken into account, with the aim to maximize the joint strength; furthermore the joint fatigue behavior was considered too. An accurate analysis on the obtained parts was carried out, with particular attention to the material microstructure evolution. The obtained results permitted to develop a proper FSW process engineering.

In this paper, unconventional methods of cutting based on ultrasonics, laser, and water jet mechanisms that might be used in orthopaedic surgery are discussed. Their advantages include no or little contact with bone or tissue that is to be cut, the application of much less mechanical force compared to traditional techniques, and reduction in localised heat effect in the region undergoing surgical cutting. A critical analysis is performed to identify their limitations and merits.

Nowadays, miniaturization is playing an important role in product redesign while complex microproducts are leaving their traditional domains. These two aspects concur to the need for increasing their production and reducing their cost. One of the main production problems is represented by microassembly. This keynote paper deals with the microassembly problems, shows the state of the art of the research, highlights the most promising R&D areas in this field and finally presents some new solutions for hybrid microproducts assembly.

The paper presents results from machining tests that are carried out to investigate the type of tool wear that occurs in interrupted cutting of Ti6A14V under different process conditions. It has been found that the type of wear is similar to the wear in continuous cutting, but the wear develops much faster. The tests show that by using high-pressure coolant (30 MPa), the cutting speed can be increased by 40 to 50 percent. Edge preparation of cutting tools is of great importance. The best results are achieved with a cutting edge that is slightly rounded. Carbide tools are recommended for the turning operations. Tests show that PCD, CVDD, and CBN have limited usefulness in interrupted cutting.

Cutting process optimization could be considered in different levels and approaches. How to select tools and how to take care of evident waste of time and costs can not be considered as a competitiveness market factor any more. Everyone responsible for cutting process planning must be up to date with these procedures and the tool makers are ready to help their customers. Otherwise, after the best selected tool and cutting conditions are settled and the process is running in shop floor many things could be done to go deeper in the cutting process optimization. One of them is how to consider the cutting process system and scenario influence on cutting condition, more specifically, on the cutting speed, which is usually to select from data published in catalogues and normally based on the pair tool/workpiece. The purpose of this paper is to present and discuss, step by step, a mathematical method and practical procedure to search the best cutting condition in different industrial scenarios.

Advanced manufacturing requires a powerful tool for reliable modeling and solving the complex machining optimization problems. This paper proposes a non-conventional approach using evolutionary algorithms inspired by Darwinian findings about the evolution of the biological species and the survival of the fittest organisms (i.e. natural selection). It is illustrated with an experiment of longitudinal hard turning. Genetic programming (GP) is used to develop the models of both the surface roughness and the tool life considering the cutting speed, the feed and the depth of cut as predetermined cutting parameters. Finally, genetic algorithm (GA) is applied for their optimization.

The choice of the tool for one determined operation and the correct determination of the machining conditions, represent an important factor in the metals working, being this determinant for the evolution of tool-machine and cutting tools. Such fact accents in the serial manufacturing, where divergences in the choice of the cutting speed and the tool may cause notables variations in manufacture costs. The decisions for tools selection, machining parameters determination and tool exchange times are carry by process planners, programmers and machine operators in different periods of manufacture. This share of responsibility and the lack of interaction with the process have difficult very the taking of decisions of a form optimized in relation to the tool rack and the process in itself. The considered work aims at to promote the optimization of the machining processes in turning in a manufacture cell, of automobile parts factory, using for this optimization methodology of the process based on the maximum production condition, through the determination of the coefficients of the Taylor’s equation of tool life in shop floor environment. The objective is to provide to real increases of productivity and quality in industries, without the requirement of investments in new means of production, and valuing the use of the information inside it productive system.

This paper deals with the modeling of cutting forces in plunge or vertical milling. The operation of rough and semi rough machining allows realizing the walls of moulds and matrices. This new technique of milling greatly contributes to shortening the entire production process, and therefore, saving significant production time and costs. In this paper, we propose a cutting model that includes the determination of tool geometry, trajectories of cutting edge, chip geometry (radial engagement, chip thickness) and the evaluation of the cutting forces. This model is validated experimentally through tests run in the machining centre. In this study, plunge cutting was carried out on the 40CrMnMo8 material using end milling.

The application of high speed machining of molds and dies with their high complex geometry have made the traditional methods of toolpath interpolation normally used by CAM systems, i.e., linear and circular interpolations, the bottle neck of the whole process. These traditional interpolation methods increase the machining time, have a negative influence in the final quality of the surfaces and are a technological limitation for the full application of HSC. As a result, the study of new methodologies on toolpath interpolation is becoming one of the main areas of research in manufacturing of molds by HSM. Among the different methodologies of toolpath interpolation there are the linear, circular and polynomial. The milling experiments were made using work pieces of AISI SAE P20 Steel and the geometry from the NC Gesellschaft test part.

In the last years, the research on metal machining has been focused on the development of tools that can support an increment of the cutting parameters instead of the increment of tool life; this strategy is focused to obtain a relevant productivity increment without getting worse the final product quality. The new design of the tool corner radius has allowed preserving the same product quality due to the “wiper effect” generated during the cut.

The employ of such re-designed tools can allow substantial productivity improvements and, by employing the same feedrate, it is possible to achieve excellent surface finish and eliminate the grinding operation. With the aim to verify the possibility to realize good finishing on hardened materials with the above mentioned new tool-manufacturing technology the Authors conducted a set of turning tests on a quenched steel.

The quality of the manufactured products are compared with the one obtained by grinding. The final product qualities are compared in terms of micro geometrical characteristics and tolerances of the obtained workpiece surfaces are investigated to completely determine its mechanical performances.

A feature when cutting many alloys is that workpiece material adheres to the cutting tool at the sliding contact surfaces, between the work material and the tool. This built-up material formed during cutting is of fundamental importance in machining operations, because it may significantly affect the surface roughness, tool wear, workpiece dimensions and tolerances, tool forces, and chip form. The agglomeration of the work material to the tool appears to be analogous to cold welding, metal transfer in tribology and dead zone in extrusion. In machining terminology this phenomenon is often called “built-up edge” (BUE). Several important factors affect the built-up material formation, e.g. cutting temperature, cutting speed, strain hardening, adhesion between the work material and the tool, micro-crack formation, plastic flow of the work material in the vicinity of the cutting edge, etc.

Surface ground workpieces can exhibit quality impairments in the shape of unwanted pattern formation. Experimental investigations show, that pattern formation in surface grinding is independent of self excited vibration and that the pattern wave length coincides with the tangential feed. The observed patterns can therefore be attributed to e. g. either residual grinding wheel imbalance, roundness error or non-uniform grinding wheel surface topography. The visibility of the patterns mainly depends on the magnitude of the tangential feed. Increasing the feed reduces pattern visibility. Due to the underlying formation mechanism, pattern formation goes hand in hand with a waviness profile, which is dominated by waves with a wavelength equal to the pattern wave length. By measuring and adjusting the phase shift between the grinding wheel rotation during consecutive grinding passes, both the workpiece waviness and the visibility of the surface patterns can be reduced during sparking out.

Assessment of the grinding process quality includes the micro geometrical quantities. The efficient surface texture modelling and optimisation is therefore essential for the competitive grinding processes. The objectives of this paper refer to development of empirical surface texture models and optimisation of precision centreless grinding (CG) with recently developed, highly-efficient, sintered aluminium-oxide-nitride (A1ON) abrasive. Investigation has been carried out to study specific effects of the CG gap set-up, the dressing condition and the process kinematical factors on component surface texture parameters. Central composite design (CCD) of experiments and linear regression analysis (LRA) has been employed to develop surface texture models. The optimisation goals are combined in an objective function called desirability and solved by numerical nonlinear programming.

Predictions on the tool condition and the surface finish of workpiece in grinding process of metal materials have been studied in the past years using physical and empirical models. In this paper, the feasibility of using neural networks, based on signals detected by multi-sensorial system to monitor tool and workpiece surface conditions in grinding operation of natural stones, has been investigated. Grinding wheel wear evaluation has been carried out measuring flat area percentage on the active surface of the tool by means of a vision system. Workpiece surface roughness has been assessed by means of a mechanical profilometer. Neural network models have allowed to predict grinding wheel cutting ability and workpiece surface finish by measuring on-line the grinding forces and the surface wheel temperature variation.

This paper studies the effects of cutting parameters in the tool wear and surface quality (roughness). The tests were carried out on a CNC lathe, using uncoating and coating cemented carbide tool under finish cutting conditions. Microestuctural characterization of tool wear and surface was made using scanning electron microscopy (SEM). The turning of the Ti (6Al-4V) alloy is very difficult due the rapid tool wear. Such behavior result of its low thermal conductivity in addition the high reactivity with the cutting tool. After the machining, the aluminum samples were analyzed with the aim to investigate the mechanisms, which influence the finish of machining surfaces. In the all analyzed samples were observed typical characteristic of machining surfaces, as feed marks, typical deformations of built-up edge (BUE) beyond deposited particles in the machining surface. A typical formation of the side flow mechanism was also observed.

The aim of our article is to propose a model of simulation of the dynamic behaviour of the creep feed grinding process. Specifically, we seek to predict the waviness of the bonded surface (depth of cut). We propose, initially, a mechanical modelling taking account of the operational parameters and the geometrical and mechanical characteristics of the workpiece, the tool and the machine-tools. The models are founded on the Newton’s second law and on the Work Energy principles with various assumptions on the contact wheel workpiece. In a second time, computer simulations (under Simulink) are proposed in order to evaluate the waviness of the profile and the stability and the precision of these models.

In the paradigm for CNC machining, tool path programming and online control of the machine are separate tasks. Though this paradigm has proved successful to date, it is now showing its limitations particularly in 5-axis machining, high-speed machining, direct model-to-part manufacturing and automated error detection and prevention. This paper describes work to implement a new paradigm for CNC machining described by Gray et al. [

1

] for direct model-to-part manufacture by providing the part definition to the NC controller. The intention here is to integrate a simulation module into the controller to detect and prevent errors by merging the physical workspace of the machine with the virtual workspace of the simulator. This paper describes the architecture for this concept and the simulation module that has been developed. Also, a machining test was conducted on a special-built machine to analyze the machine and simulation components.

The paper presents the design and the implementation of a vision system for a Cartesian robot located in the Mechatronics laboratory of the Dept. of Electrical, Management and Mechanical Engineering of the University of Udine. The system hardware is made of two monochromatic analogue cameras with charge coupled sensor JAI CV-A50 and of an image acquisition board NI PCI-1409. The software code has been implemented in MATLAB and in the NI MAX environment. The vision system can control the two cameras by making a direct image acquisition and calibrating the cameras using the Faugeras method. Moreover, it is possible to obtain the three-dimensional localization of a selected object through stereoscopic vision techniques. The vision system described in this paper will be soon integrated with the Cartesian robot located in the laboratory, so as to have a powerful tool which turns out to be very useful for several application of conventional and applied robotics.

In many robotic applications, 3D location estimation of an object with respect to a reference frame is required. Circular markers located on the object are often employed for this purpose. This paper addresses the problem of 3D location estimation of circular features from a single camera image. A mathematical closed-form solution of the problem allows to determine the normal vector to the circle feature with respect to the camera reference frame. High calculation accuracy is guaranteed by a Kalman filter which performs a sub-pixel parametric estimation. A set of experimental results shows the validity and the accuracy of the process involved in 3D angular estimation. The theory is applied to a real industrial problem, namely the 3D location of a car rim. In fact, this information is necessary to perform a pick-and-place robotic task.

In this paper a prototype of a robot platform designed for movement on large ferromagnetic plates is presented. The intention was to build a platform with a high positioning accuracy, which have an unrestricted working area and carry a universal robot on its top plate. Throughout this paper the main elements of the mobile system is presented. The robot platform has a hydraulic drive motor, 7 cylinders and six electromagnetic legs. The movement of robot can be linear or rotational in both directions, which enable it to reach any position on an extended surface.

Characteristics of main spindle and feed drives for the NC machine tool highly depend upon skillfulness of composing variable speed motors (AC or DC) and mechanical transmission elements. In order to enable interactive computer aided design and analysis of different design variants of NC machine tool drives, original computer programs have been developed.

The paper presents an efficient procedure for synthesizing PID controllers so as to maximize Smith’s vector stability margin, i.e., to minimize the

H∞

norm of the sensitivity function, while ensuring specified values of the phase margin and gain crossover frequency. In this way, a trade-off between dynamic performance and robustness is achieved. The considered problem would be hard to solve with existing techniques; the suggested method, instead, leads to the desired result with remarkable computational simplicity, as shown by meaningful examples.

This paper presents a approach for multi-objective design and reconfiguration of the current manufacturing system. A proposed model for multi-objective design and adaptable reconfiguration is based on the multi-agent principles and Emergent Synthesis concept. Emergent Synthesis is introduced in the adaptable reconfiguration within implementation of the layered based architecture and utilizing the multi-agent concept. Based on the proposed approach a simulation model has been built and evaluated. For the purpose of analysis of this approach it was simulated production in the shop-floor of the manufacturing system with the two different initial configurations. For evaluation of here presented approach the case study was performed using realistic data; it was simulated production of the cellular phone devices. From obtained results of the simulation it can be conclude that a proposed model has a high level of multi-objective adaptation of the manufacturing system shop-floor.

Mass customization can be approached from many points of view. When the focus is centered on the order acquisition and on the fulfillment process, the recourse to a computer support system, called Product Configurator, is widely adopted. To use it as a support to the design and the development of new products is a challenging application, seldom implemented in current industrial systems. Here, concepts taken from object programming are applied: namely the hereditariness of the class attributes by the children classes. The aim is to implement a hierarchic approach to the customization of the product with the advantage of a thorough applicability of postponed operations along the entire supply chain. In the work the conceptual framework and the application issues of the hierarchic Product Configurator are detailed. In order to evaluate the advantages (simplicity, flexibility and quickness) and the drawbacks (explosion of varieties and difficult stock minimization) of this methodology, it has been applied to case studies taken from production.

The purpose of this paper is to propose a method for short-term production planning, focused on control and regulation of work-in-process in a make-to-order production system. The possible improvements in terms of performance indices (production lead time and reliability of delivery dates) of the job shop are pointed out. The solution implied a revision of the production process and the application of input-output control methods for operations management at job shop level. The production stages that were independent from customers’ orders were decoupled from activities that could be performed before an order entry. For workload control the load-oriented manufacturing control (LOMC) method was applied to a manufacturing area that produces order-specified items. The experimental phase, on the one hand, gave insights on improvements that can be obtained with the proposed method and, on the other hand, made it possible to define dispatching rules that were effective for work order management in the case study.

The intention of this paper is to give some methodical approach in process planning. Within this it covers the problem of defining the sequence of operations. Quality of the product, production time and production cost determine sequence of operations. The purpose is to analyse their influences and how to apply them in making decisions. Matrix of anteriorities sometimes generates multiple solutions. Understanding these influences could lead to solution of these problems.

This paper focuses on the definition of a supervision and data acquisition system in a manufacturing plant. In particular, the work here presented refers to the implementation of a SCADA system in a company which produces components by injection molding. The supervision and data acquisition system is based on an electronic structure connecting the production machines with the supervision computer where all the production and management data are collected and treated by a suitable software (MES). Different solutions have been analyzed; the one implemented is based on a PLC logic and it is also the cheapest one able to guarantee the future expansion to additional production machines.

Many of the typical problems related to fusion welding of aluminium alloys can be avoided by using non conventional joining techniques. One of particular interest is the Friction Stir Welding (FSW) in which the joined material remains at solid state, thus allowing to avoid solidification phenomena such as formation of dendritic structures or liquation cracking. Since FSW is governed by two completely mechanical processes, i.e. mixing and forging, it is possible to join heterogeneous aluminium alloys without filler metal. Using specially designed tools and machines up to 75mm of aluminium can be welded in a single pass. This paper describes a low-cost method of transforming a conventional milling machine into a simple FSW work station. The machine adaptation process includes the implementation of a temperature measurement and a downward and horizontal forces monitoring systems, as well as designing of a tool fixing system and the tool itself. Finally are presented the results obtained using the modified FSW work station along with the cost related considerations.

Manufacturers’ main targets (high productivity, high quality and low costs) are found in a complex economic environment demanding flexibility and spirit of adaptability. The achievement of these goals is strongly dependent on the logistic technological architecture making up the planning stage, which regulates the production process. First, the internal framework of Danieli & C. Manufacturing Department is described, and the main functions and tasks of the various divisions are pointed out. A perspective based on CAM is adopted, since the CAM division plays a central role in this structure. The present situation is then compared to the CAPP approach. Finally a CAD/CAM 3D integrated approach is proposed for a marginal field.

This paper presents the ideation and implementation of a 2-axes robotic system for hotwire cutting of polystyrene plates. In particular, since the quality of the cutting process is strongly affected by, among others, the interaction force between the hotwire and the workpiece, an accurate force control is required. The force control module, which is referred to as

delayed reference control

(DRC) belongs to the category of non-time based controllers. It is recalled that in a time-based control, the desired input reference is described as a function of time only, which is referred to as reference time:

x

d

(

t

). What is relevant is that such a reference can never be modified by any external event. Conversely, according to the DRC theory, the desired input reference

x

d

is a function of the time and a variable, which plays the role of a time delay:

x

d

(

t−T

). The time delay

T

is properly calculated on-line according to the measured force signal in such a way to improve the quality cutting process during the interaction phase. DRC theory and its practical implementation on a 2-axes robot are presented as well as an accurate description of the cutting process. In fact, experimental results validate theoretical predictions.

Micromachining is related to specific techniques applied to micro and meso scale elements, in order to produce components with high precision and very restrictive dimensional and geometrical tolerances (micron or sub-micron). In the industrial world the interest in microscopic scale manufacturing is exponentially increasing in relation to the rapid growth of Micro Electro Mechanical Systems (MEMS) research. Thus a greater attention is given to improve traditional techniques and developing non-conventional machining methods, in order to obtain more precision. This paper intends to present a review of the actual state of art in micromachining, showing possible different ways to create high aspect ratio patterns or 3D sculptured workpieces. Therefore the most important techniques will be presented, focusing on photolithography (bulk & surface machining), LIGA, laser, micro-EDM, micro-USM and microme-chanical machining (microcutting and micromilling). Machinable materials, obtainable working tolerances, limits and problems will be also highlighted for every method.

Laser beam melt ablation as a non-contact process offers several advantages compared to conventional processing mechanisms. During ablation the surface of the workpiece is molten by the energy of a CO

2

-laser beam. This melt is then driven out using the momentum transfer from an additional process gas flow. Although the idea behind laser beam melt ablation is rather simple, the process itself has a major limitation in practical applications: with increasing ablation rate, the surface quality of the processed workpieces declines rapidly. To find an explanation, and to be eventually be able to control the process thorough analyses are necessary. For this, in addition to the measurements of the processed surfaces also the optical process emissions have been recorded and analyzed. These data show a pronounced 1/f-noise-like behavior, which suggests the existence of intermittency during processing.

The paper investigates the main issues of design and modeling of so-called cluster mills for cold rolling of thin and moderate thin steel products, by means of numerical tools. This preliminary discussion summarizes the relevant aspects experimented on few operating cold rolling mills, started in [1], to select models and architecture suitable to build simple tools, to be used for a preliminary prediction of the dynamic response of the whole plant, in presence of known excitation, or even to simulate condition monitoring operation, to support operators in signal processing of sensors equipping bearings and mill frame.

The pressure fluctuation in the waterjet (WJ) process is due to the mechanism of high pressure generation, characterized by a cyclical working, and to physical causes (water compressibility at the exercise pressures). This phenomenon cannot, at present, be removed; however, it can be dampened, depending on the selected constructive system, by installing a pulsation attenuator below the intensifier or by conveniently phasing the pumping cycles of more intensifiers in parallel. In this paper, the effects of the pressure on the WJ process have been investigated. The pressure signals generated by a double-acting reciprocating intensifier pump system have been analysed; the effects of the pressure fluctuation and of the pressure signal form on the cutting quality have been studied through the acquisition of the roughness profiles of the surface of various materials (rubber, polycarbonate, plasticine) generated by waterjet.

Paper describes a new manufacturing method based on the most advanced small scale laser sintering technology able to shape solid metallic objects being composed of nanophased powders. New development in powder feeding will be illustrated being able to feed particles down to three microns medium particle size using combination of different mechanical and physical principles. For hybrid objects possibility with material change on the flight is included. Several peripheral devices for process control are implemented like online temperature control, oxygen control in the process chamber, shape control of processed geometries and integrated observation microscope. Fully atomization is assured by special designed software and industrial standards of PXI technology. Agglomerated nanophased systems were developed to respond to the needs of micro fabrication in terms of phase sets, particle sizes and shapes.

This paper describes an innovative developed process of incremental sheet metal forming based on two industrial robots. Instead of using expensive dedicated dies simple and reusable tools were designed to form sheet metal into complicated geometrical shapes. These simple tools with flat or hemispherical head are mounted on the end effectors of the robots, while the forming tool on one side is driven by the robot to follow a prescribed path generated from the designed shape, the supporting tool on the other side moves along the path synchronously, by incremental steps, a sheet metal is drawn to its final shape between the forming tool and the supporting tool. As a result, various kinds of sheet metal parts have been formed using this method. The measured profile and strains from the forming process are presented and discussed.

Pultrusion is one of the most cost-effective processes for composite materials manufacturing. It allows to realize constant section products characterized by remarkable fibres alignment, mechanical properties directionality, good surface quality with high production rate. Thermo-chemical aspects, such as temperature and degree of cure, are very important in order to obtain good mechanical properties of the final product as fast as possible or to realize a post-die shaping of pultruded parts. In this paper a three-dimensional finite difference model based on A.D.I. method and realized in MATLAB language for temperature and degree of cure is proposed. The present model takes in account heat transfer due to heating platens, die-cooler at die entrance and resin exothermic cure reaction. An analysis of the influence of mesh density and Peclet number on model accuracy is presented. Numerical results are compared with experimental data.

CAE tools usage to evaluate process performances it has became a matter of fact in cases like: metal forming, foundry, casting and forging. Like in these applications, also for the extrusion processes CAE tools usage has became a convenient opportunity, not only to verify the designed process but also to tune it in a virtual way. In this specific application, it has been evaluated the chance to use an optimization tool in combination with a process solver. The chance to optimize the extrusion process has been investigated using shape design variables for the tool process design, in order to obtain the best extruded profile quality. The applied procedure has shown strength points like: the full integration between the preprocessor and the shape variables generator, without any need to exchange data with the CAD environment during the optimization and weak points, such has the reduced freedom for the shape variation, due to the risk of an excessive distortion of the finite elements which describe the process.

In impression die forging the role of the flash geometry is fundamental since a proper design of the flash land strongly influences both the complete die filling and the die wear (i.e. the die life and the related costs). In this paper an integrated approach between numerical simulations and statistical tools was developed with the aim to optimize flash thickness in order to reduce die wear and to minimize material wasting. As wear is regarded, an analytical model depending on sliding velocity, temperature, die hardness and contact pressure was utilized during the numerical simulations of the process in order to reach a wear evaluation for different values of the flash design variables. Thus, it was possible to reach a prediction of tool life for different conditions. Furthermore, a cost analysis was carried out in order to investigate the influence of flash design on tool costs and material wasting costs.

In these last few years, the need for sheet parts in low volume batches, has required the development of new production technologies for sheet forming characterized by high flexibility (like the flexible forming process, the sheet die-less forming process or the sheet fluid forming process). These technologies allow new concept products to be used in terms of shape, materials and production volumes. Since these innovative sheet production processes are not widely diffused, there is a lack of knowledge when evaluating their economic convenience even if many factories are developing and introducing economic models. The objective of the present paper is to propose a model able to identify the most convenient technical solution comparing the innovative sheet forming processes with the traditional ones (the economic convenience of hydroforming and sheet incremental forming processes will be compared with the traditional forging, deep drawing and welding production techniques).

Laser forming process is used to form metal sheets in more or less complex three-dimensional shapes with good results for small-medium series or prototypes for its remarkable flexibility and precision and for no-dies need. The process is not yet well understood and for this purpose finite element analysis is a good and cheap tool. However numerical analysis can results time expensive for complexity related to this process, modelled as a thermo-mechanical coupled problem, characterized by remarkable geometric and material nonlinearity, to convective-radiative boundary conditions and Gaussian power density distribution in laser beam spot. In this paper a 3D finite element model for laser forming is proposed with an accurate-optimized mesh in order to obtain good accuracy and to reduce computational time. The influence of spot movements simulation is also considered. Numerical results are compared with experimental data.

The quenching processes are usually, by their nature, very unstable processes, due to the great sensitivity to the product material composition, heating procedure, quenching fluid composition and flow. The paper describes the process set up in order to improve the robustness of an induction quenching process for mass production of an automotive transmission joint. The preliminary step of the study has been the evaluation of the best metric for the process robustness. The experimental part of the study has been carried out in order to investigate which parameters influence the process and which is their relative importance. The factors that could influence the product characteristic has been chosen, among the all, by the application of a process monitoring approach, where historical data were available. The effects and interactions of the remaining factors has been quantified using a Response Surface approach in order to develop a precise process characterization and to allow the definition of optimal process factors tolerances. The process optimization has led to a considerable increase in process robustness and scrap reduction.

With reference to a metallic alloy, the attribute thixotropic is utilized to indicate the behaviour of it in the semi-solid state when its microstructure consists of spheroids in a liquid matrix. Such alloys are characterized by very low values of viscosity under shearing stress in the semi-solid state, while after solidification they show relevant mechanical properties. Actually a structural change from a dendritic structure to a globular one, with the globular grains finely dispersed in a liquid matrix, is observed after particular thermo-mechanical treatments. In the present paper the authors present the results of a wide experimental campaign on the AA 7075 aluminium alloy that shows a large semi-solid window temperature range. In particular, a mechanical device was set up in order to develop a mechanical treatment with the aim to produce thixotropic material to be subsequently forged. The influence of the main operative parameters was taken into account and micrographic analysis and mechanical tests were performed highlighting properties of the obtained structures.

The measure of cutting forces is one of the most usual methods in Tool Condition Monitoring (TCM). In this paper a cutting torque sensor for tool condition monitoring in milling is proposed. The device is based on inductive sensors that measure the relative rotation, due to the cutting torque, of two slotted disks fitted on the toolholder; a modification of the toolholder has been required to enhance the sensitivity of the device. During a preliminary stage, the measuring system has been designed and the optimization of the toolholder dimensions has been carried out by using both simplified and FEM-based approaches. To check the feasibility of the proposed device, a mechanical simulator installed on a lathe has been realized and its performance has been tested under different cutting conditions. The results show the validity of the method and encourage the use of the modified toolholder as instrument for tool condition monitoring.

Even with the best process design, incidents may still occur during machining. Considerable damages for the product and the machine-tool, may then be involved by the high feeds currently used. Therefore, process monitoring is suitable to ensure both product quality and process safety. Yet there is a lack of process monitoring solutions for small batch sizes or one-off production, which usually concerns high added value parts. Researchers have proposed various criterions to detect tool breakage, based on the milling force waveform. Our work aimed at estimating the relevancy of these criterions by machining a specific part under various cutting conditions. Criterions are compared and analyzed according to the measured cutting force signals. Then, improvements are suggested in order to increase their efficiency.

High Speed Milling is demanding more and more accuracy of the tool rotation axis and overall tool holder performances. In this paper the design and performance assessment of a thermal shrink fit tool holder is described. The holder is monolithic to improve the stiffness and reduce the tool rotation axis error. The tool is assembled manually, introducing the tool in the pre-heated tool holder; the subsequent thermal shrinkage assures the transmission of the cutting force and torque by friction. The disassembly is critical as the heat flow causes the thermal expansion of both the tool and the tool holder. This retention mechanism needs an accurate study for the choice of the tool holder material and geometry, of the heather geometry and power and of the heating procedure. A mathematical model of the system, based on coupled thermal-stress finite elements, has been set up in order to optimize the design and, consequently, to improve the tool holder expected performances. The tool holder has been manufactured and experimental test has been executed to validate the model and assess the tool holder performances.

The paper describes the construction of a force-torque sensor to be employed for applications of medical robotics. The sensor was designed and built in the Mechatronics laboratory of the Dept. of Electrical, Management and Mechanical Engineering of the University of Udine. The aim of the sensor is to measure the values of the forces and torques applied by the external environment to the end effector of a robotic manipulator. This is of fundamental importance when interaction of the robot with the external world must be considered and gauged. In particular, the robot is intended to perform a surgical task, such as the perforation of vertebrae for insertion of peduncular screws. Such an operation is to be done by a master-slave robotic system, where the master robot is connected to the slave by means of a haptic interface. The master sends the command to the slave, which executes the task and feeds back to the master the information of the force and torque values obtained by measuring the interaction of the robot’s end effector with the external world. In order to perform this measurement, an adequate sensor has been designed and built. The application of the sensor described in this paper are therefore very important in the medical robotics field, as well as in many other robotic applications.

Recently, scientific and technological development, allowed new materials appearance aiming at to applications in several fields of the engineering, with the agreement between development and environment. Due of this condition, compacted cast iron is detaching in the production of motor blocks to diesel, being limited for its machinability. Therefore, this work had as objective to produze, to characterize and to apply SiAlONs cutting tools in machining of this material. A powder mixture constituted by 82.86 wt % α-Si

3

N

4

, 10.63 wt % A1N and 6.51 wt % Y

2

O

3

was homogenized, uniaxially and cold isostatically pressed, and sintered at 1900°C for 1h. After chacterization, cutting tools were submitted at the different machining conditions: Vc = 200, 350 and 500m/min, f = 0.20 mm/rot and ap = 0.50 mm. Properties obtained in SiAlONs cutting tools together with machining conditions showed higher performance to the found in literature.

Recentely, Si

3

N

4

has been used as cutting tools in several alloys machining. Such materials shows SiAlONs and β-Si

3

N

4

, that it has excellent thermomachanical properties. This work had as objetive to develop and to apply β-Si

3

N

4

cutting tools in machining of gray cast iron, starting from a mixture composed by 78.30 wt % α-Si

3

N

4

, 1.00 wt % A1

2

O

3

, 14.40 wt % A1N, 3.15 wt % CeO

2

and 3.15 wt % Y

2

O

3

, that was pressed and sintered at 1900°C. After characterization, cutting tools showed, HV = 20.50 GPa, K

IC

= 6.45 MPa.m

1/2

, with 95 % β-Si

3

N

4

phase. Then, it were submited to machining of gray cast iron using: 1

a

step - Vc=180, 240, 300 and 360 m/min, f = 0.12mm/rot and ap = 1.00 mm; and 2

a

step — Vc = 300m/min, f = 0.23, 0.33 and 0.40 mm/rot and ap = 1.00 mm. For 7500 m cutting length, results showed excellent performace.

In this paper a linear mathematical model to evaluate machinability performances of different stainless steel grades is presented. Remarks on the corrosion resistance of enhanced machinability grades of stainless steels are related to the basic metallurgy.

This paper proposes a methodology for experimental and mathematical modeling of cutting tool wear in milling condition with multipass machining operation. The paper describes experimental research, realized in real manufacturing condition for determination of the machinability data indispensable for complex mathematical model of machining process and mathematical modeling of the cutting tool wear phenomena.

Laminated Object Manufacturing of metal foil as an automated two-step procedure is a novel technology for additive manufacturing of massive three-dimensional parts. It enables for example the production of technical tools like moulds. The great advantage hereby is the high accuracy in combination with a high stability of the resulting tools.

A laser system for the automated stacking of metal foil contours has been developed. The stacking procedure is realised by a combination of layer fixing and contour generation with a laser beam. But the stability of the produced foil stack is insufficient for most kind of application. Therefore a second step to enhance the mechanical properties of the part is necessary. This can for example be realised by high temperature brazing or diffusion welding.

In this paper the laser system for the automated stacking of metal foil contours is described as well as the required preparation of the layer data. Further on some results of investigations on the sub-processes layer fixing, counter generation and final joining are shown.

In a Design For Manufacturing context, Rapid Prototyping techniques are some way still considered as “new technologies”: the peculiar characteristics of the manufacturing processes are not widely known and may deeply affect the final product functionality. A Knowledge Based System, the Design Guidelines — DGLs, was developed by our Research Group at the University of Udine; it evaluated the products design, in order to verify its feasibility by DMLS (Direct Metal Laser Sintering) Rapid Prototyping technique. During the evaluation process, the DGLs also keep into consideration the aspects relating the verification step, according to the ISO-GPS principles, thus enhancing the completeness of the tool. Aim of this work was to customise the DGLs for design optimisation in FDM (Fused Deposition Modelling), also evidencing the critical aspects and proposing alternative solutions. The contents and structure of the customised version of DGLs are presented in this work.

The quality of an injection molded part is strongly influenced by the filling balance of the mold cavity. Gate location is the principal balance factor and it heavily depends on designer’s experience and knowledge. In this paper, a three-step method is proposed which aims at determining the gate location that maximizes the filling balance of a mold cavity. First numerical simulations of the filling process are run changing gate position opportunely. Then third order regression surface method is applied to determine the gate location which minimizes the filling times standard deviation of the mesh nodes located along the cavity boundaries. The proposed method can be used for single gated mold cavities or multiple gated ones where the gates are positioned symmetrically. The results obtained from an industrial case study highlighted the effectiveness of the proposed approach in finding the optimal gate location by a restricted number of simulations.

Ceramic moulds produce castings with fine details, smooth surface (smoothness 3 mm), and a high degree of dimensional accuracy because the metal contraction can be predicted closely enough to provide castings within excellent tolerances (±0.08 mm on dimensions to 25 mm, ±0.13 mm on dimensions to 75 mm, and more).

The purpose of this paper is to study the thermal properties of ceramics shell moulds for investment casting, which is also known as “lost wax process”. A special attention was given to the analysis of the modes governing the heath transfer in the casting process and their correct mathematical modelling. Casting temperatures were measured either by a set of thermocouples and a thermo-camera. Experimental data were compared to the result predicted by commercial simulation software.

Reverse Engineering is a rapidly evolving discipline. Nowadays shape acquisition systems have reached enough capabilities to reproduce complex free form objects. This paper presents a comparison between two different acquisition systems to evaluate their performances and their easy to use capabilities and to evaluate quality and accuracy of the 3D reconstructed models. To achieve this task, a complex free form object, a steam turbine blade, was acquired. After shape acquisition and data elaboration of this particular object an evaluation of the two systems characteristics and of the 3D CAD reconstructed models were done and results are illustrated here.

A photoelastic technique is presented that is based on a photoelastic coating applied along the surface of a model of a mechanical component made with rapid prototyping. The proposed procedure allows more flexible models to be obtained in comparison to metal parts, thus favouring the outset of a higher number of photoelastic fringes. In addition, the proposed approach permits enlarged models to be easily constructed, thus easing the photoelastic readings. The preliminary study here presented addresses a wheel hub for high performance cars, with particular regard to the stress concentrations by the fin fillets.

Materials recycling and components reuse are important key points in reducing the environmental impact of Waste from Electric and Electronic Equipments (WEEE). Disassembly could represent an efficient way for the treatment of end-of-life products, although the choice of suitable tools and methods is necessary for a quick, cheap and safe disassembly.

The removal of the housing is an important step of the treatment process because it gives access to internal components allowing their disassembly.

The aim of this paper is a structured analysis through a QFD like approach of the removal of the washing machine panels by means of some commercial cutting tools. Tests have been performed to collect results on speed, cost and safety of the plasma cutting and other tools. The study shows the performances required in the removal of the domestic appliances housing and confirms that plasma is an excellent method for an economic and safe cutting.

This paper presents that quality marks do not only refer to the design phase (e.g. recycling equitable design or design for environment) but also to the process chain after the end of use. The configuration of possible QM-systems in WEEE recycling strongly depends on the demands they are driven by the following main recommendations: (1) The envisaged ways of recycling or reusing components will have different demands than a material treatment. (2) Reusing materials can be different in same usage, upgrade or downgrade of materials. (3) The materials that are utilized in products, e.g. the treatment of hazardous or precious materials. (4) The quantity and (5) the loss of quality until the end-of-life and available information about the influences during use period.

For several decades now, plastic components have been used more and more in the automotive industry, both for supporting and for aesthetic elements. For such uses, goals like reduction of weight and of production costs, improvement of production plant flexibility, have assumed an ever increasing importance and have been considered important for companies to define their capability on answering to market requirements and challenges. Also the reduction of environmental impacts related to production, use and disposal of these components, was considered as an important goal during recent years.

With the aim of investigating some alternative production cycles of plastic components, the paper shows the process and the results of comparison between some different ways to develop the molding and plating processes using the Life Cycle Assessment methodology. Such approach is introductory to the following evaluation of a specific component, a car trim, which has not a complex geometry but that was considered useful to initial targets of a comparison involving a plethora of possible different solutions.

The purpose of this paper is to show the power of the Six Sigma methodology in satisfying the requirements of the automotive market. The company of this project produces cooling air pipes for deluxe vehicles. The problem solving method applied was the DMAIC (Define, Measure, Analyse, Improve, Control). This process review takes into account the increased quality standards of the output; therefore, the real problem was not to increase the system productivity, but to eliminate those process features that the automotive market considers as defects. For example, identifying the CTC (Critical to Customer), the main defect categories were: scraps on the pipes, blows on the devices and contamination of chip. The paper shows all steps of the Six Sigma implementation suggesting the solution to increase the process performance.

The traditional use of control charts assumes the independence of data. It is widely recognized that many processes are autocorrelated thus violating the main assumption of independence. As a result, there is a need for a broader approach to quality monitoring when data are time-dependent or autocorrelated. The aim of this work is to present a new procedure for manufacturing process quality control in the case of serially correlated data. In particular, a recurrent neural network is introduced for quality control problem. Performance comparisons between the neural-based algorithm and control charts are also presented in the paper in order to validate the proposed approach. The simulation results indicate that the neural-based procedure is quite effective as it achieves improved performance over control charts.

The paper reports on a new FMEA (Failure Mode and Effects Analysis) technique for the evaluation of operating failures on machine tools. The traditional FMEA methodology focuses the analysis on failure problems and usually does not take into account other parameters, such as availability and costs. This new technique was setup for predicting operating failures during the design process of machine tools, so reducing costs and time to market. This approach is based on a new index depending on machine tool availability and customer costs related to failure time. For the validation and the evaluation of the method, an industrial case was studied; data collected from this analysis proved to be in good agreement with failures detected by the customer. The adopted method showed a higher reliability compared with traditional FMEA results.

In 1999 the author met managers of a “certified” company developing a new engine; he saw use of the “Duane Method” for predicting the in-service MTBF by elaborating the test reliability data. The paper shows the relationship between the Reliability R(t), the “mean number of failures” M(t) and the predicted MTBF using both the “Integral Theory of Reliability” and the “Duane Method”; the difference between the two methods enhances their respective real applicability. Later he saw “fuzzy Theory” used to evaluate product Quality: is that scientific? Since the absence of the scientific approach before, during and after the experiments typically results in relatively uninformative output of questionable general validity, in order to make sound decisions, managers have to be aware of the consequences of their decisions. The same is valid for Lecturers at Universities. This means that professors MUST teach, in a scientific way, Quality ideas on Quality. Unfortunately several people with very little competence, knowledge and experience are in charge of teaching. Professors need Quality metamorphosis.

Today it is possible to measure human body with completely non-invasive devices [1,2,3,4] but there is no widely used method for quick, accurate and non-invasive evaluation of spine.[5,6,7,8]. Another problem is the fact that such patient should be transported in some specialized center where the appropriate therapeutic solution could be obtained, and where there are technical and medical resources. This work presents the idea, already supported with published work of other authors, of using 3D optical scanning system for evaluating of spine deformities and asymmetry. Considering the fact that commercially available devices for 3D scanning are very expensive, the possibility to scan human body with cameras from several directions and make the reconstruction of body shape seems very promising and competitive. The reconstructed model can be measured with the computer aid which gives tool for quick and quality follow up of shape change through time, and comparison before and after applied therapy. The system could also offer a possibility to design and produce high quality spine orthotics, or highly comfortable and individually adjusted spine supports.

Measurement principle, method, procedure, and conditions can heavily affect the measuring uncertainty and in turn the measuring reliability.

Moreover, the use of data coming straight from measures taken in the working place is rising for decisional process and statistical process control. The losses from mistaken measures and high uncertainty can hit the economy of production. Therefore it is evident that a correct design of the measuring principle, method and procedure as much as the measuring conditions are required.

In this paper a total quality approach is presented for the design of the verification for the product specification of a gear for automotive application. Measurements were taken from the working place. A Doe experiment was conducted for the measure uncertainty minimisation. The approach was borrowed from EN ISO 1253 specifications.

The involvement of improvement teams and the use of quality tools, that improved business performance could be achieved only through better planning, capable processes and the involvement of people. Six Sigma (6σ) is a business-driven, multi-faceted approach to process improvement, reduced costs, and increased profits. With a fundamental principle to improve customer satisfaction by reducing defects, its ultimate performance target is virtually defect-free processes and products. Six Sigma is a revolutionary business process geared toward dramatically reducing organizational inefficiencies that translates into bottom-line profitability. This paper shows how to transform Six Sigma to address today’s most crucial business challenges: the challenge to execute and the challenge to maximize value. It also discusses practical issues related to its implementation, project management, techniques, and relations with other standards, concepts and tools for achieving synergistic effect.

Features often form the basis of knowledge about various design and manufacturing tasks like process planning, fixture design, inspection, assembly planning etc. Automatic Feature-s recognition is likely to be an essential requirement for future integrated design and manufacturing systems and in the development of fully automated process planning systems. Majority of the current design and manufacturing data used on shop floors is associated with CAD models. Planning for Product development starts with a 3 D Solid CAD model where as manufacturing drawings are represented in 2 D. Any basic manufacturing process expects the representation of the finished product in terms of an Engineering model. Solid models have replaced the 2D models owing to the trend of the industry towards automation. Any CAD model, when associated with the manufacturing attributes, can be termed as a product model in a general sense. An overview of research on extraction of feature-s from Solid models indicates that, researchers are not comfortable with the drawing interfaces such as IGES, SAT etc. due to dynamic and complex nature of coding. Also, most of the work in this category is based on complicated algorithms. In the perspective of these facts, the present work makes use of the simple and logical approach with DXF interface, which has been so far attempted, only for 2 D CAD Models. DXF has been a widely used interface for wire frame entities, due to clarity and well defined structure. An innovative theory viz.3 Segment theory has been used in for interpreting the features. Further the machining attributes such as surface finish, tolerance associated with the extracted features is used for selecting and sequencing the processes. The decisions are supported by an knowledge based expert system based on a database. The software has been developed in C and an interactive front end has been developed using Visual Basic V6. The concept and the logic used in the system is very much convincing. This would be probably one of the earliest workhaving used DXF interface for extracting the features from Solid Models successfully.

The general objective of this paper is to analyse the dependency relations that may exist between manufacturing and design specifications of a geometric object. This object will be modelled on the basis of the TTRS concept and vector modelling synthesised by the metric tensor of a set of vectors. The first problem that we propose to solve therefore is the formal expression of these relations. After that, the dependency will be analysed and illustrated considering a 3D object.

The most part of scientific discoveries of human being borrow ideas and inspiration from nature. This point gives the rationale of the conceptual model here presented, which funds on the basic assumption that it is possible to put the analogy between manufacturing systems, as perceived by decision maker, and aerobic living organisms. The aerobic living-organism (ALO) conceptual model consists of a set of axioms and criteria that allow one to translate his own view of a real manufacturing system into a schemata of an aerobic living-organism, with given features and characteristics. Starting from this schemata it is then possible to build an ALO simulation model, to better study the manufacturing system’s behaviour under different operating scenarios. Criticalities of the ALO conceptual model are also discussed.

The paper presents an application of the aerobic living-organism (ALO) conceptual model developed by the author in a previous paper, to perform an analysis of an Italian small enterprise producing and assembling components for industrial and civil applications. Starting from the ALO enterprise schemata an agent-based simulation model was built using the Starlogo® environment to support re-engineering decisions. The application presented proved its potential usefulness into practical decisional tasks. Criticalities of the implementation of the ALO conceptual model are also discussed, based on the experience gained into the specific application, driving some general hints for future researches.