Gianni Campatelli

Gianni Campatelli
University of Florence | UNIFI · Dipartimento di Ingegneria Industriale

PhD

About

93
Publications
25,981
Reads
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1,700
Citations
Additional affiliations
April 2018 - present
University of Florence
Position
  • Professor (Associate)
Description
  • Head of the Manufacturing Technology Research Laboratory
March 2001 - April 2018
University of Florence
Position
  • Professor (Assistant)
Education
September 1995 - December 2000
University of Florence
Field of study
  • Mechanical Engineering

Publications

Publications (93)
Article
This paper presents a novel approach to identify both radial and axial depth of cut in 2.5-axis peripheral milling operations using cutting force signals analysed in the frequency domain (i.e., cutting force spectrum). In detail, the method exploits the normalized cutting force spectrum, which is directly obtained through dedicated analytical formu...
Article
To sustain the transition to a greener economy and greener manufacturing, it is necessary to develop new approaches and technologies to repair metal components; this will result in a drastic reduction in energy and material usage. In this study, wire arc additive manufacturing (WAAM) was used to deposit a layer of new material on an existing surfac...
Article
In peripheral milling, surface accuracy is crucial for the quality of the machined components, and it is one of the reasons why milling is still essential in the manufacturing field. Nonetheless, both static phenomena, like tool deflections, and dynamic issues such as forced vibrations, impact on the accuracy of the components causing surface error...
Chapter
Wire Arc Additive Manufacturing (WAAM) is an emerging technology to produce metallic components thanks to its high deposition rate and low cost compared to other technologies. One step to make the WAAM technology reliable is to achieve a stable process control that can avoid collapse of the part during deposition caused by an excessive thermal inpu...
Article
Full-text available
Repairing, remanufacturing, and refurbishing high value metal components are crucial to move towards a more sustainable economy. Nowadays, repairing operations on high value parts, such as dies, are generally performed using time-consuming manual approaches that rely on the operator’s expertise. The research idea of this paper is to develop a retro...
Article
Cutting forces analysis is one of the most important means of improving machining quality and productivity. In 3-axis milling, the frequency domain analysis of the cutting forces provides information which can be adopted for both predicting and monitoring the cutting process. However, the evaluation of the cutting forces spectra requires the applic...
Article
The prediction of form surface error represents the basis of many approaches, which aims at increasing the productivity and reducing the costs of a milling operation. In peripheral end-milling the form error caused by the tool/workpiece static deflection is not constant along the axial depth of cut, and it presents different shapes due to the cutti...
Article
Additive Manufacturing (AM) has been identified as a disruptive technology, that enables the transition to Industry 4.0 and allows companies to re-think and re-design both their products and manufacturing approaches. In such a context, the opportunity of using AM to extend the life of a product through repair could also allow the founding principle...
Chapter
WAAM (Wire Arc Additive Manufacturing) is a metal additive manufacturing process based on gas metal arc welding which enables to create large parts with a high deposition rate. WAAM is prone to the heat accumulation issue, i.e. a progressive increase of the workpiece internal energy due to the high heat input of the welding process, which can cause...
Article
In 3-axis milling operations the surface error caused by the tool/workpiece static deflection assumes a certain shape along the axial depth of cut. The error shape changes considerably according to the cutting strategy, tool geometry and cutting parameters. This paper presents a comprehensive method to identify all the types of surface error profil...
Article
Full-text available
Additive manufacturing (AM) is an arising production process due to the possibility to produce monolithic components with complex shapes with one single process and without the need for special tooling. AM-produced parts still often require a machining phase, since their surface finish is not compliant with the strict requirements of the most advan...
Article
Additive manufacturing (AM) processes are gathering momentum as an alternative to conventional manufacturing processes. A research effort is being made worldwide to identify the most promising AM approaches. Within this category, wire arc additive manufacturing (WAAM) is among the most interesting, especially when large parts must be manufactured....
Article
Wire arc additive manufacturing (WAAM) is a metal additive manufacturing process based on gas metal arc welding and it is known to be economically convenient for large metal parts with low complexity. The main issue WAAM is the sensibility to heat accumulation, i.e., a progressive increase in the internal energy of the workpiece due to the high hea...
Article
Full-text available
In this paper a technique to compute the 3-axis toolpath for a thin-wall component is presented aiming at maximizing the engagement conditions, keeping the geometry in tolerance. The toolpath generation is based on the static deflection of the component, predicted by coupling a mechanistic model of the cutting forces with a FE model of the workpiec...
Article
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The turning of thin-walled components is a challenging process due to the flexibility of the parts. On one hand, static deflection due to the cutting forces causes geometrical and dimensional errors, while unstable vibration (i.e., chatter) could compromise surface quality. In this work, a method for fixturing optimization for thin-walled component...
Article
The additive manufacturing technique is becoming popular and promising in recent years. Some steel ER70S-6 specimens were produced by wire arc additive manufacturing. Before the tensile tests, 3D X-ray computed tomography was applied to detect the presence of internal defects due to the production process. Static tensile tests were performed in ord...
Article
Full-text available
Unstable vibrations (i.e., chatter) onset is one of the main limits to productivity in deep boring bar processes. Active damping systems allow to increase machining stability in different configurations (i.e., tool setup), without requiring cutting system dynamic characterization. Design of an active boring bar involves the development of monitorin...
Article
WAAM (Wire-Arc-Additive-Manufacturing) is an additive manufacturing process which uses arc welding to produce metal parts. This process is prone to the detrimental phenomenon of heat accumulation, i.e. a progressive increase of the interlayer temperature. This paper investigates the effect of air jet impingement cooling in mitigating heat accumulat...
Article
Additive Manufacturing has proved to be suitable for supporting or even replacing traditional manufacturing approaches in some industrial contexts. Among the various processes that can be used to produce metal parts, Wire Arc Additive Manufacturing (WAAM) is known to be an economically convenient, welding-based direct energy deposition technique fo...
Article
Over the last years, additive manufacturing (AM) has been gathering momentum both in the academic and in the industrial world. Besides the obvious benefits in terms of flexibility and process capabilities, the environmental performance of such processes has still to be properly analyzed. Actually, the advantages of additive manufacturing over conve...
Article
Full-text available
The setup of machining parameters for non-ferric materials such as wood and wood-based materials is not yet defined on a scientific basis. In this paper, a new rapid experimental method to assess the specific cutting coefficients when routing isotropic and orthotropic wood-based materials is presented. The method consists of routing, with different...
Chapter
In general rough-milling operations, unstable tool vibrations due to the interaction between process forces and tool flexibility could arise. The onset of these unstable vibrations, usually referred to as chatter, poses limitations in terms of the achievable material removal rates, hence directly impacting on the productivity. Moreover, chatter vib...
Article
Full-text available
The original version of this article contained a mistake. In the caption of Fig. 4, “!c =!n eq.” is not correct.
Article
Chatter vibration induces a characteristic pattern on the milled surface, known as chatter marks, causing a poor surface quality. While several works deal with the prediction of the machined surface in stable condition, surface under chatter vibration has not been extensively studied: it is not clear how vibrations at high chatter frequency return...
Article
WAAM (Wire-Arc-Additive-Manufacturing) is a metal additive manufacturing process using arc welding to create large components with high deposition rate. The workpiece quality and the process productivity are strongly dependent both on the process parameters (wire feed speed, voltage and current) and on the selected deposition path. Currently, the C...
Article
One of the most relevant open issues of the WAAM (Wire-Arc-Additive-Manufacturing) process is the heat accumulation, causing a progressive increase of the workpiece average temperature with detrimental consequences on the workpiece quality, e.g. structural collapse. This paper proposes to tackle this issue by introducing a workpiece cooling system...
Article
Wire‐arc additive manufacturing is a metal additive manufacturing process that enables the production of large components at a high deposition rate. This process transfers a large amount of heat to the workpiece, requiring the introduction of idle times between the deposition of subsequent layers so that the workpiece cools down. This procedure pre...
Article
Full-text available
This paper is about the optimal selection of process parameters for Wire Arc Additive Manufacturing technology, an emerging solution for additive production of metal parts. In particular, the selection of the process parameters is based on the evolution of the microstructure and on the mechanical properties of the final samples obtained through the...
Article
WAAM (Wire Arc Additive Manufacturing) is a metal AM (Additive Manufacturing) technology that allows high deposition rates and the manufacturability of very large components, compared to other AM technologies. Distortions and residual stresses affecting the manufactured parts represent the main drawbacks of this AM technique. FE (Finite Element) mo...
Article
Full-text available
Chatter prediction is crucial in high-speed milling, since at high speed, a significant increase of productivity can be achieved by selecting optimal set of chatter-free cutting parameters. However, chatter predictive models show reduced accuracy at high speed due to machine dynamics, acquired in stationary condition (i.e., without spindle rotating...
Article
Full-text available
Chatter vibrations in machining have collected the interest of several research activities in the last decades, mainly due to its detrimental effect on productivity and surface quality. Several approaches and techniques have been developed to mitigate the effect of these unstable vibrations, but the required expertise and setup time usually prevent...
Article
Integrating sensors in machine tools for monitoring purpose entails dealing with different issues, not only related to accessibility and safety but also to measureable bandwidth and linearity of the sensors. Those factors could be related to the sensor itself but also to sensor–machine interaction that could drastically affect sensor performances a...
Article
Tool-tip frequency response function (FRF) is essential to predict chatter vibration in milling. This key input can be acquired by experimental tests, but a new test has to be performed for every tool clamped on the machine. To avoid such time-consuming procedures, receptance coupling methods have been developed, allowing coupling of the experiment...
Article
Full-text available
Active fixtures represent one of the most industrially relevant alternatives among active chatter control techniques in milling, even though control logics and actuation strategies could directly reflect on their effectiveness. Closed-loop controls targeted in the chatter frequency range are commonly adopted for this purpose, but this approach lack...
Article
Full-text available
Combining Additive Manufacturing (AM) and traditional machining processes is essential to meet components functional requirements. However significant differences arise in machining AM and wrought parts. Previous works highlighted the increasing of tool wear and worse surface finish. In this paper cutting forces are investigated as an indicator of...
Article
Full-text available
Tool-tip Frequency Response Function (FRF) represents one of the essential inputs to predict chatter vibration and compute the Stability Lobe Diagram (SLD). Tool-tip FRFs are generally obtained for the stationary (non-rotating) condition. However, high speeds influence spindle dynamics, leading to a reduced accuracy of the SLD prediction. This pape...
Article
Full-text available
The mitigation of chatter vibrations in milling has collected the interest of several researches in the last decades. One of the most industrially oriented alternatives is represented by active fixtures, complex mechatronic devices capable of actuating the workpiece during machining operations, with the purpose of stabilizing the process by generat...
Article
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Machine tools are responsible for a relevant share of environmental impact related to production processes. This is due to their widespread use, the huge energy requirements during operations and the disposable materials involved in the process like scraps, cutting inserts and exhausted oil. This study presents a holistic analysis of the main contr...
Article
Full-text available
Wire-Arc-Additive-Manufacturing (WAAM) is an Additive-Manufacturing (AM) process, allowing to produce metal components layer by layer by means of Gas-Metal-Arc-Welding (GMAW) technology. The advantages of this technology are the capability to create large parts with a higher deposition rate with respect to other AM technologies. Despite these great...
Article
Full-text available
Among emerging additive manufacturing technologies for metallic components, WAAM (Wire and Arc Additive Manufacturing) is one of the most promising. It is an arc based technology characterized by high productivity, high energy efficiency and low raw material cost. Anyway, it has some drawbacks limiting its diffusion in the industry. One is the open...
Article
Chatter stability prediction is crucial to improve the performances of modern milling process, and it gets even more important at high speeds, for which very productive cutting parameters can be achieved if the suitable spindle speed is selected. Unfortunately, the available chatter predictive models suffer from reduced accuracy at high speed due t...
Article
Full-text available
Due to the rapid technologic change, we see the role of manufacturing workers continuously changing: the increasing automation of manufacturing processes has reduced the amount of manual work, whereas the increasing complexity of manufacturing systems requires workers to build-up broader and deeper skills. In this paper, the authors suggest a parti...
Article
Among the chatter suppression techniques in milling, active fixtures seem to be the most industrially oriented, mainly because these devices could be directly retrofittable to a variety of machine tools. The actual performances strongly depend on fixture design and the control logic employed. The usual approach in the literature, derived from gener...
Article
Full-text available
Chatter is one of the main limitations to milling performances. Prediction of such unstable phenomenon via stability lobe diagrams requires the measurement of the Frequency Response Functions (FRFs) for each tool and machine tool setup. This paper presents a hybrid FE-experimental approach to identify tool-tip FRFs with only one set of measurements...
Article
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This article presents a new method to evaluate the geometry of dull cutting tools in order to verify the necessity of tool re-sharpening and to decrease the tool grinding machine setup time, based on a laser scanning approach. The developed method consists of the definition of a system architecture and the programming of all the algorithms needed t...
Article
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Receptance coupling substructure analysis (RCSA) allows to estimate tool-tip FRF of different spindle-holder-tool configurations with the minimum set of measurements. This technique requires accurate holder-tool connection modelling. In this paper fully predictive modelling strategies of holder-tool connection are presented. Proposed procedures are...
Article
Full-text available
Milling is one of the most used machining processes thanks to its high flexibility and high achievable quality. The performance of milling machines is constantly increasing, improving the convenience and increasing the competitiveness of this operation. However, the trend of performance improvement has found a technological limit: self-excited vibr...
Article
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The increase in the global population and the improvement of the life style of many poorer countries are leading to a relevant growth for mobility. Such increase in circulating vehicles would have a negative impact on environment pollution. Given this picture, the traditional internal combustion engine vehicles could not be the best solution for th...
Chapter
This article describes possible scenarios for wireless charged electric vehicles, as they are discussed within the UNPLUGGED project. It gives a brief introduction into wireless technology and explains the three possible implementation steps for charging electric vehicles: stationary, static en-route and dynamic en-route. Based on these scenarios t...
Article
Chatter prediction requires Frequency Response Function (FRF) at the tool-tip, which can be reliably identified by modal testing. However this procedure is time-consuming and unsuitable for industrial application since measurements must be performed for each tool attached to the machine. Receptance coupling technique can be adopted to speed up FRF...
Article
Chatter prediction requires tool-tip FRF to be identified for every tool clamped on the machine. To avoid repetitive time-consuming tests, receptance coupling approaches are used to predict tool-tip FRFs: experimental dynamic behavior of the machine is coupled to a numerical model of the tool. To achieve required accuracy, such techniques require j...
Article
The efficiency of high-speed milling process is often limited by the occurrence of chatter. Active control systems seem to represent a suitable solution for chatter suppression, because of their high adaptivity. Nevertheless, efforts still need to be made for the definition of the best control strategy. Accurate simulation tools are therefore neces...
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Full-text available
The modeling of milling forces is a crucial issue to understand milling processes. In the literature, many force models and experiments to identify force coefficients are found. The objective of this article is to develop a new approach, based on the traditional average force method, able to measure and compute the cutting coefficients for end mill...
Article
Accurate simulation of the machining process is crucial to improve milling performance, especially in High-Speed Milling, where cutting parameters are pushed to the limit. Various milling critical issues can be analyzed based on accurate prediction of cutting forces, such as chatter stability, dimensional error and surface finish. Cutting force mod...
Article
Full-text available
In a World with an increasing population and related mobility needs, a traditional internal combustion engine based mobility paradigm cannot be considered the only possible solution. This is particularly true for cities full of masterpieces and historical buildings as Firenze, used as case study. Specifically it combines very high mobility needs fo...
Article
Within the last years, under the push of the most important institutions, new models of private and public transport systems have been studied in order to reduce polluting impact of petroleum-based public and private mobility. EU focuses its attention especially on electric mobility, which seems the best solution in terms of economic and environmen...
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In recent years electric vehicles have become the most plausible alternative to the current transportation system based on fossil fuels. Electric mobility advantages are clear in terms of both air emissions and energy consumption. Recent increase in sales testifies the growing interest towards electric vehicles also from private consumers together...
Article
Accurate cutting-force measurements appear to be the key information in most of the machining related studies as they are fundamental in understanding the cutting processes, optimizing the cutting operations and evaluating the presence of instabilities that could affect the effectiveness of cutting processes. A variety of specifically designed tran...
Article
Electrospinning is a technology used for the production of nanometric fibers starting from a solution of material spun by a needle in an electrostatic field. The jet starts from a needle and its diameter is reduced thanks to the instability of the process that stretch the fiber till nanometric dimension. The productivity of a single needle is very...
Article
Chatter is one of the most limiting factors in improving machining performances. Stability Lobe Diagram (SLD) is the most used tool to select optimal stable cutting parameters in order to avoid chatter occurrence. Its prediction is affected by reliability of input data such as machine tool dynamics or cutting coefficients that are difficult to be e...
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Full-text available
Energy consumption in the manufacturing sector is becoming a very hot topic due to its significant ecological relevance, especially for energy intensive processes such as machining. Machining finds nowadays large application mainly due to its high performance, in terms of both surface finish and tolerances achievable; as an example this is the key...