@palbit.pt
Department of Mechanical Engineering/University of Aveiro
Palbit SA
Mechanical Engineering, Mechanics of Materials, Engineering, Industrial and Manufacturing Engineering
Scopus Publications
B. Guimarães, C.M. Fernandes, D. Figueiredo, O. Carvalho, G. Miranda, and F.S. Silva
Elsevier BV
Daniel Figueiredo, Joana Silva, Tiago E. F. Silva, AbÍlio M. P. de Jesus, Cristina M. Fernandes, and J. Paulo Davim
Springer Science and Business Media LLC
AbstractMicro-milling of cemented carbides is a challenging task due to their high hardness, low toughness and high wear resistance. Ensuring good surface quality and dimensional accuracy is crucial for extending parts service life, which in turn enhances economical and environmental sustainability. This paper is mainly focused on evaluating surface formation mechanisms, scale effects, fracture behaviour and chip formation using distinct cemented carbide micro-milling tools with multi-layer diamond HF-CVD. In order to achieve higher precision and more efficient micro-milling operations on WC-15Co and WC-10Co, a systematic experimental approach has been carried out. The influence of cutting parameters, achievable surface quality and defects occurrence were thoroughly examined. Experimental results evidence the influence of operational conditions on the chip formation of cemented carbides as well as an important impact of the utilized cutting tool. Micro-pits, cracks, thin ploughing layer and fractured workpiece edges are amongst the observed surface damage mechanisms. A ductile cutting regime of the high-hardness composite material is confirmed, exhibited by the plastic deformation even when small depths of cut are considered.
Bruno Sousa, Tiago Silva, Vitor Sousa, Daniel Figueiredo, Cristina Fernandes, Alexandre Ferreira, and Abílio de Jesus
Elsevier BV
Francisco Matos, Henrique Coelho, Omid Emadinia, Rui Amaral, Tiago Silva, Nelson Gonçalves, João Marouvo, Daniel Figueiredo, Abílio de Jesus, and Ana Reis
Elsevier BV
A. Teixeira, V.F.C. Sousa, T.E.F. Silva, D. Figueiredo, F. Marques, C. Fernandes, A.M.P. Jesus, and A. Reis
Elsevier BV
R.D.F.S. Costa, J.N.S. Duro, V.F.C. Sousa, T.E.F. Silva, D.A. Figueiredo, and A.M.P. Jesus
Elsevier BV
António José Festas, Daniel Amaral Figueiredo, Sílvia Ribeiro Carvalho, Thang Hoang Vo, Pierre-Thomas Doutre, François Villeneuve, António Manuel Ramos, and João Paulo Davim
Springer Science and Business Media LLC
AbstractHybrid manufacturing (HM) is a process that combines additive manufacturing (AM) and subtractive manufacturing (SM). It is becoming increasingly recognized as a solution capable of producing components of high geometric complexity, while at the same time ensuring the quality of the surface finish, rigour and geometric tolerance on functional surfaces. This work aims to study the surface finish quality of an orthopaedic hip resurfacing prosthesis obtained by HM. For this purpose, test samples of titanium alloy Ti-6Al-4V using two Power Bed Fusion (PBF) processes were manufactured, which were finished by turning and 5-axis milling. It was verified that, upon the machining tests, no differences in Ra and Rt were found between the various types of AM. Regarding the type of SM used, 5-axis milling provided lower roughness results with a consistent value of Ra = 0.6 µm. The use of segmented circle mills in 5-axis milling proved to be an asset in achieving a good surface finish. This work successfully validated the concept of HM to produce a medical device, namely, an orthopaedic hip prosthesis.As far as surface quality is concerned, it could be concluded that the optimal solution for this case study is 5-axis milling.
Ricardo Mineiro, C.M. Fernandes, E.L. Silva, M.R. Soares, D. Figueiredo, B. Ferrari, A.J. Sanchez-Herencia, and A.M.R. Senos
Elsevier BV
Gonçalo Oliveira, Ana Senos, Cristina Fernandes, Daniel Figueiredo, and Teresa Vieira
MDPI AG
Material extrusion (MEX) allows for the production of advanced cutting tools with new internal cooling systems, which are suitable for new machining equipment. To produce cutting tools via this process, hardmetal and cermet feedstock must be prepared for the extrusion of 3D printing filaments. After shaping the 3D object (green), debinding and sintering must be performed to achieve densification. Defects and microstructural heterogeneities were studied according to the powder material. The present study shows that, although MEX is a viable solution for hardmetals, it needs to produce homogeneous filaments for cermets. The WC-Co bulk microstructures versus hardness were similar to the ones that were measured with pressing and sintering. While cermet (Ti(CN)/WC-Ni/Co) microstructures were heterogeneous, their hardness, when compared with that from the pressing and sintering manufacturing process, decreased significantly.
Liudmila Basílio, Bruno Guimarães, Óscar Carvalho, Cristina Fernandes, Daniel Figueiredo, Filipe Silva, and Georgina Miranda
Springer Science and Business Media LLC
AbstractWC–Co cutting tools are widely used in harsh conditions, but the brittleness of this material can limit their use. Joining steels to WC–Co can provide an alternative, by combining the toughness of steel with the high hardness and wear resistance of WC–Co. The creation of textures at the bonding interface is known to increase the adhesion between materials, through a mechanical interlocking effect and an increase in the contact area. In this sense, this work proposes the laser surface texturing of WC–Co green compacts with cross-hatched and circular micropatterns and subsequent pressure-assisted sintering of the textured and sintered WC–Co with 316L SS powder to improve the bonding between materials. Results showed that the bonding of the textured multi-material was successfully processed and an interdiffusion zone was formed at the bonding interface without the presence of detrimental compounds. The addition of textures showed a tendency to increase the shear bond strength, with the cross-hatched micropatterns generally showing a higher bonding strength than the circular micropatterns. This approach showed to have the potential to improve the bonding between materials, thus contributing to the development of novel multi-material WC–Co/316L stainless steel cutting tools with enhanced properties and performance.
M.S. Faria, M.F.R.P. Alves, R. Cintra, F.J. Oliveira, C.M. Fernandes, D. Figueiredo, and S.M. Olhero
Elsevier BV
Francisco Matos, Tiago E. F. Silva, Vitor F. C. Sousa, Francisco Marques, Daniel Figueiredo, Francisco J. G. Silva, and Abílio M. P. de Jesus
MDPI AG
Inconel 718 is a highly valued material in the aerospace and nuclear industries due to the fact of its exceptional properties. However, the processing of this material is quite difficult, especially through machining processes. Machining this material results in rapid tool wear, even when low material removal rates are considered. In this study, instrumented turning experiments were employed to evaluate the machinability of Inconel 718 alloy using PCBN tools while assessing the usage of two distinct binder phases, TiN and TiC, for those cutting tools. It was found that the tool life was highly sensitive to the cutting speeds but also affected by the workpiece mechanical properties. At lower cutting speeds, notch wear significantly impacted the tool integrity, whereas at higher cutting speeds, flank wear was the primary failure mode of the tool. The flank wear of the tools with TiN-based binder outperformed TiC by almost 30%, presenting a more consistent behavior when machining.
B. Guimarães, A. Guedes, C.M. Fernandes, D. Figueiredo, F. Bartolomeu, G. Miranda, and F.S. Silva
Elsevier BV
Bruno Guimarães, José Rosas, Cristina M. Fernandes, Daniel Figueiredo, Hernâni Lopes, Olga C. Paiva, Filipe S. Silva, and Georgina Miranda
MDPI AG
During machining processes, a high temperature is generated in the cutting zone due to deformation of the material and friction of the chip along the surface of the tool. This high temperature has a detrimental effect on the cutting tool, and for this reason, it is of the utmost importance to assess the cutting temperature in real time during these processes. Despite all the advances and investigation in this field, accurately measuring the cutting temperature remains a great challenge. In this sense, this work intends to contribute to solving this problem by experimentally evaluating the potential of the developed approach for embedding thermocouples into the rake face of cutting tools for measuring cutting temperature in real time during dry turning of AISI 1045 steel for different cutting parameters and comparing the obtained results with infrared thermography measurements at the exact same point. A well-defined, smooth micro-groove with good surface quality was produced by laser surface modification. Then a laser-welded K-type thermocouple was fixated in the micro-groove with a MgO ceramic adhesive, ensuring protection from wear and chips, which allowed the creation of WC-Co cutting inserts with the ability to measure cutting tool temperature with a maximum error of 0.96%. Results showed that, despite yielding the same trend, the tool temperature measured by the IR thermographic camera was always lower than the temperature measured by the K-type embedded thermocouple. The proposed embedded thermocouple method proved to be a reliable, precise, accurate, and cost-effective approach for real-time temperature measurement capable of providing useful information for cutting parameter optimization, thus allowing increased productivity and tool life.
N. Azurmendi, A. Lores, I. Agote, C.M. Fernandes, and D. Figueiredo
EPMA
Additive manufacturing of hard metals is gaining attention due to the possibility of fabricating complex shaped parts and new functional designs. Among all of them, Binder Jetting (BJ) appears to be one of the most promising technology due to its low-cost, fast manufacturing process that produces stress and crack-free parts with isotropic properties. In the present work, the feasibility of using hard metal thermal spray powders (WC-12%Co) for binder jetting technology has been studied. Properties of two different agglomerated and sintered powders (AMPERIT 519.059 from Höganäs and WOKA 3111FC from Oerlikon Metco) have been analysed and compared. In addition, physical, mechanical and microstructural properties (density, hardness) of the printed parts sintered in a sinter-hip-furnace at 1455°C and 30bars have been evaluated and compared. The obtained results demonstrated the feasibility of using this type of powders for binder jetting, obtaining near full density parts (>99%) with hardness values around 1320 HV and homogeneous fine-medium microstructure.
Ricardo Mineiro, J. Rodrigues, C.M. Fernandes, D. Figueiredo, B. Ferrari, A.J. Sanchez-Herencia, and A.M.R. Senos
EPMA
Cubic boron nitride (cBN) is normally used as the hardest phase of composites, together with ceramic and/or metallic matrixes, to form PcBN (Polycrystalline cubic Boron Nitride) materials applied in machining and finishing operations. While high PcBN (70–90 vol% cBN) is only produced by HPHT (High Pressure High Temperature) techniques, low PcBN (40–70 vol% cBN) can also be consolidated by SPS (Spark Plasma Sintering) since higher volume of binders are present. In this work, a cBN micrometer powder is combined with TiCN and Ni to produce composites with hard matrix phases, predicted by the calculated phase diagram. The SPS technique is used for the thermal consolidation of different PcBN compositions with a varied content of Ni, up to 15 vol%. A structural and microstructural characterization of the PcBN composites was performed for different compositions and maximum SPS temperatures.
Gonçalo Oliveira, Ricardo Mineiro, Ana Maria Rocha Senos, Cristina Fernandes, Daniel Figueiredo, and Teresa Vieira Maria
EPMA
Advanced cutting tools are required for the new challenge of the machining industry to make more sustainable solutions. Material extrusion (MEX), as an indirect additive manufacturing technology, could be used to process hardmetals (WC-Co) and, also, the designated cermets (TiCN/WC and Co, Ni). While versatile for different feedstock possibilities, it is capable to produce complex internal structures that could lead to more efficient cooling solutions. However, it is not yet easy to replicate the main MEX parameters developed for organic or metallic materials when the feedstocks are based on hardmetal and cermet powder. The main objective of this study is to add a better understanding of these materials processed by MEX, considering that the defects, from shaping to debinding and sintering, have a significant role in the performance of the tool.
G. Miranda, L. Basílio, B. Guimarães, O. Carvalho, C. M. Fernandes, D. Figueiredo, and F. S. Silva
EPMA
Laser surface texturing has a high potential for the development of innovative solutions for the cutting tool industry, by allowing the fabrication of high-precision micro-scale geometries. In this study, different cross-hatched micro patterns were explored, by using an Nd:YAG laser to texture WC-10wt% Co green compacts. After dewaxing and sintering, a complete characterization was performed to evaluate topography, roughness, and dimensions of the fabricated textures. This study allowed to conclude on the better scanning strategy and laser parameters for obtaining a given texture geometry with defined dimensions on a reproducible manner. Besides allowing to modify a selected surface area, targeting to higher wettability or increased contact area, this approach has shown not to compromise the integrity and mechanical strength of the compact, allowing to preserve the tool conventional functionality.
B. Guimarães, C. M. Fernandes, D. Figueiredo, F. S. Silva, and G. Miranda
EPMA
During machining processes, a large amount of heat is generated, especially in the cutting zone, due to the deformation of the material and to the friction of the chip along the surface of the cutting tool, resulting in, a wear increase and consequent reduction of tool life. Surface texturing can help improve these tools tribological performance by increasing their load carrying capacity, providing a more efficient lubricant supply at the tool-chip interface and reducing the tool-chip contact area. In this context, the fabrication of cross-hatched micropatterns on WC-Co cutting tools by laser surface texturing of green compacts is proposed, aiming to improve these tools performance and life. This work is focused on evaluating the morphology of the chip obtained when turning 316L stainless steel with tools textured with different cross-hatched micropatterns, these findings being benchmarked against conventional cutting tools and correlated with the tool wear. For such purpose, morphological characterization using optical and scanning electron microscopy was used.
F. Matos, T.E.F. Silva, F. Marques, D. Figueiredo, P.A.R. Rosa, and A.M.P. de Jesus
Elsevier BV
Bruno Miguel Pereira Guimarães, Cristina Maria da Silva Fernandes, Daniel Amaral de Figueiredo, Filipe Samuel Correia Pereira da Silva, and Maria Georgina Macedo Miranda
Springer Science and Business Media LLC
B. Guimarães, J. Silva, C.M. Fernandes, D. Figueiredo, O. Carvalho, G. Miranda, and F.S. Silva
Elsevier BV
Sérgio Pratas, Eduardo L. Silva, Miguel A. Neto, Cristina M. Fernandes, António J. S. Fernandes, Daniel Figueiredo, and Rui F. Silva
MDPI AG
Among the unique opportunities and developments that are currently being triggered by the fourth industrial revolution, developments in cutting tools have been following the trend of an ever more holistic control of manufacturing processes. Sustainable manufacturing is at the forefront of tools development, encompassing environmental, economic, and technological goals. The integrated use of sensors, data processing, and smart algorithms for fast optimization or real time adjustment of cutting processes can lead to a significant impact on productivity and energy uptake, as well as less usage of cutting fluids. Diamond is the material of choice for machining of non-ferrous alloys, composites, and ultrahard materials. While the extreme hardness, thermal conductivity, and wear resistance of CVD diamond coatings are well-known, these also exhibit highly auspicious sensing properties through doping with boron and other elements. The present study focuses on the thermal response of boron-doped diamond (BDD) coatings. BDD coatings have been shown to have a negative temperature coefficient (NTC). Several approaches have been adopted for monitoring cutting temperature, including thin film thermocouples and infrared thermography. Although these are good solutions, they can be costly and become impractical for certain finishing cutting operations, tool geometries such as rotary tools, as well as during material removal in intricate spaces. In the scope of this study, diamond/WC-Co substrates were coated with BDD by hot filament chemical vapor deposition (HFCVD). Scanning electron microscopy, Raman spectroscopy, and the van der Pauw method were used for morphological, structural, and electrical characterization, respectively. The thermal response of the thin diamond thermistors was characterized in the temperature interval of 20–400 °C. Compared to state-of-the-art temperature monitoring solutions, this is a one-step approach that improves the wear properties and heat dissipation of carbide tools while providing real-time and in-situ temperature monitoring.