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.

Cobalt-cemented carbide micro-end mills were coated with diamond grown by chemical vapor deposition (CVD), with the purpose of micro-machining cemented carbides. The diamond coatings were designed with a multilayer architecture, alternating between sub-microcrystalline and nanocrystalline diamond layers. The structure of the coatings was studied by transmission electron microscopy. High adhesion to the chemically pre-treated WC-7Co tool substrates was observed by Rockwell C indentation, with the diamond coatings withstanding a critical load of 1250 N. The coated tools were tested for micro-end-milling of WC-15Co under air-cooling conditions, being able to cut more than 6500 m over a period of 120 min, after which a flank wear of 47.8 μm was attained. The machining performance and wear behavior of the micro-cutters was studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Crystallographic analysis through cross-sectional selected area electron diffraction patterns, along with characterization in dark-field and HRTEM modes, provided a possible correlation between interfacial stress relaxation and wear properties of the coatings. Overall, this work demonstrates that high adhesion of diamond coatings can be achieved by proper combination of chemical attack and coating architecture. By preventing catastrophic delamination, multilayer CVD diamond coatings are central towards the enhancement of the wear properties and mechanical robustness of carbide tools used for micro-machining of ultra-hard materials.

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.

Hybrid 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.

Micro-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.

The rapid growth of the machining market and advancements in additive manufacturing (AM) present new opportunities for innovative tool designs. This preliminary study proposes a design for additive manufacturing (DfAM) approach to redesign a milling cutter head in 17-4 PH stainless steel by integrating topology optimization (TO) and internal coolant channel optimization, enabled by laser powder bed fusion (LPBF). An industrial eight-insert milling cutting tool was reimagined with conformal cooling channels and a lightweight topology-optimized structure. The design process considered LPBF constraints and was iteratively refined using computational fluid dynamics (CFD) and finite element analysis (FEA) to validate fluid flow and structural performance. The optimized milling head achieved approximately 10% weight reduction while improving stiffness (reducing maximum deformation under load from 160 μm to 151 μm) and providing enhanced coolant distribution to the cutting inserts. The results demonstrate that combining TO with internal channel design can yield a high-performance and lightweight milling tool that leverages the freedom of additive manufacturing. As proof of concept, this integrated CFD–FEA validation approach under DfAM guidelines highlights a promising pathway toward superior cutting tool designs for industrial applications.