Open Access
Análisis de la influencia de las condiciones de proceso sobre el acabado superficial de materiales cerámicos fabricados por electroerosión
(CENIM, 2004) Puertas Arbizu, Ignacio; Luis Pérez, Carmelo Javier; Ingeniería Mecánica, Energética y de Materiales; Mekanika, Energetika eta Materialen Ingeniaritza
El mecanizado por electroerosión (en inglés, Electrical Discharge Machining, EDM) constituye una alternativa emergente frente a otros procesos de fabricación de materiales cerámicos conductores, tales como: mecanizado por láser, mecanizado electroquímico, chorro de agua con abrasivos, mecanizado por ultrasonidos y rectificado con muela de diamante. Debido a su interés en el ámbito industrial, en este trabajo se lleva a cabo un estudio de la influencia de las condiciones de operación sobre el aspecto superficial de tres materiales cerámicos conductores: carburo de boro prensado en caliente (B4C), carburo de silicio infiltrado con silicio (SiSiC) y carburo de wolframio en matriz metálica de cobalto (WC-Co), electroerosionados bajo diferentes condiciones de mecanizado y para el caso particular de regímenes de acabado (Ra ≤ 1 μm).
Open Access
A study on the EDM drilling of reaction-bonded silicon carbide using different electrode materials
(Springer, 2023) Torres Salcedo, Alexia; Luis Pérez, Carmelo Javier; Puertas Arbizu, Ignacio; Corres Sanz, Jesús María; Ingeniería; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Today, there is a growing demand for efficient hole manufacturing technology in many industries such as aeronautics, automotive and nuclear, among others. Thus, the present study deals with the machining of through holes on SiSiC advanced ceramic by using Electrical Discharge Machining (EDM) drilling technology. Since recommendations related to the electrode characteristics and settings parameters are found to be scant for the industrial use of EDM drilling of SiSiC ceramics, this research work comes to cover this gap as it presents a complete study focused on the influence on different electrodes under rough and finish machining conditions. In particular, the influence of four electrodes materials (copper, copper-tungsten, graphite and copper infiltrated graphite) and three different electrode diameters ranging from 2 to 4 mm are investigated. In addition, the rotational speed of the electrode is also analysed. From the experimental results, both electrode material and machining regime, seem to be the most relevant factors of all. In the case of 2 mm diameter electrode, material removal rate (MRR) with Cu electrode was, approximately, 4.5 times higher than that obtained with a C electrode. In fact, it was found that copper electrode rotating at 20 rpm combined with high values of discharge energy (I = 2 A; ti = 70 µs) is the most economical option in terms of production cost and production time, as it gives a high MRR of 0.4754 mm3/min and a minimum electrode wear (EW) value of 7.52%. Moreover, slightly higher values of MRR were achieved for CuC electrode compared to those obtained with C electrode, indicating that the addition of Cu in the electrode contributes to a greater removal of material. However, a value of Ra of 0.37 µm could be obtained by setting low current intensity values (I = 0.5 A; ti = 45 µs) combined with C electrodes and with no rotation.
Open Access
Experimental analysis of the machinability of 94 WC-6 Co by die-sinking EDM
(MDPI, 2024-12-10) Salvide-González, Unai; Puertas Arbizu, Ignacio; Luis Pérez, Carmelo Javier; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
Cobalt-bonded tungsten carbide (WC-Co) is widely used in heavy-duty machining applications due to its exceptional hardness and wear resistance, and it is increasingly being adopted in industries such as aerospace and the automotive sector, among others. Its superior mechanical properties make it difficult to machine with conventional methods such as turning or milling. Electrical Discharge Machining (EDM) has emerged as an efficient alternative, as it allows for the machining of hard materials to be carried out without direct contact between the tool and the workpiece, provided that the material has sufficient electrical conductivity. In this study, a multilevel Design of Experiments (DOE) was conducted to analyze the influence of EDM parameters¿specifically, the current intensity and pulse time—on the surface roughness (SR), electrode wear (EW), and material removal rate (MRR) for 94WC—6Co. The results indicate that the current intensity was the most significant factor across all responses, while the pulse time played a secondary role. Surface finishes as low as Ra = 0.47 μm were achieved at I = 2 A and ti = 10 μs.. For each outcome variable, mathematical models were obtained in order to improve the EDM processes and better understand the machining of WC-Co.
Open Access
EDM machinability and surface roughness analysis of TiB2 using copper electrodes
(Elsevier, 2017-01-05) Torres Salcedo, Alexia; Luis Pérez, Carmelo Javier; Puertas Arbizu, Ignacio; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
Titanium diboride (TiB2) is a sintered ceramic material which has a high industrial interest due to its excellent mechanical properties, such as immense hardness, elastic modulus, and abrasion resistance. Unlike most ceramics, this material can be machined by using an electrical discharge machining (EDM) process because of its good thermal and electrical conductivity. In this present study the applicability of an EDM process for manufacturing titanium diboride is analysed. To do that, the influence of EDM parameters is studied on three of the most important technological characteristics in EDM: material removal rate (MRR), electrode wear (EW) and surface roughness (Ra). Results confirm that the most influential factor on MRR and Ra is the current intensity whereas in the case of EW, it is the pulse time. Additionally, the control of these parameters allows technological tables to be obtained in order to determine the optimum operating conditions. Such technological tables exist for the case of steels but they do not exist for TiB2, in which the optimal conditions are to be determined experimentally.
Open Access
Development of a machining strategy to manufacture SiSiC nuts by EDM
(SAGE Publications, 2024) Torres Salcedo, Alexia; Puertas Arbizu, Ignacio; Luis Pérez, Carmelo Javier; Ingeniería; Ingeniaritza
Today, the high-precision manufacturing of small cavities in difficult-to-machine materials is still a challenge, even more so if they need to be threaded. The machining time, the wear suffered by the electrodes and the surface finish are determining factors in the efficiency of the threading process. However, there is scant literature on this subject so there is a need to study the process and the parameters involved. Thus, this study presents a novel machining strategy for the manufacture of nuts using die-sinking electrical discharge machining (EDM). Moreover, the novelty of this strategy is that it is carried out in a single stage and with a conventional EDM generator. To do so, a design of experiments (DOE) methodology has been followed. First, the optimal machining conditions are determined by studying the influence of EDM parameters on operation variables and mathematical models are developed using multiple linear regression. These models allow the behavior of the response variables under study to be predicted. Finally, this machining strategy developed from the previous experimental results is validated in the manufacturing process of a final part, specifically a square nut. It can be concluded that the mathematical model is good enough to predict the experimental results. Thus, the new method presented and described in this present study allowed a nut to be obtained with a real arithmetic mean deviation of the roughness profile (Ra) value of 1.27 μm whereas the predicted value from the model was 1.28 μm. To do so, the machining conditions selected were: 4 A (current intensity), 5 µs (pulse time) and 0.4 (duty cycle), which also gave a material removal rate (MRR) value of 0.5370 mm3/min. The machining strategy proposed here may be used for future research works related to the manufacturing of mechanical joints made of conductive ceramic materials.