[en] In the world of aeronautics, the machining of titanium components with thin walls is a common practice. However, this practice is not a simple job, since it is very common the appearance of distortions generated by the effect of residual stresses, which are generated by the high mechanical and thermal loads induced on the surface by the machining. For this reason, this report proposes an empirical model focused on making predictions of residual stresses that are generated after the performance of a finishing method of a face milling process on Ti6Al4V titanium alloy. In order to carry out this study, previous studies have been done where a comparison of two methods of measuring residual stresses determines the most appropriate method for this study. In fact, these two methods are Hole Drilling and X-ray diffraction. In the same way, to evaluate the quality of the data, the variability of the selected measurement system has been analyzed by a study of repeatability and reproducibility. After both preliminary studies, milling tests were carried out to obtain the residual stress measurements required to build the model and validate it. By using an exponentially decaying cosine function and polynomial fits, the residual stress has been modelled as a function of the stress penetration depth from the surface and two cutting parameters, i.e., cutting speed and feed rate per tooth. Once the model was obtained, it was validated using experimental data different from those used for the development of the model. The results obtained show that the empirical model based on a exponentially decaying cosine function and first degree polynomial regressions can predict the residual stress profiles generated in the machining process. Therefore, the possibility of predicting the trend of these stresses allows a future implementation of distortion minimization methods through the control of these stresses.

[eu] Aeronautikaren munduan, lodiera txikiko paretak dituzten titaniozko osagaien mekanizazioa ohikoa da. Hala ere, praktika hori ez da lan erraza, oso ohikoa baita hondar-tentsioen eraginez sortutako distortsioak agertzea. Tentsio horiek mekanizazio gainazalean ematen diren karga mekaniko eta termiko handietatik sortzen direlarik. Hori dela eta, txosten hau Ti6Al4V titanio aleazioan fresaketa prozesu baten akabera metodo bat egin ondoren sortuko liratekeen hondar-tentsioen iragarpenean oinarritutako eredu enpiriko bat proposatzen du. Azterketa hori egiteko, aldez aurreko azterlan batzuk egin dira, zeintzuetan hondar-tentsioak neurtzeko bi metodo konparatu diren, proiektu hau aurrera eramateko metodorik egokiena aukeratzeko asmoz. Zehazki, bi metodo horiek zulo zulatuaren metodoa eta X izpien difrakzioa dira. Era berean, datuen kalitatea ebaluatzeko aukeratutako neurketa sistemaren errepikagarritasun eta erreproduzigarritasun azterketa bat egin da. Azaldutako bi azterketak egin ondoren, fresaketa saiakuntza batzuk egin dira, eta horietatik lortu dira eredua eraikitzeko eta balioztatzeko beharrezkoak diren hondar-tentsioen neurketak. Doitze ekuazio polinomikoak eta beheratze esponentzialeko funtzio kosenoidala erabiliz, hondar tentsioa modelizatu da gainazaletik tentsioen sartze-sakoneraren eta bi ebaketa parametroen arabera, hau da, ebaketa abiadura eta hortzeko aitzinapena. Eredua lortu ondoren, eredua sortzeko erabili ez diren datu esperimentalen bidez balioztatu da. Lortutako emaitzen arabera, beheratze esponentzialeko funtzio kosenoidala eta lehen mailako erregresio polinomikoetan oinarritutako eredu enpirikoak mekanizazio prozesuan sortzen diren hondar-tentsioaren profilak aurreikus ditzake. Beraz, tentsio horien joera aurreikusteko aukerari esker, etorkizunean distortsioak minimizatzeko metodoak ezar daitezke, tentsio horiek kontrolatuz.