Experimental study of laser dissimilar joining for Usibor 2000 and Al-T7075 with Tepex 102

Due to the needs of weight reduction in the automobile structures and of time reduction in the Body-In-White (BIW) manufacturing stage, effective and accurate dissimilar joining is demanded to take advantage of metal-polymer structures. Automotive industry is highly interested in the combination of metal alloys and composite materials; however, dissimilar joining of this type of materials without using mechanic or adhesive joining is a challenge. As an alternative to the classical joining techniques, laser technology can be used to join dissimilar materials. In laser direct joining, a laser beam is used to heat the metal and by conduction to heat the polymer up to melting temperature in the interface without reaching degradation temperature. In this work, an experimental procedure is proposed to set the basis of dissimilar joining between metal and composite parts for the automobile industry. To do that, laser texturing on metallic parts was studied and a wide battery of experimental test were performed to obtain the proper joining process parameters for dissimilar joining between Usibor 2000 and Al-T7075 with Tepex 102. Results show that is possible to reach over 17 MPa in lap shear adhesion test which is similar to the performance of typical adhesives used in automotive industry.Authors wish to thank Basque Country Government for financial support provided through MULTIMAT project Elkartek KK2017/00088 as well as the Spanish Industry ministry for support provided in INTEGRADDI project DPI 2016-79889

Laser Texturing and Dissimilar Material Joining

Laser texturing is a process used to remove material selectively. Metallic parts were processed in order to create a surface texture that enables metal-polymer joining. This kind of dissimilar joining is carried out combining a pressure fixture and heating using a direct diode laser source. In order to reach a good result, it is critical to texture the surface with correct parameters to generate surface features that maximizes the contact between materials and heating enough the materials to soften the polymer but without melting and degrading the material, so, a temperature control system is necessary to get best results. In this work, the texturing capabilities of conventional CW laser source were explored and numerical model was developed in order to simulate and control the process temperature in the joining interface.This work was carried out with the funding help received from PARADDISE project ID723440 under FoF-13 H2020 progra

Optimización del fresado de piezas de rigidez reducida mediante un modelo de estabilidad tridimensional

El fresado de alta velocidad ha permitido la producción de componentes estructurales aeronáuticos de aluminio a partir de un bloque de partida, obteniendo las conocidas piezas monolíticas. Este proceso es más productivo respecto al ensamblaje de varias piezas para constituir una mediante remaches, debido en parte, a los grandes caudales de viruta que se consiguen. Sin embargo, la agresividad de las condiciones de corte trae pareja una serie de problemas, siendo unos de los más importantes las vibraciones autoexcitadas conocidas como chatter regenerativo, que pueden producir la rotura o desgaste prematuro del husillo en cortes de desbaste o la aparición de marcas y roturas en la pieza durante el acabado. En este trabajo se presenta un modelo de estabilidad tridimensional que considera la flexibilidad dinámica del conjunto husillo-herramienta y de la pieza para la obtención de diagramas de lóbulos, permitiendo una mejor planificación del mecanizado

Fracture-pattern growth in the deep, chemically reactive subsurface

Arrays of natural opening-mode fractures show systematic patterns in size and spatial arrangement. The controls on these factors are enigmatic, but in many cases the depth of formation appears to be critical. Physical, potentially depth-dependent factors that could account for these variations include confining stress, fluid pressure, and strain rate; these factors are common inputs to existing fracture models. However, temperature-dependent chemical processes likely exert an equally important control on patterns, and such processes have not yet been rigorously incorporated into models of fracture formation. Here we present a spring-lattice model that simulates fracturing in extending sedimentary rock beds, while explicitly accounting for cementation during opening of fractures, and for rock failure via both elastic and time-dependent failure criteria. Results illustrate three distinct fracturing behaviors having documented natural analogs, which we here term fracture facies. “Exclusionary macrofracturing” occurs at shallow levels and produces large, widely spaced, uncemented fractures; “multi-scale fracturing” occurs at moderate depth and produces partially cemented fractures having a wide range of sizes and spacings; and “penetrative microfracturing” occurs at great depth and produces myriad narrow, sealed fractures that are closely and regularly spaced. The effect of depth is primarily to accelerate both dissolution and precipitation reactions via increased temperature and porewater salinity; the specific depth range of each fracture facies will vary by host-rock lithology, grain size, strain rate, and thermal history

Effects of laser-textured on rake face in turning PCD tools for Ti6Al4V

The demand inherent to the aeronautical industry in terms of productivity and quality requirements leads to develop new cutting tools. Hence, PCD tools meet the requirements in productivity while machining low machinability aeronautical alloys such as Ti6Al4V. Tool chipbreakers play a considerable role in terms of tool life. However, due to the extreme conditions (temperature and pressure) required to manufacture PCD tools, any complex geometry on tool rake faces is not viable, so chipbreakers are not possible, except for those external to inserts. This work proposes a groove-type laser engraved chipbreaker design and a manufacturing methodology, with experimental validation on turning a Ti6Al4V workpiece. The so-manufactured chipbreakers achieve titanium alloy chip fragmentation, making easy chip removal from the cutting zone. A set of experiments involving various laser parameters to characterize the PCD depth and surface integrity and experimental validation for those chipbreakers designs were carried out in finishing cutting conditions. The optimum parameters for the engraving of PCD were found, obtaining satisfactory breakage of titanium chips. Chip length was always below 17.29 mm.Authors are grateful to Basque government group IT IT1337- 19, the Ministry of Mineco REF DPI2016-74845-R and PID2019- 109340RB-I00, and the UPV/EHU itself for the financial aid for the pre-doctoral grants PIF 19/96

Continuous Coaxial Nozzle Design for LMD based on Numerical Simulation

AbstractThe LMD technology is becoming one of the most important emerging manufacturing technologies in the modern industry, due to its benefits when building-up geometries, repairing damaged parts or the creation of coatings to improve material properties and behaviour. One of the most relevant parameters in LMD process is the efficiency of the trapped powder into the melt pool, since metallic material powders use to be very expensive.With the aim of improving the ratio between the trapped powder in the deposited area and the total injected powder, the work presents a new methodology for continuous coaxial nozzle design for the LMD process based on a complete CFD model. The numerical model can predict particle flow, speed, powder concentration, etc. and design can be optimized using this input data.The model has been validated and then, it has been used for the design of two different nozzles: one discrete and one continuous coaxial nozzle

Data for: Outcrops as Guides to Subsurface Natural Fractures: Example from the Nikanassin Formation tight-gas sandstone, Grande Cache, Alberta Foothills, Canada

Method

Data for: Cataclastic deformation and metasomatism in the subduction zone of mafic blocks in shale-matrix mélange near San Simeon, California

Appendix Method

Data for: Outcrops as Guides to Subsurface Natural Fractures: Example from the Nikanassin Formation tight-gas sandstone, Grande Cache, Alberta Foothills, Canada

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