The use of replicative processes has become strategic and critical in industry to produce precise, microscopically detailed metallic parts and devices via low cost manufacturing routes. Metal powder hot embossing is an emerging process that brings some advantages associated with the reduction of production costs relative to powder injection moulding (PIM). The technology involves four distinct steps: preparation of the selected feedstock material (powder and binder); hot embossing; debinding; and sintering. The effect of continuous pressure during the hot embossing step as a means of replicating microdetails in 316L stainless steel parts is examined. Dimensional accuracy, microstructure and mechanical properties of the parts produced were evaluated. For the configuration tested, the most promising results were achieved when processing at 180°C for 30 min at a pressure of 14 MPa.
The microfabrication technologies not only possess a considerable market potential but are also regarded as leading technologies of our days and key technologies for the future, due to the growing demand for microengineering applications such as micromoulds, micromechanical structures, sensors and micro-medical devices [1,2]. Metal powder hot embossing is an emerging replicative process that can provide dimensional precision and microdetails of metallic parts. Metal powder hot embossing requires four distinctive steps: (1) preparation of feedstocks (implying the selection and characterization of powder and binder); (2) shape-forming of the part by hot embossing (green part); (3) debinding (brown part); and (4) sintering (final part).The goal of this study was to characterize metallic parts produced by micro metal hot embossing technology. To manufacture metallic parts with quality it was necessary to optimize all parameters involved in the four steps. To prepared the feedstock was used 316L stainless steel powder, which has a d 50 = 7.34 µm, with a commercial binder (Licomont, Lc). The production of feedstock was performed by torque rheometry at 140º C, during 45 minutes and using a blade speed rotation of 30 rpm. The feedstocks produced have a fixed powder load equal to 60 vol.% and the final torque average value was 2.2 N.m. Previous studies report the characterization of the powder and binder and show that the feedstocks are homogeneous mixtures [3,4]. Different pressures of embossing (4, 7, 14 and 28 MPa) were tested in order to optimize the process. To evaluate the replication of micro details, all the samples produced were observed in a stereomicroscope before and after sintering. Additionally, the best samples were analyzed by optical microscopy and Scanning Electron Microscopy (SEM) and 3D measured with Alicona IFM, before and after sintering.Similar microstructures consisting of equiaxed austenite grains with several twins present in the matrix are observed for all tested pressures; however, for lower pressures (4 and 7 MPa) porosity is more frequent and larger. The best final parts have been obtained by processing at a pressure of 14 MPa (Figure 1). In order to enhance the microstructural characterization of these components an EBSD (Electron Backscatter Diffraction) analysis was performed. The results show a grain size significantly smaller in the periphery than in the central region of the sample (Figure 2). These differences are related to sintering kinetic due to the size of metallic parts [5].
Resumo-Este trabalho apresenta uma análise sobre a aplicabilidade de materiais flexíveis como substrato de filtro planar de microfita. Projetou-se um filtro passa-banda usando ressoador Hairpin construído sobre substrato de tecido composto por fibras acrílicas. O filtro foi projetado para aplicações em sistemas wireless operando em 2,45 GHz. As análises foram realizadas utilizando o software Ansoft HFSS. Um protótipo do filtro foi construído para fins de caracterização experimental. Os resultados teóricos e medidos foram satisfatórios, sendo possível alcançar uma resposta em frequência desejada, mesmo, com a alta tangente de perdas que o tecido possui.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.