1,721,245 research outputs found
Feasibility Study of an Extrusion-based Direct Metal Additive Manufacturing Technique
Get PDFA new extrusion-based additive manufacturing technique is described in this paper together with the main components of the machine capable of carrying out the process. Innovative characteristics of the machine are the fixed extrusion head and the workpiece moving thanks to a 5-axis parallel kinematics handling system, allowing the capability of inclining the part during the material deposition and consequently avoiding support structures. The extrusion head and nozzle have been designed in order to be able to extrude high viscosity mixtures with low polymeric content. Preliminary tests prove that a good final density can be obtained after de-binding and sintering and that it is possible to achieve a good bonding of extruded and deposited wires in case of AISI 630 stainless steel
A device for direct additive manufacturing by means of extrusion of metal powders and ceramic materials on a parallel kinematic table
No full textThe present invention describes an additive production system (1) based on extrusion and 3D deposition of a metal mixture (or advanced ceramic material) in powder and polymer binder. The system comprises a) a CNC injection unit (3) of material for metal or ceramic injection molding, which is fixed in space and provided with a nozzle (3d) for extrusion of a filament; and b) a parallel kinematic machine (4) with 5 degrees of freedom
Water jet velocity uncertainty in laser Doppler velocimetry measurements
No full textThe present work deals with the uncertainty evaluation in water jet velocity measurements carried out by means of a laser Doppler dual-incident-beam velocimeter in reference-beam configuration developed at the WJLab (Water Jet Laboratory of Dipartimento di Meccanica of Politecnico di Milano). The applied experimental procedure makes it possible to calculate the measurement uncertainty through the determination of its various components. Once uncertainty is known, the laser Doppler system is suitable for objective and significant velocity evaluations but also for improvements allowed by the knowledge of the most effective uncertainty sources. Such a subject is typically not considered by the specific water jet literature, but is becoming more and more important due to the evolution of water jet machining towards high precision applications
An innovative machine for Fused Deposition Modeling of metals and advanced ceramics
Get PDFThe design of a new additive manufacturing (AM) system based on extrusion and 3D deposition of a mixture of metal (or advanced ceramic) powder and polymeric binder is described in this paper. The proposed system is totally innovative in terms of combination of deposited work material, extrusion system (head and nozzle), and deposition work table, which is based on a 5-axes parallel kinematics machine (PKM). The extrusion head and nozzle have been designed in order to be able to extrude high viscosity mixtures with low polymeric content. The 5-axes PKM is aimed at obtaining a good surface quality of the deposited work and reducing the need for supports during deposition. After the deposition, the material is de-binded and sintered to nearly the density of the solid material as-cast. The design and kinematics of the machine and especially the PKM table is described in this paper, the main design issues are discussed and some preliminary extrusion and sintering results are presented
Metodo e apparato per la stampa 3D di gioielli e componenti a alto valore aggiunto
No full textThe building chamber reducer is an aluminium plate with a central 20x20x40 (h) mm3 hole. The plate is 15 mm thick, but its building chamber has a depth of 40 mm. The plate external dimensions have been designed to fit the internal ones of the existing building box. Due to this modification, also the powder bed platform had to be modified to fit the new dimensions of the building plate. The new powder bed platform is divided in two main parts: a cylindrical part and a parallelepiped part with a flat top surface, where the powder will be deposited during the printing. The new system includes two thin aluminium plates connected to the cylindrical part and needed to couple the grasping machine system with the new powder bed platform. Characteristic elements of the invention:
A reducer to diminish the job box of the binder jetting machine aimed at reducing the amount of powder deposited on the building platform.
A customised hopper to store the powder and release it during the deposition phase
Tramoggia con azionamento magnetico per apparato per la stampa 3D di gioielli e componenti multimateriale
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