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Contactless dosing of minute amounts of molten metals in the form of micron sized droplets is a promising technology with applications in the area of three dimensional printing (3DP) and electronics manufacturing. However the generation of droplets of higher melting point metals, such as aluminum and its alloys, has proven to be a challenging task. Difficulties arise mainly due to the high temperatures...
Additive manufacturing technologies have recently attracted a lot of attention as a new highly flexible prototyping and fabrication method. Machines that use polymers as building materials are now a common occurrence in laboratories and production settings across the industry. Despite their superior strength, metals are a far less common building material for three dimensional printing (3DP). Although...
This paper presents a novel software tool for the evaluation of the CT-reconstructed models that offers automatic conformity evaluation and interpretation without any reference models. The evaluation of the reconstructed models typically involves their comparison with their predefined reference geometries and includes the following steps: object scanning, suitable format conversion, registration with...
This paper presents a new method for filling the arbitrarily shaped closed contours with identical circles, as a part of the slicing software for droplet-generating 3D printers. 3D printers, as a part of Rapid prototyping technology, offer engineers and designers the possibility of producing models and prototypes layer wise in a fast way and directly from a CAD model. A Rapid prototyping process can...
This paper presents an evaluation of an algorithm that optimises the infills of the geometries that contain at least one pointed end. Computation of the infills, as a part of path planning, falls within the slicing procedure, which in turn is a standard process step in creating a 3D part via rapid prototyping techniques. The computation of the infill trajectories were conducted according to its final...
In the present paper a compact model for a piezoelectric drop-on-demand (DoD) printhead is derived from basic electrical, mechanical and fluid mechanical relationships. The model covers the whole droplet generation process, spanning over the electrical as well as the mechanical and fluidmechanical domains. It allows predictions about essential droplet characteristics, such as droplet volume and flight...
This paper describes a squeegee device for a manual microassembly system. The device consists basically of a height axis, of a squeegee clamp, and of a squeegee blade. The squeegee device is connected via a supporting arm to the base frame of a microassembly system. The objective of this work is to obtain a homogenous, thin, and defined adhesive layer for piezoelectric actuators which are used in...
In this paper a new slicing method for filling an arbitrary polygon with 3D-balls for a 3D plastic droplet generation process is presented. The work principle of the 3D plastic droplet generation is to squeeze the plastic material through a nozzle, out of which small hardened balls are formed and based on the contour and infill algorithm the 3D objects filled with plastic droplets are layer-wise created...
A novel experimentation platform, which is based on a piezoelectrically driven inkjet printhead and on a support plate, is presented. A huge number of fluids has to be ejected due to the large variety of possible applications for inkjet printheads. Each fluid with its special characteristics usually requires a redesign of the printhead to be able to be ejected. This inkjet printhead is manufactured...
Laser micro machining belongs to the most important processes in rapid prototyping / rapid manufacturing. Especially Nd:YAG lasers with a galvanometer scanner are extremely common in manufacturing Micro-Electro-Mechanical-Systems (MEMS) in a time and cost saving manner. Moreover, laser micro milling is one of the most significant processes in laser micro machining apart from laser micro cutting and...
Dosing liquids in small quantities is present in a lot of different applications as inkjet printing, heating devices, and 3D-printing methods. This paper deals with a drop on demand (DOD) printhead based on a piezo-element bender actuator which can generate drops out of wax. The aim is to provide a testing system where changes of significant design parameters can be done easily in order to proof the...
Since invention of ink-jet printing many new techniques and solutions to dose liquid media as drops have been developed. Today there are numerous drop on demand printheads for different fluids and applications. However characteristics of the fluid and working conditions have significant influence on the drop on demand printhead itself. Adapting a printhead to using other fluids often means extensive...
During the last four decades laser beam machining has been used as a powerful tool in rapid prototyping. Nd:YAG lasers are most widely used in machining of engineering materials, especially silicon for Micro-Electro-Mechanical-Systems (MEMS). Apart from laser micro-welding or laser micro-drilling, laser micro-cutting is one of the most important processes in rapid prototyping. In recent years the...
Der Massenstrom von Polypropylenschmelzen durch Mikrodüsen mit Durchmessern kleiner 500 μm wurde in Abhängigkeit des Drucks untersucht. Messungen zeigen einen exponentiellen Einfluss des Drucks und des Düsendurchmessers. Die Messung korreliert nicht mit dem gewählten Ansatz, daher ist das Power‐Law‐Modell nicht auf Mikrodüsen anwendbar. Der höher gemessene Massenstrom gegenüber der Simulation ist...
In this paper a system for solder printing is presented. With the printing system solder bumps can be directly printed on a substrate. The printhead is actuated by an electro-magnetic working principle. After printing the bumps, flip-chips can be placed and reflow soldered. A model to describe the printhead is presented. A differential equation for the movement of the actuated piston was developed...
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