Material jet system

#The invention concerns “hot-melt” jet systems, especially arranged for deposition of materials with a relative high melting temperature.

#Material jet systems (often called “inkjet systems) may work with materials which are supplied to the printer head in their fluid phase. However, in so-called “hot melt” systems, e.g. using wax-like materials, the printing material only becomes fluid at increased temperature, and thus has to be processed by a heated jet printer head. However, regular and controlled supply of solid “ink” (material, in general) may be a problem. A heated supply system may be used, in which the ink is heated and kept above its melting temperature in a rather large storage container and supplied—in molten form—to the printer head. In this way a large part of the device has to be kept above melting temperature. A known alternative is to use a heated reservoir at the printer head that is filled up now and then by addition of a piece of solid ink. A disadvantage of this type of system is that a considerable quantity of ink must be kept at temperature in the neighbourhood of the printer head.

#Conventional printing of solid ink materials is known, for example, from EP1552941 which discloses a printer having a solid ink stick feed. However, these printers function at temperatures which are not suitable for printing solid materials which have higher melting temperatures like lead, tin, copper, silver etc., the system has to be heated in that way that in practice this not only becomes very complicated, but in view of the reactivity of metals in fluid phase, even almost impossible.

#FIG. 1 shows schematically an exemplary embodiment of the present invention.

#FIG. 2 shows a detail of the same embodiment.

#FIG. 3 shows a more extended embodiment of the invention.

#The exemplary embodiment of FIG. 1 shows a material jet system, comprising a container for molten jet material 3 to be ejected, high frequency induction heating means 4 arranged for electric heating and thus melting (and keeping molten) said jet material. Moreover the embodiment comprises jetting means which comprise a jet nozzle 5, a vibration conductor 6 and a vibration actuator 7, all arranged to form and eject (jet)—via jet nozzle 5—material droplets (particles) 8 e.g. for building a micro-sized component (not shown). The system, moreover, comprises means 2 which are arranged for an uninterrupted supply of said material, e.g. a metal, in solid form, preferably having the shape of a wire 1, bar or tape.

#As FIG. 2 shows more in detail the wire 1 may be fed towards the container 3 by means of a couple of drive “wheels” 9 which are controllable by control means 14 (FIG. 3). To maintain an adequate pressure in the container 3 heat insulating fluid 20 is pressure controlled and contained in the container 3, e.g. a source of inert gas under pressure indicated in FIGS. 1 and 3 by “p”, the wire 1 may be sealed by means of a couple of e.g. rubber O-rings 25.

#A disadvantage of supplying the material in this way is the fact that the material cannot be filtered before, causing that contaminations may introduced into the system. When use is made of metals as “ink” this is not a real problem because in that case all contaminations (e.g. oxides) will float to the surface. When the system is heavily used of when relatively contaminated material is used the system, however, may become contaminated and unusable in short time.