EXTRUDER ASSEMBLY FOR A THREE-DIMENSIONAL PRINTER

Abstract

An extruder assembly for a three-dimensional printer having one nozzle, attached to a heating block, a temperature control element for controlling the temperature of the heating block, a mixer, a heat sink arranged between the heating block and the mixer. The extruder assembly is suitable for 3D printing.

Claims

1: An extruder assembly for a three-dimensional printer comprising one nozzle, attached to a heating block, a temperature control element for controlling the temperature of the heating block, a mixer, a heat sink arranged between the heating block and the mixer, and a plurality of feeding means for feeding a plurality of printing material filaments from filament storage means to the mixer and for retracting the printing material filaments from the mixer.

2: The extruder assembly according to claim 1, wherein the extruder assembly is adapted for printing using two printing material filaments, and comprises two feeding means.

3: The extruder assembly according to claim 1, wherein the feeding means comprise a leading tube for leading the filament, mounted with tube connector with a locking element, a stepper motor connected to an extruder cog, and downforce means.

4: The extruder assembly according to claim 3, wherein the downforce system comprises a plurality of shoulders engaged with a plurality of bearings and at least one spring for generating pressure to achieve a stable downforce and to prevent slipping of the printing material filaments.

5: The extruder assembly according to claim 1, wherein the mixer comprises a plurality of input leading channels for inserting the printing material filaments and one output leading channel for feeding the printing material filament further to the nozzle, wherein each input leading channel contacts the output leading channel, and wherein each input leading channel is arranged for accepting the filament from one feeding device.

6: The extruder assembly according to claim 1, wherein the heat sink comprises a tube for leading the printing material filament, and cooling means such as aluminum fins, stainless-steel tubes and/or Peltier element.

7: The extruder assembly according to claim 1, wherein the components of the extruder assembly are arranged on a planar aluminum support.

8: A method of three-dimensional printing using the extruder assembly according to claim 1, wherein a plurality of printing material filaments are fed into the mixer by a plurality of feeding means, whereas a first filament of the printing material to be used for printing is fed by means of the first feeding means through the mixer and heat sink to the heating block where the first filament material is melted and forced out through the nozzle, and when the filament of the printing material is to be changed, the first printing material filament is retracted by means of the feeding means from the heating block and the mixer, and a second printing material filament is fed into the mixer by means of the second feeding means and through the heat sink to the heating block and forced out of the nozzle.

9: The method of claim 8, wherein the printing material filaments include polyvinyl alcohol, polylactic acid, acrylonitrile butadiene styrene, high impact polystyrene filaments.

10: Use of the extruder assembly according to claim 1 in a three-dimensional printer.

11: A three-dimensional printer comprising the extruder assembly according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0028] FIG. 1 is a schematic representation of the extruder assembly described herein below as an example of carrying out the invention.

[0029] FIG. 2 is a schematic representation of the plates forming a mixer.

EXAMPLE OF CARRYING OUT THE INVENTION

[0030] An example of a extruder assembly of the present invention is described herein with reference to FIG. 1.

[0031] The extruder assembly comprises a nozzle 1, a heating block 2 through which a polytetrafluoroethylene tube 3 leads to the nozzle 1, a heat sink 4 separating the heating block 2 from the other components of the extruder assembly, a mixer 5, and two feeding means. Each feeding means contains a dosing motor 9, an extruder cog 8, a leading tube 15, a tube connector 11 with locking element and a tube connector extension 10. The downforce is ensured by bearing 14, pressure shoulders 12 and downforce spring 13 pressing on both pressure shoulders 12.

[0032] The heating block 2 is arranged on a heating block holder 6 and the remaining components of the extruder assembly are arranged on an aluminum planar support 7.

[0033] As shown in FIG. 2, the mixer is composed of two superimposed plates, wherein each plate is provided with two input (shown in the upper part) and one output (in the bottom part of the figure) leading grooves. When the plates are superimposed, the superimposed grooves form input leading channels for the printing material filaments and output leading channels for the printing material filament which is further fed to the nozzle. The mixer is preferably made of a glossy and wear-resistant material.