Object made by additive manufacturing and method to produce said object

Abstract

A three-dimensional object created by Fused Deposition Modeling (FDM) of a modeling material from polyaryletherketones (PAEK), polyphenylsulfides, polyamide-imide, polyethersulfon, polyetherimide, polysulfon, polyphenylsulfon, polycarbonates (PC), polyacrylonitrile butadiene styrene) (ABS), polymethylmethacrylate (PMMA), polyethyleneterephtalate (PET), polystryrene (PS), acrylonitrilstyrene acrylate, polypropylene (PP), polylactic acid (PLA), polyvinylalcohol (PVA), polyethylene (PE), polyoxymethylene, polyurethane (PU), copolymers of polyvinylalcohol and butenediolvinylalcohol and mixtures thereof, optionally filled with inorganic or organic fillers, wherein the object has a porosity of less than 5 vol %, as determined according to the porosity test procedure ‘Porosity test’. The objects are leak tight and show improved mechanical properties. FDM printing of PEEK generating parts having high isotropy.

Description

FIELD OF THE INVENTION[0001]The invention relates to a three-dimensional object made by additive manufacturing of a modeling material, like for example a thermoplastic polymer composition.BACKGROUND OF THE INVENTION[0002]In additive manufacturing objects are formed by layering modeling material in a controlled manner such that a desired three-dimensional shaped object can be created. Very often for additive manufacturing an additive manufacturing printer is used. The printer has a two or three dimensionally moveable printhead which dispenses the modeling material, while the printhead is moved over previously deposited tracks of the modeling material. A preferred examples of additive manufacturing is fused deposition modeling (FDM).[0003]The object to be printed can be placed on a base. The printhead is movable in a three-dimensional space relative to the object being modeled or printed or vice versa. In some cases, the object is movable in one or more dimensions relative to the prin...

AI Technical Summary

Benefits of technology

Results in three-dimensional objects with significantly reduced porosity, improved leak-tightness, and enhanced mechanical properties, with ultimate tensile strength in the Z-direction comparable to the X and Y directions, achieving high isotropic strength and preventing debris formation.

Problems solved by technology

When the gap between the printhead nozzle and the previously deposited layer for example increases due to lack of calibration, the flow of modeling material can become too small to fill up the gap, thereby causing the occurrence of spaces between the printed tracks, resulting in cavities in the printed object.

On the other hand, when the gap between the printhead nozzle and the previously deposited layers decreases due to lack of calibration, the flow of modeling material can become too high for the track being deposited, so too much material will be extruded.

This may result in excessive forces between the object and the printhead and in a rough surface of the object due to overflow of the modeling material.

The overflow of modeling material may lead to debris or residue on the nozzle tip of the printhead which may come off the nozzle tip and fuse with the object being printed and cause potential loss of the object.

Also, the print head smears over the object being printed, causing a very rough top surface of the object and excessive forces which ultimately cause the object from breaking loose from the build plate.

Loss of calibration may also be caused by thermal expansion while printing and subsequent shrinking after printing of thermally fused material.

When the thermal expansion and shrinking are insufficiently compensated, the gap between nozzle and previously deposited layers may not have constant dimensions.

Another cause of under- or over extrusion may lie in variation of the modeling material feedstock dimensions.

When for example filament of modeling material is used, its diameter may vary causing variations in the amount of modeling material deposited when printing, giving cause to under-or over-extrusion when using constant flow control of the modeling material being deposited.

When performing the calibration of the X-Y-Z system and of the feeding means of the modeling material, the highest priority is to prevent over-extrusion, since this will make the process unreliable.

Therefore, additive manufacturing (like fused deposition modeling) extrusion printers usually have some degree of under-extrusion causing formation of open spaces or cavities.

Generally, the mechanical properties of an object prepared by fused deposition modelling (FDM) of a modeling material (like for example a thermoplastic polymer composition) are less favorable than an object with the same dimensions made by injection molding.

The polymer chains of the new layer have a limited possibility to entangle with the solidified material of the existing layer, and also bonding with the existing layer will be limited.

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