A method of generating a mold and using it for printing a three-dimensional object

Abstract

This invention relates to three-dimensional printing. This invention in particular relates to a method of generating mold and printing a three-dimensional object. The mold thickness is controlled and holes are generated in the mold surface for releasing moisture easily. The mold surface having holes is designed initially digitally and then combined with the three-dimensional model before printing the three-dimensional object. In case the thickness of the mold surface is more then it reduces the overall quality of the three-dimensional object. When the model is enclosed inside the mold, there will be some residue moisture in the model even if the drying apparatus can improve this by drying layer by layer. This affects the final quality of the part. A solution of these problems is provided in the present invention. The thickness of the mold layer is between 0.5 to 1 mm and holes having 0.1 to 0.4 mm diameter. The holes are evenly distributed on the mold. The mold having the holes is prepared from which moisture can easily escape. A method of digitally generated a mold having thin layer and holes is used for fabricating three dimensional objects with high precision and quality.

Description

FIELD OF THE INVENTION[0001]The present invention generally relates to the field of three-dimensional (also “3-D”) printing of objects based on a crafting medium and molding techniques. The invention, particularly relates to a method of generating a mold (“mould”) and printing a three dimensional object. An advantage of the present invention is that it provides a mold of desired skin thickness for containing a crafting medium. The mold thickness is controlled during via the printing process. Furthermore, perforations or holes are generated in the mold surface to facilitate drying and moisture release after printing.BACKGROUND OF THE INVENTION[0002]Three-dimensional printers are used to build solid models by performing layer by layer printing of building materials. The building material can be of different forms, such as liquids or semi-liquids at the three-dimensional printhead. For example, a solid material can be heated and then extruded from a three-dimensional printer nozzle. Th...

AI Technical Summary

Benefits of technology

[0001]The present invention generally relates to the field of three-dimensional (also “3-D”) printing of objects based on a crafting medium and molding techniques. The invention, particularly relates to a method of generating a mold (“mould”) and printing a three dimensional object. An advantage of the present invention is that it provides a mold of desired skin thickness for containing a crafting medium. The mold thickness is controlled during via the printing process. Furthermore, perforations or holes are generated in the mold surface to facilitate drying and moisture release after printing.

[0002]Three-dimensional printers are used to build solid models by performing layer by layer printing of building materials. The building material can be of different forms, such as liquids or semi-liquids at the three-dimensional printhead. For example, a solid material can be heated and then extruded from a three-dimensional printer nozzle. The layers of building materials can be solidified on a substrate. Three-dimensional printer systems can use a fused filament fabrication (FFF) process (sometimes called fused deposition modeling (FDM) process) in which a filament is moved by a filament moving mechanism, toward a heated zone. The filament can be melted and extruded on a platform to form a three-dimensional object. The melted filament can have the disadvantage of adhering to the walls of the heated printhead, resulting in deformed printed lines. A commercially available FFF system uses a heated nozzle to extrude a melted material like a plastic wire. The starting material is in the form of a filament which is being supplied from a spool. The filament is introduced into a flow passage of the nozzle and is driven to move like a piston inside this flow passage. The front end, near the nozzle tip, of this piston is heated to become melted. The rear end or solid portion of this piston pushes the melted portion forward to exit through the nozzle tip. The nozzle is translated under the control of a computer system in accordance with previously generated computer-aided design (CAD) data sliced into constituent layers. Further, the additive manufacturing devices and processes are largely used for creating very complex three-dimensional objects and also for creating body part materials. In known physical reconstructing methods, a CAD system either is directly sending signals to the devices or converting it to the any suitable file format. Various additive techniques are used for three-dimensional printing.

[0003]The manufacturing of precision components is performed with exceptional control and either post process characterization or in situ characterization or both. For larger or complex structures it is very challenging, or not even possible, to make very large or complex objects with exceptional precision. For achieving high quality and precision, it is important to prepare digitally generated molds, to print the molds having high quality, while also leaving no residue on the surface of the object upon removal of the mold material.

[0004]A number of different types of accessories for three-dimensional printing are available in the prior art. For example, the following patents are provided for their supportive teachings and are all incorporated by reference: Prior art document, EP3301597 discloses a method for computationally designing a re-usable flexible mold having a verified cut layout for reproduction of objects having rich surface details or complex shape structures. The re-usable flexible mold is prepared by three-dimensional printing. The mold has a wall thickness between 1 to 5 mm, more preferably between 2 to 3 mm, and further the mold wall also has holes. The reference appears to disclose a liquid casting material but does not appear to disclose the use of a paste or crafting material in conjunction with the mold. Further, the reference does not appear to disclose either the formation of a removable mold or the use of any crafting medium.

[0005]Another prior art document, IN201621002997 discloses a device for controlling particle collection in a continuously flowing multi-particle water-based liquid-particle suspension system. The reference appears to discuss the incorporation of holes with a mold and also discloses fabrication of the mold by three-dimensional printing. However, this prior art document does not appear to discuss a layer-by-layer deposition and the use of crafting material.

[0006]Yet another prior art document, U.S. Pat. No. 5,121,329 discloses an apparatus for making three-dimensional physical objects of a predetermined shape by sequentially depositing multiple layers of a solidifying material on a base member in a desired pattern. The reference does not appear to disclose the formation of a mold or the use of any crafting medium.

Problems solved by technology

The melted filament can have the disadvantage of adhering to the walls of the heated printhead, resulting in deformed printed lines.

For larger or complex structures it is very challenging, or not even possible, to make very large or complex objects with exceptional precision.

Further, the reference does not appear to disclose either the formation of a removable mold or the use of any crafting medium.

However, this prior art document does not appear to discuss a layer-by-layer deposition and the use of crafting material.

Further, this prior art document does not appear to discuss the use of a crafting material paste.

However, the prior art document does not appear to discuss the use of paste crafting materials.

Separation is challenging given the vast surface area.

Small holes are induced throughout the mold however, the purpose of preparing the holes is to remove the dish, and not to facilitate drying of the object or evaporation of solvents.

The problem which needs to be addressed here is that the paste needs to be dried evenly to avoid cracks.

Also, the method for building the 3D model by extruding a crafting medium in parallel with a molding material as described in the prior art document, SE1500245, is difficult to use for some heavy geometries or overhanging geometries.

However, above mentioned references and many other similar references have one or more of the following shortcomings: (a) do not adequately discuss the preparation of a re-usable mold; (b) employ a thick layer of the mold for preparing complex structures whereby the subsequent removal of the mold to provide a high quality surface area is challenging; (c) do not discuss a molding technique; (b) do not discussing the use of a paste form of a building or crafting medium; (d) these prior art three-dimensional printing methods use a powder clay which is mixed with water and printed out on a layer by layer basis using a syringe to obtain ceramic objects; (e) the resulting ceramic objects can have low resolution; (f) finishing of the final three-dimensional printed object is not satisfactory; (g) digital mold generation is not disclosed; (h) comparison of the digital mold and digitally generated three-dimensional model is not disclosed; and (i) the purpose and utility for making holes is for mold removal.

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