A method for additive manufacturing is provided, including: mixing a hardener with a sand material, so that the hardener is evenly coated on a surface of the sand material, and then spraying a binder through a nozzle, reacting the binder sprayed through the nozzle with the surface of the sand material evenly coated with the hardener to harden a sand mold. Therefore, the problem of nozzle clogging may be overcome, and a solid with a particle size of less than 0.6 m may be obtained by the additive manufacturing. In addition, the hardening speed can be adjusted according to the size of the sand mold. Compared with a general sand mold product, the hardening speed may be increased and the storage life of the binder may be prolonged when the sand mold has a large size.

A method for producing molding sand includes mixing an artificial sand with a furan resin composition including a furan resin precursor, and mixing a curing agent with the artificial sand with which the furan resin composition is mixed, wherein the curing agent includes xylene sulfonic acid.

The present invention is a granular material that can be well recoated regardless of the type of the granular material, and enables a refractory aggregate in an unprinted portion to be used without any regeneration process, in the manufacture of a three-dimensional laminated and shaped mold. This granular material is a granular material for use in three-dimensional laminated mold shaping, and obtained by adding a material that causes a hydration reaction having a moisture absorbing function and generates a catalytic effect to a coating material mixed with or coated with an acid as a catalyst which activates and hardens an organic binder for binding the granular material.

The invention relates to a method for producing three-dimensionally layered shaped bodies by means of layer-by-layer construction using a resin component which contains at least one furane resin, and more than 5% by weight and less than 50% by weight monomer furfuryl alcohol, and an acid. The shaped bodies produced in this manner are suitable inter alia as casting molds and casting cores for metal casting.

The subject matter of the invention is mold material mixtures for producing molds or cores for metal casting, consisting of at least one refractory base mold material, a binder and an additive based on factice. The invention also relates to a component system, a method for producing molds and cores using the mold material mixtures or the component system respectively, and to molds and cores produced by said method.

Providing a method of modifying refractory particles used to produce a casting mold by using a furan resin as a binder, so as to effectively improve a strength of the casting mold and to reduce a required amount of the binder. An artificial aggregate which is artificially produced and which has an apparent porosity of not more than 5% is used as the refractory particles, and the artificial aggregate is subjected to a heat treatment at a temperature of 400-1500 C. for not shorter than one hour in a heating atmosphere having an oxygen concentration of not higher than 15%.

The present invention relates to a mold material mixture for producing moldings for the foundry industry, in particular for producing foundry molds, cores or feeders for the foundry industry, which comprises A) one or more pourable, refractory fillers, B) a binder system comprising i) formaldehyde, a formaldehyde donor and/or precondensates of formaldehyde and ii) an amino acid. The present invention additionally relates to the use of amino acids in a mold material mixture for producing moldings for the foundry industry or for producing moldings for the foundry industry, a process for producing a mold material mixture and a process for producing a molding for the foundry industry.

A binder system for metal casting has a reactive furan resin, furfuryl alcohol, and a plasticizer that includes an epoxidized fatty acid. The reactive furan resin is a resin modified with phenolic resole, present at from about 18 wt. % to about 22 wt. %, based on the weight of the binder system. The plasticizer may include plant seed oil, such as soybean oil, linseed oil, rapeseed oil, cottonseed oil, sunflower oil and mixtures thereof, present at between about 4 wt. % to about 9 wt. %, based on the weight of the binder system. The furfuryl alcohol and the plasticizer are collectively present in an amount ranging from about 75 wt. % to about 85 wt. %, based on the weight of the binder system. Silane may also be present in an amount from about 0.1 wt. % to about 0.5 wt. %, based on the weight of the binder system.

In order to well perform recoating regardless of the type of granular material and reuse a refractory aggregate in an unprinted portion without any regeneration process in the manufacture of a three-dimensional lamination-shaped mold, this invention provides a granular material for use in shaping a three-dimensional laminated mold, which is coated with an acid as a catalyst which activates and cures an organic binder for binding the granular material. The acid contains at least one of sulfuric acid, phosphoric acid, a sulfonic acid and a carboxylic acid, and is one of a mixture of sulfuric acid and another acid, phosphoric acid only, a mixture of phosphoric acid and another acid, sulfonic acid only, a mixture of sulfonic acid and another acid and a mixture of a carboxylic acid and another acid.

The invention relates to a method of producing an article selected from the group consisting of casting mold, core, feeder and molding compound for production of part of a casting mold, core or feeder, comprising the following steps: (S1) producing or providing in the foundry: a first component (A), comprising a first binder component (b1) of a binder system and an amount of a first mold base material and, spatially separated therefrom, a second component (B), comprising a second binder component (b2) of the binder system and an amount of a second mold base material wherein the first binder component (b1) and the second binder component (b2) are suitable for chemical reaction with one another and for curing of a mixture of the first component (A) and the second component (B), (S2) mixing by contacting the first component (A) and the second component (B) in a particular mass ratio, so as to result in a self-curing molding compound.