WO2023238113A1

WO2023238113A1 - An apparatus for lost foam casting of a metal using vacuum during solidification and an improved method for lost foam casting of a metal using the apparatus

Info

Publication number: WO2023238113A1
Application number: PCT/IB2023/058191
Authority: WO
Inventors: Hamid MOSHAVER; Seyed Mohammad Amin MOUSAVI KHORASANI; Muhammad MAHMOUDI; Javad YAZDI; Reza EMAMI DOUST
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-08-15
Filing date: 2023-08-15
Publication date: 2023-12-14
Anticipated expiration: 2026-02-15

Abstract

An apparatus for lost foam casting of a metal preferably magnesium and an improved method for lost foam casting of a metal preferably magnesium using the apparatus is developed. Using of a multifunction protection door for the sand flask including a inlet valve connected to a neutral gas capsule and a negative pressure applying system with a suctioned gas purification ability along with a non-bonded sand compaction system cause to full-filled the mold and avoid oxidation of the molten magnesium and can solve the viscosity and fluidity problems of the magnesium through maintaining a vacuum condition caused from the negative pressure applying system with a suctioned gas purification ability along with creating a neutral condition, and using of the synergetic effect of the negative pressure applying system with a suctioned gas purification ability and a non-bonded sand compaction system including vibration table and air suction window.

Description

An apparatus for lost foam casting of a metal using vacuum during solidification and an improved method for lost foam casting of a metal using the apparatus

The present disclosure is generally related to lost foam casting of a metal apparatus for production of complex and bulky parts with unique properties, including lightness and high strength, especially an apparatus for lost foam casting of magnesium and an improved method for lost foam casting of a metal using the apparatus.

Casting manufacturing is a process in which liquefied material, such as molten metal, is poured into the cavity of a specially designed mold and allowed to harden. After solidification, the desired-shape metal parts removed from the mold to undergo various finishing treatments or for use as final products. One of typical casting methods is Investment casting, also known as lost-wax casting, a method of producing metal castings by investing a wax pattern with refractory material and a binding agent to shape a disposable ceramic mold, and then pouring molten metal into the mold. Lost-foam casting (LFC) is a newer generation of casting process that is similar to investment casting except foam is used for the pattern instead of wax. This process takes advantage of the low boiling point of polymer foams to simplify the investment casting process by removing the need to melt the wax out of the mold.

For example, in 2000 Kim at.al. optimized the process for AZ91HP magnesium alloy investment casting and in 2009 AZ91 magnesium Alloy based pyramidal lattice sandwich structures were successfully fabricated using the lost foam casting process for the first time by Samson Shing Chung Ho.

This summary is intended to provide an overview of the subject matter of this disclosure, and is not intended to identify essential elements or key elements of the subject matter, nor is it intended to be used to determine the scope of the claimed implementations. The proper scope of this disclosure may be ascertained from the claims set forth below in view of the detailed description below and the drawings.

In a general aspect, the present disclosure is directed to an exemplary apparatus for lost foam casting of a metal preferably magnesium and magnesium alloy for production of complex and bulky a polarity of parts. The exemplary apparatus for lost foam casting of a metal may comprise a sand flask and a negative pressure applying system with a suctioned gas purification ability. The sand flask may comprise a protection door, a non-bonded sand compaction system, a first escape pipe, and a first negative pressure gauge. A lost foam pattern may embedded among a non-bonded sand bath into the sand flask.

The above general aspect may have one or more of the following features. In an exemplary implementation, the protection door may comprise a melt inlet duct, a first covering door, and an inlet valve connected to the neutral gas capsule. In an exemplary implementation, the neutral gas capsule may be an argon gas capsule. In an exemplary implementation, the exemplary apparatus for lost foam casting of a metal may further comprise a non-bonded sand compaction system and an electrical enclosure. In an exemplary implementation, the non-bonded sand compaction system may include a vibration table connected to the sand flask which at least one vibration motor may shake the vibration table and at least one air suction window under the protection door. In an exemplary implementation, the air suction window may include a grid to avoid exhaust of the non-bonded sand and at least one vibration motor. In an exemplary implementation, the negative pressure applying system may comprise a purification tank and a vacuum pump, which the purification tank may configure between the sand flask and the vacuum pump. In an exemplary implementation, a negative pressure amount of the negative pressure applying system may be in a range of 30-80 kilopascal. In an exemplary implementation, the purification tank may include a first gas inlet pipe connected to the first escape pipe of the sand flask, a second escape pipe connected to a second gas inlet pipe of the vacuum pump, vacuum adjustment valve, and a second negative pressure gauge, which the purification tank may semi-fill with a fluid which the first gas inlet pipe may take deep into the fluid. In an exemplary implementation, the fluid may be water. In an exemplary implementation, the metal may comprise aluminum, magnesium, or an alloy of therefor.

In another general aspect, the present disclosure is directed to an exemplary improved method for lost foam casting of a metal using an exemplary apparatus for production of complex and bulky polarity of parts. The exemplary improved method for lost foam casting of a metal may comprise making a first mold by embedding a porosity ceramic coated lost foam pattern among a non-bonded sand bath, obtaining an isolated first mold by applying a sealing film on the first mold, making a mold contained sand flask by putting the isolated first mold into a sand flask, obtaining a compact sand flask by compacting the non-bonded sand bath of the mold contained sand flask by a non-bonded sand compaction method using a non-bonded sand compaction system, creating a first molten metal inlet system by applying a protection door on the compact sand flask wherein the protection door comprising a melt inlet duct, a covering door, and an inlet valve connected to the neutral gas capsule, obtaining an under vacuum molten metal inlet system by applying a negative pressure on the first molten metal inlet system using a negative pressure applying system with a suctioned gas purification ability to establish a vacuum condition in the first molten metal inlet system, wherein the protection door of the first molten metal inlet system may help to maintain the vacuum condition in the first molten metal inlet system, creating a molten metal contained sand flask by casting a molten metal into the compact sand flask of the under vacuum molten metal inlet system through the melt inlet duct of the protection door and then punching the sealing film by the molten metal and opening the inlet valve of the protection door as same time as casting the molten metal to transform a neutral gas into the compact sand flask to avoid oxidation of the molten metal, obtaining a second molten metal inlet system by applying the covering door of the protection door on the molten metal contained sand flask, making a second mold by exiting a plurality of the gases resulted from a thermal decomposition of the porosity ceramic coated lost foam pattern and transferred to the non-bonded sand bath through a first escape pipe of the sand flask connected to a first escape pipe of a purification tank of the negative pressure applying system to fully replacing the porosity ceramic coated lost foam pattern to the molten metal, obtaining a solidified second mold by solidifying the second mold; and exiting the solidified second mold out of the sand flask.

The above general aspect may have one or more of the following features. In an exemplary implementation, the non-bonded sand compaction method may comprise applying a vibration using a vibration table and sucking of the air using an air suction window. In an exemplary implementation, the sealing film may be a plastic sealing film. In an exemplary implementation, the neutral gas capsule may be an argon gas capsule. In an exemplary implementation, a negative pressure amount of the negative pressure applying system may be in a range of 30-80 kilopascal. In an exemplary implementation, a molten temperature of the molten metal is in a range of 810-850 ˚c. In an exemplary implementation, the metal may comprise aluminum, magnesium, or an alloy of therefor.

There are some problems and challenges in using lost foam casting method for production of complex and bulky parts with unique properties such as lightness and high strength. One of the problems of the lost foam casting method of magnesium is lower enthalpy, lower fluidity, higher viscosity and higher oxidation of molten magnesium and magnesium alloys compared to aluminum alloys. In the other words, due to unsuitable enthalpy of magnesium alloys, filling the last foam mold with molten magnesium is a serious problem. Also, lost foam casting method of magnesium alloys face with some serious limitation due to low fluidity as well as high oxidation of molten magnesium alloys.

For solving above mentioned problems an apparatus for lost foam casting of a metal preferably magnesium and magnesium alloys is developed. Designing of a multifunction protection door comprising an inlet valve connected to the neutral gas capsule for a sand flask and a negative pressure applying system with a suctioned gas purification ability can lead to obtain successful magnesium lost foam casting. In the other words, the multifunction protection door of the sand flask with the inlet valve connected to the neutral gas capsule not only can help to maintain a vacuum condition cased from the negative pressure applying system with a suctioned gas purification ability, but also can create a neutral condition in the sand flask to avoid oxidation of the molten magnesium through the inlet valve connected to the neutral gas capsule. In addition, the synergetic effect of using the negative pressure applying system with a suctioned gas purification ability along with a non-bonded sand compaction system including vibration table and air suction window can lead to full-fill of the mold by the molten magnesium and can solve the viscosity and fluidity problems of the magnesium.

An exemplary apparatus for lost foam casting of a metal in the present disclosure has the following advantages:

1. The existence of a multifunction protection door for helping to maintain a suctioned and nutria condition in a sand flask;

2. Using of a negative pressure applying system with a suctioned gas purification ability;
3. Using of vacuum system along with suction system and synergetic effect of therefore;
4. The ability of using the apparatus for a molten metal with a molten temperature of above 810 ˚C.

The drawing figure only demonstrates one or more embodiments in accord with the present teaching, by way of example only, not by way of limitation. Therefore, the drawing figure does not limit the extent of the present disclosure. Also, reference numerals with similar numbers in the figures demonstrate similar or the same elements.

Fig.1

illustrates a schematic view of an apparatus for lost foam casting of a metal, consistent with one or more exemplary embodiments of the present disclosure.

In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent that the present teachings may be practiced without such details. In other instances, well-known processes, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined only by the appended claims.

The following detailed description is presented to enable a person skilled in the art to make and use the processes and devices disclosed in exemplary embodiments of the present disclosure. For purposes of explanation, specific nomenclature is set forth provide a thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that these specific details are not required to practice the disclosed exemplary embodiments. Descriptions of specific exemplary embodiments are provided only as representative examples. Various modifications to the exemplary implementations will be readily apparent to one skilled in the art, and the general principles defined herein may be applied to other implementations and applications without departing from the scope of the present disclosure. The present disclosure is not intended to be limited to the implementations shown, but is to be accorded the widest possible scope consistent with the principles and features disclosed herein.

In an exemplary embodiment, an exemplary apparatus for lost foam casting of a metal may be developed to provide complex and bulky parts with unique properties, such as lightness and high strength. In the exemplary embodiment, an exemplary apparatus.

illustrates an exemplary apparatus for lost foam casting of a metal, consistent with one or more exemplary embodiments of the present disclosure. In an exemplary embodiment, as illustrated in , the exemplary apparatus (100) may comprise a sand flask (102) and a negative pressure applying system with a suctioned gas purification ability, which a lost foam pattern embedded among a non-bonded sand bath into the sand flask (102). In an exemplary embodiment, the metal comprising aluminum, magnesium, or an alloy of therefor.

In an exemplary embodiment, the sand flask (102) may comprise a protection door (104), a non-bonded sand compaction system, a first escape pipe (106), and a first negative pressure gauge (108). In an exemplary embodiment, the protection door (104) may comprise a melt inlet duct (110), a first covering door (112), and an inlet valve (114) connected to the neutral gas capsule (14 6). In an exemplary embodiment, the neutral gas capsule (14 6 ) is an argon gas capsule.

In an exemplary embodiment, the exemplary apparatus (100) may further comprise a non-bonded sand compaction system, at least one vibration absorber (116), at least one vertical holder leg (118), a horizontal holder (120) and an electrical enclosure (122), which the horizontal holder (120) may be connected to the holder leg (118) and the holder leg (118) may be connected to the vibration absorber (116) and vibration absorber (116) may be connected to the non-bonded sand compaction system to stabilization of the exemplary apparatus (100). In an exemplary embodiment, the non-bonded sand compaction system may include a vibration table (124) connected to the sand flask (102) and at least one air suction window protection door (104). In an exemplary embodiment, the air suction window may include a grid to avoid exhaust of the non-bonded sand and at least one suction motor (128).

In an exemplary embodiment, the negative pressure applying system may comprise a purification tank (130), a vacuum pump (132) and a fluid tank (148), wherein the vacuum pump (132) may be connected to the fluid tank (148). In an exemplary embodiment, the purification tank (130) may configure between the sand flask (102) and the vacuum pump (132). In an exemplary embodiment, a negative pressure amount of the negative pressure applying system is in a range of 30-80 kilopascal. In an exemplary embodiment, the purification tank (130) may include a first gas inlet pipe (134) connected to the first escape pipe (106) of the sand flask (102), a second escape pipe (136) connected to a second gas inlet pipe (138) of the vacuum pump (132), vacuum adjustment valve (140), a second covering door (142) and a second negative pressure gauge (14 4), wherein the purification tank may semi-fill with a fluid which the first gas inlet pipe (134) may take deep into the fluid. In an exemplary embodiment, the fluid may be water.

Furthermore, the present disclosure describes an exemplary improved method for lost foam casting of a metal using an exemplary apparatus (100). In an exemplary embodiment, the exemplary improved method may comprise making a first mold by embedding a porosity ceramic coated lost foam pattern among a non-bonded sand bath, obtaining an isolated first mold by applying a sealing film on the first mold, making a mold contained sand flask by putting the isolated first mold into a sand flask (102); obtaining a compact sand flask by compacting the non-bonded sand bath of the mold contained sand flask by a non-bonded sand compaction method using a non-bonded sand compaction system, creating a first molten metal inlet system by applying a protection door (104) on the compact sand flask wherein the protection door (104) may comprise a melt inlet duct (110), a first covering door (112), and an inlet valve (114) connected to the neutral gas capsule (14 6 ), obtaining an under vacuum molten metal inlet system by applying a negative pressure on the first molten metal inlet system using a negative pressure applying system with a suctioned gas purification ability to establish a vacuum condition in the first molten metal inlet system, wherein the protection door (104) of the first molten metal inlet system may help to maintain the vacuum condition in the first molten metal inlet system, creating a molten metal contained sand flask by casting a molten metal into the compact sand flask of the under vacuum molten metal inlet system through the melt inlet duct (110) of the protection door and then punching the sealing film by the molten metal and opening the inlet valve (114) of the protection door as same time as casting the molten metal to transform a neutral gas into the compact sand flask to avoid oxidation of the molten metal, obtaining a second molten metal inlet system by applying the first covering door (112) of the protection door (104) on the molten metal contained sand flask, making a second mold by exiting a plurality of the gases resulted from a thermal decomposition of the porosity ceramic coated lost foam pattern and transferred to the non-bonded sand bath through a first escape pipe (106) of the sand flask (102) connected to a first escape pipe of a purification tank (130) of the negative pressure applying system to fully replacing the porosity ceramic coated lost foam pattern to the molten metal, obtaining a solidified second mold by solidifying the second mold, and exiting the solidified second mold out of the sand flask.

In an exemplary embodiment, the non-bonded sand compaction method may comprise applying a vibration using a vibration table and sucking of the air using an air suction window. In an exemplary embodiment, the sealing film may be a plastic sealing film. In an exemplary embodiment, the neutral gas capsule (14 6 ) may be an argon gas capsule. In an exemplary embodiment, a negative pressure amount of the negative pressure applying system may be in a range of 30-80 kilopascal. In an exemplary embodiment, a molten temperature of the molten metal may be in a range of 810-850 ˚c. In an exemplary embodiment, the metal may comprise aluminum, magnesium, or an alloy of therefor.

Examples

EXAMPLE 1: Conducting A Test On An E xemplary A pparatus (100) Using An Exemplary Improved Method For Lost foam Casting Of A Magnesium

In Example 1 , a test was conducted on a casting of magnesium utilizing an exemplary apparatus (100), by using of an exemplary method consistent with the teachings of the exemplary embodiments of the present disclosure. After preparation of a desired porosity ceramic coated lost foam pattern and embedding it among a non-bonded sand bath into a sand flask (102), the molten magnesium with a molten temperature of 830 ˚c cast into the sand flask (102) through a melt inlet duct (110). A complex and bulky magnesium part with unique properties, such as lightness and high strength successfully fabricated due to using of a multifunction protection door (104) of the sand flask (102) with a inlet valve (114) connected to a neutral gas capsule (14 6 ) and a negative pressure applying system with a suctioned gas purification ability along with a non-bonded sand compaction system which cause to full-filled the mold and avoid oxidation of molten magnesium.

While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this subject matter described herein. Furthermore, it is to be understood that the invention is solely defined by the appended claims. It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations or two

It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein. Relational terms such as first, second, and third and the like may be used solely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” “include,” “including,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, apparatus, or device that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, apparatus, or device. An element proceeded by “a” or “an” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or device that comprises the element. Moreover, “may” and other permissive terms are used herein for describing optional features of various embodiments. These terms likewise describe selectable or configurable features generally, unless the context dictates otherwise.

An exemplary apparatus (100) and an exemplary improved method for lost foam casting of a metal in the present disclosure is practical for use in various industries, such as automotive, oil and gas, military, aerospace industries and any industries which need the complex and bulky metal parts with unique properties, such as lightness, uniform surface and high strength.

Claims

An apparatus for lost foam casting of a metal comprising:
a sand flask comprising a protection door, a non-bonded sand compaction system, a first escape pipe, and a first negative pressure gauge; and
a negative pressure applying system with a suctioned gas purification ability, wherein a lost foam pattern embedded among a non-bonded sand bath into the sand flask.
The apparatus for lost foam casting of claim 1, wherein the protection door comprising a melt inlet duct, a first covering door, and an inlet valve connected to the neutral gas capsule.
The apparatus for lost foam casting of claim 2, wherein the neutral gas capsule is an argon gas capsule.
The apparatus for lost foam casting of claim 1, further comprising a non-bonded sand compaction system and an electrical enclosure, wherein the non-bonded sand compaction system including a vibration table connected to the sand flask and at least one air suction window under the protection door, wherein the air suction window including a grid to avoid exhaust of the non-bonded sand and at least one suction motor.
The apparatus for lost foam casting of claim 1, wherein the negative pressure applying system comprising a purification tank and a vacuum pump, wherein the purification tank configured between the sand flask and the vacuum pump.
The apparatus for lost foam casting of claim 5, wherein a negative pressure amount of the negative pressure applying system is in a range of 30-80 kilopascal.
The apparatus for lost foam casting of claim 1 and 5, wherein the purification tank including a first gas inlet pipe connected to the first escape pipe of the sand flask, a second escape pipe connected to a second gas inlet pipe of the vacuum pump, vacuum adjustment valve, and a second negative pressure gauge, wherein the purification tank semi-filled with a fluid which the first gas inlet pipe taken deep into the fluid.
The apparatus for lost foam casting of claim 5, wherein the fluid is water.
The apparatus for lost foam casting of claim 1, wherein the metal comprising aluminum, magnesium, or an alloy of therefor.
An improved method for lost foam casting of a metal using an apparatus of any one of claims 1 to 9 comprising:
making a first mold by embedding a porosity ceramic coated lost foam pattern among a non-bonded sand bath;
obtaining an isolated first mold by applying a sealing film on the first mold;
making a mold contained sand flask by putting the isolated first mold into a sand flask;
obtaining a compact sand flask by compacting the non-bonded sand bath of the mold contained sand flask by a non-bonded sand compaction method using a non-bonded sand compaction system;
creating a first molten metal inlet system by applying a protection door on the compact sand flask wherein the protection door comprising a melt inlet duct, a covering door, and an inlet valve connected to the neutral gas capsule;
obtaining an under vacuum molten metal inlet system by applying a negative pressure on the first molten metal inlet system using a negative pressure applying system with a suctioned gas purification ability to establish a vacuum condition in the first molten metal inlet system, wherein the protection door of the first molten metal inlet system help to maintain the vacuum condition in the first molten metal inlet system;
creating a molten metal contained sand flask by casting a molten metal into the compact sand flask of the under vacuum molten metal inlet system through the melt inlet duct of the protection door and then punching the sealing film by the molten metal and opening the inlet valve of the protection door as same time as casting the molten metal to transform a neutral gas into the compact sand flask to avoid oxidation of the molten metal;
obtaining a second molten metal inlet system by applying the covering door of the protection door on the molten metal contained sand flask;
making a second mold by exiting a plurality of the gases resulted from a thermal decomposition of the porosity ceramic coated lost foam pattern and transferred to the non-bonded sand bath through a first escape pipe of the sand flask connected to a first escape pipe of a purification tank of the negative pressure applying system to fully replacing the porosity ceramic coated lost foam pattern to the molten metal;
obtaining a solidified second mold by solidifying the second mold; and
exiting the solidified second mold out of the sand flask.
An improved method for lost foam casting 10, wherein the non-bonded sand compaction method comprising applying a vibration using a vibration table and sucking of the air using an air suction window.
An improved method for lost foam casting 10, wherein the sealing film is a plastic sealing film.
An improved method for lost foam casting 10, wherein the neutral gas capsule is an argon gas capsule.
An improved method for lost foam casting 10, wherein a negative pressure amount of the negative pressure applying system is in a range of 30-80 kilopascal.
An improved method for lost foam casting 10, wherein a molten temperature of the molten metal is in a range of 810-850 ˚c.
An improved method for lost foam casting 10, wherein the metal comprising aluminum, magnesium, or an alloy of therefor.