Disclosure of Invention
The invention aims to provide an investment casting process based on 3D printing and rapid forming, which solves the problems of the existing 3D printing castable photosensitive resin and investment casting in the background technology.
In order to achieve the above purpose, the invention provides a technical scheme that an investment casting process based on 3D printing and rapid forming comprises the following steps:
S1, building three-dimensional model data of a product;
s2, printing a model;
s3, model pretreatment;
s4, installing a riser;
S5, manufacturing a shell;
S6, dewaxing and roasting;
S7, pouring.
Preferably, in the step S1, the specific step of creating the three-dimensional model data of the product is:
a) Adopting Computer Aided Design (CAD) software or a scanner and other tools to design a three-dimensional model of the product according to the structure, the size and the material requirements of the product;
b) The three-dimensional model data is converted into a data format suitable for recognition by a 3D printer.
Preferably, in the step S2, the specific steps of the printing model are as follows:
a) Selecting proper printing materials such as fusible resin or wax according to the data obtained in the step S1 by adopting a 3D printer;
b) And printing out a fusible model with the same shape as the product in a layer superposition mode.
Preferably, in the step S3, the specific steps of the model preprocessing are as follows:
a) Carrying out surface treatment such as support removal, trimming, polishing and the like on the fusible model obtained in the step S2, so that the surface of the fusible model is smooth and defect-free;
b) And detecting whether the dimensional accuracy and the surface quality of the treated fusible model meet the requirements.
Preferably, in the step S4, the specific step of installing the riser is:
a) After checking that the surface and the tissue of the model in the step S3 are defect-free, adhering a riser at a pre-designed riser position;
b) After the riser is bonded, the model, the riser and the joint are checked and confirmed to have no adhesive and gaps left.
Preferably, in the step S5, the specific steps of shell making are as follows:
a) Immersing or spraying a layer of viscous liquid coating on the fusible module obtained in the step S4, uniformly scattering a layer of fine refractory particles such as ceramic powder or gypsum powder on the surface of the fusible module, and then placing the fusible module into a drying chamber for drying and curing;
b) This step is repeated several times until a refractory shell of sufficient thickness and strength is formed on the fusible module surface.
Preferably, in the step S6, the specific steps of dewaxing and roasting are as follows:
a) Putting the fire-resistant shell obtained in the step S5 into high-temperature steam or hot water for heating, so that the fusible module in the fire-resistant shell is melted or dissolved and flows out, and leaving a hollow fire-resistant shell;
b) Placing the fire-resistant shell into a high-temperature kiln for roasting treatment to remove residues and moisture and improve the strength and fire resistance
Preferably, in the step S7, the concrete steps of pouring are as follows:
a) Placing the refractory shell obtained in the step S6 on a pouring table, and fixing the refractory shell by using fillers such as sand; heating the required metal material to a liquid state, and pouring the metal material into the refractory shell from a pouring gate according to a certain temperature and speed;
b) And after the molten metal is solidified, the required metal casting is obtained.
Compared with the prior art, the invention has the beneficial effects that:
1. The precision of the 3D printing model adopted in the investment casting process based on the 3D printing rapid forming is higher than that of a common wax matrix model, and the model structure is more complex and changeable because the investment casting process is not limited by a wax paste injection method;
2. The investment casting process based on 3D printing rapid forming adopts a 3D printing model with higher strength than a common wax-based model, and the model is not easy to be damaged, broken and scratched on the surface in the processes of molding, shell manufacturing, transportation and the like;
3. The investment casting process based on 3D printing rapid forming adopts a 3D printing model, and ash content after high-temperature roasting is extremely low;
4. the investment casting procedure based on the 3D printing rapid forming is in small-batch production and scientific experiments, because the traditional wax pattern or injection mold does not need to be manufactured and stored, the manpower resources and time can be saved, the production efficiency is obviously improved, and the cost is reduced.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific direction, be configured and operated in the specific direction, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "provided," "connected," and the like are to be construed broadly, and may be fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Referring to fig. 1, the present invention provides a technical solution: an investment casting process based on 3D printing rapid prototyping, comprising the following steps:
S1, building three-dimensional model data of a product;
s2, printing a model;
s3, model pretreatment;
s4, installing a riser;
S5, manufacturing a shell;
S6, dewaxing and roasting;
S7, pouring.
Specifically, the defects and difficulties in the prior art can be greatly improved by adding a 3D printing technology, the 3D printing technology is a technology for designing a three-dimensional model of a product by utilizing tools such as Computer Aided Design (CAD) software or a scanner and the like according to the structure, the size and the material requirements of the product, converting the three-dimensional model into a data format suitable for being identified by a 3D printer, and then printing a fusible model with the same shape as the product by using the 3D printer in a layer superposition mode, wherein the 3D printing technology applicable to investment casting mainly has two types: stereolithography (SLA) and multi-jet ink jet (MJP). The SLA is a 3D printing technology using ultraviolet light to solidify liquid resin, which can generate a fusible model with a hollow structure and an exhaust hole, called QuickCast, and the mxp is a 3D printing technology using a spray nozzle to spray wax material, which can generate a fusible model with 100% wax, called RealWax.
In the step S1, the specific steps for establishing the three-dimensional model data of the product are as follows:
a) Adopting Computer Aided Design (CAD) software or a scanner and other tools to design a three-dimensional model of the product according to the structure, the size and the material requirements of the product;
b) The three-dimensional model data is converted into a data format suitable for recognition by a 3D printer.
In the step S2, the specific steps of the printing model are as follows:
a) Selecting proper printing materials such as fusible resin or wax according to the data obtained in the step S1 by adopting a 3D printer;
b) And printing out a fusible model with the same shape as the product in a layer superposition mode.
Specifically, in step S2, the 3D printer may use a stereoscopic light curing (SLA) or multi-jet ink jet (MJP) type, and the printing material is a resin or wax material that can be completely burned out or gasified, so that residues or pollutants can be avoided during dewaxing and roasting, and the quality of the shell and the surface quality of the casting can be improved.
In the step S3, the specific steps of the model preprocessing are as follows:
a) Carrying out surface treatment such as support removal, trimming, polishing and the like on the fusible model obtained in the step S2, so that the surface of the fusible model is smooth and defect-free;
b) And detecting whether the dimensional accuracy and the surface quality of the treated fusible model meet the requirements.
Specifically, in the step S3, the surface treatment such as supporting, trimming, polishing and the like may be performed manually or mechanically, or may be performed chemically or physically, such as solvent soaking, ultrasonic cleaning, laser polishing and the like, so as to remove defects such as supporting structures, burrs, gaps and the like generated during the printing process, and improve the surface smoothness and flatness of the model.
In the step S4, the concrete steps of installing the riser are as follows:
a) After checking that the surface and the tissue of the model in the step S3 are defect-free, adhering a riser at a pre-designed riser position;
b) After the riser is bonded, the model, the riser and the joint are checked and confirmed to have no adhesive and gaps left.
Specifically, before installing the riser, a slot may be drilled or cut in the model to connect with the riser system, so as to enhance the bonding strength between the model and the riser and prevent breakage or air leakage during the shell making or casting process, in step S4, the casting system components such as the riser and the gate may be made of the same or similar material as the fusible model, or may be made of a different material from the fusible model, such as metal or ceramic, and the connection or welding method may be a different method such as mechanical connection, thermal connection, adhesion, and the like, and an appropriate connection or welding method may be selected according to the material characteristics and shapes of the fusible model and the casting system components.
In the step S5, the specific steps of shell making are as follows:
a) Immersing or spraying a layer of viscous liquid coating on the fusible module obtained in the step S4, uniformly scattering a layer of fine refractory particles such as ceramic powder or gypsum powder on the surface of the fusible module, and then placing the fusible module into a drying chamber for drying and curing;
b) This step is repeated several times until a refractory shell of sufficient thickness and strength is formed on the fusible module surface.
Specifically, before shell making, a layer of release agent can be coated on the surface of the model to prevent the slurry from adhering to the model, so that damage to the model in the dewaxing process can be reduced, the integrity and stability of the model can be maintained, in the S5 step, the viscous liquid coating can be made of silica sol, water glass, resin and other different materials, a proper coating formula can be selected according to the strength and the fire resistance required by the fire-resistant model, fine fire-resistant particles can be made of ceramic powder, gypsum powder, silicon carbide and other different materials, and proper particle size and distribution can be selected according to the thickness and the roughness required by the fire-resistant model.
Specifically, the investment structure can be immersed into the slurry in advance during shell making, and the slurry can be water-based or alcohol-based ceramic slurry containing an adhesive and a dispersing agent, so that the fluidity and wettability of the slurry can be improved, the surface of the model can be better covered, and a uniform, compact and bubble-free ceramic layer can be formed.
In the step S6, the specific steps of dewaxing and roasting are as follows:
a) Putting the fire-resistant shell obtained in the step S5 into high-temperature steam or hot water for heating, so that the fusible module in the fire-resistant shell is melted or dissolved and flows out, and leaving a hollow fire-resistant shell;
b) The fire-resistant shell is put into a high-temperature kiln for roasting treatment, so that residues and moisture are removed, and the strength and fire resistance of the fire-resistant shell are improved.
Specifically, the heating in high-temperature steam or hot water can be performed by adopting different equipment and methods such as a steam boiler, an autoclave, microwave heating and the like, the proper heating temperature and time are selected according to the material characteristics and the size of the fusible module, the roasting treatment in the high-temperature kiln can be performed by adopting different equipment and methods such as resistance heating, induction heating, gas heating and the like, and the proper roasting temperature and time are selected according to the material characteristics and the size of the refractory shell.
Specifically, dewaxing and roasting are carried out simultaneously, namely, the ceramic shell is directly put into a high-temperature kiln, so that printing materials in the ceramic shell are burnt out or gasified at high temperature and discharged, thus shortening the working procedure time, reducing the energy consumption and reducing the environmental pollution.
In the step S7, the concrete steps of pouring are as follows:
a) Placing the refractory shell obtained in the step S6 on a pouring table, and fixing the refractory shell by using fillers such as sand; heating the required metal material to a liquid state, and pouring the metal material into the refractory shell from a pouring gate according to a certain temperature and speed;
b) And after the molten metal is solidified, the required metal casting is obtained.
Specifically, the molten metal can be aluminum alloy, magnesium alloy, titanium alloy, steel or other metals or alloys, so that the casting of different materials can be realized according to the application and performance requirements of the casting.
Example 1
A 3D printing investment casting process for manufacturing an automotive transmission housing comprising the steps of:
s1, establishing three-dimensional model data of a gearbox shell, adopting CAD software, designing a three-dimensional solid model of the gearbox shell according to the structure, the size and the material requirements of the gearbox shell, and converting the three-dimensional solid model into an STL format;
S2, printing a model, namely selecting QuickCast resin as a printing material by adopting a SLA type 3D printer, and printing a fusible model with a hollow structure identical to the shape of the gearbox shell in a laminating mode;
s3, model pretreatment, namely carrying out surface treatment such as support removal, trimming, polishing and the like on the printed fusible model to enable the surface of the fusible model to be smooth and defect-free, and detecting whether the dimensional accuracy and the surface quality of the fusible model meet the requirements;
s4, installing a riser, drilling or cutting a groove on the fusible model so as to be connected with a riser system, and coating an adhesive on the connection part to form an integral fusible module;
S5, manufacturing a shell, namely coating a layer of isolating agent on the surface of the fusible module to prevent the slurry from adhering to the module, immersing the fusible module in water-based ceramic slurry containing an adhesive and a dispersing agent, uniformly scattering a layer of fine ceramic powder on the surface of the fusible module, and then placing the fusible module in a drying chamber for drying and curing; repeating the steps for a plurality of times until a layer of fire-resistant shell with enough thickness and strength is formed on the surface of the fusible module;
s6, dewaxing and roasting, namely directly putting the fireproof shell into a high-temperature kiln, heating to about 800 ℃, burning out or gasifying the fusible module in the fireproof shell at high temperature to discharge the fusible module, continuously heating the fireproof shell to about 1200 ℃ for roasting treatment, removing residues and moisture, and improving the strength and the fireproof performance of the fireproof shell;
S7, pouring, namely placing the refractory shell on a pouring table, and fixing the refractory shell by using fillers such as sand; heating the required aluminum alloy material to about 750 ℃, and pouring the aluminum alloy material into a refractory shell from a pouring gate according to a certain temperature and speed; and after the aluminum alloy liquid is solidified, obtaining the required aluminum alloy gearbox shell.
Example two
A 3D printing investment casting process for manufacturing an aircraft engine turbine blade comprising the steps of:
s1, establishing three-dimensional model data of a turbine blade, adopting tools such as a scanner and the like, scanning out a three-dimensional solid model of the turbine blade according to the structure, the size and the material requirements of the turbine blade, and converting the three-dimensional solid model into an OBJ format;
S2, printing a model, namely adopting a 3D printer of an MJP type, selecting RealWax wax materials as printing materials, and printing out a fusible model with 100% wax, which has the same shape as the turbine blade, in a laminating mode;
s3, model pretreatment, namely carrying out surface treatment such as support removal, trimming, polishing and the like on the printed fusible model to enable the surface of the fusible model to be smooth and defect-free, and detecting whether the dimensional accuracy and the surface quality of the fusible model meet the requirements;
s4, installing a riser, adhering the riser to the fusible model to form an integral fusible module, and smearing adhesive at the joint;
S5, manufacturing a shell, namely coating a layer of isolating agent on the surface of the fusible module to prevent the slurry from adhering to the module, immersing the fusible module in alcohol-based ceramic slurry containing an adhesive and a dispersing agent, uniformly scattering a layer of fine ceramic powder on the surface of the fusible module, and then placing the fusible module in a drying chamber for drying and curing; repeating the steps for a plurality of times until a layer of fire-resistant shell with enough thickness and strength is formed on the surface of the fusible module;
S6, dewaxing and roasting, namely putting the fireproof shell into high-temperature steam or hot water for heating, so that the fusible module in the fireproof shell is dissolved and flows out, and a hollow fireproof shell is left; then placing the fireproof shell into a high-temperature kiln for roasting treatment, removing residues and moisture, and improving the strength and fireproof performance of the fireproof shell;
s7, pouring, namely placing the refractory shell on a pouring table, and fixing the refractory shell by using fillers such as sand; heating the required titanium alloy material to about 1700 ℃, and pouring the titanium alloy material into a refractory shell from a pouring gate according to a certain temperature and speed; and after the titanium alloy liquid is solidified, obtaining the required titanium alloy turbine blade.
Example III
A 3D printing investment casting process for manufacturing a medical prosthetic joint, comprising the steps of:
S1, establishing three-dimensional model data of an artificial joint, adopting CAD software or a scanner and other tools, designing a three-dimensional solid model of the artificial joint according to the structure, the size and the material requirements of the artificial joint, and converting the three-dimensional solid model into an STL or OBJ format;
s2, printing a model, namely adopting a 3D printer of the SLA or MJP type, selecting QuickCast resin or RealWax wax as a printing material, and printing a fusible model with the same shape as the artificial joint in a laminating mode;
s3, model pretreatment, namely carrying out surface treatment such as support removal, trimming, polishing and the like on the printed fusible model to enable the surface of the fusible model to be smooth and defect-free, and detecting whether the dimensional accuracy and the surface quality of the fusible model meet the requirements;
s4, installing a riser, adhering the riser to the fusible model to form an integral fusible module, and smearing adhesive at the joint;
s5, manufacturing a shell, namely coating a layer of isolating agent on the surface of the fusible module to prevent the slurry from adhering to the module, immersing the fusible module in water-based or alcohol-based ceramic slurry containing an adhesive and a dispersing agent, uniformly scattering a layer of fine ceramic powder on the surface of the fusible module, and then placing the fusible module in a drying chamber for drying and curing; repeating the steps for a plurality of times until a layer of fire-resistant shell with enough thickness and strength is formed on the surface of the fusible module;
S6, dewaxing and roasting, namely putting the fireproof shell into high-temperature steam or hot water for heating, so that the fusible module in the fireproof shell is dissolved and flows out, and a hollow fireproof shell is left; then placing the fireproof shell into a high-temperature kiln for roasting treatment, removing residues and moisture, and improving the strength and fireproof performance of the fireproof shell;
s7, pouring, namely placing the refractory shell on a pouring table, and fixing the refractory shell by using fillers such as sand; heating the required steel materials to about 1600 ℃, and pouring the steel materials into the refractory shell from the pouring gate according to a certain temperature and speed; and after the steel liquid is solidified, obtaining the required steel artificial joint.
Although the present invention has been described with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described, or equivalents may be substituted for elements thereof, and any modifications, equivalents, improvements and changes may be made without departing from the spirit and principles of the present invention.