CN103223466B - Rapid metal die manufacturing method for turbine blades - Google Patents

Abstract

The invention discloses a rapid metal die manufacturing method for turbine blades. The method includes: designing a die structure, subjecting the structure to shell extraction by 3-5mm and removing the non-mating surface, using stereolithography equipment to prepare a die resin part, carrying out electric arc spraying to obtain a low-melting-point alloy with a thickness of 3-6mm, employing strong alkali corrosion to remove light-cured resin so as to obtain a metal die shell, assembling it with a metal conformal cooling pipeline obtained also by photocuring spraying corrosion, then conducting filling with metal powder and a melted low-melting-point solder mixture, carrying out curing and polishing, thus obtaining the die. The metal die is manufactured by combining photocuring rapid formation, electric arc spraying, resin corrosion and other technologies within 5-8 days, its precision can reach the CT4 grade, and the die has good thermal conductivity and high strength, thus ensuring uniform and rapid cooling of a wax die during formation.

Description

A Method for Rapid Manufacturing of Metal Molds for Turbine Blades

technical field

The invention belongs to the technical field of rapid molding, and relates to a rapid manufacturing method of a metal mold for turbine blades.

Background technique

The lost wax method is a method of investment casting. The surface of the wax mold is covered with refractory materials to make a mold shell. After melting the mold and losing the wax, it can be cast at a high temperature after roasting to obtain precision castings. Castings obtained by investment casting can achieve near-net shape, and are widely used in aerospace, automotive and other parts that require high precision. In lost wax casting, the wax pattern is the intermediate three-dimensional shape transfer part of precision casting, and its quality directly determines the precision of the casting. Turbine blade is one of the parts with the worst working environment and the most complex structure in the engine, and its manufacturing method has always been the focus and difficulty in the industry. Traditional precision casting uses wax pressing molds to manufacture wax patterns in batches, but manufacturing metal molds using machining methods is time-consuming and labor-intensive. Especially for parts with complex structures, manufacturing metal molds requires a lot of time and cost.

Light-curing rapid prototyping technology has the advantages of high manufacturing precision and the ability to manufacture complex inner cavity structures. It is an effective way to shorten the mold cycle and reduce the manufacturing cost by using the light-curing rapid prototyping technology as an intermediate state for transformation, and then rapidly making metal molds.

The conformal cooling channel is a structure to be considered in the design of the injection mold. The conformal cooling channel of the resin material can be manufactured by using the light curing rapid prototyping technology. Since the thermal conductivity of the general resin material is very low (less than 0.5W/(m·℃)), The cooling speed of the resin mold wax pattern is slow, resulting in a long wax pattern manufacturing cycle, large thermal deformation of the wax pattern and the mold, and many quality defects of the wax pattern during the cooling process, which directly affects the quality of precision casting castings.

Contents of the invention

The problem to be solved by the present invention is to provide a rapid manufacturing method for metal molds for turbine blades. The metal molds for turbine blades can be obtained by combining technologies such as light-curing rapid prototyping, arc spraying, and resin corrosion, which saves mold manufacturing costs and can quickly manufacture complex metal molds. Blade mold.

The present invention is achieved through the following technical solutions:

A method for rapid manufacturing of metal molds for turbine blades, comprising the following steps:

1) Design the mold structure according to the structure of the target preparation. The mold structure is decomposed into a male mold and a female mold. After shelling the mold structure for 3-5mm and removing a non-fitting surface, use the light-curing rapid prototyping method to manufacture mold resin parts; The inner surface and the inner side wall of the manufactured mold resin part are sprayed with a 3-6mm thick low-melting point alloy, and then the resin is corroded to obtain a metal mold shell;

2) Design the conformal cooling pipe according to the mold structure, and then use the light-curing rapid prototyping method to manufacture the conformal cooling pipe resin part; spray a 2-4mm thick low-melting point alloy on the outer wall of the prepared cooling pipe resin part, and then resin Obtain metal-shaped cooling pipes after corrosion;

3) Assemble the metal mold shell and the metal cooling pipe to obtain the assembled shell, fill the cavity of the assembled shell with a mixture of molten low-melting solder and metal powder, fill the assembled shell and coat the surface evenly Flat; then cooled and solidified under normal temperature conditions to obtain a metal mold, and then polished its surface smooth.

The internal profile of the male mold and the female mold is repeatedly copied from the profile of the resin mould;

The male mold and the female mold are respectively prepared into metal molds and then assembled to form a complete metal mold.

The light-curing rapid prototyping method includes: firstly, using layered software to convert the designed resin mold into several thin-layer planar graphics data and input them into the light-curing rapid prototyping machine; The resin liquid surface, the resin cured layer by layer constitutes the required resin mold; the curing time is 6-24h at room temperature, and 3-12h at 30-35°C.

The light-curing resin used in the light-curing rapid prototyping method has a liquid viscosity of about 240cps at 30°C, a density of 1.1-1.2g/cm ³ , a tensile strength of 45.4-45.7MPa after light curing, and an elastic modulus of 2460-2500MPa, Shore hardness D is about 81.

The spraying is arc spraying, and the low-temperature alloy used in the spraying is ZnAl alloy. During the spraying process, the spraying voltage is 28-30V, the current is 50-80A, the air pressure is 0.4-0.5MPa, the scanning speed is 8m/min, and the spraying distance is 200mm.

The melting point of the low melting point alloy material is lower than 200°C.

The resin corrosion process is to corrode the resin in a chemical corrosion solution for 1 to 4 hours to remove the light-cured resin; the chemical corrosion solution is an alcoholic solution of sodium hydroxide or potassium hydroxide.

The melting temperature of the low-melting solder is lower than that of the sprayed low-melting alloy, and the mass ratio of the metal powder in the mixed material is 30-60%.

The mixed material is filled at a temperature of 180-220°C, and the melting point of the low-melting solder is lower than 200°C; the metal powder is copper powder, aluminum powder or iron powder; it is used when filling the mixed slurry Vibrating equipment assists grouting.

The dimensional accuracy and surface quality of the mold are higher than the precision quality of the wax mold of the target preparation, and at the same time, the outer dimensions of the assembly mold are kept from being deformed when the mixed material is poured; the surface of the metal mold is smooth after being polished, without bubbles or protrusions rise.

Compared with the prior art, the present invention has the following beneficial technical effects:

The rapid manufacturing method of the metal mold provided by the present invention, by designing the mold structure, shelling the structure body by 3-5mm and removing the non-matching surface, using light-curing molding equipment to prepare SL mold resin parts, and arc spraying the inner surface of the resin parts to a height of 3-6mm Melting point alloy, use strong alkali corrosion to remove photocurable resin to obtain metal mold shell, assemble with metal conformal cooling pipe obtained by spraying corrosion after photocuring, then fill metal powder and melted low melting point solder mixed material, solidify and polish Get metal turbine blade molds. The metal mold obtained through the combination of light curing rapid prototyping, arc spraying, resin corrosion and other technologies can be manufactured within 5-8 days. The precision can reach CT4 level, and the mold has good thermal conductivity and high strength, ensuring the wax mold forming It can cool down evenly and quickly.

In the rapid manufacturing method of the metal mold provided by the invention, the low-melting-point alloy can be sprayed on the light-curing resin by using the arc spraying technology, and the low-melting-point alloy has better strength and thermal conductivity. Etching removes the photocurable resin, further reducing the thermal resistance of the mold. The metal powder has good thermal conductivity. The mixture obtained by mixing and solidifying these metal powders with low melting point solder has a high thermal conductivity, which can realize rapid heat loss inside the wax mold, shorten the wax mold preparation cycle, and improve the quality of the wax mold.

Compared with traditional metal molds, the rapid manufacturing method of metal molds provided by the present invention has short preparation period, and the production period is about 3-7 days depending on the complexity of the mold; any complex mold can be prepared; it is comparable to molds made of complete resin Compared with, the mold structure is completely made of metal, which has better thermal conductivity, saves materials and costs, completely removes the resin component, and the structure of the metal conformal cooling pipe also increases the thermal conductivity of the mold and the strength of the mold, greatly shortening the wax mold Preparation cycle and improving the quality of wax patterns. The wax mold can be solidified in a shorter time, greatly shortening the wax mold manufacturing cycle, and improving the quality of the wax mold. The metal conformal cooling channel not only increases the forced heat transfer inside the mold, but also increases the structural strength of the mold.

The metal mold rapid manufacturing method provided by the invention can be used as a wax pressing mold, an injection mold, a stamping mold, etc., and the precision of the obtained parts can reach CT4-CT5.

Description of drawings

Fig. 1 is a structural schematic diagram of a turbine blade;

Fig. 2 is a schematic structural view of a mold composed of a male mold and a female mold.

Figure 3-1 is a schematic diagram of the male mold shell;

Figure 3-2 is a schematic diagram of the metal cooling channel;

Figure 3-3 is a schematic diagram of the shell and water channel assembly;

3-4 are schematic diagrams of curing forming molds.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments, which are explanations of the present invention rather than limitations.

In the present invention, the metal mold consists of a male mold and a female mold. The inner surface of the male mold and the female mold is repeatedly copied from the complex shape surface produced by light curing. The complex mold is manufactured by light curing, and the surface and side wall of the mold are sprayed with 3-6mm For thick low-melting alloys, metal mold shells can be obtained by removing the outer layer of light-cured resin by etching with a strong base. Use photocuring to manufacture conformal pipes, and obtain metal conformal pipes after spraying and corrosion. After the metal mold shell and the metal conformal cooling pipe are assembled according to the design, the metal powder and the melted low melting point solder are mixed in a certain proportion and then filled into the assembled mold, and the metal mold can be obtained after cooling and solidification.

A method for rapid manufacturing of metal molds for turbine blades, comprising the following steps:

1) Design the mold structure according to the structure of the target preparation. The mold structure is decomposed into a male mold and a female mold. After shelling the mold structure for 3-5mm and removing a non-fitting surface, use the light-curing rapid prototyping method to manufacture mold resin parts; The inner surface and the inner side wall of the manufactured mold resin part are sprayed with a 3-6mm thick low-melting point alloy, and then the resin is corroded to obtain a metal mold shell;

2) Design the conformal cooling pipe according to the mold structure, and then use the light-curing rapid prototyping method to manufacture the conformal cooling pipe resin part; spray a 2-4mm thick low-melting point alloy on the outer wall of the prepared cooling pipe resin part, and then resin Obtain metal-shaped cooling pipes after corrosion;

3) Assemble the metal mold shell and the metal cooling pipe to obtain the assembled shell, fill the cavity of the assembled shell with a mixture of molten low-melting solder and metal powder, fill the assembled shell and coat the surface evenly Flat; then cooled and solidified under normal temperature conditions to obtain a metal mold, and then polished its surface smooth.

The internal profile of the male mold and the female mold is repeatedly copied from the profile of the resin mould;

The male mold and the female mold are respectively prepared into metal molds and then assembled to form a complete metal mold.

Specifically, the mold structure is designed according to the structure of the part. The dimensional accuracy and surface quality of the mold structure are higher than the accuracy and quality of the target wax model, and at the same time, the external dimensions are kept from deformation when the slurry is poured. Carry out volume shelling of the designed three-dimensional structure of the mold for 3-5mm, and remove a non-fitting surface.

The resin part of the mold is made by light-curing rapid prototyping technology, and the inner surface and side wall of the male mold and the female mold are sprayed with 3-6mm thick low-melting point alloy by arc spraying technology, and the light-cured outer layer of the mold is removed by strong alkali corrosion method resin, to obtain a metal mold shell.

Use light-curing rapid prototyping technology to manufacture mold conformal cooling pipes, spray 2-4mm thick low melting point alloy on the outer wall of conformal pipes, use strong alkali corrosion method to remove internal resin, obtain metal conformal cooling pipes, and metal conformal cooling pipes The cooling pipeline and the metal mold shell are assembled according to the designed structure.

Specifically, the light-curing rapid prototyping method includes: firstly, using layered software (the layer thickness is 0.1 mm), the designed resin mold is converted into several thin-layer planar graphic data and input into the light-curing rapid prototyping machine ( For example, "Shaanxi Hengtong Intelligent Machine Co., Ltd." produces SPS450B light-curing rapid prototyping machine); during light-curing rapid prototyping, lasers are used to scan the liquid resin surface layer by layer, and the resin cured layer by layer forms the required resin mold; at room temperature The curing time is 6-24h, and the curing time is 3-12h at 30-35°C.

The photocurable resin used in the photocurable rapid prototyping method is Somos14120 photosensitive resin, which has a viscosity of about 240cps at 30°C in liquid state, a density of 1.1-1.2g/cm ³ , and a tensile strength of 45.4~ 45.7MPa, elastic modulus 2460-2500MPa, Shore hardness D is about 81.

The spraying is arc spraying, and the low-temperature alloy used in the spraying is ZnAl alloy. During the spraying process, the spraying voltage is 28-30V, the current is 50-80A, the air pressure is 0.4-0.5MPa, the scanning speed is 8m/min, and the spraying distance is 200mm. The melting point of the low melting point alloy material is lower than 200°C.

In the resin etching process, the resin is etched in a chemical etching solution for 1 to 4 hours to remove the light-cured resin; the chemical etching solution is an alcoholic solution of sodium hydroxide or potassium hydroxide.

After the metal mold shell is obtained, heat the low-melting solder to 180-220°C to melt, mix it with metal powder in a certain proportion, fill it into the assembled mold, and evenly coat the surface of the mold. The mold is cooled and solidified at room temperature, and the surface of the mold is polished with sandpaper to obtain a metal mold.

When preparing the filling slurry, it is necessary to ensure that the low-melting solder is in a melting state without affecting the structure of the metal mold. Therefore, in order to achieve a good flow filling effect and ensure that the material is densely filled, the melting point should be selected lower than the melting point of the sprayed alloy (approximately 200 ℃) brazing filler metal, the molten brazing filler metal and metal powder are mixed to prepare slurry, and vibration equipment can be used to assist grouting when filling the slurry.

The mixed material is filled at a temperature of 180-220°C, and the melting point of the low-melting solder is lower than 200°C; the metal powder is copper powder, aluminum powder or iron powder; it is used when filling the mixed slurry Vibrating equipment assists grouting. The melting temperature of the low-melting solder is lower than that of the sprayed low-melting alloy, and the mass ratio of the metal powder in the mixed material is 30-60%.

The metal mold obtained by the combination of photocuring rapid prototyping, arc spraying, resin corrosion and other technologies in the present invention can manufacture the metal mold within 5-8 days, and its precision can reach CT4 level, and the mold has good thermal conductivity and high strength, ensuring wax It can be cooled evenly and rapidly during mold forming. Compared with the traditional technology, the method has a shorter manufacturing period, saves materials and costs, and can quickly manufacture complex metal molds. The dimensional accuracy and surface quality of the mold are higher than the precision quality of the wax mold of the target preparation, and at the same time, the outer dimensions of the assembly mold are kept from being deformed when the mixed material is poured; the surface of the metal mold is smooth after being polished, without bubbles or protrusions rise.

Referring to Figure 3-1 to Figure 3-4, a specific example is given below to manufacture a certain type of turbine blade mold (as shown in Figure 1) according to the above process, specifically including the following operations:

1. Formwork design and light curing manufacturing. According to the parting of the blade structure, the structure of the male and female molds is designed, and the structure of the male and female molds is extracted by 2.5mm, and the upper surface is removed to obtain the structure diagram of the male and female molds of the blade mold. Use photocuring equipment to manufacture photocured mold shell structures according to each layer of 0.1mm, and obtain resin parts of male and female molds. After the resin part is arc sprayed, the resin is corroded to remove the resin, and the metal shell can be obtained, as shown in Figure 3-1.

2. Manufacture metal cooling channels. Design the structure of the cooling water channel, and manufacture the resin parts of the cooling water channel structure by light curing. The metal cooling water channel can be obtained by corroding and removing the resin after the resin water channel is arc sprayed, as shown in Figure 3-2.

3. Mold skeleton assembly. Assemble the metal cooling channel with the metal mold shell to obtain the assembled mold skeleton structure, as shown in Figure 3-3.

4. Solder filling and solidification forming. Heat the low-melting solder to 200 degrees Celsius, fill it into the skeleton structure of the mold, and after cooling and solidifying, polish the surface to obtain the upper and lower metal molds, as shown in Figure 3-4.

5. Mold assembly. The final turbine blade mold can be obtained by assembling the obtained upper and lower metal molds, as shown in Fig. 2 .

Claims (7)

1. A method for rapid manufacturing of metal molds for turbine blades, comprising the following steps: 1) Design the mold structure according to the structure of the target preparation. The mold structure is decomposed into a male mold and a female mold. After shelling the mold structure for 3-5mm and removing a non-fitting surface, use the light-curing rapid prototyping method to manufacture mold resin parts; The inner surface and the inner side wall of the manufactured mold resin part are sprayed with a 3-6mm thick low-melting point alloy, and then the resin is corroded to obtain a metal mold shell; 2) Design the conformal cooling pipe according to the mold structure, and then use the light-curing rapid prototyping method to manufacture the conformal cooling pipe resin part; spray a 2-4mm thick low-melting point alloy on the outer wall of the prepared cooling pipe resin part, and then resin Obtain metal-shaped cooling pipes after corrosion; 3) After assembling the metal mold shell and the metal cooling pipe to obtain the assembled shell, fill the cavity of the assembled shell with a mixture of melted low melting point solder and metal powder, fill the assembled shell and evenly coat the surface Flat; then cooled and solidified under normal temperature conditions to obtain a metal mold, and then polished its surface; Wherein, in the above steps, the spraying is arc spraying, the low-temperature alloy used for spraying is ZnAl alloy, the spraying voltage is 28-30V, the current is 50-80A, the air pressure is 0.4-0.5MPa, and the scanning speed is 8m/min , the spraying distance is 200mm; The resin corrosion process is to corrode the resin in a chemical corrosion solution for 1 to 4 hours, and remove the light-cured resin; the chemical corrosion solution is an alcohol solution of sodium hydroxide or potassium hydroxide; The melting point temperature of the low-melting-point solder is lower than that of the sprayed low-melting-point alloy, and the mass ratio of the metal powder in the mixed material is 30-60%. 2. the metal mold rapid manufacturing method facing turbine blades as claimed in claim 1, is characterized in that, the internal shape surface of described male mold, female mold is duplicated by the shape surface of resin mould; The male mold and the female mold are respectively prepared into metal molds and then assembled to form a complete metal mold. 3. The rapid manufacturing method of metal molds facing turbine blades as claimed in claim 1, wherein said light-curing rapid prototyping method comprises: first using layered software to convert the designed resin mold into several thin-layer planes The graphic data is input into the light-curing rapid prototyping machine; during the light-curing rapid prototyping machine, the laser is used to scan the liquid resin surface layer by layer, and the resin cured layer by layer forms the required resin mold; the curing time at room temperature is 6-24h, and in The curing time is 3-12h at 30-35°C. 4. The rapid manufacturing method of metal molds facing turbine blades as claimed in claim 3, wherein the photocurable resin used in the photocurable rapid prototyping method has a viscosity of about 240cps at 30°C when liquid, The density is 1.1-1.2g/cm ³ , the tensile strength after photocuring is 45.4-45.7MPa, the elastic modulus is 2460-2500MPa, and the Shore hardness is about 81. 5. The method for rapid manufacturing of metal molds for turbine blades according to claim 1, wherein the melting point of the low melting point alloy material is lower than 200°C. 6. The method for rapid manufacturing of metal molds facing turbine blades according to claim 1, wherein the mixed material is filled at a temperature of 180-220°C, and the melting point of the low-melting solder is lower than 200°C; The metal powder is copper powder, aluminum powder or iron powder; vibrating equipment is used to assist grouting when filling the mixed slurry. 7. the metal mold rapid manufacturing method facing turbine blades as claimed in claim 1, is characterized in that, described mold dimensional accuracy and surface quality are higher than the precision quality of target preparation wax pattern, when mixing material perfusion Keep the outer dimensions of the assembly mold without deformation; the surface of the metal mold after being ground is smooth without bubbles or protrusions.