CN1631577A - Manufacturing method of mold with inner channel and its application in directional solidification - Google Patents

Abstract

The invention provides a production method of a mould with inner channels and its application. The technique includes following procedures and requirements: first shape the tube pieces in the needed shape and size, then placing several tube pieces at corresponding location where the mould needs channels; fix the tube pieces in the mould which shaping the mould in order to obtain a mould with inner channels and the tube pieces will not melt in the process. The tube pieces at least more than one piece have respective entrance and exit while temperature sensor may set on the mould to gather the temperature information according to which the control system controls the liquor flowing and the on and off of the current in heating components so to control the temperature distribution in time directional solidifying the liquor material in the mould cavity. The invention is of simple operation and handily control which is able to produce molding of large size and complex shape with fine structure property adapting mass production application.

Description

Manufacturing method of mold with inner channel and its application in directional solidification

Technical field

The invention belongs to the technical field of casting, and in particular relates to a manufacturing method and application of a mold with inner channels which can be applied to directional solidification.

Background technique

When sand mold casting is used, in order to obtain higher quality castings and directional solidify the liquid metal, chill iron is usually set in the sand mold ("Simulation and Quality Control of Foundry Engineering", edited by Liu Baicheng, Jing Tao, etc., Machinery Industry Press , January 2002, P22, P70-71). However, the heat absorption of chilled iron is certain, once it is set in the sand mold, it cannot be adjusted, and for complex shapes and large castings, it is difficult to control the solidification sequence of liquid metal by setting chilled iron in the sand mold to ensure The quality of the casting. For metal molds, block metal blanks are usually used, and the bulk metal blanks are manufactured into various shapes of molds after removing excess metal by cutting machining methods such as turning, milling, grinding, planing, and drilling. When an inner channel is required in the mold, as the Chinese Utility Model Patent No. 02263967.5 discloses a cooling system for a die-casting mold, through-holes are formed by drilling holes from different directions, and water nozzles are installed at the entrance and exit, and The process holes are plugged to form cooling circuit channels in the metal mold. However, the drilling method can only process straight holes, and the position of the holes is also limited by the drilling method; when a circular passage or an irregular-shaped passage is required, it cannot be realized by the drilling method. The application number is 02152824.1 Chinese invention patent discloses a directional solidification casting method and equipment, which can directional solidify multiple castings at one time, but the equipment and operation process are still complicated, and complex shapes and large castings cannot be formed. The Chinese Invention Patent Application No. 03146852.7 describes a directional solidification casting method and its device, but does not disclose the manufacturing method of the mold device.

Contents of invention

The purpose of the present invention is to overcome the shortcomings of the prior art, to provide a simple operation, easy to control, reliable, can meet the large size and irregular, complex shape can be applied to the method of directional solidification containing inner channel mold manufacturing, and Suitable for mass production.

The purpose of the present invention is achieved through the following technical solutions: the manufacturing method of the inner channel mold includes the following steps and process conditions: first, the pipe is formed into the required shape and size, and then at least two pipes are arranged in the required channel of the mould. Corresponding position; in the process of forming the mold, the pipe fittings are fixed in the mold, and the inner channel in the mold is formed by the pipe fittings to form a mold with inner passages; the process conditions set in this process satisfy that the pipe fittings do not melt; arrange in the mold All pipe fittings have independent entrances and exits.

In the process of forming the mold, the pipe fittings are placed in the molding of the molding material, and the inner passages in the molding are formed by the pipe fittings to form a mold containing the inner passages; the molding material can be molding sand for casting, forming a mold containing the inner passages Channel sand mold.

In the process of forming the mould, the pipe fittings are placed in the molding of ceramic mud, and the inner passages in the molding are formed by the pipe fittings, and the ceramic mold containing the inner passages is formed after drying and sintering.

In the process of forming the mould, the pipe fittings are placed in the fluid, and when the fluid is solidified, the pipe fittings are fixed in the parts, and the inner passages in the parts are formed by the pipe fittings to form the parts containing the inner passages.

In the process of forming the mold, the fluid is hot metal fluid, so that the pipe fittings are placed in the hot fluid metal. When the fluid metal is lowered and solidified, the pipe fittings are fixed in the metal, and the inner passages in the metal are formed by the pipe fittings. , forming a metal part containing an inner channel, and the metal part is a metal mold, or a metal mold blank.

In the process of forming the mould, the metal fluid is metal liquid or semi-solid metal with thixotropic properties, and the metal fluid may contain non-metal components or ceramic powder.

The metal mold blank can be subjected to subsequent machining to achieve precise dimensions and low surface roughness.

In order to better realize the present invention, the fluid material input into the mold cavity is directional solidified by using the mold manufactured by the method of manufacturing the mold containing inner channels. The mold with inner channel can be applied, and the fluid temperature lower than the mold temperature is input into the channel formed by pipe fittings to cool the mold, the temperature field on the mold is controlled, and the fluid material input into the mold cavity is directional solidified. The mold with inner channel can be used, and the fluid temperature higher than the temperature of the mold can be input into the channel formed by the pipe fittings to heat the mold, and the temperature field on the mold can be controlled to make the fluid material input into the mold cavity undergo directional solidification. The above mold with internal channels can be used, electric heating elements are arranged in the pipe fittings, the mold is heated by electricity, the temperature field on the mold is controlled, and the fluid material input into the mold cavity is directional solidified. A temperature sensor can be arranged on the mold to collect temperature information on the mold, and the control system controls the flow of fluid and the on-off of the current of the heating element according to the collected relevant information, so as to control the temperature distribution on the mold in good time and make the fluid in the cavity Directional solidification of materials.

The hollow cooling channels formed by pipe fittings in the mold can be set separately; in this way, the flow rate and flow rate of the cooling liquid in each hollow cooling channel can be individually controlled, thereby controlling the cooling range of the local area of the mold.

Each heating element in the mold is connected to a different control switch, so that the heating state of each heating element can be individually controlled, thereby controlling the temperature rise in a local area of the mold.

The hollow cooling channels and heating elements formed by the pipes are arranged alternately, and can also be arranged in other structural forms as required; the arrangement and distribution of the hollow cooling channels and heating elements must ensure that the temperature of any area in the mold cavity can be effectively controlled.

Compared with the prior art, the present invention has the following advantages and effects:

(1) The present invention provides a method for manufacturing a mold containing an inner channel, which can easily form an inner channel made of pipe fittings in the mold, and the shape of the inner channel and its position in the mold can be flexibly designed, solving the problem of Difficulties in the manufacture of large and irregular, complex-shaped internal channel molds.

(2) The mold containing internal channels manufactured by the method of the present invention can conveniently control the temperature field on the mold, and can directional solidify the fluid material in the mold cavity, thereby ensuring the quality of the casting, and can produce high-quality large-scale casting.

(3) The mold with internal channels manufactured by the method of the present invention can realize precision casting with no allowance or less allowance.

(4) The present invention has simple operation, easy and reliable control, is suitable for mass production and use, has a wide application range, and has a good market prospect.

Description of drawings

Fig. 1 is a schematic diagram of the structure of a sand mold with internal channels described in Example 1 of the present invention.

Fig. 2 is a schematic diagram of the pipe fitting structure and pipe fitting arrangement used in a mold with an inner channel described in Embodiments 1 to 5 of the present invention,

Fig. 3 is a schematic cross-sectional view of the pipe fittings in Fig. 1 and Fig. 4-6.

Fig. 4 is a schematic diagram of the structure of a sand mold casting metal mold with internal passages according to Embodiment 2 of the present invention.

Fig. 5 is a schematic diagram of the structure of a metal mold for sand mold casting with internal passages according to Embodiments 3 and 4 of the present invention.

Fig. 6 is a schematic diagram of the tooling structure for directional solidification casting using a metal mold with inner channels in Example 5 of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1

What is to be prepared in this embodiment is a sand mold with internal passages and the sand mold with internal passages is used for directional solidification.

The structure is shown in Figure 1. In Figure 1, 1 is the box body, 2 is the box cover, 3 is the molding sand, 4 is the heating element, 5 is the pipe fitting, 6 is the temperature sensor, 7 is the cavity, and 8 is the sprue , 9 is a heating insulation element, and 10 is a riser. The pipe fitting 5 used as the hollow cooling channel is connected with the cooling liquid supply component through the control valve, and its structural form is shown in Figure 2. Figure 2 is a schematic diagram of the pipe fitting structure and pipe fitting arrangement (not all pipe fittings are drawn in the figure). 3 is a schematic diagram of the cutting position of the cut section of the pipe fitting in Fig. 1; The structure is determined. The shape and size of the pipe fitting 5 can be determined according to the shape of the molded part and the position in the mold. When the molded parts are different, the pipe fitting can be bent into different shapes and arranged in different positions. The heating element 4 is connected to the power supply through the switch, the control valve and the switch are connected to the control unit, and the temperature sensor 6 is attached close to the mold wall of the cavity to transmit the collected temperature information to the control system.

The preparation process of the sand mold containing the inner channel is as follows: first, the steel pipe is bent into the structural form shown in Figure 2, and the size of the corresponding position of the pipe fittings 5 shown in Figure 1 is consistent, and the molding sand is used in the box body 1. When molding, the pipe fitting 5, heating element 4 and temperature sensor 6 are pre-embedded in the corresponding positions and fixed, so that the cooling water inlet 11 and water outlet 12 of the pipe fitting are outside the box body 1, so as to connect the water pipe; connect the wire and the heating element 4 and the temperature sensor 6 are connected and connected to the control system. The control system includes a heating element control part, a cooling channel control part, and a thermocouple temperature acquisition part, which are connected to the PLCI/O module, operated through the interface, and controlled by the control software. The shape of the cavity 7 is molded by foam material, and communicated with the runner 8 covered with the heating and insulating element 9 . After the box cover is closed, a sand mold with internal channels formed by the pipe fittings is obtained, which can be applied to directional solidification.

The specific process of directional solidification of sand molds with internal passages in this application is as follows: first, the heating elements 4 and 9 distributed in the sand mold 3 and on the riser 10 and runner 8 are energized to preheat the sand mold 3 and the runner 8, and then the The superheated metal liquid is poured into the riser 10, and the metal liquid enters the mold cavity 7 through the runner 8, so that the foam material in the mold cavity 7 is vaporized, and the gas in the mold cavity is discharged until the mold cavity is filled with the metal liquid, and The molten metal required for sufficient feeding remains in the riser 10; the temperature sensor 6 can measure the temperature of various parts; the heating element 4 and the hollow cooling channel 5 formed by the pipe fittings are used to control the temperature of the mold and the inside of the mold through the obtained temperature information. It can not only control the on-off of the cooling liquid in each hollow cooling channel and the size of the water supply, but also independently control the on-off and power of each heating element. At the beginning of the cooling process, first pass cooling water to the hollow cooling channel 5 formed by the pipe fittings at the top of the mold, so that the liquid metal starts to crystallize from the top, and the crystallization surface moves continuously from top to bottom, and the temperature information of each part obtained through Determine the position of the crystallization surface, sequentially stop heating the heating elements distributed in the sand mold area in contact with the crystallized material, and let the hollow cooling channels distributed in the sand mold area in contact with the solid phase of the crystallized material pass cooling water, As the crystallization surface moves from top to bottom, the heating of the heating element 4 and the cooling of the hollow cooling channel 5 formed by the pipe fittings are dynamically controlled; when the crystallization surface reaches the transition position between the runner 8 and the cavity 7, the casting The casting in the mold has been fully formed, all heating elements are cut off, and cooling water is passed through all hollow cooling passages, and the liquid metal in the riser 10 finally solidifies. After the mold has cooled, the mold is opened and the casting is removed. During the solidification process of the liquid material, it can always ensure that the crystallization surface and the liquid material input port or riser are connected through the liquid material, and the liquid material can continuously replenish the crystallization surface due to the solidification shrinkage caused by the liquid material solidification and temperature drop. The material required for liquid shrinkage and solid shrinkage will not be separated by solidified material between the crystallization surface and the liquid material input port or riser. According to this method, large-sized castings can be formed, and the quality of the castings can be guaranteed.

Example 2

What is to be prepared in this embodiment is a metal mold containing an inner channel, which can also be directly formed into a metal part. This embodiment is the same as Embodiment 1 except for the following process: the steel pipe fitting 5 is arranged in the cavity 7 as shown in Fig. Fill in the cavity 7 with a wax pattern, and the metal liquid poured in after losing the wax is a copper alloy liquid. After the copper alloy liquid solidifies, the steel pipe fitting 5 is fixed in the copper alloy part to form a shape and shape as shown in Figure 6. A copper alloy mold part module 15 with an inner channel whose size is consistent with that of the cavity 7 .

Example 3

What is to be prepared in this embodiment is a metal mold part containing an inner channel. This embodiment is the same as Embodiment 1 except the following process: the steel pipe fitting 5 is arranged in the cavity 7 as shown in Fig. Fill in the cavity 7 with a wax pattern, and the metal liquid poured in after the wax is lost is a copper alloy liquid. After the copper alloy liquid solidifies, the piece 5 is fixed in the copper alloy part to form the shape and shape as shown in Figure 6. A copper alloy mold part module 16 with an inner channel whose size is consistent with that of the cavity 7 .

Example 4

What is to be prepared in this embodiment is a metal mold part containing an inner channel. This embodiment is the same as Embodiment 3 except the following process: the copper alloy liquid is mixed with silicon carbide ceramic powder.

Example 5

What is to be prepared in this embodiment is a metal mold with internal channels and its application in directional solidification.

The preparation process of this inner channel metal mold is specifically as follows: the copper alloy parts module 15 and module 16 with inner channel manufactured in embodiment 2 and embodiment 3 are processed to achieve precise size and low surface roughness through subsequent machining, A small hole is drilled from the back of the mold cavity surface, a temperature sensor 6 is arranged in the small hole, and the temperature sensor 6 is closely attached to a position close to the cavity mold wall, and assembled into a metal mold with the structure shown in FIG. 6 . In Fig. 6, the module 16 and the module 15 are locked by screws to form a mold, the riser 10 is inserted into one end of the mold, the runner 8 is arranged in the riser 10, and the hollow cooling channel 5 composed of pipes passes through the control valve. It is connected with the cooling liquid supply component, the heating element 4 is connected with the power supply through the switch, and the control valve and the switch are connected with the control member. Connect the wires to the heating element 4 and the temperature sensor 6, and connect to the control system. The control system includes the heating element control part, the cooling channel control part, and the thermocouple temperature acquisition part, which are connected to the PLC I/O module, operated through the interface, and controlled by the control software. The present metal mold with internal channels can be applied to directional solidification.

In this embodiment, the metal mold with inner channels is used to prepare directionally solidified thin-shell castings. Used mold as shown in Figure 6, the preparation process of this directionally solidified thin-shell casting is specifically as follows: first, release agent is coated on the mold cavity surface, and is distributed in module 16, module 15, riser 10 and sprue The heating element 4 on 8 is energized, the module 16, the module 15, the riser 10, and the runner 8 are preheated to 520°C, and then the aluminum-magnesium alloy liquid superheated to 720°C is poured into the riser 10, the aluminum-magnesium alloy The liquid enters the mold cavity through the runner 8, and discharges the gas in the mold cavity until the mold cavity is filled with the aluminum-magnesium alloy liquid, and the riser 10 retains sufficient metal liquid required for feeding. The temperature sensors 6 distributed on the module 16, the module 15, the riser 10, and the runner 8 measure the temperature of each part, and the heating element 4 and the hollow cooling channel 5 formed by the pipe fittings are used to control the mold and the casting through the obtained temperature information. The molten aluminum alloy in the mold is kept warm or cooled. The on-off and supply volume of cooling liquid in each hollow cooling passage 5 formed by pipes can be individually controlled, and the on-off and power of each heating element 4 can also be controlled separately. At the beginning of the cooling process, first pass cooling water to the hollow cooling channel 5 at the bottom of the mold, so that the aluminum-magnesium alloy liquid starts to crystallize from the bottom, and the crystallization surface moves from bottom to top, and the crystallization surface is judged by the obtained temperature information of each part position, successively make the heating elements 4 distributed in the mold area in contact with the crystallized material stop heating, and make the hollow cooling channels 5 distributed in the mold area in contact with the solid phase of the crystallized material flow through cooling water, along with the crystallization The surface continuously moves from bottom to top, and dynamically controls the heating of the heating element 4 and the cooling of the hollow cooling channel 5 composed of pipe fittings; when the crystallization surface reaches the transition position between the runner 8 and the cavity 7, the casting in the mold Completely formed, all heating elements are cut off, and cooling water is passed through to all hollow cooling passages, and the metal liquid in the riser 10 solidifies at last. After the mold has cooled, the riser 10 is removed from the mold, the mold is opened, and the shell-shaped casting is taken out. During the solidification process of the liquid material, it can always ensure that the crystallization surface and the liquid material input port or riser are connected through the liquid material, and the liquid material can continuously replenish the crystallization surface due to the solidification shrinkage caused by the liquid material solidification and temperature drop. The material required for liquid shrinkage and solid shrinkage will not be separated by solidified material between the crystallization surface and the liquid material input port or riser. In the rapid cooling process, the module can only be distributed in order, and it can be cooled according to a certain program, and there is no need to control it according to the collected temperature information. cooling channel. After the cooling and solidification process program is determined, as long as the flow of the cooling channel through the cooling water is controlled

Example 6

The ceramic tube is placed in the shape of ceramic mud, dried and sintered to form a ceramic mold with inner channels.

Claims (10)

1. A method of manufacturing a mold with an inner channel, which is characterized in that it includes the following steps and its process conditions: first, the pipe is formed into a required shape and size, and then at least two pipes are arranged at the corresponding positions of the required channels of the mold; In the process of forming the mold, the pipe fittings are fixed in the mold, and the inner channel in the mold is formed by the pipe fittings to form a mold with inner passages; the process conditions set in this process satisfy that the pipe fittings do not melt; the pipe fittings arranged in the mold are uniform There are independent entrances and exits. 2. The manufacturing method of a mold with internal channels according to claim 1, characterized in that: in the process of forming the mold, the pipe fittings are placed in the molding of the molding material, and the inner passages in the molding are formed by the pipe fittings, forming A mold with internal passages; the molding material can be molding sand for casting to form a sand mold with internal passages. 3. The manufacturing method of a mold with internal channels according to claim 1, characterized in that: in the process of forming the mold, the pipe fittings are placed in the molding of the ceramic mud, and the inner passages in the molding are formed by the pipe fittings, After drying and sintering, a ceramic mold with internal channels is formed. 4. The manufacturing method of a mold with inner channels according to claim 1, characterized in that: during the molding process, the pipe fittings are placed in the fluid, and when the fluid solidifies, the pipe fittings are fixed in the parts, Internal passages in a part are formed from pipe fittings to form a part with internal passages. 5. The manufacturing method of a mold with internal passages according to claim 4, characterized in that: in the process of forming the mold, the fluid is a hot metal fluid, so that the pipe fittings are placed in the hot fluid metal, and when the fluid metal lowers After the temperature is solidified, the pipe fittings are fixed in the metal, and the inner passages in the metal are formed by the pipe fittings to form metal parts containing inner passages. The metal parts are metal molds, or metal mold blanks; metal fluid is metal liquid or A semi-solid metal with thixotropic properties, the metal fluid may contain non-metal components or ceramic powder. 6. The application of the mold manufactured by the manufacturing method of the inner channel mold according to claims 1-5, characterized in that the fluid material input into the mold cavity is directional solidified. 7. The application of the mold with inner channel according to claim 6, characterized in that: in the channel formed by pipe fittings, a fluid with a temperature lower than the temperature of the mold is input to cool the mold, and the temperature field on the mold is controlled so that the input mold The fluid material in the cavity undergoes directional solidification. 8. The application of the mold with inner channel according to claim 6, characterized in that: in the channel formed by pipe fittings, a fluid with a temperature higher than the temperature of the mold is input to heat the mold, and the temperature field on the mold is controlled so that the input mold The fluid material in the cavity undergoes directional solidification. 9. The application of the mold with internal channels according to claim 6, characterized in that: electric heating elements are arranged in the pipe fittings, the mold is heated by electricity, the temperature field on the mold is controlled, and the fluid material input into the mold cavity is directional solidified . 10. The application of the mold with inner channel according to claim 6, characterized in that: a temperature sensor is arranged on the mold to collect temperature information on the mold, and the control system controls the circulation of the fluid and the current of the heating element according to the collected relevant information On and off, so as to timely control the temperature distribution on the mold, so that the directional solidification of the fluid material in the mold cavity.

Images