CN108057873A - Process method of low-pressure casting thin-walled aluminum alloy castings - Google Patents

Abstract

The invention provides a process method for casting a thin-wall aluminum alloy casting at low pressure, which solves the problems of long research and development period and high research and development cost caused by continuous trimming or new manufacturing of a mold due to continuous adjustment of a product structure in a product research and development period. The method comprises the following steps: s001, establishing a three-dimensional model of the casting in three-dimensional software according to a two-dimensional drawing of the product; step S002, arranging a gating system and a riser on the three-dimensional casting model according to the process requirements, and obtaining a core body of the casting after the differences among the three-dimensional casting model, the gating system and the riser are solved on the premise of minimum sand-carrying capacity; and S003, performing core splitting and/or parting on the casting core body, and splitting the casting core body into an inner cavity sand core, an outer sand mold and a riser sand mold, wherein the inner cavity sand core is used for forming an inner cavity structure of the casting, the outer sand mold is used for forming an outer shape structure of the casting, the riser sand mold is used for accommodating a riser, and a riser and sprue seat is arranged on the outer surface of the riser sand mold.

Description

Process method of low-pressure casting thin-walled aluminum alloy castings

technical field

The invention relates to a low-pressure casting technology, in particular to a casting process of an aluminum alloy thin-walled casting.

Background technique

The aluminum alloy casing casting shown in Figure 1 is a typical large-scale thin-walled aluminum casting with a diameter of Φ400mm-1200mm. For this type of product, the outer surface needs to be fully processed, and there are many reinforcing ribs and navels (which need to be punched) inside. In the molding process, most of these products are produced by mold technology, and are divided along the largest cross-section of the casting. The outer contour is brought out by the mold, and the inner cavity structure is formed by a sand core. It is thin and high, and it is difficult to remove the mold. It is necessary to make the mold of the rib plate into a live material, resulting in poor dimensional accuracy of the casting. In addition, during the product development cycle, due to product structure modification or casting process adjustment, molds need to be frequently modified, resulting in high R&D costs and long cycles. At the same time, in the process of core assembly, the accuracy of core assembly is generally controlled by special fixtures combined with manual measurement, which is difficult to operate. Such existing core-making and molding processes produce a large number of sand cores, complex core assembly methods, cumbersome process control requirements, and high skill levels for on-site workers. At the same time, the size of the product is difficult to control, resulting in large dimensional errors.

Contents of the invention

In view of the above problems, it is necessary to propose a process method for low-pressure casting thin-walled aluminum alloy castings to solve the problem of long development cycle and high development cost caused by continuous adjustment of product structure or new production in the product development cycle. At the same time, through the use of additive manufacturing technology, the problems of large number of sand cores, difficult core assembly and low precision caused by core separation and/or parting according to product structure are avoided.

A process method for low-pressure casting thin-walled aluminum alloy castings, specifically:

Step S001, establishing a three-dimensional model of the casting in three-dimensional software according to the two-dimensional drawing of the product;

Step S002, arrange the gating system and riser on the three-dimensional model of the casting according to the process requirements, and obtain the core of the casting after calculating the difference with the three-dimensional model of the casting, the gating system and the riser under the premise of the minimum amount of sand intake body;

Step S003, performing core separation and/or parting on the casting core body, cutting the casting core body into three parts: inner cavity sand core, outer molding sand mold and riser sand mold, the inner cavity sand core It is used to form the inner cavity structure of the casting, the external sand mold is used to form the external structure of the casting, the riser sand mold is used to accommodate the riser, and the riser and the gate seat are arranged on the outer surface.

As a further limitation of the present invention, snap buttons for positioning and fixing are provided on the mating surfaces of the inner cavity sand core, the outer sand mold and the riser sand mold.

As a further limitation of the present invention, the pouring chassis matched with the core body is made of a metal material that can withstand high temperatures above 900°C, and its specific structure is a circular or directional flat plate with a liquid riser in the middle, so as to realize the The repeated utilization of the casting chassis not only reduces the production cost, but also facilitates the versatility of production. At the same time, the riser is also the sprue, from which the molten metal enters the gating system to fill the casting.

The technical effect of this technical solution is: by implementing the process method of low-pressure casting thin-walled aluminum alloy castings described in the present invention, the long research and development cycle caused by the continuous adjustment of the product structure caused by the continuous adjustment of the mold in the product development cycle is solved. , The problem of high research and development costs shortens the research and development cycle by more than 80%; at the same time, the use of additive manufacturing technology avoids the problems of large number of sand cores, difficult core assembly, and low precision caused by core separation and/or parting according to product structure . The invention improves the production efficiency and reduces the production cost by setting the common pouring base. By adopting the core-integrated parting method, the non-planar core assembly process is avoided, the operation difficulty of the core assembly process is reduced, the accuracy of the assembly type is improved, the process yield rate is improved, and the qualified rate of the casting reaches above 95.

Description of drawings

Fig. 1 is a structural diagram of a thin-walled aluminum alloy casting of the present invention;

Fig. 2 is a gating system and riser layout diagram of the present invention;

Fig. 3 is a schematic diagram of core assembly of the present invention;

Fig. 4 is the explosion diagram of the first kind of splitting scheme of the present invention;

Fig. 5 is an exploded view of the second splitting scheme of the present invention.

In the figure, 1-sprue; 2-runner; 3-inner runner; 4-riser; 5-pouring chassis; 5A-riser pipe; -sprue type; 6B-inner cavity column core; 7-outer sand mold; 8-riser sand mold; 8A-riser cover; 8B-riser core; 9A-first parting surface; 9B-second point Surface; 10-inner cavity sand core with window; 11-half mold outer sand mold.

Detailed ways

In order to illustrate the technical solution of the present invention more clearly, it will be described in detail according to the embodiments of the accompanying drawings. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without paying Under the premise of creative work, other drawings can also be obtained based on these drawings.

As shown in Figure 1, it is a columnar body structure with reinforcing ribs in the inner cavity, and windows are opened on the outer peripheral wall. The columnar body casting adopts low-pressure casting technology, and its first parting scheme is:

Step S101, establishing a three-dimensional model of the columnar casting in three-dimensional software according to the two-dimensional drawing of the product;

Step S102, arrange the gating system and riser on the three-dimensional model of the columnar casting according to the process requirements, and obtain the said The core body of the cylindrical body casting;

Step S103, performing core separation and/or parting on the core body of the columnar casting, the surface perpendicular to the axial direction of the casting along the upper edge of the window on the columnar casting is the first parting surface 9A, along the vertical The junction surface of the runner and the runner is the second parting surface 9B, and the first parting surface 9A and the second parting surface 9B divide the core body of the cylindrical casting into three parts, which are respectively inner cavity sand Core 6, outer sand mold 7 and riser sand mold 8, the inner cavity sand core 6 includes the inner cavity structure of the columnar body casting, runner 2 and sprue 1 and runner 2 junction section, the outer mold The sand mold 7 includes the outer mold structure of the columnar casting and the inrunner 3 , and the riser sand mold 8 is provided with a riser 4 connected with the inrunner 3 .

Preferably, on the three-dimensional model of the cylindrical casting, the processing amount can also be set on the product surface to be processed according to the technical quality requirements, and the process correction amount can be set on the key thin-walled parts. Half of the wall thickness of the key thin-walled part is 3mm-12mm.

Preferably, the pouring system adopts a low-pressure casting system, specifically, the sprue 1 is located at the center of the bottom of the core body of the cylindrical casting; the runner 2 is along the radial direction of the bottom of the core body of the cylindrical casting There are several lines evenly distributed in the direction; the inner runner 3 is distributed from the end of the runner 2 away from the sprue 1 along the axial direction of the cylindrical casting core body, and runs through to the cylindrical casting mold. Core top.

Preferably, each ingate 3 is provided with a corresponding riser 4 at the end of the top surface of the cylindrical casting core body, so as to realize the stamping of molten metal to ensure that the product can be filled and avoid shrinkage cavities , shrinkage and other defects.

Preferably, the riser sand mold 8 can also be set up as a riser core 8B and a riser cover 8A to facilitate the assembly of the core, so that the riser and the ingate 3 can be well aligned, thereby facilitating the smooth flow of molten metal. The riser core 8B is provided with a positioning core head, so as to facilitate the cooperation between the riser sand mold 8 and the inner cavity sand core 6 .

Preferably, when the inner cavity sand core 6 affects the arrangement of the chill iron, the inner cavity sand core 6 can be divided into inner cavity column core 6B and runner type 6A.

Preferably, a fit gap of 0.2mm-1.0mm is provided among the inner cavity sand core 6, the outer sand mold 7 and the riser sand mold 9, and a sealing strip is provided at the fit gap during the core assembly process.

Preferably, a chill iron accommodation cavity is reserved on the core body of the cylindrical casting where the chill iron needs to be placed, and a matching gap of 0.3mm-0.5mm is left between the chill iron accommodation cavity and the chill iron piece.

Preferably, the runner type 6A of the inner cavity sand core 6 is provided with a snap-in structure for matching and positioning.

The assembly and pouring process of the columnar castings are:

1) Place the inner cavity sand core on the pouring chassis;

2) Assemble the external sand mold on the inner cavity sand core through the positioning structure of the snap button;

3) Fasten the riser sand mold on the outer sand mold and the upper part of the inner cavity sand core to complete the assembly of the entire cylindrical casting core body;

4) Use a sealing strip to seal the matching gap between the inner cavity sand core, riser sand mold and outer sand mold;

5) Put the sealed cylindrical casting core body together with the pouring chassis in the corresponding sand box, flow the resin sand back the sand, and after the resin sand hardens, move the entire box to the pouring area to be poured.

Preferably, the molten metal is injected into the pouring system of the core body of the cylindrical casting through a riser at a low pressure of 0.3MPa-0.7MPa, and the pressure is maintained for 15min-30min, thereby completing the pouring of the cylindrical casting .

As shown in Figure 1, it is a columnar body structure with reinforcing ribs in the inner cavity, and windows are opened on the outer peripheral wall. The columnar body casting adopts low-pressure casting technology, and its second parting scheme is:

Step S201, establishing a three-dimensional model of the columnar casting in three-dimensional software according to the two-dimensional drawing of the product;

Step S202, arrange the gating system and riser on the three-dimensional model of the cylindrical casting according to the process requirements, and obtain the described The core body of the cylindrical body casting;

Step S203, performing core separation and/or parting on the core body of the cylindrical casting, core out the inner cavity of the cylindrical casting as a whole, and form an inner cavity with a window in the runner type where the runner structure is located. Cavity sand core 10, along the axis of symmetry of the window of the cylindrical body casting, cuts the sand mold of the outer shape of the cylindrical body casting into two symmetrical half-shaped shapes 11, and the two symmetrical half-shaped shapes 11 can effectively wrap The structure of the window part, the riser cover 8A is directly fastened on the inner cavity sand core 10 with a window.

The second parting scheme can make the ingate 3 and the riser 4 integrally formed, thereby avoiding the turbulent flow of the molten metal caused by the misalignment of the two parts, resulting in the deterioration of the surface quality of the casting.

The grouping process of the second scheme is:

1) Place the pouring chassis 5 on the assembly platform, and seat the inner cavity sand core 10 with a window on the casting chassis 5 through the positioning snap-in structure;

2) Fasten the half-shaped shape 11 to the inner cavity sand core 10 with a window through the positioning buckle;

3) Fasten the riser cover 8A on the inner cavity sand core 10 with the window through the positioning buckle, and complete the assembly of the core body of the entire cylindrical casting.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some or all of the technical features; these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. a kind of process of low pressure casting thin-walled aluminium alloy castings, which is characterized in that comprise the following steps that：

S001 establishes the threedimensional model of casting according to product two dimension drawing in three-dimensional software；

S002, according to technological requirement on the Casting Three-dimensional model arrangement of pouring system and riser, and in minimum mold thickness Under the premise of the core body of the casting is obtained after difference by being asked with Casting Three-dimensional model, running gate system and riser；

S003 carries out point core and/or parting to the core for cast body, is inner cavity sand core by core for cast body cutting, outer Molding sand type and riser sand mold three parts, the inner cavity sand core are used for being formed the inner-cavity structure of casting, and the external form sand mold is used for shape Into the appearance structure of casting, the riser sand mold is used for accommodating riser, and riser is set on external face to do and gate pad.

2. the process of low pressure casting thin-walled aluminium alloy castings as described in claim 1, which is characterized in that the inner cavity sand It is equipped in the mating surface of core, external form sand mold and riser sand mold for positioning and fixed snap fastener.

3. the process of low pressure casting thin-walled aluminium alloy castings as described in claim 1, which is characterized in that the cast bottom Disk is made of the metal material for being resistant to 900 DEG C or more high temperature, and it is circular or square flat with stalk that concrete structure is middle part Disk.

4. the process of low pressure casting thin-walled aluminium alloy castings as described in claim 1, which is characterized in that the first parting side Case is specially：

S101 establishes the threedimensional model of column casting according to product two dimension drawing in three-dimensional software；

S102, according to technological requirement on the column Casting Three-dimensional model arrangement of pouring system and riser, and in most snack By obtaining the column casting after seeking difference with column Casting Three-dimensional model, running gate system and riser on the premise of sand amount Core body；

S103 carries out point core and/or parting, the window top along on the column casting to the column core for cast body Edge is the first die joint perpendicular to the face of casting axial direction（9A）, it is the second die joint along the interface of sprue and cross gate （9B）, first die joint（9A）With the second die joint（9B）It is three parts by the cutting of column core for cast body, is respectively Inner cavity sand core（6）, external form sand mold（7）With riser sand mold（8）, the inner cavity sand core（6）Inner-cavity structure including column casting, Cross gate（2）And sprue（1）With cross gate（2）Switching phase, the external form sand mold（7）Include the external form of the column casting Structure and ingate（3）, the riser sand mold（8）It is equipped with and ingate（3）Connected riser（4）.

5. the process of low pressure casting thin-walled aluminium alloy castings as claimed in claim 4, which is characterized in that in the column The face to be processed of body casting is equipped with processing capacity, and molding allowance is equipped at the crucial thin-walled position of the column casting.

6. the process of low pressure casting thin-walled aluminium alloy castings as claimed in claim 4, which is characterized in that the cast system System is specially sprue using low pressure casting system（1）At the center location of the column core for cast body bottom；It is horizontal Running channel（2）Several are evenly distributed with along the radial direction of the column core for cast body bottom；Ingate（3）From cross gate （2）Away from sprue（1）One end have several along the column core for cast body axial directional distribution, and penetrate into always At the top of the column core for cast body, the ingate at the top of the column core for cast body（3）Correspondence is additionally provided in outlet Riser（4）.

7. the process of low pressure casting thin-walled aluminium alloy castings as claimed in claim 4, which is characterized in that the riser sand Type（8）It can also be established as riser core（8B）With emit lid（8A）, the inner cavity sand core（6）It cuts as inner cavity column core（6B）And horizontal stroke Pour channel type（6A）.

8. the process of low pressure casting thin-walled aluminium alloy castings as claimed in claim 4, which is characterized in that the column Group type and the casting process of casting be：

The first step, by the inner cavity sand core（6）It is placed in cast chassis（5）On；

External form sand mold is passed through snap fastener location structure group type to the inner cavity sand core by second step（6）On；

3rd step, by riser sand mold（8）It is fastened on external form sand mold（7）With inner cavity sand core（6）Entire column casting is completed on top The group type of core body；

4th step, with sealing strip by the inner cavity sand core（6）, riser sand mold（8）With external form sand mold（7）Between fit clearance it is close Envelope；

Column core for cast body after the sealing is placed in together with cast chassis in corresponding sandbox, flows by the 5th step After resin sand hardening, it is to be cast to be moved to cast region by resin sand floor sand for entire babinet.

9. the process of low pressure casting thin-walled aluminium alloy castings as claimed in claim 8, which is characterized in that molten metal exists Pass through stalk under the low pressure of 0.3MPa-0.7MPa（5A）It injects in the running gate system of the column core for cast body, and protects 15min-30min is pressed, so as to complete the cast of the column casting.

10. the process of low pressure casting thin-walled aluminium alloy castings as described in claim 1, which is characterized in that the second parting Scheme is specially：

S201 establishes the threedimensional model of column casting according to product two dimension drawing in three-dimensional software；

S202, according to technological requirement on the column Casting Three-dimensional model arrangement of pouring system and riser, and in most snack By obtaining the column casting after seeking difference with column Casting Three-dimensional model, running gate system and riser on the premise of sand amount Core body；

S203 carries out point core and/or parting to the column core for cast body, the inner cavity of the column casting is integrally gone out Core simultaneously forms the inner cavity sand core with window in the cross gate type where cross gate structure（10）, it is symmetrical along column casting window The sand mold cutting of column casting appearance structure is two symmetrical half mould external forms by axis（11）, described two symmetrical half moulves External form（11）The structure of window portion can be effectively wrapped up, it is described to emit lid（8A）Directly it is fastened on the inner cavity with window Sand core（10）On.