CN103372638A - Die-casting mold structure of a zinc alloy USB thin-walled part - Google Patents

Abstract

The application discloses zinc alloy USB thin wall spare die casting die structure, it is including the sprue that connects gradually, the cross gate, ingate and mould die cavity, through the ingate intercommunication between ingate and the mould die cavity, the sprue, the cross section area of ingate and ingate dwindles along the molten metal flow direction gradually, the molten metal gets into the jet angle that is provided with 30 degrees to 45 degrees acute angles between the direction of mould die cavity and the plane of ingate place through the ingate, and the incident position of the molten metal in the ingate is close to the rear end face of mould die cavity. The mold is simple in structure, the direction of the molten metal entering the mold cavity is controlled, the flowing process of the molten metal entering the mold cavity through the pouring system is effectively controlled, the degree of mixing of the molten metal and air is reduced, the molten metal is well filled in the mold integrally, the proportion of surface foaming, surface flow lines, loose structure, low strength and conductivity reduction of a zinc alloy thin-wall part product is reduced, and the qualified rate of the product is improved.

Description

Die-casting mold structure of a zinc alloy USB thin-walled part

technical field

The application belongs to the technical field of pouring micro thin-walled parts, and in particular relates to a zinc alloy USB thin-walled die-casting mold structure.

Background technique

At present, thin-walled micro-zinc alloys mainly refer to zinc alloy products with a wall thickness of 0.1mm~0.5mm. The filling speed of thin-walled micro-zinc alloy die-castings is generally about 40 m/s. Under the action of high pressure and high speed, When the molten metal enters the cavity, it is filled with the jet flow. When the filling process is subjected to continuous loss such as collision, friction, and resistance, the jet flow becomes a pressure flow. The surface quality is better, but the generation of defects, especially bubbles, is easy to appear in the part filled with pressure flow. During the production process of this kind of zinc alloy products, defects such as air bubbles and under-casting are extremely prone to occur. Therefore, reasonable pouring process and mold design play an important role in casting forming. The most common defects of zinc alloy die castings are blistering on the surface and loose structure, resulting in a decrease in strength and conductivity, failing to meet quality standards, resulting in a high defect rate and seriously affecting the normal production of the product. What's more serious is that some defects are difficult to detect in the semi-finished products of die castings, but they will be revealed in the subsequent processing technology, such as electroplating, which will undoubtedly cause more serious losses to production.

There are many reasons for the above defects, but in the prior art, the ingate is used to be perpendicular to the mold cavity structure. It is believed that there is no horizontal component velocity of the molten metal, so the speed loss is small when entering the mold cavity, which is sufficient. Conditions are better.

Contents of the invention

The purpose of this application is to overcome the shortcomings in the prior art and provide a zinc alloy USB thin-wall die-casting mold structure, which has a simple structure, low manufacturing cost, and effectively reduces the mixing of molten metal with air during the filling process. The eddy current and air entrainment produced make the product filling complete, the surface bubbles and flow lines are reduced, the surface finish is improved, and the product qualification rate is improved.

In order to solve the above technical problems, the application is achieved through the following technical solutions:

A die-casting mold structure for a zinc alloy USB thin-walled part, including a sprue, a runner, an ingate and a mold cavity connected in sequence, the ingate and the cavity of the mold are connected through an ingate, and the sprue , The cross-sectional area of the runner, the ingate and the ingate gradually decreases along the flow direction of the molten metal, and the direction in which the molten metal enters the mold cavity through the ingate and the plane where the ingate is located are set at 30 degrees to 45 degrees. The jet angle is acute, and the incident position of the molten metal in the ingate is close to the rear end surface of the mold cavity.

Further, an acute jet angle of 30° to 40° is set between the direction in which the molten metal enters the mold cavity through the ingate and the plane where the ingate is located.

Further, the connection between the runner and the inrunner is set as an R angle, and the radius of the R angle is 10mm to 15mm.

Further, the distance from the midpoint of the ingate to the rear end surface of the mold cavity is 2 mm to 3 mm.

Further, the distance from the midpoint of the ingate to the rear end surface of the mold cavity is 2.5mm.

Compared with prior art, the beneficial effect of the present application is:

The zinc alloy USB thin-wall die-casting mold structure described in this application has a simple structure and a reasonable design. In the runner, the molten metal enters the mold cavity through the inner runner at a certain angle rather than at a right angle. , the jet angle of the molten metal entering the mold cavity is between 30° and 45°, the direction of the molten metal entering the mold cavity is controlled, and the flow process of the molten metal entering the cavity through the gating system is effectively controlled , to reduce the degree of mixing with air, so that the metal liquid can be filled well in the mold as a whole, reducing the ratio of surface foaming, surface flow lines, loose structure, low strength, and decreased electrical conductivity of zinc alloy thin-walled products, and improving the product’s durability. Pass rate.

Description of drawings

The accompanying drawings are used to provide a further understanding of the application, and are used to explain the application together with the embodiments of the application, and do not constitute a limitation to the application. In the accompanying drawings:

Fig. 1 is the structural representation of a kind of zinc alloy USB thin-walled part die-casting mold structure of the present application;

FIG. 2 is a schematic diagram of an enlarged structure at point A in FIG. 1 .

Figures 1 and 2 include:

1——mold cavity,

2——Ingate,

3——sprue,

4 - sprue,

5——Inner runner,

α——jet angle,

a——horizontal sub-velocity,

b—Vertical component velocity. the

Detailed ways

The preferred embodiments of the present application will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present application, and are not intended to limit the present application.

As shown in Figure 1 and Figure 2, a zinc alloy USB thin-walled die-casting mold structure described in the present application includes a sprue 4, a runner 3, an ingate 5 and a mold cavity 1 connected in sequence, The ingate 5 communicates with the mold cavity 1 through the ingate 2, and the cross-sectional areas of the sprue 4, the runner 3, the ingate 5 and the ingate 2 gradually shrink along the direction of the molten metal flow. Increase the flow rate of the molten metal so that the flow rate of the molten metal near the ingate 2 reaches the required flow rate for good mold filling. There is an acute jet angle of 30° to 45° between the direction in which the molten metal enters the mold cavity 1 through the ingate 5 and the plane where the ingate 2 is located, and the incident position of the molten metal in the ingate 5 is close to the mold type. The rear end of chamber 1. With the angle of incidence, it is convenient for the complete mold filling.

Wherein, the connection between the runner 3 and the ingate 5 is set as an R angle, and the radius of the R angle is 12mm. The R angle makes the molten metal flow smoothly in the runner, and smoothly transitions from the runner 3 to the inrunner 5 .

The distance from the midpoint of the ingate 2 to the rear end surface of the mold cavity 1 is 2.5mm. When the flow velocity of the molten metal at the inner gate 2 is too high, the impact on the mold is buffered to reduce mold corrosion.

The angle of the jet flow of molten metal entering the cavity through the ingate is a major factor affecting product quality. The angle of the jet flow is determined by two component velocities, as shown in Figure 2: a is the horizontal component velocity of the molten metal advancing along the runner; b is the vertical component velocity generated by the pressure of the metal fluid, and α is the jet angle.

Specifically, taking the die-casting USB3.0 front iron shell as an example, the casting molding process parameters are as follows:

Name: USB3.0 Front Iron Shell

Material: zinc alloy (Zemark3)

Melting temperature: 420°C

Single casting weight: 0.830g

Spout weight: 6.349 g

Figure 1 is the overall billet diagram of the casting, and the two castings account for a small proportion of the entire billet. The weight of the whole billet is 8.009g, while the single weight of the casting is only 0.830g. According to the single weight and shape of the casting, the shape and size specifications of the sprue 4, runner 3, ingate 5 and ingate 2 are designed and calculated. the

According to the structure of the casting, analyze its fluidity, make the following five gating system schemes, the size and shape of the sprue 4, runner 3, ingate 5 and ingate 2 of the five schemes are the same, by changing The ingate 5 and the ingate 2 change the angle between the direction in which the molten metal enters the mold cavity 1 through the ingate 5 and the cross section of the ingate 2, and the jet angles are 45°, 40°, and 35° respectively. °, 33°, 30°. the

Through digital simulation analysis of casting forming process, for the above five casting schemes, use Huake simulation software INTER-CAST to digitally simulate the filling process of castings, and the following simulation results are obtained:

                                                

When the jet angle is 45°, through the analysis of the film of the filling process, it can be seen that the temperature field of the casting changes less, the molten metal confluence area is smaller, the entrainment is less, the eddy current is very little, the overall filling state is better, and the quality is better .

When the jet angle is 40°, through the analysis of the film of the filling process, the temperature field of the casting changes little, the confluence area of the molten metal on the casting is small, there is very little entrained gas, very little eddy current, and the overall filling state of the casting is good.

When the jet angle is 35°, through the analysis of the film of the filling process, the temperature field changes very little, the confluence area of the molten metal on the casting is very small, there is very little air entrainment, and there is no eddy current, and the overall filling state of the casting is good.

When the jet angle is 33°, through the analysis of the film of the filling process, the change of the temperature field is very small, the confluence area of the molten metal on the casting is small, and there is no air entrainment or eddy current, and the overall filling state is good.

When the jet angle is 30°, through the analysis of the film of the filling process, the change of the temperature field is very small, and the molten metal finally converges in a very small area, and the overall filling state is good, without air entrainment and eddy current phenomenon.

Looking at the filling status of castings from the perspective of digital simulation, the filling effect is undoubtedly the best when the jet angle is 30°.

Comparison of the effect of trial mold products:

According to the process drawing of each casting, design the corresponding mold, test the mold on the Fulai die-casting machine, and get the following samples:

 

The jet angle is 45° for the test sample, the surface bubbles are less, the volume of the bubbles is small, there is a small amount of flow lines on the surface, and the surface finish of the casting is better;

The jet angle is 40° for the test sample, the surface bubbles are less, the volume of the bubbles is small, there is a small amount of flow lines on the surface, and the surface finish of the casting is better;

The jet angle is 35° for the mold test sample, there are few bubbles on the surface, the volume of the bubbles is small, there is a small amount of flow lines on the surface, and the surface finish of the casting is better;

The jet angle is 33° for the mold test sample, there are very few bubbles on the surface, the volume of the bubbles is small, there is no flow pattern on the surface, and the surface finish of the casting is better;

The jet angle is 30° for the test sample, the surface bubbles are very few, the volume of the bubbles is small, there is no flow pattern on the surface, and the surface finish of the casting is good.

Through the digital analysis of the filling process of the castings, comparing the filling results, and combining the samples after the mold test, it can be seen that for the micro-zinc alloy thin-walled castings, the metal fills the cavity at a non-perpendicular angle, and the jet angle is 30 When the temperature is between 30° and 45°, the molten metal fills well in the mold. Therefore, when designing the mold, it is necessary to ensure that the angle between the inrunner 5 and the mold cavity 1 is between 30° and 45°, and the obtained Zinc alloy thin-walled products have less air bubbles on the surface, small bubble volume, high strength, and normal electrical conductivity, which improves the pass rate of the product. When the jet angle is 30°, the filling effect of the casting is the best, and the product yield is the highest.

Finally, it should be noted that the above are only preferred embodiments of the application, and are not intended to limit the application. Although the application has been described in detail with reference to the embodiments, those skilled in the art can still understand the foregoing The technical solutions recorded in each embodiment are modified, or some of the technical features are replaced equivalently, but any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included in this application. within the scope of protection.

Claims (5)

1. kirsite USB thin-wall part structure of cast die, it is characterized in that: comprise the sprue that connects successively, cross gate, ingate and mold cavity, be communicated with by ingate between described ingate and the described mold cavity, described sprue, cross gate, the cross-sectional area of ingate and ingate dwindles gradually along the mobile direction of molten metal, molten metal enters by ingate and is provided with 30 degree between the direction of described mold cavity and the plane, described ingate place to the flow angle of 45 degree acute angles, and the rear end face of the contiguous described mold cavity of the incoming position of the molten metal in the described ingate.

2. a kind of kirsite USB thin-wall part structure of cast die according to claim 1 is characterized in that: molten metal enters between the direction of described mold cavity and the plane, described ingate place by ingate and is provided with 30 degree to the flow angle of 40 degree acute angles.

3. a kind of kirsite USB thin-wall part structure of cast die according to claim 1, it is characterized in that: described cross gate and described ingate junction are set to the R angle, and the radius at described R angle is 10mm to 15mm.

4. a kind of kirsite USB thin-wall part structure of cast die according to claim 1, it is characterized in that: the mid point of described ingate is 2mm to 3mm to the distance of the rear end face of described mold cavity.

5. a kind of kirsite USB thin-wall part structure of cast die according to claim 4, it is characterized in that: the mid point of described ingate is 2.5mm to the distance of the rear end face of described mold cavity.

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