An injection mold for automotive dashboard trim panels

Abstract

This invention discloses an injection mold for automotive dashboard trim panels, belonging to the field of injection mold technology. The mold includes a fixed mold and a moving mold. The moving mold integrates a cold slug control device, a vacuum exhaust device, and an independent conformal cooling device. The cold slug control device uses side injection and a cold slug well at the gate position to trap the first cold slug entering the mold, eliminating silver streaks on the product surface. The vacuum exhaust device includes a vacuum generator installed on the outer side of the moving mold. Through exhaust holes and grooves on the first insert, it draws the mold cavity to a negative pressure of -0.06 to -0.09 MPa within 0.3 to 1.0 seconds after mold closing, allowing gas to be pre-expelled during rapid filling, preventing trapped air bulging and burning. The independent conformal cooling device provides parallel independent cooling water channels directly connected to the interior of the gate insert for each second insert, without bridging by other mold plates, achieving rapid and precise cooling of the gate area and solving the problem of gate whitening.

Description

Technical Field

[0001] This invention relates to the field of injection mold technology, and specifically to an injection mold for an automotive dashboard decorative panel. Background Technology

[0002] Automotive engine hoods and other exterior parts typically require a textured surface finish and no obvious defects. Currently, in injection molding, a rapid filling process is used to improve surface gloss and color difference. However, rapid filling has the following technical drawbacks: 1. During rapid filling, the cold material that first enters the mold mixes with the hot material that follows, forming silver streaks on the product surface; 2. Rapid filling prevents gas from being expelled from the mold cavity in a timely manner through conventional physical venting, resulting in trapped air bulges or even scorching; 3. Rapid filling causes excessively high shear rates at the gate, leading to a rapid rise in material temperature and causing whitening around the gate. Summary of the Invention

[0003] The purpose of this invention is to provide an injection mold for automotive dashboard decorative panels that simultaneously solves three major defects—silver streaks, trapped air burning / bulging, and gate whitening—through the coordinated operation of a cold material control device, a vacuum exhaust device, and an independent conformal cooling device during a rapid filling process.

[0004] The technical solution of this invention is to provide an injection mold for an automotive dashboard decorative panel with the following structure: a fixed mold and a moving mold; the moving mold includes a cold slug control device, a vacuum exhaust device, and an independent cooling device; the injection molding material used in the injection mold is PA6+10%GF+20MX; the moving mold has a first insert and several second inserts; the cold slug control device includes side injection at each gate, and a cold slug well is designed at the gate position to allow the cold slug entering the mold first to flow into this groove for storage; the vacuum exhaust device includes a vacuum generator; the first insert has multiple exhaust holes and is connected to the vacuum generator through air pipes; the vacuum generator is connected inside the moving mold; the vacuum suction device is used to extract gas from the mold cavity to form a negative pressure before injection, and the vacuum suction channel is independent of the conventional exhaust channel; the independent conformal cooling device includes an independent cooling water channel for each second insert, the water channel is directly connected to the interior of the gate insert without being bridged by other mold plates, and achieves independent control between phases.

[0005] The vacuum generator is installed on the outer side of the moving mold. All the air pipes coming out of the first insert are connected to the vacuum generator. The air inlet of the vacuum generator is connected to the solenoid valve, and the air outlet is discharged outside the moving mold.

[0006] The outer side of the first insert is provided with exhaust grooves, which connect all the outer surfaces of the first insert to the space inside the cavity, so as to quickly extract the air from the cavity where the first insert is located when the vacuum generator is pumping air.

[0007] All cold water pipes connected to the second insert are connected in parallel and pass through their respective through holes on the moving mold.

[0008] Each second insert is connected to an inlet pipe and an outlet pipe. All inlet and outlet pipes from the second inserts are connected to the water collection block for distributing water inflow and collecting return water.

[0009] The depth of the exhaust groove in the sheet-like exhaust insert is 0.02–0.05 mm, and the width is 10–20 mm.

[0010] The vacuum suction device starts pumping air within 0.3 to 1.0 seconds after the mold is closed, and the vacuum degree of the mold cavity reaches -0.06 to -0.09 MPa.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. By using the side injection + cold slug well design, cold material is intercepted at the source, eliminating cold material silver streaks; 2. Vacuum negative pressure exhaust is introduced. Before injection molding, the vacuum generator set in the moving mold is used to draw the mold cavity to a negative pressure of -0.06 to -0.09 MPa, so that the gas is discharged in advance during rapid filling, avoiding trapped air bulging and scorching; 3. By using an independent conformal cooling water channel that does not pass through other templates, the heat of the template is avoided from affecting the temperature rise of the cooling medium, achieving rapid and precise cooling of the gate area; 4. The three devices target different defect mechanisms under the same rapid filling process, forming an organic whole, and none of them can be omitted. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of an automotive dashboard trim panel formed by injection molding according to the present invention.

[0013] Figure 2 This is a perspective view of the fixed mold of the injection mold for the automotive dashboard decorative panel of the present invention.

[0014] Figure 3 This is a split view of the injection mold for the automotive dashboard decorative panel of the present invention.

[0015] Figure 4 This is a schematic diagram showing the connection between all the second inserts of the automotive dashboard decorative panel injection mold of the present invention and the cooling water circuit.

[0016] Figure 5 This is a schematic diagram showing the connection between the first insert of the injection mold for the automotive dashboard decorative panel of the present invention and the vacuum exhaust device.

[0017] Figure 6 This is a schematic diagram of the first insert of the injection mold for the automotive dashboard decorative panel of the present invention.

[0018] The figure shows: 1. Fixed mold, 2. Moving mold, 3. First insert, 4. Second insert. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0020] like Figure 1 The present invention describes an injection mold for manufacturing an automotive dashboard decorative panel.

[0021] like Figure 2 and Figure 3 As shown, the present invention provides an injection mold for an automotive dashboard decorative panel, characterized in that it includes a fixed mold 1 and a moving mold 2, wherein the moving mold 2 includes a cold material control device, a vacuum exhaust device, and an independent cooling device; The injection mold uses PA6+10%GF+20MX as the injection molding material; the moving mold 2 is provided with a number of first inserts 3 and a number of second inserts 4.

[0022] The cold material control device includes side injection of the material at each gate, and a cold material well is designed at the gate position to allow the cold material that enters the mold first to flow into this groove for storage, thereby solving the problem of cold material at the head and preventing cold material from entering the product cavity and forming silver threads.

[0023] like Figure 5 As shown, the vacuum exhaust device includes a vacuum generator. The first insert 3 has multiple exhaust holes, each connected to the vacuum generator via an air pipe. The vacuum generator is connected inside the moving mold 2. The vacuum suction device is used to extract gas from the mold cavity to create negative pressure before injection molding. The vacuum suction channel is independent of the conventional exhaust channel and does not share an exhaust slot. The vacuum generator is installed on the outer side of the moving mold 2. All air pipes from the first insert are connected to the vacuum generator. The inlet of the vacuum generator is connected to a solenoid valve, and the outlet of the vacuum generator discharges gas outside the moving mold 2. This invention uses a vacuum generator and a solenoid valve for active air extraction, rather than passively relying on filling pressure for exhaust.

[0024] The outer side of the first insert is provided with exhaust grooves, which connect all the outer surfaces of the first insert to the space inside the cavity, so as to quickly extract the air from the cavity where the first insert is located when the vacuum generator is pumping air.

[0025] like Figure 6 As shown, the exhaust groove of the sheet-like exhaust insert has a depth of 0.02-0.05 mm and a width of 10-20 mm, and is an integrated structure with the vacuum system.

[0026] The vacuum suction device starts pumping air within 0.3 to 1.0 seconds after mold closing, and the vacuum degree of the mold cavity reaches -0.06 to 0.09 MPa, which is completed before the injection molding action.

[0027] like Figure 4 As shown, the independent conformal cooling device includes an independent cooling water channel for each second insert. This water channel connects directly to the interior of the gate insert without bridging with other mold plates, enabling independent control between inserts and preventing heat from other mold plates from being transferred to the gate area via the water channel medium. All cooling water pipes connected to the second inserts are connected in parallel and pass through their respective through holes on the moving mold 2. Each second insert is connected to one inlet pipe and one outlet pipe. All inlet and outlet pipes from the second inserts are connected to a water collection block for distributing inlet water and collecting return water.

[0028] Taking a dashboard trim panel of a certain car model as an example, this product uses PA6+10%GF+20MX raw materials, and the surface needs to be textured. Using the injection mold of this invention, the specific process parameters are as follows: Cold slug control: The gate uses side injection, with a cold slug well depth of 5mm and a width equal to the gate width; Vacuum degassing: The vacuum generator is started 0.5 seconds after mold closing, and the mold cavity vacuum reaches -0.08MPa within 30 seconds, maintaining this level until injection begins; Independent cooling: The second insert 4 adopts a parallel independent water channel with an inlet water temperature of 25℃ and a flow rate of 5L / min. The cooling water is directly introduced into the interior of the gate insert without passing through other mold plates. Actual production verification shows that after using the injection mold of this invention, the product surface silver streak defect elimination rate is 100%, the air entrapment bulge and scorching defect elimination rate is 100%, the gate whitening defect elimination rate is over 98%, and the product qualification rate is increased from 82% with traditional molds to over 97%.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An injection mold for an automotive dashboard decorative panel, characterized in that: It includes a fixed mold (1) and a moving mold (2), wherein the moving mold (2) includes a cold material control device, a vacuum exhaust device and an independent conformal cooling device; The injection mold uses PA6+10%GF+20MX as the injection molding material; The moving mold (2) is provided with a number of first inserts (3) and a number of second inserts (4); The cold material control device includes side injection of the material at each gate, and a cold material well is designed at the gate position to allow the cold material that first enters the mold to flow into this groove and be stored. The vacuum exhaust device includes a vacuum generator. The first insert (3) is provided with multiple exhaust holes and is connected to the vacuum generator through air pipes. The vacuum generator is connected inside the moving mold (2). The vacuum exhaust device is used to extract the gas in the mold cavity to form a negative pressure before injection molding. The vacuum suction channel is independent of the conventional exhaust channel. The independent conformal cooling device includes an independent cooling water path for each second insert (4), which is directly connected to the interior of the gate insert without passing through other templates, so as to achieve independent control between phases.

2. The injection mold for an automotive dashboard decorative panel according to claim 1, characterized in that: The vacuum generator is installed on the outer side of the moving mold (2). All the air pipes coming out of the first insert (3) are connected to the vacuum generator. The air inlet of the vacuum generator is connected to the solenoid valve, and the air outlet is discharged outside the moving mold (2).

3. The injection mold for an automotive dashboard decorative panel according to claim 1, characterized in that: The outer side of the first insert (3) is provided with exhaust grooves, which connect all the outer surfaces of the first insert (3) with the space inside the cavity, so as to quickly extract the air inside the cavity where the first insert (3) is located when the vacuum generator is pumping air.

4. The injection mold for an automotive dashboard decorative panel according to claim 1, characterized in that: All cooling water pipes connected to the second insert (4) are connected in parallel and pass through their respective through holes on the moving mold (2).

5. An injection mold for an automotive dashboard decorative panel according to claim 1 or 4, characterized in that: Each second insert (4) is connected to an inlet pipe and an outlet pipe. All the inlet and outlet pipes from the second inserts (4) are connected to the water collection block for distributing water in and collecting return water.

6. The injection mold for an automotive dashboard decorative panel according to claim 3, characterized in that: The depth of the exhaust groove is 0.02-0.05 mm and the width is 10-20 mm.

7. An injection mold for an automotive dashboard decorative panel according to claim 1 or 2, characterized in that: The vacuum exhaust device starts pumping air within 0.3 to 1.0 seconds after the mold is closed, and the vacuum degree of the mold cavity reaches -0.06 to -0.09 MPa.

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