A structure of a cloth hanging needle of an injection mold, an injection mold and an injection production line

Abstract

The application discloses a kind of injection mold cloth hanging needle structure, including needle body, the rear section of the needle body is fixed section, the front section of the needle body is function section, the front section of the needle body protrudes from the mold face of injection mold, the function section is needle tip, single blade section and cylindrical section in turn from front to back, the single blade section is provided with single blade edge extending along the axial direction of the needle body.This application also discloses an injection mold with injection mold cloth hanging needle structure on the periphery of the cavity in the fixed mold, and an injection molding production line using such injection mold and freezer cooperation.This application can speed up the production rhythm, improve efficiency and ensure that cloth does not wrinkle.

Description

Technical Field

[0001] This invention relates to the field of injection mold technology, and in particular to an injection mold hanging pin structure, an injection mold, and an injection production line. Background Technology

[0002] In mid-to-high-end automobiles, the pillar interior panels are typically made by covering the plastic surface with flexible fabric. Low-pressure injection molding (LPI) is a good way to achieve rapid molding of these parts. The LPI process generally includes injection of granules, holding pressure, plasticizing, and cooling. Injection process parameters (such as injection speed, pressure, and holding time) are relatively fixed. Current LPI production lines struggle to improve the production cycle time and efficiency of interior parts.

[0003] If the production cycle is to be further increased, two issues need to be considered. One is how to increase the cooling speed of the mold and reduce the cooling time. If the mold cooling speed is slow, the heat accumulation due to repeated operation of the injection mold will prolong the cooling time of the injection molded parts and slow down the production cycle. The second issue is that when accelerating the cooling speed of the injection molded parts and the mold, the pressing speed between the fabric and the injection molded parts is further increased. However, the flexible fabric may wrinkle during the rapid pressing process, which will affect the appearance of the product.

[0004] Existing fabric-hanging needles use a round needle or triangular needle structure. The round needle tip is used to pierce the fabric. During the molding process, the fabric gradually tends to conform to the curved surface of the mold's inner surface, thus shrinking inward. However, since the fabric can only move axially along the round needle, the inward stretching of the fabric is hindered, affecting the fabric's adhesion. Triangular needles, on the other hand, are machined into a triangular structure with cutting edges on the sides. During the molding process, the fabric can be cut by the cutting edges, causing the fabric to move inward to conform to the injection molded part. However, as the molding speed increases, the tensile force on the fabric changes more intensely, leading to excessive cutting of the fabric. It is difficult to maintain appropriate stress during molding, which also causes wrinkles. Summary of the Invention

[0005] To address the aforementioned deficiencies in the prior art, the present invention aims to provide a fabric hanging needle structure for injection molds, an injection mold, and an injection production line, thereby solving the problem of wrinkles generated in fabric during low-pressure injection molding and further improving the production speed and efficiency of low-pressure injection molding.

[0006] The technical solution of the present invention is as follows: a fabric hanging needle structure for injection mold, comprising a needle body, the rear section of the needle body being a fixed section, the front section of the needle body being a functional section, the front section of the needle body protruding from the mold closing surface of the injection mold, the functional section being, from front to back, a needle tip, a single-edged section and a cylindrical section, the single-edged section being provided with a single cutting edge extending axially along the needle body.

[0007] This invention divides the front section of the needle body into three parts. After the needle tip pierces the fabric, it is cut by a single-blade section. Furthermore, the final section of the mold pressing is changed to a cylindrical structure to avoid excessive cutting of the fabric by the hanging needle. This provides appropriate stress to the fabric to maintain tension and ensures a smooth fit between the fabric and the injection molded part.

[0008] Furthermore, the single-blade segment has a cylindrical surface connected to the cylindrical segment on the back side of the cutting edge. By setting the back side of the single-blade segment as a cylindrical surface, the tension applied to the hanging needle by the fabric during the stretching process is perpendicular to the axial direction. Due to the presence of the cylindrical surface, there is still a large moment of inertia in this direction, resulting in strong bending resistance and avoiding the problem of the hanging needle easily bending after repeated use.

[0009] Furthermore, the needle tip is composed of a triangular pyramid structure formed by three oblique cut surfaces, and the single-edged section includes two side planes and a cylindrical surface. The two side planes intersect to form the cutting edge, and the intersection line of the oblique cut surface and the side plane is located after the intersection line of the oblique cut surface and the cylindrical surface.

[0010] Another technical solution of the present invention is: an injection mold, including a moving mold and a fixed mold, wherein the moving mold and the fixed mold are provided with mating surfaces for mutual contact, the fixed mold is provided with a cavity for product molding, and a plurality of the aforementioned injection mold hanging pin structures are provided on the fixed mold around the cavity, and the moving mold is provided with clearance holes corresponding to the injection mold hanging pin structures, the clearance holes being used for the injection mold hanging pin structures to pass through.

[0011] Furthermore, the fabric hanging needle structure of the injection mold is set within the range of the apex angle of the adjacent side forming curved surfaces of the cavity, and the cutting edge of the needle body is away from the cavity.

[0012] Furthermore, the needle body is located at the angle bisector of the opposite vertices.

[0013] Furthermore, the moving mold has a convex structure opposite to the concave cavity, and a pressing block for cooperating with the fixed mold to press the fabric is provided on the periphery of the convex structure between adjacent clearance holes.

[0014] Furthermore, the fixed mold and the moving mold are provided with a number of conformal water wells, which are connected by water channels, and the distance between adjacent conformal water wells is no more than 40cm.

[0015] Furthermore, the water channel is 15-20 cm away from the mold closing surface, the bottom surface of the cavity, and the surface of the convex structure in the normal vertical direction. The water channel is provided with an insert, and the insert has a network structure channel inside. The network structure is composed of multiple connected units, and the channel in each unit corresponds to the grid points and grid line connecting the grid points of the body-centered cubic structure.

[0016] Another technical solution of the present invention is: an injection molding production line, including the aforementioned injection mold and a chiller, wherein the chiller provides a coolant at a temperature not higher than 11°C to the water channel.

[0017] The advantages of this invention compared to the prior art are:

[0018] This invention utilizes a single-edged fabric-hanging needle to slit the fabric during mold closing, creating a displacement perpendicular to the needle's axis to meet fabric deformation requirements. Simultaneously, it ensures sufficient stress to maintain tension in the fabric at the end of mold closing, guaranteeing continuous fabric flattening during mold closure and preventing localized fabric accumulation and wrinkling during rapid mold pressing. Molds employing this fabric-hanging needle structure can reduce mold closing speed from 6 seconds to 3 seconds. Correspondingly, by incorporating conformal water wells, water channels, and a chiller, rapid mold cooling can be achieved, ensuring the fabric remains wrinkle-free and reducing single-piece injection molding production time from 60 seconds to 30 seconds. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the fixed mold of an injection mold.

[0020] Figure 2 This is a schematic diagram of the moving mold of an injection mold.

[0021] Figure 3 This is a schematic diagram of the coolant flow channel structure of an injection mold.

[0022] Figure 4 This is a schematic diagram showing the location of the coolant flow channels.

[0023] Figure 5 This is a schematic diagram of the waterway insert structure.

[0024] Figure 6 This is a schematic diagram of the cutting edge of the fabric hanging needle structure in an injection mold.

[0025] Figure 7 This is a schematic diagram of the back side view of the fabric hanging needle structure of an injection mold.

[0026] Figure 8 This is a schematic diagram of the position of the fabric hanging needle structure in the fixed mold of an injection mold. Detailed Implementation

[0027] The present invention will be further described below with reference to embodiments, but these are not intended to limit the scope of the invention.

[0028] This embodiment relates to an injection molding production line, which mainly includes an injection mold used for injection molding products. The invention adds a chiller to the existing production line. The injection mold is equipped with a coolant channel for rapid cooling. Coolant flows into the injection mold from the inlet of the coolant channel, absorbs heat from the mold, and flows out from the outlet. After cooling, the coolant is circulated back into the injection mold. The chiller is located in the coolant circulation loop to cool and lower the temperature of the coolant flowing into the injection mold, maintaining it at a temperature not exceeding 11°C, thereby meeting the rapid cooling requirements of the injection mold.

[0029] Please combine Figure 1 and Figure 2 As shown, the injection mold includes a moving mold 2 and a fixed mold 1, with the mating surface of the moving mold 2 and the fixed mold 1 being the parting surface 3. The moving mold 2 includes a base 201 and a moving block 202, with the parting surface 3 located on the moving block 202. A guide post 4 is provided on the base 201 to guide the moving block 202, allowing it to move towards the fixed mold 1 to achieve mold closing. The fixed mold 1 has a cavity 5 for product molding, and correspondingly, the moving block 202 has a protrusion 6 opposite to the cavity 5. After the moving block 202 moves towards the fixed mold 1, the parting surfaces 3 of the two are mated, and the protrusion 6 extends into the cavity 5, forming an injection cavity between the protrusion 6 and the cavity 5.

[0030] Several injection mold hanging pin structures are provided on the fixed mold 1 around the cavity 5. In this embodiment, the injection mold is used to produce the pillar interior panel. The four corners of the pillar interior panel are the included angles formed by curved surfaces. That is to say, the cavity 5 is roughly rectangular in shape, and the four sides of the rectangle are actually curved surfaces, which are the side forming curved surfaces 501 of the cavity 5. Injection mold hanging pin structures are provided at the positions corresponding to the included angles formed by adjacent side forming curved surfaces 501, such as... Figure 8 As shown. The corresponding position mentioned here refers to the range of the apex angle 7 of the angle between the adjacent side molding surfaces 501 of the cavity 5. In this embodiment, it is preferable that the injection mold hanging pin structure is located at the angle bisector 701 of the apex angle 7. Setting the injection mold hanging pin structure at this position can make the stress on the fabric during mold closing evenly distributed at the corner position, ensuring balanced stretching on both sides and avoiding wrinkles accumulating on one side.

[0031] Since the fabric hanging pin structure of the injection mold protrudes from the mold closing surface 3 of the fixed mold 1 and the moving mold 2, the moving block 202 is provided with a clearance hole 8 corresponding to the fabric hanging pin structure of the injection mold. When the fixed mold 1 and the moving mold 2 are closed, the clearance hole 8 is used for the fabric hanging pin structure of the injection mold to pass through. In addition, a pressing block 9 is provided on the periphery of the protruding structure 6 between adjacent clearance holes 8 for cooperating with the fixed mold 1 to press the fabric. The pressing block 9 can be driven by a cylinder to move in the mold closing direction. After the fixed mold 1 and the moving mold 2 are closed, the pressing block 9 moves towards the fixed mold 1 to press the fabric against the surface of the fixed mold 1 to ensure the flatness of the fabric.

[0032] Please combine Figure 3 and Figure 4 As shown, coolant channels are provided on both the fixed mold 1 and the moving mold 2. These channels include conformal water wells 10, which are connected by water channels 11. The distance between adjacent conformal water wells 10 is no greater than 40cm. Simultaneously, the normal vertical distance d between the water channels 11 and the parting surface 3, the bottom surface of the cavity 5 on the fixed mold 1, and the surface of the convex structure 6 on the moving mold 2 is 15-20cm. This ensures that the coolant channels cover the entire area of ​​the product, guaranteeing rapid cooling of the injection molded part. To further enhance the cooling effect of the coolant channels, a 3D-printed insert 1101 is embedded within the water channel 11. The structure of the insert 1101 is as follows... Figure 5 As shown, a network structure channel is provided inside the embedding 1101. The network structure is composed of multiple units 1101a connected together. The channel in each unit 1101a corresponds to a grid point A and a grid line B formed by a body-centered cubic structure.

[0033] The following is combined with Figure 6 and Figure 7 As shown, the fabric hanging needle structure of the injection mold is further described. The fabric hanging needle structure of the injection mold includes a needle body 12, which is divided into a front section and a rear section. It should be noted that the distinction between the front and rear sections here is based on the purpose of the needle body 12, not on its specific structure. Therefore, there is no obvious dividing line between the front and rear sections on the needle body 12. The rear section of the needle body 12 is a fixed section 1201, used for fixed connection with the fixed mold 1. The front section of the needle body 12 is a functional section 1202, used for piercing, cutting, and pulling the fabric. The front section of the needle body 12 protrudes from the mold parting surface 3 of the injection mold. The functional section 1202 consists of three parts from front to back: a needle tip 1203, a single-edged section 1204, and a cylindrical section 1205.

[0034] The needle tip 1203 is a triangular pyramid structure composed of three beveled surfaces 1206, which facilitates piercing the fabric. The single-blade section 1204 includes two side planes 1207 and a cylindrical surface 1208. The two side planes 1207 of the single-blade section 1204 intersect to form a single cutting edge 1209 extending axially along the needle body 12. This cutting edge 1209 cuts the fabric to form a slit as the fabric moves axially along the needle body 12, allowing the fabric to move along the slit. The intersection line of the beveled surfaces 1206 of the needle tip 1203 and the side planes 1207 is located after the intersection line of the beveled surfaces 1206 and the cylindrical surface 1208, making it easier for the fabric to extend to the single-blade section 1204 after being pierced by the needle tip 1203, reducing the fabric's tension time and accelerating the mold closing speed. During the stretching process, the tension applied to the hanging needle by the fabric is perpendicular to the axial direction. Based on the setting of the cylindrical surface 1208 on the back side of the single-blade section 1204, there is still a large moment of inertia in this direction due to the presence of the cylindrical surface 1208, which has strong bending resistance and avoids the problem of the hanging needle being easy to bend after repeated use.

[0035] The cylindrical segment 1205 is an extension of the single-blade segment 1204. Specifically, the cylindrical segment 1205 is attached to the cylindrical surface 1208 of the single-blade segment 1204. In other words, the cylindrical surface of the cylindrical segment 1205 extends forward to become the cylindrical surface 1208 of the single-blade segment 1204. Furthermore, the cutting edge 1209 of the single-blade segment 1204 is also located on the extended surface of the cylindrical segment 1205 (i.e., the maximum distance from the cutting edge 1209 of the single-blade segment 1204 to the cylindrical surface 1208 is equal to the diameter of the cylindrical segment 1205). When the fabric hanging needle structure of the injection mold is set in the fixed mold 1, the cylindrical segment 1205 of the needle body 12 remains protruding from the mold closing surface 3, and the cutting edge 1209 of the needle body 12 faces away from the cavity 5. In this embodiment, all cutting edges 1209 of the needle body 12 are arranged laterally.

[0036] Therefore, the present invention divides the front section of the needle body 12 into three parts. After the needle tip 1203 pierces the fabric, it is cut by the single-blade section 1204. Furthermore, the final section of the mold pressing is changed to a cylindrical structure to avoid excessive cutting of the fabric by the hanging needle, to provide appropriate stress to the fabric and maintain tension, and to ensure smooth adhesion between the fabric and the injection molded part.

Claims

1. A fabric hanging needle structure for injection molds, comprising a needle body, characterized in that, The rear section of the needle body is a fixed section, and the front section of the needle body is a functional section. The front section of the needle body protrudes from the mold closing surface of the injection mold. The functional section consists of a needle tip, a single-edged section, and a cylindrical section from front to back. The single-edged section has a single cutting edge extending along the axial direction of the needle body. The needle tip is a triangular pyramid structure composed of three oblique facets. The single-edged section includes two side planes and a cylindrical surface. The two side planes intersect to form the cutting edge. The intersection line of the oblique facet and the side plane is located after the intersection line of the oblique facet and the cylindrical surface.

2. The injection mold hanging needle structure according to claim 1, characterized in that, The single-edged section has a cylindrical surface on the back side of the cutting edge that connects to the cylindrical section.

3. An injection mold, comprising a moving mold and a fixed mold, wherein the moving mold and the fixed mold are provided with parting surfaces for mutual engagement, characterized in that, The fixed mold is provided with a cavity for product molding, and a plurality of injection mold hanging needle structures as described in claim 1 or 2 are provided on the periphery of the cavity on the fixed mold. The moving mold is provided with clearance holes corresponding to the injection mold hanging needle structures, and the clearance holes are used for the injection mold hanging needle structures to pass through.

4. The injection mold according to claim 3, characterized in that, The fabric hanging needle structure of the injection mold is set within the range of the apex angle of the adjacent side forming curved surfaces of the cavity, and the cutting edge of the needle body is away from the cavity.

5. The injection mold according to claim 4, characterized in that, The needle body is located at the angle bisector of the opposite vertical angle.

6. The injection mold according to claim 3, characterized in that, The moving mold has a convex structure opposite to the concave cavity, and a pressing block for cooperating with the fixed mold to press the fabric is provided on the periphery of the convex structure between adjacent clearance holes.

7. The injection mold according to claim 6, characterized in that, The fixed mold and the moving mold are provided with a number of conformal water wells, which are connected by water channels, and the distance between adjacent conformal water wells is no more than 40cm.

8. The injection mold according to claim 7, characterized in that, The water channel is 15-20 cm away from the mold closing surface, the bottom surface of the cavity, and the surface of the convex structure. The water channel is provided with an insert, and the insert has a network structure channel inside. The network structure is composed of multiple connected units, and the channel in each unit corresponds to the grid points and grid line connecting the grid points of the body-centered cubic structure.

9. An injection molding production line, characterized in that, Includes the injection mold as described in claim 7 or 8 and a chiller, the chiller providing a coolant at a temperature not exceeding 11°C to the waterway.

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