A precision mold with built-in venting insert

Abstract

This utility model discloses a precision mold with a built-in venting insert, including an upper mold base, a lower mold base, a cavity located at the bottom of the upper mold base, and a core located at the top of the lower mold base. A split venting insert is embedded in the melt end region of the core. The venting insert is composed of at least two layers of permeable steel stacked and fixed along the thickness direction. The pore diameter of the upper layer of permeable steel is smaller than that of the lower layer. The venting insert has an internal venting channel penetrating through the multiple layers of permeable steel, with one end extending to the molding surface of the venting insert and the other end connected to a venting interface on the mold sidewall. The multi-layer permeable steel design, combined with a spiral guide groove, uses small pores in the upper layer to prevent melt overflow and large pores in the lower layer to accelerate venting. Combined with the spiral guide for efficient venting, this significantly reduces defects such as bubbles and depressions in the plastic part, and significantly improves molding quality.

Description

Technical Field

[0001] This utility model relates to the field of mold technology, specifically a precision mold with built-in venting inserts. Background Technology

[0002] In the field of precision injection molding, mold venting performance directly affects the quality of plastic parts and production efficiency. Traditional molds often use single-layer venting steel or simple venting channel structures, resulting in low venting efficiency and easy melt overflow. Residual gas at the end of the cavity can easily lead to defects such as bubbles, depressions, and scorching in the plastic parts, especially in the production of complex structural parts. Meanwhile, traditional mold cooling systems are mostly integrated designs with insufficient temperature control precision, and venting components are prone to performance degradation due to long-term impact from high-temperature molten metal, affecting venting stability. Furthermore, venting inserts are often rigidly fixed with bolts, making disassembly and assembly cumbersome, maintenance and replacement time-consuming, and increasing production costs. Utility Model Content

[0003] In order to overcome the shortcomings of existing technical solutions, this utility model provides a precision mold with a built-in venting insert, which can effectively solve the problems mentioned in the background art.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] A precision mold with a built-in venting insert includes an upper mold base, a lower mold base, a cavity located at the bottom of the upper mold base, and a core located at the top of the lower mold base. A split venting insert is embedded in the melt end region of the core. The venting insert is composed of at least two layers of permeable steel stacked and fixed along the thickness direction. The pore diameter of the upper layer of permeable steel is smaller than that of the lower layer of permeable steel. The venting insert has an venting channel that penetrates through the multiple layers of permeable steel. One end of the channel extends to the forming surface of the venting insert, and the other end connects to the air guide port on the side wall of the mold.

[0006] As a further description of the above technical solution, the forming surface of the exhaust insert is provided with a spiral guide groove, the spiral guide groove is connected to the exhaust channel inlet, and its spiral direction is parallel to the mold opening and closing direction.

[0007] As a further description of the above technical solution, the exhaust insert is provided with an annular cooling cavity on its outer periphery. The cross-section of the annular cooling cavity is trapezoidal, and the width of the upper base of the trapezoid is smaller than the width of the lower base. The annular cooling cavity is connected to an external cooling source through an independent cooling pipeline, and the cooling pipeline is provided with a flow control valve.

[0008] As a further description of the above technical solution, the bottom of the venting insert is fixed to the core by a quick-release structure. The quick-release structure includes a dovetail groove at the bottom of the venting insert and a matching convex rail inside the mold. The opening direction of the dovetail groove is perpendicular to the parting surface.

[0009] As a further description of the above technical solution, the inner wall of the dovetail groove is provided with radial anti-slip texture, and the convex rail and the groove are fitted with a clearance of 0.02-0.05mm.

[0010] As a further description of the above technical solution, a pressure sensor is provided at the air inlet, which is linked to the mold opening and closing drive device through the controller.

[0011] As a further description of the above technical solution, the core is provided with an auxiliary ejector pin, and the ejector pin has an auxiliary exhaust micro-hole with a diameter of 0.3-0.5mm and is connected to the exhaust channel. The ejector pin is provided with a sealing ring made of polytetrafluoroethylene.

[0012] As a further description of the above technical solution, the layers of permeable steel in the exhaust insert are fixed together by diffusion welding.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] The precision mold with a built-in venting insert of this utility model has at least one of the following beneficial effects during use:

[0015] The multi-layered permeable steel design, combined with spiral flow channels, features small pores in the upper layer to prevent melt overflow and large pores in the lower layer to accelerate venting. This, along with the spiral flow channel, efficiently guides air, significantly reducing defects such as bubbles and depressions in the molded parts, thus greatly improving molding quality. An annular trapezoidal cooling chamber increases the cooling contact area, and a flow control valve enables precise temperature control, preventing performance degradation of the permeable steel and dimensional instability of the molded parts caused by high temperatures, ensuring continuous and stable mold operation. The quick-release structure, with its dovetail grooves and anti-slip texture, allows for rapid installation and removal of the venting inserts, reducing maintenance costs. A pressure sensor-linked control system adjusts mold opening and closing parameters in real time, improving production stability. Micro-holes in the auxiliary ejector pins enhance corner venting, and a PTFE sealing ring prevents leakage, further reducing the defect rate. Diffusion welding ensures a strong bond between the permeable steel layers, extending service life and comprehensively improving the efficiency and reliability of precision injection molding production. Attached Figure Description

[0016] Figure 1 This is an exploded view of the overall structure of a precision mold with a built-in venting insert according to the present invention.

[0017] Figure 2 This is a schematic diagram of the core structure of a precision mold with a built-in venting insert according to the present invention.

[0018] Figure 3 This is a schematic diagram of the core side structure of a precision mold with a built-in venting insert according to the present invention;

[0019] Figure 4This is a first perspective structural diagram of the core of a precision mold with a built-in venting insert according to the present invention.

[0020] Figure 5 This is a second perspective structural diagram of the core of a precision mold with a built-in venting insert according to the present invention.

[0021] Numbering on the map:

[0022] 1. Upper mold base; 101. Lower mold base; 102. Auxiliary ejector pin; 103. Sealing ring; 2. Core; 201. Cavity; 202. Venting insert; 203. Forming surface; 204. Annular cooling cavity; 205. Spiral guide groove; 206. Quick release structure; 207. Venting channel; 208. Dovetail groove; 209. convex rail; 210. Ventilation steel. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] like Figure 1-5 As shown, this utility model provides a precision mold with a built-in venting insert 202, including an upper mold base 1, a lower mold base 101, a cavity 201 located at the bottom of the upper mold base 1, and a core 2 located at the top of the lower mold base 101. The melt end region of the core 2 is embedded with a split venting insert 202. The venting insert 202 is composed of at least two layers of permeable steel 210 stacked and fixed along the thickness direction. The pore diameter of the upper layer of permeable steel 210 is smaller than that of the lower layer of permeable steel 210. The venting insert 202 is provided with an venting channel 207 that penetrates multiple layers of permeable steel 210. One end of the channel extends to the forming surface 203 of the venting insert 202, and the other end is connected to the air guide port on the side wall of the mold.

[0025] In this embodiment, during injection molding, the melt fills the cavity 201 under pressure. As the melt continues to advance, the gas at the end of the cavity 201 is compressed. The molding surface 203 of the venting insert 202 is provided with a spiral guide groove 205, which is connected to the inlet of the venting channel 207, and the spiral direction is parallel to the mold opening and closing direction. Under the compression, the gas is guided along the spiral guide groove 205 to the inlet of the venting channel 207, and then enters the interior of the venting insert 202. Since the venting insert 202 is composed of layers of breathable steel 210 with small upper pore diameter and large lower pore diameter, the gas can pass smoothly through the breathable steel 210 and finally be discharged from the air guide port on the side wall of the mold through the venting channel 207.

[0026] During the mold injection process, the annular cooling cavity 204 is connected to an external cooling source via an independent cooling pipeline, and the cooling medium provided by the external cooling source enters the annular cooling cavity 204. Because the annular cooling cavity 204 has a trapezoidal cross-section, and the width of the upper base is smaller than the width of the lower base, the contact area between the cooling medium and the venting insert 202 is increased, improving cooling efficiency. Simultaneously, the flow control valve on the cooling pipeline can adjust the flow rate of the cooling medium, thereby precisely controlling the temperature of the venting insert 202.

[0027] The bottom of the venting insert 202 is fixed to the core 2 via a quick-release structure 206. The quick-release structure 206 includes a dovetail groove 208 at the bottom of the venting insert 202 and a matching convex rail 209 within the mold. The opening direction of the dovetail groove 208 is perpendicular to the parting surface. The inner wall of the dovetail groove 208 is provided with radial anti-slip textures, which increases the friction between the groove and the convex rail 209 and prevents the venting insert 202 from shifting during operation. The convex rail 209 and the groove are fitted with a clearance of 0.02-0.05mm, which ensures the smooth installation and removal of the venting insert 202 and also limits its wobbling to a certain extent.

[0028] A pressure sensor is installed at the venting interface. During the injection molding venting process, the pressure sensor monitors the gas pressure in the venting channel 207 in real time and transmits the pressure signal to the controller. The controller, based on a preset pressure threshold, activates the mold opening and closing drive device. When the venting pressure reaches the set value, the controller can control the mold opening and closing drive device to perform corresponding actions, such as adjusting the mold opening and closing speed or timing, to ensure the stability of the injection molding process.

[0029] The core 2 is equipped with an auxiliary ejector pin 102, with auxiliary venting micropores inside the ejector pin. The micropores have a diameter of 0.3-0.5 mm and are connected to the venting channel 207. During the melt filling process, gas in some corners or areas that are difficult to vent can enter the venting channel 207 through the auxiliary venting micropores, thus achieving auxiliary venting. A polytetrafluoroethylene sealing ring 103 is provided on the outer periphery of the ejector pin, which can effectively prevent the melt from overflowing from the gap between the ejector pin and the core 2, ensuring the normal operation of the auxiliary venting system. The layers of permeable steel 210 of the venting insert 202 are fixed together by diffusion welding. This welding method can tightly bond the two layers of permeable steel 210 to form a solid whole, ensuring the structural stability of the venting insert 202 during long-term operation and avoiding problems such as decreased venting performance due to weak connection.

[0030] Furthermore, the venting insert 202 has a spiral guide groove 205 on its molding surface 203. The spiral guide groove 205 is connected to the inlet of the venting channel 207, and its spiral direction is parallel to the mold opening and closing direction. The venting insert 202 is constructed by stacking at least two layers of permeable steel 210 with different pore diameters. The upper layer has a smaller pore diameter, which can effectively prevent melt overflow, while the lower layer has a larger pore diameter, which is conducive to the rapid discharge of gas. Combined with the spiral guide groove 205 on the molding surface 203, it can guide the gas out more efficiently, greatly improve the venting efficiency, reduce defects such as bubbles and depressions caused by gas residue in the plastic part, and improve the molding quality of the plastic part.

[0031] Furthermore, the venting insert 202 is provided with an annular cooling cavity 204 on its outer periphery. The cross-section of the annular cooling cavity 204 is trapezoidal, with the upper base width being smaller than the lower base width. The annular cooling cavity 204 is connected to an external cooling source via an independent cooling pipeline, and the cooling pipeline is equipped with a flow control valve. The trapezoidal cross-section design of the annular cooling cavity 204 increases the cooling area and improves cooling efficiency. The independent cooling pipeline and flow control valve allow for precise adjustment of the cooling medium flow rate, achieving precise temperature control of the venting insert 202. This avoids problems such as performance degradation of the permeable steel 210 and unstable dimensional stability of the molded parts caused by excessively high temperatures, ensuring the normal working performance of the mold and the quality of the molded parts.

[0032] Furthermore, the bottom of the venting insert 202 is fixed to the core 2 via a quick-release structure 206. The quick-release structure 206 includes a dovetail groove 208 located at the bottom of the venting insert 202 and a matching protruding rail 209 within the mold. The opening direction of the dovetail groove 208 is perpendicular to the parting surface. The inner wall of the dovetail groove 208 is provided with radial anti-slip textures. The protruding rail 209 is in clearance fit with the groove, and the clearance is 0.02-0.05mm.

[0033] The venting insert 202 is fixed using a quick-release structure 206. The dovetail groove 208 and the convex rail 209, along with the reasonable clearance, make the installation and removal of the venting insert 202 more convenient. When the venting insert 202 wears out or needs to be replaced with a different specification, it can save a lot of maintenance time and costs, and improve the maintenance efficiency of the mold.

[0034] Furthermore, a pressure sensor is installed at the air vent, which is linked to the mold opening and closing drive device via a controller. The pressure sensor at the air vent, in conjunction with the controller and the mold opening and closing drive device, enables real-time monitoring of the exhaust pressure and intelligent control of the mold opening and closing process. Timely adjustments to the mold opening and closing actions based on changes in exhaust pressure prevent production failures caused by poor exhaust or abnormal pressure, thus improving the stability and reliability of the injection molding process.

[0035] Furthermore, the core 2 is equipped with an auxiliary ejector pin 102. The ejector pin has internal auxiliary venting micro-holes with a diameter of 0.3-0.5 mm that communicate with the venting channel 207. A polytetrafluoroethylene (PTFE) sealing ring 103 is provided around the outer periphery of the ejector pin. The auxiliary venting micro-holes inside the auxiliary ejector pin 102, connected to the venting channel 207, effectively vent areas that are difficult to vent, such as corners within the cavity 201, further enhancing the overall venting effect of the mold and reducing the defect rate of the plastic parts. The PTFE sealing ring 103 ensures the sealing of the auxiliary venting system, preventing melt leakage.

[0036] Furthermore, the layers of permeable steel 210 in the venting insert 202 are fixed together by diffusion welding. This diffusion welding ensures a strong connection and high overall structural stability. During long-term injection molding production, issues such as interlayer separation and loosening are less likely to occur, extending the service life of the venting insert 202 and guaranteeing the long-term stable operation of the mold.

[0037] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A precision mold with a built-in venting insert, comprising an upper mold base, a lower mold base, a cavity disposed at the bottom of the upper mold base, and a core disposed at the top of the lower mold base, characterized in that, The core has a split venting insert embedded in the melt end region. The venting insert is composed of at least two layers of permeable steel stacked and fixed along the thickness direction. The pore diameter of the upper layer of permeable steel is smaller than that of the lower layer of permeable steel. The venting insert has an venting channel that penetrates multiple layers of permeable steel inside. One end of the channel extends to the forming surface of the venting insert, and the other end connects to the air guide port on the side wall of the mold.

2. The precision mold with built-in venting insert of claim 1, wherein: The venting insert has a spiral guide groove on its molding surface. The spiral guide groove is connected to the venting channel inlet, and its spiral direction is parallel to the mold opening and closing direction.

3. The precision mold with built-in exhaust insert according to claim 1 or 2, characterized in that: The exhaust insert has an annular cooling cavity on its outer periphery. The cross-section of the annular cooling cavity is trapezoidal, and the width of the upper base of the trapezoid is smaller than the width of the lower base. The annular cooling cavity is connected to an external cooling source through an independent cooling pipe, and the cooling pipe is equipped with a flow control valve.

4. The precision mold with built-in venting insert of claim 1, wherein: The bottom of the venting insert is fixed to the core by a quick-release structure. The quick-release structure includes a dovetail groove at the bottom of the venting insert and a matching convex rail inside the mold. The opening direction of the dovetail groove is perpendicular to the parting surface.

5. The precision mold with built-in venting insert of claim 4, wherein: The inner wall of the dovetail groove is provided with radial anti-slip texture, and the convex rail and the groove are fitted with a clearance of 0.02-0.05mm.

6. The precision mold with built-in venting insert of claim 1, wherein: A pressure sensor is installed at the air inlet, which is linked to the mold opening and closing drive device via a controller.

7. The precision mold with built-in venting insert of claim 1, wherein: The core is provided with an auxiliary ejector pin, and an auxiliary venting micro-hole is opened inside the ejector pin. The micro-hole has a diameter of 0.3-0.5mm and is connected to the venting channel. A sealing ring made of polytetrafluoroethylene is provided on the outer periphery of the ejector pin.

8. The precision mold with built-in venting insert of claim 1, wherein: The layers of permeable steel in the exhaust block are fixed together by diffusion welding.

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