Injection mold frame system for preparing small multi-cavity thin-wall plastic parts

Abstract

The utility model discloses an injection mold frame system for preparing a small multi-cavity thin-wall plastic part, which relates to the technical field of injection molds, and comprises a movable mold seat, a fixed mold seat matched with each other for use is arranged at the upper part of the movable mold seat, a plurality of thimbles are mounted in the middle of the movable mold seat through bolts, and adjusting mechanisms are arranged at the end parts of the plurality of thimbles. After the positioning rod at the bottom end of the connecting piece is embedded into the groove body, the threaded sleeve is rotated to drive the threaded piece to get close to the connecting piece and be tightly attached to the connecting piece, so that fixing of the ejector pin end assembly is completed, when replacement is needed, the threaded sleeve is rotated reversely to enable the threaded piece to be separated from the connecting piece, and the ejector pin end assembly is replaced. By means of the design, abrasion or shape adaptation adjustment of the end of the ejector pin does not need to be integrally disassembled, only the end of the ejector pin needs to be locally disassembled and assembled, the maintenance time is remarkably shortened, the ejector pin structure is particularly suitable for the scene that an ejection end structure needs to be frequently replaced in a multi-cavity mold, and the production efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of injection mold technology, specifically to an injection mold frame system for preparing small, multi-cavity, thin-walled plastic parts. Background Technology

[0002] The mold base, also known as the mold body, is the skeleton and base of the injection mold. Every part of the mold is parasitic within it, and it is also the unprocessed assembly of the cavity. In addition, except for the cavity and core which depend on the plastic part, the rest of the mold base is extremely similar, making the standardization of the mold base possible. Small multi-cavity thin-walled injection molded parts are widely used in electronics, medical, automotive and other fields. These plastic parts are usually characterized by small size, thin wall thickness and many cavities.

[0003] Referring to the patent document: Patent Publication No. CN216100163U, Patent Publication Date 2022-03-22, a precision small plastic part injection mold is disclosed, including a mounting plate and a protective cover. Four sets of guide rods are fixedly mounted on the upper surface of the mounting plate. A fixing plate is fixedly mounted on the upper end of each guide rod. Connecting grooves are formed through the upper and lower surfaces of the fixing plate. There are two sets of mounting plates. A mold base is fixedly mounted on the upper surface of both sets of mounting plates. A mating groove is formed on the upper surface of the mold base. Buckles are fixedly mounted on both sides of the mold base. A module is snapped onto the upper surface of the mold base. Locking blocks are fixedly mounted on both sides of the module. A mating block is fixedly mounted on the lower surface of the module. This design enables the injection mold to have heat dissipation capabilities, allowing for adjustment according to user needs. It enables faster molding of compact small plastic parts and facilitates easy disassembly and assembly of the injection mold. It allows for quick replacement of modules required for different injection molded parts, demonstrating practicality.

[0004] Based on the search of patent numbers and the shortcomings of existing technologies, the following was found:

[0005] Traditional molds generally use a fixed ejector pin design. When the ejector pin tip wears or the ejection structure needs to be adjusted, the entire ejector pin must be disassembled and replaced, resulting in long maintenance time and low efficiency. Especially in multi-cavity molds, where there are many ejector pins, frequent ejector pin replacements significantly increase downtime and affect production efficiency. At the same time, most existing molds lack effective ejector pin buffer designs, resulting in rigid contact between the ejector pin and the plastic part. For thin-walled plastic parts, this rigid ejection can easily lead to defects such as dents and cracks on the product surface, seriously affecting product quality.

[0006] Therefore, this utility model provides an injection mold frame system for preparing small, multi-cavity, thin-walled plastic parts. Utility Model Content

[0007] To address the problems of traditional molds using fixed ejector pin designs, which require complete disassembly and replacement when the ejector pin ends wear or the ejection structure needs adjustment, increasing maintenance time and downtime frequency of multi-cavity molds, and the lack of buffer design which results in rigid contact between the ejector pin and the plastic part, easily causing quality defects such as surface dents and cracks in thin-walled products; the purpose of this utility model is to provide an injection mold base system for preparing small multi-cavity thin-walled plastic parts.

[0008] To achieve the above objectives, this utility model provides the following technical solution: a mold base system for preparing small, multi-cavity, thin-walled plastic parts, comprising a movable mold base, a fixed mold base for mutual cooperation on the upper part of the movable mold base, and multiple ejector pins mounted on the middle of the movable mold base by bolts. Each ejector pin has an adjustment mechanism at its end for buffering and replacing the ejector pin ends. The adjustment mechanism includes:

[0009] The mounting assembly includes a connector fixedly mounted on the top of the ejector pin, a threaded sleeve rotatably mounted on the upper part of the connector, a threaded component provided on the upper part of the connector, the threaded component and the threaded sleeve being connected by threads, a positioning rod fixedly mounted on the bottom end of the connector, a lower sleeve fixedly mounted on the top end of the threaded component, and an upper sleeve slidably mounted on the outer side of the lower sleeve.

[0010] A buffer assembly, located on the upper part of the lower sleeve, is used to cushion the impact when the top pin ejects the plastic part.

[0011] Preferably, the buffer assembly includes a sliding rod that is slidably engaged in the middle of the lower sleeve, the top end of the sliding rod being fixedly installed on the inner upper surface of the upper sleeve, a buffer spring being fixedly installed at the bottom end of the sliding rod, the bottom end of the buffer spring being fixedly installed at the top end of the threaded part, a pressure spring being fixedly installed at the top end of the lower sleeve, and the top end of the pressure spring being fixedly installed on the inner upper surface of the upper sleeve.

[0012] Preferably, the connector has a groove in the middle, and the positioning rod is slidably engaged in the middle of the groove.

[0013] Preferably, the outer wall of the threaded sleeve is uniformly distributed with anti-slip ridges to enhance rotational friction.

[0014] Preferably, the outer side of the lower sleeve has two symmetrically distributed sliding grooves, and the inner wall of the upper sleeve has two symmetrically distributed sliders fixedly installed, both of which are slidably engaged inside the sliding grooves.

[0015] Preferably, a pressure sensor is fixedly installed at the top center of the upper sleeve, the sensing end face of the pressure sensor is flush with the top surface of the upper sleeve, and the pressure sensor is sealed to the upper sleeve through potting compound.

[0016] Beneficial effects

[0017] This invention provides an injection mold base system for manufacturing small, multi-cavity, thin-walled plastic parts. Compared with the prior art, it has the following advantages:

[0018] 1. This application fixes the ejector pin end assembly by embedding the positioning rod at the bottom of the connector into the groove, and then rotating the threaded sleeve to drive the threaded part to approach and fit tightly with the connector. When replacement is needed, the threaded sleeve is rotated in the opposite direction to disengage the threaded part from the connector, and the lower sleeve and upper sleeve and other components can be removed. This design eliminates the need to completely disassemble the ejector pin for wear or shape adaptation adjustment at the ejector pin end, requiring only partial disassembly and assembly of the ejector pin end, which significantly shortens maintenance time. It is especially suitable for scenarios in multi-cavity molds where the ejector end structure needs to be frequently changed, thus improving production efficiency.

[0019] 2. When the ejector pin extends, the upper sleeve contacts the injection molded part, causing the reverse force to push the upper sleeve to move, squeezing the pressure spring and driving the sliding rod to compress the buffer spring, forming a double buffer force, so that the ejection force gradually increases. At the same time, the pressure sensor detects the contact pressure between the upper sleeve and the injection molded part in real time. If it exceeds the preset threshold, it immediately feeds back a signal to the control system, controls the ejector pin to reset and push again, avoiding excessive force that could cause the thin-walled plastic part to dent or crack. This design not only ensures the smoothness of the ejection process, but also reduces the scrap rate through intelligent overload protection. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model.

[0021] Figure 2 This is a schematic diagram of the moving mold base structure of this utility model.

[0022] Figure 3 This utility model Figure 2 Enlarged view of point A in the middle.

[0023] Figure 4 This is a schematic diagram of the structure after the installation components are disassembled in this utility model.

[0024] Figure 5 This is a cross-sectional structural diagram of the buffer component of this utility model.

[0025] In the diagram: 1. Moving mold base; 11. Fixed mold base; 2. Adjustment mechanism; 21. Mounting assembly; 211. Ejector pin; 212. Connector; 213. Threaded sleeve; 214. Groove; 2141. Positioning rod; 215. Threaded part; 216. Lower sleeve; 217. Upper sleeve; 2171. Slider; 2172. Slide groove; 218. Pressure sensor; 22. Buffer assembly; 221. Buffer spring; 222. Sliding rod; 223. Pressure spring. Detailed Implementation

[0026] 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.

[0027] Please see Figure 1-5 This utility model provides a technical solution: an injection mold base system for manufacturing small multi-cavity thin-walled plastic parts, including a movable mold base 1, a fixed mold base 11 for mutual cooperation on the upper part of the movable mold base 1, and a plurality of ejector pins 211 mounted on the middle part of the movable mold base 1 by bolts. The ejector pins 211 are fixed to the movable mold base 1 by machining screw holes at their tails and using special screws. Each of the multiple ejector pins 211 has an adjustment mechanism 2 at its end for buffering and replacing the ends of the ejector pins 211. The adjustment mechanism 2 includes:

[0028] The mounting assembly 21 includes a connector 212 fixedly mounted on the top of the ejector pin 211. A threaded sleeve 213 is rotatably mounted on the upper part of the connector 212. A threaded component 215 is provided on the upper part of the connector 212. The threaded component 215 and the threaded sleeve 213 are connected by threads. A positioning rod 2141 is fixedly mounted on the bottom end of the connector 212. By aligning the positioning rod 2141 with the middle of the groove 214 and pushing it inward, the threads on the threaded sleeve 213 and the threads on the outer surface of the threaded component 215 are engaged with each other. By rotating the threaded sleeve 213, the threaded component 215 is moved closer to the connector 212 until the threaded component 215 and the connector 212 are completely fitted together, thereby completing the installation and fixing of the threaded component 215. A lower sleeve 216 is fixedly mounted on the top of the threaded component 215. An upper sleeve 217 is slidably sleeved on the outer side of the lower sleeve 216.

[0029] The buffer assembly 22 is disposed on the upper part of the lower sleeve 216 and is used to buffer the ejector pin 211 when it ejects the plastic part.

[0030] The buffer assembly 22 includes a sliding rod 222 slidably engaged in the middle of the lower sleeve 216. The top end of the sliding rod 222 is fixedly installed on the inner upper surface of the upper sleeve 217. A buffer spring 221 is fixedly installed at the bottom end of the sliding rod 222. The bottom end of the buffer spring 221 is fixedly installed at the top end of the threaded part 215. A pressure spring 223 is fixedly installed at the top end of the lower sleeve 216. The top end of the pressure spring 223 is fixedly installed on the inner upper surface of the upper sleeve 217. After injection molding, the spring extends outward through the ejector pin 211. This causes the upper sleeve 217 to come into contact with the injection molded part, pushing the injection molded part out of the mold cavity. At the same time, during the pushing process, the upper sleeve 217 will move towards the ejector pin 211. The compression spring 223 will simultaneously drive the sliding rod 222 to move in the middle of the lower sleeve 216, causing the compression buffer spring 221 to contract. Thus, under the buffer of the compression spring 223 and the buffer spring 221, direct hard contact can be avoided when ejecting the injection molded part, which would cause dents, cracks or other phenomena on the surface of the injection molded part.

[0031] The connector 212 has a groove 214 in the middle, and the positioning rod 2141 is slidably locked in the middle of the groove 214. The groove 214 is designed to lock the positioning rod 2141 in the groove 214, which can only slide back and forth and cannot rotate, thus facilitating the installation and removal of the threaded parts 215 by rotating the threaded sleeve 213.

[0032] The outer wall of the threaded sleeve 213 is evenly distributed with anti-slip ridges to enhance rotational friction and facilitate the installation and fixing of the threaded part 215 by rotating the threaded sleeve 213.

[0033] The lower sleeve 216 has two symmetrically distributed sliding grooves 2172 on its outer side. The upper sleeve 217 has two symmetrically distributed sliders 2171 fixedly installed on its inner wall. Both sliders 2171 are slidably locked inside the sliding grooves 2172. By slidably locking the two sliders 2171 inside the sliding grooves 2172, the upper sleeve 217 can be limited, ensuring that the upper sleeve 217 can only slide stably along the outer surface of the lower sleeve 216 and will not rotate.

[0034] A pressure sensor 218 is fixedly installed at the top center of the upper sleeve 217. The sensing end face of the pressure sensor 218 is flush with the top face of the upper sleeve 217, and the pressure sensor 218 is sealed to the upper sleeve 217 through potting compound. The pressure sensor 218 is a piezoresistive pressure sensor 218, which is connected to the control system through a shielded cable to detect the pressure value between the upper sleeve 217 and the injection molded part in real time. When the pressure exceeds the preset threshold, the ejector pin 211 will reset and re-drive, repeatedly pushing the injection molded part to avoid excessive force causing damage to the injection molded part, while ensuring that the demolding force is controlled within the optimal range.

[0035] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0036] During operation, in the mold closing stage, the fixed mold base 11 and the moving mold base 1 close, and the molten plastic is injected into the mold cavity for molding. After injection molding, the demolding stage begins. The injection molding machine drives the ejector pin 211 on the moving mold base 1 to extend outward. At this time, the adjusting mechanism 2 at the end of the ejector pin 211 plays a role, and the ejector pin 211 continues to extend. The upper sleeve 217 contacts the injection molded part first. Since the injection molded part is stuck in the molding cavity, it generates a reverse force on the part. Under the action of the force, the upper sleeve 217 moves towards the ejector pin 211, squeezing the pressure spring 223 and driving the sliding rod 222 to slide in the middle of the lower sleeve 216, so that the buffer spring 221 is also compressed. The pressure spring 223 and the buffer spring 221 provide buffering force together to avoid direct hard contact between the ejector pin 211 and the injection molded part, and prevent damage such as dents and cracks on the surface of the injection molded part during ejection.

[0037] During this process, the pressure sensor 218 at the top of the upper sleeve 217 monitors the pressure value between it and the injection molded part in real time. Once the pressure exceeds the set threshold, the pressure sensor 218 feeds the signal back to the control system. The control system controls the ejector pin 211 to reset and re-drive. Through repeated pushing, the injection molded part is successfully demolded while avoiding damage to the injection molded part due to excessive force.

[0038] When the upper sleeve 217 at the top of the ejector pin 211 is worn, the operator can rotate the threaded sleeve 213 to separate it from the threaded part 215, and remove the positioning rod 2141 from the groove 214, so that the lower sleeve 216, upper sleeve 217 and other buffer components 22 can be removed.

[0039] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0040] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An injection mold base system for preparing small, multi-cavity, thin-walled plastic parts, comprising a moving mold base (1), characterized in that: The upper part of the moving mold base (1) is provided with a fixed mold base (11) for mutual cooperation. Multiple ejector pins (211) are bolted to the middle of the moving mold base (1). Each ejector pin (211) has an adjustment mechanism (2) at its end for buffering and replacing the ends of the ejector pins (211). The adjustment mechanism (2) includes: The mounting assembly (21) includes a connector (212) fixedly mounted on the top of the ejector pin (211), a threaded sleeve (213) rotatably mounted on the upper part of the connector (212), a threaded part (215) provided on the upper part of the connector (212), the threaded part (215) and the threaded sleeve (213) being connected by threads, a positioning rod (2141) fixedly mounted on the bottom end of the connector (212), a lower sleeve (216) fixedly mounted on the top end of the threaded part (215), and an upper sleeve (217) slidably mounted on the outer side of the lower sleeve (216). A buffer assembly (22) is provided on the upper part of the lower sleeve (216) for buffering when the ejector pin (211) ejects the plastic part.

2. The injection mold base system for preparing small multi-cavity thin-walled plastic parts according to claim 1, characterized in that: The buffer assembly (22) includes a sliding rod (222) that is slidably engaged in the middle of the lower sleeve (216). The top end of the sliding rod (222) is fixedly installed on the inner upper surface of the upper sleeve (217). A buffer spring (221) is fixedly installed at the bottom end of the sliding rod (222). The bottom end of the buffer spring (221) is fixedly installed at the top end of the threaded part (215). A pressure spring (223) is fixedly installed at the top end of the lower sleeve (216). The top end of the pressure spring (223) is fixedly installed on the inner upper surface of the upper sleeve (217).

3. The injection mold base system for preparing small multi-cavity thin-walled plastic parts according to claim 1, characterized in that: The connector (212) has a groove (214) in the middle, and the positioning rod (2141) is slidably engaged in the middle of the groove (214).

4. The injection mold base system for preparing small multi-cavity thin-walled plastic parts according to claim 1, characterized in that: The outer wall of the threaded sleeve (213) is uniformly distributed with anti-slip ridges to enhance rotational friction.

5. The injection mold base system for preparing small multi-cavity thin-walled plastic parts according to claim 1, characterized in that: The lower sleeve (216) has two symmetrically distributed sliding grooves (2172) on its outer side, and the upper sleeve (217) has two symmetrically distributed sliders (2171) fixedly installed on its inner wall. Both sliders (2171) are slidably engaged inside the sliding grooves (2172).

6. The injection mold base system for preparing small multi-cavity thin-walled plastic parts according to claim 1, characterized in that: A pressure sensor (218) is fixedly installed at the top center of the upper sleeve (217). The sensing end face of the pressure sensor (218) is flush with the top face of the upper sleeve (217), and the pressure sensor (218) is sealed to the upper sleeve (217) by potting compound.

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