Small hole injection molding mold and injection molding method

Abstract

The invention discloses a small hole injection molding mold and an injection molding method. The small hole injection molding mold comprises a fixed mold plate, a movable mold plate, an insert, a mold core and an ejector pin, the movable mold plate and the fixed mold plate are combined to form a cavity space, the insert comprises a small hole with a small-taper front section, the ejector pin comprises a main body part and a pin part, the main body part is located in the front section of the mold core, and the rear end of the main body part is connected with a spring. The needle part extends out of the front end of the insert, and when the movable mold plate and the fixed mold plate are combined, the needle part enters the small hole of the insert and abuts against the insert. According to the injection molding method, the movable mold plate and the fixed mold plate are combined to form the cavity space, the pin part of the ejector pin enters the small hole of the insert and abuts against the insert, and then injection molding is conducted in the cavity space. The problems that in the prior art, the coaxiality of mold cores is difficult to guarantee, needle tips are prone to being eccentric, inclined and broken, the sizes of small holes of products are uneven and difficult to control, and the edges of the small holes are scratched during demolding are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of molds, and more specifically, to the technical field of injection molding molds, and particularly to a micro-injection molding mold for a needleless syringe medicine tube and an injection molding method. Background Art

[0002] Needleless injection, also known as needle-free injection, needleless type injection, or jet injection, is a technology that uses a power source to generate instantaneous high pressure to pressurize the liquid medicine or freeze-dried powder medicine in the syringe, and the medicine penetrates the skin to reach the internal skin, subcutaneous, or muscle tissue in the form of high pressure and high speed through a nozzle, so as to achieve injection without using a needle. The technology of needleless injection enables the medicine to be diffusely distributed under the skin and is commonly used for the injection of insulin, vaccines, interferons, etc. Compared with the traditional needle injection technology using stainless steel needles, it has the advantages of fast drug absorption, uniform dispersion, high absorption rate, small trauma, reduced pain, and elimination of injection fear.

[0003] The basic structure of a needleless syringe includes a medicine tube, a power device, and an injection orifice. Among them, the inside of the medicine tube is used to load the medicine, and one end of it is connected to the power device; the power device can be powered by a spring mechanism, carbon dioxide gas, magnetism, or electricity; the other end of the medicine tube has an injection orifice, and the injection orifice is used to suck and inject the medicine. The injection orifice is a key component of the needleless syringe, and strict requirements are imposed on its shape, size, tolerance, angle, etc. For example, its diameter is generally required to be about 0.1 mm, the tolerance is generally required to be between ±0.01 mm, and it is required that it does not shift, deform, or bend during use.

[0004] There are two common methods for manufacturing a needleless syringe medicine tube. One is the traditional glass syringe processing method, where one end of the glass tube is heated and softened and a spray hole is formed by some means. The injection orifice manufactured by this method is difficult to meet the above requirements; the other is the mold injection method, which is to pre-manufacture a fine mold and perform mold injection in it to manufacture the needleless syringe medicine tube. The method of forming the injection orifice by this injection method is also called the mold small hole forming process.

[0005] Figure 1 It is a schematic structural diagram of a mold for manufacturing a needleless syringe used in the prior art for the mold small hole forming process. Figure 2 It is Figure 1 a partial enlarged schematic diagram. It includes an upper template 1, a lower template 2, a mold core 3, a needle tip part 4, a copper rod 5, etc. Among them, the upper template 1 includes a medicine tube cavity 11 and a copper rod 5. The mold core 3 is inserted into the medicine tube cavity 11. The end of the mold core 3 is the needle tip part 4, and the needle tip part 4 extends out of the medicine tube cavity 11 and is inserted into the copper rod 5.

[0006] In the above-mentioned small-hole forming process of the mold, since the tip of the needle and the mold core are an integral whole and the length of the entire mold core is relatively long, it is not easy to ensure coaxiality during processing. In particular, the tip of the needle is prone to eccentricity, and the cumulative error is relatively large after being installed on the mold, resulting in the front tip of the needle being inclined when poked on the positioning copper rod. The small holes of the injection-molded product are uneven in size and difficult to control. During the demolding step, when the mold core is withdrawn, due to the cumulative error, the mold core will have slight shaking, which will scratch the edge of the small hole, causing debris in the liquid ejected from the product during use. This leads to a high rejection rate of the product, high production costs, and low production efficiency. At the same time, since the entire long mold core is prone to deformation during the injection molding process, it is impossible for the tip of the needle to poke in the same hole every time when poking the positioning copper rod, which will make the small holes on the product elliptical, the tip of the needle is easily broken, and the mold core needs to be replaced and re-adjusted, increasing the workload and cost. Summary of the Invention

[0007] Aiming at the current situation and defects of the above-mentioned prior art, the purpose of the present invention is to provide a manufacturing mold and manufacturing method for a needleless syringe medicine tube, which can avoid the eccentricity of the needle tip, reduce the cumulative error, accurately control the size, shape and tolerance of the needle hole, will not scratch the edge of the small hole to generate debris during demolding, protect the needle tip from being easily broken, reduce the rejection rate and production cost, and improve the production efficiency.

[0008] The technical solution adopted by the present invention to solve the above technical problems is as follows: A small-hole injection molding mold includes a fixed template, a moving template, an insert block, a mold core, and a thimble. The moving template and the fixed template are combined to form a cavity space. It is characterized in that the insert block includes a small hole, the thimble includes a main body part and a needle part, the main body part is located in the front section inside the mold core, and the needle part passes through the small hole at the end of the mold core and enters the small hole of the insert block and abuts against the insert block.

[0009] Further, the mold core includes a spring, and the spring is connected to the rear end of the thimble. The spring generates an elastic force to push the thimble in the direction of the front end of the mold core.

[0010] Further, the mold core is a hollow structure with a small hole at the end, the spring and the main body part of the thimble are located in the hollow structure, and the needle part at the front end of the thimble passes through the small hole.

[0011] Further, the insert block is located on the fixed template, and the front section of the small hole has a small taper, and the small taper is a conical frustum or an arc chamfered space with a larger outer part and a smaller inner part. The setting of the small taper can play a guiding role, and the needle part of the thimble can enter the reserved small hole along it when the fixed template and the moving template are combined, ensuring that the needle part is in the small hole every time the injection mold is closed.

[0012] Further, the core is disposed on the moving template, the fixed template includes a chamber, and after the moving template and the fixed template are combined, a part of the needle portion enters into the small hole of the insert block and abuts against the insert block to form the cavity space.

[0013] Further, the core is disposed on the moving template, the moving template includes a chamber, and after the moving template and the fixed template are combined, a part of the needle portion enters into the small hole of the insert block and abuts against the insert block to form the cavity space.

[0014] Further, the needle portion abuts against the insert block, that is, the two cooperate closely under the action of the spring. The specific process is as follows: during the stroke of the core and the ejector pin moving towards the fixed template along with the moving template, the needle portion of the ejector pin enters the small taper region of the insert block. At this time, the needle portion may contact the insert block located in the small taper region. Then, the moving template drives the core and the ejector pin to continue moving towards the fixed template. As the stroke continues, the conical frustum or arc chamfer of the small taper will play a guiding role, and the needle portion of the ejector pin will enter the small hole of the insert block, that is, the middle section of the small hole, along it. The stroke continues until the needle portion contacts the rear end of the small hole of the insert block.

[0015] Further, after the needle portion contacts the rear end of the small hole of the insert block, the stroke continues. The moving template drives the core and the ejector pin to continue moving towards the fixed template, and the spring contracts to prevent the tip of the needle from hitting the insert block hard, protecting the tip of the needle. After continuing to move a certain distance, the stroke ends. Under the action of the spring, the needle portion abuts against the insert block.

[0016] Further, during the process that the needle portion of the ejector pin enters the small taper region of the insert block until the needle portion passes through the small taper region in the front section of the small hole and enters the middle section of the small hole, the needle portion of the ejector pin may not contact the insert block. After that, the stroke continues until the needle portion contacts the rear end of the small hole of the insert block. Then, the stroke continues. The moving template drives the core and the ejector pin to continue moving towards the fixed template, and the spring contracts to prevent the tip of the needle from hitting the insert block hard, protecting the tip of the needle. After continuing to move a certain distance, the stroke ends. Under the action of the spring, the needle portion abuts against the insert block.

[0017] Further, the needle portion and the core are made of the same material.

[0018] Further, the mold further includes a cooling pipe disposed inside the core. The cooling pipe is independent of the core, and cold oil is provided inside the cooling pipe for cooling the inside of the mold during the injection molding process. After injection, the heat of the medicine pipe cavity and the core area is quickly transferred to the outside through the cooling pipe to reduce the temperature of the core, accelerate the molding speed, facilitate demolding, prevent the product from being scalded, and improve the efficiency.

[0019] Further, the cooling pipe is located in the hollow space area of the spring.

[0020] Another technical solution adopted by the present invention to solve the above technical problems is: an injection molding method, including the following steps:

[0021] Step 1: Combine the moving template and the fixed template to form a cavity space;

[0022] Step 2: Inject and mold into the cavity space;

[0023] It is characterized in that Step 1 includes: making the needle part of the ejector pin enter into the small hole of the insert block and abut against the insert block.

[0024] Further, the injection molding method is applied to the aforementioned small hole injection molding die.

[0025] Further, the moving template at least includes a mold core and a spring, and the fixed template at least includes an insert block.

[0026] Further, the ejector pin further includes a main body part connected to the needle part. The spring is connected to the rear end of the ejector pin, that is, to the rear end of the main body part of the ejector pin. The mold core is a hollow structure with a small hole at the end. The spring and the main body part of the ejector pin are located in the hollow structure. The needle part at the front end of the ejector pin passes through the small hole. The insert block is located in the fixed template. The front section of the small hole has a small taper, and this small taper is a conical frustum shape or an arc chamfer shape space with a larger outer part and a smaller inner part.

[0027] Further, the main body part of the ejector pin can be in the shape of a cuboid, a cube, a cylinder, a conical frustum, etc., and the area of the inner space of the mold core that matches the main body part of the ejector pin is set to the corresponding shape.

[0028] Further, in Step 1, when combining the moving template and the fixed template, it includes: moving the moving template towards the fixed template. The mold core and the ejector pin move towards the insert block as the moving template moves. During the moving stroke, the needle part of the ejector pin enters the small taper area of the insert block. Then the moving template drives the mold core and the ejector pin to continue moving towards the fixed template. As the stroke continues, the needle part of the ejector pin enters the middle section of the small hole until the needle part contacts the rear end of the small hole of the insert block. Then, as the stroke continues, the moving template drives the mold core to continue moving towards the fixed template, and the spring contracts to avoid the tip part of the needle hitting the insert block hard and protect the tip. After moving a certain distance, the stroke ends. Under the action of the spring, the needle part and the insert block achieve abutment. That is, the two cooperate closely under the action of the spring, and the combination of the moving template and the fixed template is completed.

[0029] Further, when the needle part of the thimble enters the small taper region of the insert, the needle part may contact the insert located in the small taper region. If the needle part contacts the insert located in the small taper region, the conical frustum or arc chamfer of the small taper will play a guiding role, and the needle part of the thimble will enter the small hole in the insert, that is, the middle section of the small hole, and the stroke will continue until the needle part contacts the rear end of the small hole in the insert.

[0030] In an embodiment of the present invention, the fixed template includes a chamber. After the movable template is combined with the fixed template, the needle part abuts against the rear end of the small hole in the insert to form the chamber space.

[0031] In an embodiment of the present invention, the movable template includes a chamber. After the movable template is combined with the fixed template, the needle part abuts against the rear end of the small hole in the insert to form the chamber space.

[0032] In an embodiment of the present invention, the needle part and the mold core are made of the same material.

[0033] Furthermore, the mold further includes a cooling pipe disposed inside the mold core. The cooling pipe is independent of the mold core, and cold oil is provided inside the cooling pipe. During the process of the movable template moving towards the fixed template and the mold core and the thimble moving towards the insert along with the movement of the movable template, the cooling pipe moves together with the mold core, which is used to cool the inside of the mold during the injection molding process, and quickly transfer the heat of the medicine tube cavity and the mold core area to the outside through the cooling pipe after injection, so as to reduce the temperature of the mold core, accelerate the molding speed, facilitate demolding, prevent the product from being scalded, and improve the efficiency.

[0034] Compared with the prior art, the advantages of the present invention are as follows:

[0035] By providing a thimble independent of the mold core, the present invention improves the needle tip originally located at the front end of the mold core into a thimble including a needle part independent of the main body part of the mold core, reduces the processing difficulty of the thimble, and improves the processing accuracy.

[0036] The present invention fixes the needle part through the main body part of the thimble, sets the main body part of the thimble inside the mold core, and sets a small hole at the front end of the mold core to enable the needle part of the thimble to pass through, so that the main body part and the needle part of the thimble are more accurately and stably positioned, avoiding the problem of needle tip eccentricity caused by the difficulty in ensuring coaxiality during processing due to the long length of the mold core in the prior art, and ensuring the size of the needle hole.

[0037] In the present invention, a compression spring is arranged at the rear end of the ejector pin. Its function is that during each mold trial, when the ejector pin just contacts the insert, the return spring contracts, and the ejector pin will not collide hard with the front section of the mold core, protecting the tip of the needle. When the mold stroke reaches the position, the compression spring resets. Under the action of the compression spring, the ejector pin and the insert always maintain a tight fit, and there will be no gap during injection molding, thus ensuring that there will be no burrs at the edge of the small hole. Because the length of the ejector pin is short and there is a return spring for buffering, and the material used is the same as that of the insert, there will be no deformation or bending of the tip of the needle during the injection molding process, nor will there be fracture of the ejector pin or the needle part of the ejector pin.

[0038] The present invention does not use a copper rod, and there is no need to insert the copper rod into the needle part. It only needs to be in contact with and abut against the rear end of the small hole of the insert. Therefore, the elliptical shape phenomenon caused by the tip of the needle not being able to pierce into the same hole every time when piercing the positioning copper rod in the prior art will not occur.

[0039] Based on the above beneficial effects, the present invention can further improve the qualified rate of products, increase the service life of the mold core, shorten the mold adjustment time, improve production efficiency, and reduce costs. Description of the Drawings

[0040] Figure 1 It is a schematic structural diagram of a mold for manufacturing a needleless syringe medicine tube used in the small hole forming process of the mold in the prior art.

[0041] Figure 2 For Figure 1 The partial enlarged schematic diagram in

[0042] Figure 3 It is a partial schematic diagram of an embodiment of a small hole injection molding mold for manufacturing a needleless syringe medicine tube according to the present invention.

[0043] Figure 4 It is a partial cross-sectional view of the mold core in a small hole injection molding mold for manufacturing a needleless syringe medicine tube according to the present invention.

[0044] Figure 5 It is a partial enlarged schematic diagram of the insert in a small hole injection molding mold for manufacturing a needleless syringe medicine tube according to the present invention.

[0045] Figure 6 It is a partial enlarged schematic diagram of a small hole injection molding mold for manufacturing a needleless syringe medicine tube according to the present invention.

[0046] Figure 7 It is a partial schematic diagram of another embodiment of a small hole injection molding mold for manufacturing a needleless syringe medicine tube according to the present invention.

[0047] Figure 8 It is a flowchart of an injection molding method according to the present invention. Detailed Embodiments

[0048] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following provides preferred embodiments with reference to the accompanying drawings to further elaborate on the present invention in detail. It should be noted that many details listed in the specification are only for enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0049] The structure and working principle of the mold in the present invention will be elaborated in detail through specific embodiments below. In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings.

[0050] A small-hole injection molding mold of this embodiment, as Figures 3 to 6 shown, includes a fixed template 1, a movable template 2, an insert block 5, a mold core 3, and a thimble 4. The movable template 2 and the fixed template 1 are combined to form a cavity space 11. The insert block 5 includes a small hole 51. The thimble 4 includes a main body part 41 and a needle part 42. The main body part 41 is located in the front section inside the mold core 3. The needle part 42 passes through the small hole 31 at the end of the mold core 3 and enters the small hole 51 of the insert block 5 and abuts against the insert block 5.

[0051] Furthermore, the fixed template 1 further includes a spring 6, and the spring 6 is connected to the rear end of the thimble 4, that is, connected to the rear end of the main body part 41 of the thimble 4.

[0052] Furthermore, as Figure 4 shown, the mold core 3 is a hollow structure with a small hole 31 at the end.

[0053] Furthermore, the spring 6 and the main body part 41 of the thimble 4 are located in the hollow structure, and the needle part 42 at the front end of the thimble 4 passes through the small hole 31.

[0054] Furthermore, the main body part 41 of the thimble 4 can be in the shape of a cuboid, a cube, a cylinder, a frustum of a cone, etc., and the area of the inner space of the mold core that cooperates with the main body part of the thimble is set to the corresponding shape. The shape shown in the accompanying drawings is only an example.

[0055] Furthermore, the fixed template 1 includes the insert block 5, as Figure 5As shown, the front section of the small hole 51 of the insert 5 has a small taper 52. The small taper 52 is a truncated cone or arc chamfered space with a large outside and a small inside, which can play a guiding role. When the fixed plate 1 and the movable plate 2 are combined, the needle part 42 of the ejector 4 may contact the insert in the area of ​​the small taper 52. When the stroke continues, the needle part 42 will enter the small hole 51 along the inclined surface or curved surface of the insert 5 in this area, ensuring that the needle part 42 is in the small hole 51 every time the injection mold is closed.

[0056] In one embodiment of the present invention, Figure 3 As shown, the core 3 is arranged on the movable template 2, and the fixed template 1 includes a cavity, which can accommodate the core 3. After the movable template 2 is combined with the fixed template 1, the core 3 enters the cavity, and the needle part 42 enters the small hole 51 of the insert 5 and abuts against the insert 5 to form the cavity space 11, that is, the space in the cavity not occupied by the core 3 and the needle part 42.

[0057] Furthermore, the needle portion 42 abuts against the insert 5, that is, the two are closely matched under the action of the spring. The specific process is that during the travel of the mold core 3 and the ejector pin 4 moving toward the fixed mold plate 1 along with the movable mold plate 2, the needle portion 42 of the ejector pin 4 enters the small taper 52 area of ​​the insert 5, at which time the needle portion 42 may contact the insert 5 located in the small taper 52 area, and then the movable mold plate 2 drives the mold core 3 and the ejector pin 4 to continue to move toward the fixed mold plate 1, and the travel continues. At this time, the truncated cone shape or arc chamfer shape of the small taper 52 will play a guiding role, and the needle portion 42 of the ejector pin 4 will follow it to enter the small hole 51 of the insert 5, and the travel continues until the needle portion 42 contacts the rear end of the small hole 51 of the insert 5.

[0058] Furthermore, after the needle portion 42 contacts the rear end of the small hole 51 of the insert 5, the stroke continues, the movable template 2 drives the mold core 3 and the ejector pin 4 to continue to move toward the fixed template 1, and the spring 6 contracts to prevent the needle tip from colliding head-on with the insert 5 and protect the needle tip. After continuing to move for a distance, the stroke ends, and under the action of the spring 6, the needle portion 42 comes into contact with the insert 5.

[0059] Further, during the process that the needle portion 42 of the ejector pin 4 enters the small taper 52 region of the insert 5 until the needle portion 42 passes through the small taper 52 region in front of the small hole 51 and enters the middle section of the small hole 51, the needle portion 42 of the ejector pin 4 may not contact the insert 5. After that, the stroke continues until the needle portion 42 contacts the rear end portion of the small hole 51 of the insert 5. Then, the stroke continues, and the moving template 2 drives the mold core 3 and the ejector pin 4 to continue moving towards the fixed template 1. The spring 6 contracts to avoid the hard contact between the tip portion and the insert 5 and protect the tip. After continuing to move a certain distance, the stroke ends. Under the action of the spring 6, the needle portion 42 abuts against the insert 5.

[0060] In another embodiment of the present invention, as Figure 7 shown, the mold core 3 is arranged on the moving template 2. The moving template 2 includes a chamber that can accommodate the mold core 3. After the moving template 2 and the fixed template 1 are combined, the mold core 3 enters the chamber, and the needle portion 42 enters the small hole 51 of the insert 5 and abuts against the insert 5, forming the cavity space 11, that is, the space in the chamber not occupied by the mold core 3 and the needle portion 42.

[0061] Further, the needle portion 42 and the mold core 3 are made of the same material.

[0062] Further, as Figure 3 、 Figure 7 shown, the mold may include a cooling pipe 7 arranged inside the mold core 3. The cooling pipe 7 is located in the hollow space region of the spring 6. The cooling pipe 7 is used to cool the inside of the mold during the injection molding process.

[0063] Another technical solution adopted by the present invention to solve the above technical problems is: an injection molding method, as Figure 8 shown, includes the following steps:

[0064] Step 1: Combine the moving template 2 and the fixed template 1 to form the cavity space 11;

[0065] Step 2: Inject and mold into the cavity space 11;

[0066] Among them, Step 1 includes: making the needle portion 42 of the ejector pin 4 enter the small hole 51 of the insert 5 and abut against the insert 5.

[0067] Further, the injection molding method is applied to the aforementioned small hole injection molding mold.

[0068] Further, the fixed template 1 at least includes the insert 5, and the moving template 2 at least includes the mold core 3, the ejector pin 4, and the spring 6.

[0069] Further, the core 3 is a hollow structure with small holes 31 at its end. The ejector pin 4 and the spring 6 are both located in the hollow structure of the core 3. The ejector pin 4 includes a main body portion 41 and a needle portion 42. The spring 6 is connected to the rear end of the ejector pin 4, that is, the rear end of the main body portion 41. The needle portion 42 at the front end of the ejector pin 4 passes through the small holes 31. The main body portion 41 of the ejector pin 4 can be in the shape of a cuboid, a cube, a cylinder, a frustum of a cone, etc. The area of the inner space of the core that matches the main body portion of the ejector pin is set to the corresponding shape. The shapes shown in the drawings are just examples.

[0070] Further, as Figure 5 shown, the insert block 5 has small holes 51, and its front section has a small taper 52. The small taper 52 is a frustum of a cone or an arc chamfer with a larger outer and smaller inner shape, which can play a guiding role. When the fixed template 1 and the moving template 2 are combined, the needle portion 42 of the ejector pin 4 may contact the insert block in the area of the small taper 52. After that, when the stroke continues, the needle portion 42 will enter the small holes 51 along the inclined surface or curved surface of the insert block 5 in this area, ensuring that the needle portion 42 is in the small holes 51 every time the injection mold is closed.

[0071] Further, the mold further includes a cavity that can accommodate the core 3.

[0072] The cavity can be located in the fixed template 1. In this case, during the combination of the moving template 2 and the fixed template 1, the core 3 enters the cavity, and the needle portion 42 enters the small holes 51 of the insert block 5 and abuts against the insert block 5 to complete the combination, forming the cavity space 11, that is, the space in the cavity that is not occupied by the core 3 and the needle portion 42.

[0073] The cavity can also be located in the moving template 2. In this case, there are two implementation methods. The first is that the core 3 is fixedly connected or integrally formed with the moving template 2 and moves simultaneously. After the moving template 2 and the fixed template 1 are combined, the needle portion 42 enters the small holes 51 of the insert block 5 and abuts against the insert block 5 to form the cavity space 11. The second is that the core 3 is not fixedly connected and not integrally formed with the moving template 2 and can move at different times. After the moving template 2 contacts the fixed template 1, the core 3 enters the cavity, and the needle portion 42 enters the small holes 51 of the insert block 5 and abuts against the insert block 5 to form the cavity space 11, that is, the space in the cavity that is not occupied by the core 3 and the needle portion 42.

[0074] Further, in step 1, the movable plate 2 and the fixed plate 1 are combined, including: the movable plate 2 is moved toward the fixed plate 1, and the mold core 3 and the ejector pin 4 move toward the insert 5 as the movable plate 2 moves. During the moving stroke, the needle portion 42 of the ejector pin 4 enters the small taper 52 area of ​​the insert 5, and then the movable plate 2 drives the mold core 3 and the ejector pin 4 to continue to move toward the fixed plate 1, and the stroke continues, and the needle portion 42 of the ejector pin 4 enters the middle section of the small hole 51 until the needle portion 42 contacts the rear end of the small hole 51 of the insert 5, and then,

[0075] The stroke continues, the movable platen 2 drives the mold core 3 to continue to move toward the fixed platen 1, the spring 6 contracts to prevent the needle tip from colliding with the insert 5, and protects the needle tip. After moving for a distance, the stroke ends, and under the action of the spring 6, the needle portion 42 abuts against the insert 5. That is, the two cooperate closely under the action of the spring 6, and the movable platen 2 and the fixed platen 1 are combined.

[0076] Furthermore, when the needle portion 42 of the ejector pin 4 enters the small taper 52 area of ​​the insert 5, if the needle portion 42 contacts the insert 5 located in the small taper 52 area, the frustum or arc chamfer of the small taper 52 will play a guiding role, and the needle portion 42 of the ejector pin 4 will follow it into the small hole 51 of the insert 5, and the stroke continues.

[0077] Furthermore, the needle portion 42 and the insert 5 are made of the same material.

[0078] Furthermore, the mold also includes a cooling pipe 7 arranged inside the mold core 3, and the cooling pipe 7 is independent of the mold core. Cold oil is arranged in the cooling pipe 7. When the mold core 3 and the ejector pin 4 move toward the insert 5, the cooling pipe 7 moves with the mold core 3, and is used to cool the inside of the mold during the injection molding process. After injection molding, the heat in the medicine tube cavity 11 and the mold core 3 area is quickly transferred to the outside through the cooling pipe 7 to reduce the mold core temperature, speed up the molding speed, facilitate demolding, prevent the product from being scalded, and improve efficiency.

[0079] The present invention provides an ejector pin independent of the mold core, thereby improving the needle tip originally located at the front end of the mold core into an ejector pin including a needle portion independent of the main body of the mold core, thereby reducing the difficulty of ejector pin processing and improving processing accuracy.

[0080] The present invention fixes the needle portion by the main body of the ejector, arranges the main body of the ejector inside the mold core, and arranges a small hole at the front end of the mold core to allow the needle portion of the ejector to pass through, so that the main body and the needle portion of the ejector are positioned more accurately and stably, avoiding the problem of needle tip eccentricity caused by difficulty in ensuring coaxiality during processing due to the long length of the mold core in the prior art, and ensuring the size of the pinhole.

[0081] In the present invention, a compression spring is provided at the rear end of the ejector pin. Its function is that during each mold trial, when the ejector pin just contacts the insert, the return spring contracts, and the ejector pin will not collide hard with the front section of the mold core, protecting the tip of the pin. When the mold stroke reaches the position, the compression spring returns to its original state. Under the action of the compression spring, the ejector pin and the insert always maintain a tight fit, and there will be no gap during injection molding, thus ensuring that there will be no burrs at the edge of the small hole. Since the length of the ejector pin is short, and there is a return spring for buffering, and the same material as the insert is used, there will be no deformation or bending of the tip of the pin during the injection molding process, nor will there be any breakage of the ejector pin or the needle part of the ejector pin.

[0082] The present invention does not use a copper rod, and there is no need to insert the needle part into the copper rod. It only needs to fit and abut against the rear end of the small hole of the insert. Therefore, the elliptical shape phenomenon caused by the tip of the needle not being able to pierce the same hole every time when piercing the positioning copper rod in the prior art will not occur.

[0083] Based on the above beneficial effects, the present invention can further improve the qualified rate of products, increase the service life of the mold core, shorten the mold adjustment time, improve production efficiency, and reduce costs.

[0084] It should be noted that in this article, the term "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0085] The above has introduced a small hole injection molding mold and an injection molding method provided by the embodiments of the present invention. In this article, specific embodiments are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A small-hole injection molding die, comprising a fixed template, a movable template, an insert block, a mold core, and a thimble. The movable template and the fixed template are combined to form a cavity space, and it is characterized in that, The insert includes small holes, and the ejector pin includes a main body portion and a pin portion. The main body portion is located at the front section inside the mold core, and the pin portion passes through the small holes at the end of the mold core, enters the small holes of the insert, and abuts against the insert.

2. The small-hole injection molding die according to claim 1, characterized in that, The mold core includes a spring, and the spring is connected to the rear end of the ejector pin.

3. The small-hole injection molding die according to claim 2, wherein The mold core is a hollow structure with small holes at the end. The spring and the main body portion of the ejector pin are located in the hollow structure, and the pin portion at the front end of the ejector pin passes through the small holes.

4. The small-hole injection molding die according to claim 1, characterized in that, The insert is located on the stationary template, and the front section of the small holes has a small taper.

5. The small-hole injection molding die according to claim 1, wherein The mold core is arranged on the moving template. The stationary template includes a chamber. After the moving template and the stationary template are combined, the pin portion enters the small holes of the insert and abuts against the insert to form the cavity space.

6. The small-hole injection molding die according to claim 1, characterized in that, The mold core is arranged on the moving template. The moving template includes a chamber. After the moving template and the stationary template are combined, the pin portion enters the small holes of the insert and abuts against the insert to form the cavity space.

7. The small-hole injection molding die according to claim 1, characterized in that, The pin portion and the mold core are made of the same material.

8. The small-hole injection molding die according to claim 1, wherein It further includes a cooling pipe arranged inside the mold core.

9. An injection molding method, comprising the following steps: Step 1: Combine the moving template and the stationary template to form a cavity space; Step 2: Inject and mold into the cavity space; It is characterized in that Step 1 includes: making the pin portion of the ejector pin enter the small holes of the insert and abut against the insert.

10. The injection molding method according to claim 9, characterized in that, The method is applied to the small-hole injection molding die according to any one of claims 1-8.

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