CN111571970A - A micro-stress mold core and a mold comprising the micro-stress mold core - Google Patents

Abstract

The invention provides a micro-stress mold core and a mold including the micro-stress mold core, belonging to the field of mold structure. The micro-stress mold core of the present invention includes a mold core body, and the mold core body includes a mounting surface for mounting the mold core body, a mold cavity surface for setting a product cavity, and a side surface disposed on the periphery of the mounting surface and the mold cavity surface , wherein the mounting surface is provided with a reinforcing structure, the mounting surface is also provided with a mold core heating expansion positioning guide structure, the reinforcing structure and the mold core heating expansion positioning guide structure are provided with a heating expansion expansion and contraction groove, and the side There is an expansion gap between the core and the mounting plate. The beneficial effect of the present invention is that the deformation of the product caused by the warpage of the mold core is minimized.

Description

A micro-stress mold core and a mold comprising the micro-stress mold core

technical field

The invention relates to a mold structure, in particular to a mold for realizing mold temperature balance.

Background technique

In the injection mold, the mold core is the key operation precision part in the center of the mold, and it is a very important part in the mold. Its structure directly determines the fineness of the product. The mold core will have thermal expansion during the heating process. If the heat is unbalanced, the mold core will be thermally expanded and warped. For products that require precision machining, the deformation will directly affect the accuracy of the product. However, none of the cores currently take this into account. Therefore, there is an urgent need for a micro-stress mold core to solve the product deformation caused by the micro-strain of the mold core due to thermal expansion deformation.

In addition, there is only one set of heating pipes and cooling pipes in the existing mold core, which is controlled by the controller uniformly and cannot keep the mold temperature balance. This structure has the following defects:

(1) The place where the mold cavity is close to the heating tube heats up quickly and the temperature is high, and the place far from the heating tube heats up slowly and the temperature is low, which is not conducive to the flow of the injection liquid; in addition, the core steel will expand when heated, and the higher the temperature, After cooling, the greater the shrinkage, the easier it is to cause product deformation due to uneven shrinkage of the mold;

(2) The cooling temperature of the product surface cannot be controlled. The product surface is cooled first in the area with low temperature, and then cooled in the area with high temperature, which will affect the appearance quality of the product and easily cause the product to warp and deform.

In addition, the water outlet and water inlet of the cooling pipe in the prior art are both arranged on one side of the mold, the cooling pipe is long in the mold, which is not conducive to cooling, and the temperature difference between the water inlet pipe and the water outlet pipe is large, thereby aggravating the unbalance of the mold temperature .

SUMMARY OF THE INVENTION

In order to solve the problems in the prior art, the present invention provides a micro-stress mold core, and also provides a mold comprising the micro-stress mold core.

The micro-stress mold core of the present invention includes a mold core body, and the mold core body includes a mounting surface for mounting the mold core body, a mold cavity surface for setting a product cavity, and a side surface disposed on the periphery of the mounting surface and the mold cavity surface , wherein the mounting surface is provided with a reinforcing structure, the mounting surface is also provided with a core heating expansion positioning guide structure, both the strengthening structure and the core heating expansion positioning guide structure are provided with a heating expansion expansion and contraction groove, and the side There is an expansion gap between the core and the mounting plate.

The present invention makes a further improvement, and the reinforcing structure includes a reinforcing rib disposed on the periphery of the installation surface and integrally formed with the side surface, and a reinforcing bone disposed inside the reinforcing rib.

The present invention makes a further improvement, the heating and expansion positioning guide structure of the mold core comprises positioning ribs arranged at the lateral center and the longitudinal center of the mounting surface, and the positioning ribs are arranged protruding from the surface of the reinforcing structure.

The present invention is further improved, and the positioning guide structure for heating and expansion of the mold core further comprises a plurality of positioning columns arranged on the reinforcing ribs.

The present invention is further improved. The mold core body is provided with more than one temperature zone, and each temperature zone is provided with a set of heating device, cooling device and a temperature measuring device for detecting the temperature of the corresponding mold cavity in the temperature zone. The heating device and cooling device in each temperature zone are controlled independently by the controller.

The present invention is further improved, the heating device is a heating pipe, the cooling device is a cooling pipe with cooling water inside, the water inlet of the cooling pipe is set on one side of the core body, and the water outlet is set on the core body The other side opposite the water inlet.

The present invention is further improved. The number of the heating pipes and the cooling pipes is multiple, the heating pipes and the cooling pipes are arranged at intervals, and the distances between the temperature measuring device, the cooling pipes and the heating pipes are equal.

The present invention is further improved, and the vertical distance between the temperature measuring device and the product cavity, the distance between the temperature measuring device and the cooling pipe, and the distance between the temperature measuring device and the heating pipe are equal.

The present invention is further improved, and the distance between the heating tube and the mounting surface of the core body and the distance between the heating tube and the product cavity of the core body are equal.

The present invention also provides a mold including the micro-stress mold core, including a heat insulation support plate and a mounting plate, wherein one side of the heat insulation support plate is provided with a mounting groove corresponding to the heating and expansion positioning guide structure of the mold core , the core heating expansion positioning guide structure of the micro-stress core is fixed in the installation groove, the installation plate is provided with an accommodation groove for accommodating the core body and the heat insulation support plate, and the outer side of the installation plate is provided with a accommodating groove. There are water inlet pipes and water outlet pipes connected with the cooling pipes.

Compared with the prior art, the present invention has the following beneficial effects: the deformation of the product caused by the warpage of the mold core is reduced to the greatest extent, and the precise processing of the product can be realized; by dividing the mold and embedding the temperature measuring device, the mold temperature is individually controlled in each zone. , can ensure the mold temperature balance, not limited by product size, shape, structure, wall thickness, so as to avoid the phenomenon of thermal expansion and deformation of the mold core caused by thermal imbalance, and also avoid product warping caused by mold cavity temperature imbalance. warp deformation.

Description of drawings

Fig. 1 is the mold structure schematic diagram of the present invention;

Fig. 2 is a schematic diagram of the structure of the cavity surface of the front mold core;

3 is a cross-sectional view of FIG. 2B-B;

FIG. 4 is an enlarged view of part C of FIG. 3;

5 and 6 are sectional views of FIG. 2A-A;

7 and 8 are schematic views of the front mold core mounting surface;

FIG. 9 is a schematic diagram of a partition of another embodiment of the front mold core.

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

As shown in FIGS. 1 to 6 , as an embodiment of the present invention, the mold of the present invention includes a front mold core 3 , a rear mold core 4 , and a mold cavity 5 disposed between the front mold core 3 and the rear mold core 4 . , in this example, a heating device 16, a cooling device 15 and a temperature sensor 17 for detecting the temperature of the corresponding mold cavity in the temperature zone are provided in the front mold core 3. The front mold core in this example is set by 1 to 2, that is, a mold setting Two front cores 3.

As shown in FIGS. 3-5 and 7 , the mold core 3 of the present invention includes a mold core body 301 , and the mold core body 301 includes a mounting surface 3012 on which the mold core body 301 is installed, and a product cavity is provided for injection molding products. The cavity surface 3011 of 19, and the side surface 3013 arranged on the mounting surface 3012 and the periphery of the cavity surface 3011, wherein the mounting surface 3012 is provided with a reinforcing structure, and the mounting surface 3012 is also provided with the heating and expansion positioning of the mold core. The guide structure, the reinforcing structure and the core heating expansion positioning guide structure are provided with heating expansion expansion and contraction grooves 305, and between the side surface 3012 and the mounting plate (the front core in this example, then the mounting plate is the A plate 7). There is a core expansion gap d. The width of the core expansion gap d in this example is 0.01mm. The width of the core expansion gap d is calculated according to the expansion coefficient of the material of the front core 3 and the required mold temperature. Different core materials have different expansion gaps. Preferably, the material of the mold core in this example is a steel with fast heat conduction, high corrosion resistance, high toughness and elongation, so as to minimize the warpage of the mold steel.

If the heating expansion expansion groove 305 and the expansion gap d of the mold core are not provided, due to the limited installation, when the front mold core 3 is heated and expanded, the front mold core 3 will be arched toward the product mold cavity, thereby affecting the product mold cavity. 5 appearances of products within 19. The micro-stress mold core in this example can well avoid the micro-strain phenomenon of the front mold core 3 .

As shown in FIG. 7 , the reinforcing structure of this example includes a reinforcing rib 304 disposed around the mounting surface and integrally formed with the side surface, and a reinforcing rib 302 disposed inside the reinforcing rib 304 . The reinforcing rib 302 is longitudinal and transverse Staggered arrangement, connecting the reinforcing ribs 304 at both ends, can improve the rigidity of the steel, and can make the core body 301 as thin as possible, thereby reducing the absorption and conduction of the energy of the core body 301, making the mold temperature heating faster, The temperature is easier to control and avoids a situation where the energy build-up in the core causes the cavity temperature to increase significantly after the heating is stopped. In this example, the core body 301 achieves a lightweight design on the premise that the rigidity is not affected. Save raw materials.

The heating and expansion positioning guide structure of the core in this example includes positioning ribs 303 arranged at the lateral center and the longitudinal center of the mounting surface 3012, so as to fix the overall central position of the front core 3 and avoid the deviation from the center due to the shrinkage of the core body 301. phenomenon, the positioning ribs 303 are arranged protruding from the surface of the reinforcing structure. The front mold core 3 is fixed as a fixing structure.

The heating and expanding positioning guide structure of the mold core in this example further includes four positioning columns 306 arranged on the reinforcing ribs 304. The positioning columns 306 are arranged on the four corners of the core body 301 and combined with the positioning ribs 303, thereby To limit the position of the center and four corners of the core body 301, preferably, the positioning ribs 306, the positioning ribs 304 and the heating expansion and expansion grooves 305 are axially symmetrically arranged with the positioning ribs 303 as the central axis, which is more conducive to the core body. 301 shrinks and balances after thermal expansion. The micro-deformation of the mold core caused by the unbalanced shrinkage after heating and thermal expansion is avoided, thereby causing the surface deformation of the product 19.

As shown in FIG. 2 , FIG. 7 and FIG. 8 , the higher the temperature of the core body 301 is, the greater the shrinkage is. Therefore, the unbalanced heating of the core body 301 will also cause the micro-strain of the core body 301 . In this example, the temperature of the core body 301 and the cavity are kept in balance. In this example, each front core 3 is provided with two temperature zones, and the two front cores 3 are set with four temperature zones in total, and each temperature zone is A set of heating devices 1601-1604, a cooling device 15 and a temperature sensor 17 are provided. The heating device 16 and the cooling device 15 in each temperature zone are individually controlled by the controller. The number of the rear mold cores 4 in this example is also 2 , each rear core 4 is provided with 2 cooling zones (not shown in the figure, the installation method of the cooling and frying device is the same as that of the front core 3), each cooling zone is provided with a set of cooling devices 15, and each cooling zone 15 The cooling device inside is individually controlled by the controller.

The heating device 16 in this example is a heating pipe, and the cooling device 15 is a cooling pipe with a cooling medium inside. The cooling medium in this example can be water or other liquid medium that absorbs heat.

As shown in FIGS. 1-6 , the heating device 16 of this example is arranged on the front mold core. Therefore, the mold is also provided with a heat insulating support plate 5 on the top surface of the front mold core 3 to prevent heat loss. One side of the heat insulating support plate 5 is provided with an installation groove corresponding to the heating and expansion positioning and guiding structure of the mold core, and the heating and expanding positioning and guiding structure of the mold core of the micro-stress mold core is fixed in the installation groove, and the A The plate 7 is provided with an accommodating groove for accommodating the core body 301 and the heat insulating support plate 5, the heat insulating support plate 5 is fixed on the bottom surface of the A plate 7, and the water inlet 1501 of the cooling pipe 15 is arranged on one side of the mold , the water outlet 1502 of the cooling pipe 15 is arranged on the other side of the mold. The water inlet 1501 and the water outlet are both arranged on the A plate 7 and communicate with the cooling pipe in the front core 3. The cooling water enters from one side of the mold and flows out from the other side, which greatly shortens the time that the cooling water stays in the cooling pipe, so that more cooling water passes through per unit time, and the cooling efficiency is better. Each cooling pipe is arranged in parallel in the mold core, and the water flow to the vicinity of the mold cavity is basically the same, which is conducive to maintaining the mold temperature balance.

A flow channel plate 9 is provided on the top surface of the A plate 7 , and the top surface of the flow channel plate 9 is a panel 10 . In this example, the back mold core 4 is fixed on the B plate 8, two square irons 11 are arranged on both sides between the bottom plate 14 and the B plate 8, and the thimble bottom plate 13 is fixed on the bottom plate between the two square irons, and the thimble plate 12 is arranged on the thimble bottom plate 13, and two thimbles pass through the B plate 8 and are connected to the mold cavity.

Of course, the temperature zone in this example can also be set on the rear core 4, so that the front core 3 and the rear core 4 can achieve heating and cooling functions at the same time, or the temperature zone can be set on the rear core 4, while the cooling zone is set On the front mold core 3, the heating device on the rear mold core 4 heats the mold cavity 5, and the cooling device on the front and rear mold cores cools the product. At this time, the heat insulating support plate is provided on the side with the heating device.

Multiple temperature zones are used for heating or cooling respectively, each temperature zone and cooling zone are controlled separately, and a separate temperature sensor 17 is set to accurately control the temperature of the mold cavity, so that the temperature difference can be controlled within 2 degrees Celsius, so as to ensure the mold core The micro-stress of the body 301 prevents its thermal expansion and deformation, which is beneficial to maintain the mold temperature balance of the mold cavity and prevent the product 19 from being warped and deformed due to unbalanced heating and cooling.

As shown in Fig. 9, the micro-stress mold core of this example is especially suitable for the processing of high-precision products. As an example, if the product is a flat arc shape, this example can make its front mold core according to the shape of the mold cavity. 3 and the back mold core are divided into 8 zones (the vertical line is the dividing line of each zone), so as to control the temperature of each temperature zone independently, avoiding the prior art to set the cooling pipe and the heating pipe horizontally, distance from the mold. The distance between the cavity 5 is too large, so that the mold temperature difference of the product is too large, and the temperature of the mold cavity is different, resulting in different fluidity of the molten liquid during injection molding, different shear rates, and the quality of the product cannot be guaranteed; the asynchronous cooling causes the product to warp and deform . The present invention is especially suitable for a mold cavity with a three-dimensional complex shape, and partitions are set according to the shape of the product, so that the temperature difference between each area of the product can be ensured. The solution of the present invention is not limited by product size, shape, structure and wall thickness. It can process thin-walled products greater than or equal to 0.5mm without causing warpage of the product.

The mounting surface 3012 of the front mold core 3 in this example can also be processed into a non-planar structure according to the shape of the product, as long as the surface of the reinforcing structure is in horizontal contact with the surface of the heat insulating support plate 6. Of course, the surface of the heat insulating support plate 6 in this example can also be adapted to the surface of the front mold core 3012, and the heat insulating effect is better.

As shown in Figures 5-8, in this example, there are multiple heating pipes and cooling pipes in each temperature zone, and the heating pipes and cooling pipes are arranged at intervals. Thereby, it is beneficial to control the balance of temperature difference.

The distances between the temperature sensor 17 , the cooling pipe 15 and the heating pipe 16 are equal, preferably in an equilateral triangle. The distance between the temperature sensor 17 and the mold cavity, the distance between the temperature sensor 17 and the cooling pipe 15, and the distance between the temperature sensor 17 and the heating pipe are equal. Therefore, the mold temperature measured by the temperature sensor 17 is more accurate. The reason for the design with equal distances between multiple points is that during the heating or cooling process (steel), the front mold core 3 will have energy accumulation and heat conduction time when it is hot or cold, so the sensor 17 is arranged between the cooling pipe 15, the heating pipe 16 and the surface of the mold cavity. The average value of the distance between them makes the test results of heating, cooling, and cavity surface (ie, the surface temperature of the workpiece) more accurate.

In this example, the distance x from the heating tube to the top surface of the front core is equal to the distance y from the heating tube to the cavity surface of the front core. The measurement is more accurate. Again, the cooling pipes in the front core are the same distance from the top surface of the front core and the cavity surface of the front core in this example.

By dividing the mold and inserting the temperature measuring device, each zone can control the mold temperature independently, which can effectively ensure the mold temperature balance, and is not limited by the size, shape, structure and wall thickness of the product. It can process products of various shapes, and can guarantee its quality and appearance quality.

As shown in Fig. 3 and Fig. 4 , the thermal expansion phenomenon of the steel material of the front core 3 is fully considered in the design of the A plate in this example. Therefore, there is a 0.01mm core between the outer periphery of the front core and the A plate. Expansion gap d, however, the front mold cores 3 in this example are set by one for two, and the runner is set between the two front mold cores 3. Therefore, in order to avoid the branch runner interference between the runner and the gate 3 The micro-strain of the front mold core 3, therefore, in this example, a bridge insert 18 is provided on the A plate 7, and the bridge insert 18 rides in the mold core expansion gap between the A plate 7 and the front mold core 3. Above d, the runner and the branch runner of the gate 3 are arranged above the bridging insert 18, and the bridging insert 18 is clearance fit with the front mold core 3, so as not to interfere with the thermal expansion and cooling of the front mold core 3 shrink. In addition, it is also possible to effectively prevent the melt from flowing into the core expansion gap d and block the core expansion gap d.

The specific embodiments described above are the preferred embodiments of the present invention, and are not intended to limit the specific implementation scope of the present invention. The scope of the present invention includes but is not limited to the specific embodiments. All equivalent changes made in accordance with the present invention are within the protection scope of the present invention.

Claims (10)

1. The micro-stress mold core is characterized in that: the die core comprises a die core body, wherein the die core body comprises an installation surface for installing the die core body, a die cavity surface for arranging a product die cavity, and side surfaces arranged on the periphery of the installation surface and the periphery of the die cavity surface, a reinforcing structure is arranged on the installation surface, a die core heating expansion positioning guide structure is further arranged on the installation surface, heating expansion telescopic grooves are formed in the reinforcing structure and the die core heating expansion positioning guide structure, and a die core expansion gap is formed between the side surfaces and the installation plate.

2. The micro-stress mold core of claim 1, wherein: the reinforcing structure comprises reinforcing ribs which are arranged on the periphery of the mounting surface and are integrally formed with the side surface, and reinforcing bones arranged in the reinforcing ribs.

3. The micro-stress mold core of claim 2, wherein: the die core heating expansion positioning guide structure comprises positioning ribs arranged at the transverse center and the longitudinal center of the mounting surface, and the positioning ribs protrude out of the surface of the reinforcing structure.

4. The micro-stress mold core of claim 3, wherein: the mold core heating expansion positioning guide structure further comprises a plurality of positioning columns arranged on the reinforcing ribs.

5. The microstress mandrel of any of claims 1-5, wherein: the mold core body is provided with more than 1 temperature zone, each temperature zone is provided with a set of heating device, a set of cooling device and a set of temperature measuring device for detecting the temperature of the mold cavity corresponding to the temperature zone, and the heating device and the cooling device in each temperature zone are independently controlled by a controller.

6. The micro-stress mold core of claim 5, wherein: the heating device is a heating pipe, the cooling device is a cooling pipeline with cooling water arranged inside, a water inlet of the cooling pipeline is arranged on one side of the mold core body, and a water outlet of the cooling pipeline is arranged on the other side, opposite to the water inlet, of the mold core body.

7. The micro-stress mold core of claim 6, wherein: the quantity of the heating pipes and the cooling pipelines is multiple, the heating pipes and the cooling pipelines are arranged at intervals, and the distances between the temperature measuring device and the heating pipes are equal to each other.

8. The micro-stress mold core of claim 6, wherein: the vertical distance between the temperature measuring device and the product cavity, the distance between the temperature measuring device and the cooling pipeline, and the distance between the temperature measuring device and the heating pipe are equal.

9. The micro-stress mold core of claim 6, wherein: the distance between the heating pipe and the installation surface of the mold core body is equal to the distance between the heating pipe and the cavity of the mold core body product.

10. A mold comprising the microstress core of any of claims 5-9, wherein: including thermal-insulated backup pad and mounting panel, wherein, one side of thermal-insulated backup pad is equipped with the mounting groove that corresponds with mold core thermal expansion location guide structure, the mold core thermal expansion location guide structure of microstress mold core is fixed in the mounting groove, the mounting panel is equipped with and holds the holding tank of mold core body and thermal-insulated backup pad, the mounting panel outside is equipped with inlet channel and outlet conduit who is linked together with cooling duct.

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