JP2004237727A - Mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot runner mold by which a molding having high shape precision and a uniform shape can be obtained inexpensively. <P>SOLUTION: The hot runner mold 1 is provided with the main molds 10 and 20, and the fixing side and movable side unit molds 30 and 40 which are separable from the main molds 10 and 20 and have a cavity 50 to be injected with a melted resin through the side gates 18a and 18b. In this case, a plurality of cavities 50 are arranged in a minimal circumcircle on which the hot runner gates 17a and 17b for feeding the molten resin into the cavities are circumscribed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a mold used for injection molding, and particularly to a hot runner mold using a side gate.

  Injection molding is widely used for resin molding because it is suitable for mass production.

  A mold called cold runner mold is used for injection molding, and the molten resin of the runner part that leads into the molding cavity is solidified together with the molded product, and the molded product is integrated with the molded product. I was taking it out of the mold.

  Then, the resin molded product and the runner portion are separated by post-processing to obtain a final product.

However, in order to eliminate post-processing in the cold runner mold in recent years and use the resin of the runner part for the next molding, a hot runner mold that keeps the resin of the runner part in a molten state by heating and maintaining the temperature of the runner part Came to be used.
JP-A-8-300414

  By the way, in the mold for resin molding, in order to reduce the manufacturing cost of the mold, the mold is divided into a main mold and a unit, and only the unit is manufactured for each molded product shape, and the main mold is shared. Has been adopted. Then, a large number of molded products are taken in order to increase productivity.

  However, since the unit portions were manufactured by the number of cavities, the manufacturing cost was high.

  In addition, since each unit is arranged at a predetermined interval, the cavity cannot be arranged at a location close to the center of the main mold, and the cavity is affected by a temperature change of the mold due to disturbance such as an increase or decrease in room temperature. It is not easy to obtain a molded product with high shape accuracy.

  Further, since each unit is disposed at a predetermined interval, a temperature difference between the cavities is large, and a molded article having a uniform shape cannot be obtained in each unit.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a mold having high shape accuracy and capable of obtaining a molded product having a uniform shape at low cost.

  In order to solve the above-mentioned problem, the invention according to claim 1 includes a main mold and a unit portion which is separable from the main mold and has a cavity into which a molten resin is injected through a side gate. In the mold, a plurality of hot runner gates of a hot runner for feeding the molten resin into the cavity are arranged in the main mold, and a plurality of cavities of the unit portion are set to include a position of the hot runner gate. Characterized in that all the cavities are arranged in the set minimum circumscribed circle.

  According to a second aspect of the present invention, in the mold according to the first aspect, a heat insulating unit is disposed between the unit and the resin melting unit that holds the molten resin in the hot runner in a molten state. It is characterized by.

  According to a third aspect of the present invention, in the mold according to the first or second aspect, a fluid pipe is disposed between the resin melting portion and the unit portion.

  According to a fourth aspect of the present invention, in the mold according to the third aspect, the fluid pipe is disposed between the heat insulating means and the unit or between the heat insulating means and the resin melting portion. Features.

  According to a fifth aspect of the present invention, in the metal mold according to any one of the first to fourth aspects, an optical component is molded.

  ADVANTAGE OF THE INVENTION According to the metal mold | die of this invention, a high precision of a shape and a molded article of a uniform shape can be obtained at low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a conceptual diagram showing a cross section of a hot runner mold according to a first embodiment of the present invention.

  This hot runner mold 1 is a so-called two-piece mold that has runners 19a and 19b on the PL surface (divided surface) of the molded product and can take out the molded product simply by opening the PL surface.

  The hot runner mold 1 includes a fixed main mold 10, a movable main mold 20, a fixed unit mold 30, and a movable unit mold 40.

  The fixed-side main die 10 includes a fixed-side die plate 11 and a fixed-side mounting plate 12, and the movable-side main die 20 includes a movable-side die plate 21 and a movable-side mounting plate 22. The main mold is composed of the fixed main mold 10 and the movable main mold 20.

  The fixed-side mounting plate 12 mounted on the back of the fixed-side template 11 and the movable-side mounting plate 22 mounted on the back of the movable-side template 21 are plate bodies, respectively.

  A sprue bush 13 that opens to the outside is provided in a hole 12 a formed in the center of the fixed-side mounting plate 12.

  A cavity 14 is formed in the fixed mold plate 11. A hot runner manifold 15 is disposed in the cavity 14. The rear ends (entrances) of the hot runner bodies 16A and 16B are attached to one side of the hot runner manifold 15.

  The other end of the hot runner manifold 15 is connected to the sprue bush 13, and the sprue 13a of the sprue bush 13 communicates with the runner 15a of the hot runner manifold 15. The runner 15a of the hot runner manifold 15 branches into two runners 15b and 15c.

  The hot runner bodies 16A, 16B are attached to the tip of the hot runner manifold 15. The runners 16a and 16b of the hot runner body 16A communicate with the runner 15b of the hot runner manifold 15. The runners 16c and 16d of the hot runner body 16B communicate with the runner 15c of the hot runner manifold 15.

  The hot runner gates 17a and 17b of the hot runner bodies 16A and 16B communicate with runners 19a and 19b using side gates 18a and 18b provided on the PL surface (divided surface) of the molded product.

  As a result, the sprue bush 13, the hot runner manifold 15, the hot runner body 16A and the runner 19a using the side gate 18a communicate with each other, and the sprue bush 13, the hot runner manifold 15, the hot runner body 16B and the runner 19b using the side gate 18b. Communicate with each other to form a hot runner.

  The sprue bush 13, the hot runner manifold 15, and the hot runner body 16A constitute a resin melting portion. The sprue bush 13, the hot runner manifold 15, and the hot runner body 16B constitute a resin melting portion.

  The stationary main mold 10 has a heater (not shown) for heating and keeping the resin in the hot runner in the same state as the cylinder of the injection molding machine, and a temperature sensor (not shown) for detecting the temperature of the heater. ) And are built-in.

  The heaters are arranged around the sprue bush 13, around the hot runner manifold 15, around the main body of the hot runner manifold 15, and around the hot runner bodies 16A, 16B.

  As the heater, a coil heater, a sheath heater, a high-frequency induction heater or the like is used. The temperature sensors are provided at positions corresponding to the respective heaters. As the temperature sensor, a thermocouple, a measurement resistor, or the like is used.

  The temperature of each heater is individually controlled by a control circuit (not shown) so as to be a predetermined temperature. As this temperature control, for example, PID control is performed to correct overshoot with respect to the target temperature.

  Further, the fixed main mold 10 is provided with channels 2 and 3 for cooling and controlling the temperature of the fixed main mold 10. A cooling medium flows through the cooling flow path 2, and a temperature control medium flows through the temperature control flow path 3. Here, the temperature control means that the temperature of the hot runner mold 1 is appropriately maintained by cooling or heating.

  The movable main mold 20 is provided with a flow path 6 for controlling the temperature of the movable main mold 20.

  The movable unit mold 40 includes a movable unit mold plate 41, a movable unit unit mounting plate 42, a movable nest (a mirror part in the case of an optical component) 43, and a unit ejector plate 44.

  The movable unit mold 40 is formed integrally with the fixed unit mold 30 to form a cavity 50 for molding a molded product such as an optical component. The movable side insert 43 is provided with a one-sided recess of the molded product. I have. The movable unit mold 40 is nested in a movable space A formed at the center of the movable mold plate 21.

  A temperature control channel 46 is provided in the movable unit template 41, and a temperature control medium flows through the temperature control channel 46.

  The fixed-side unit mold 30 includes a fixed-side unit mold plate 31, a fixed-side unit mold mounting plate 32, and fixed-side inserts (mirror parts in the case of optical components) 33.

  As in the case of the movable unit mold 40, a one-sided concave portion is provided on the surface of the fixed unit mold 30 facing the movable unit mold 40, similarly to the movable unit mold 40. The fixed unit mold 30 is nested in a fixed space B formed at the center of the fixed mold plate 11.

  The unit unit is constituted by the fixed unit unit 30 and the movable unit unit 40.

  A temperature control channel 36 is provided in the fixed-side unit template 31, and a temperature control medium flows through the temperature control channel 36.

  The molten resin is supplied to the cavity 50 formed by the fixed unit mold 30 and the movable unit mold 40 via the runners 19a and 19b provided on the PL surface (divided surface) of the molded product, and the desired molded product is formed. Is injection molded.

  At this time, the influence of the heat generated by the heaters of the hot runner manifold 15 and the hot runner bodies 16A and 16B by the cooling flow path 2 on the temperature control of the fixed unit mold 30 is reduced.

  Although not shown, a heat insulating material (heat insulating means) is provided between the hot runner manifold 15 or the hot runner bodies 16A, 16B and the fixed unit 30 instead of or in addition to the cooling flow path 2. You may do so.

  FIG. 2 is a partially enlarged view of the hot runner mold according to the first embodiment of the present invention as viewed from a division surface.

  FIG. 2 shows an example in which two cavities 5 a and 5 b are arranged in the movable unit mold 40.

  The two cavities 5a and 5b are arranged to face each other, and two runners 19a and 19b extending from the respective cavities 5a and 5b in opposite directions are formed.

  The two cavities 5a and 5b are arranged in a minimum circumscribed circle C1 where the two hot runner gates 17a and 17b of each runner 19a and 19b circumscribe. The minimum circumscribed circle C1 is a circumscribed circle having a minimum radius circumscribing the hot runner gates 17a and 17b.

  That is, the hot runner mold of the first embodiment has a configuration in which the cavities 5a and 5b and the runners 19a and 19b are arranged in the minimum circumscribed circle C1.

  According to this embodiment, it is not necessary to manufacture a unit portion for each cavity as in the conventional example, and the number of manufacturing steps of the unit portion can be reduced.

  In addition, since the cavities 5a and 5b can be arranged at the center of the movable unit mold 40, it is difficult for the temperature change of the mold 1 due to a disturbance such as an increase or decrease in room temperature to reach the cavities 5a and 5b. The temperature of the portion 5b can be kept constant, and the shape accuracy of the molded product can be improved.

  Further, since the cavities 5a and 5b can be arranged close to each other, the temperature difference between the cavities 5a and 5b can be reduced, and a molded product having a uniform shape can be obtained.

  FIG. 3 is a partially enlarged view of a hot runner mold according to a second embodiment of the present invention as viewed from a division surface.

  FIG. 3 shows an example in which four cavities 105a, 105b, 105c, and 105d are arranged in the movable-side unit mold 140.

  Runners 119a and 119b extending parallel to each other are formed in the cavities 105a and 105b. Runners 119c and 119d extending parallel to each other are formed in cavities 105c and 105d facing the cavities 105a and 105b.

  The four cavities 105a, 105b, 105c, and 105d are arranged in a minimum circumscribed circle C2 in which the hot runner gates 117a, 117b, 117c, and 117d of the respective runners 119a, 119b, 119c, and 119d circumscribe.

  That is, the hot runner mold of the second embodiment has a configuration in which the cavities 105a, 105b, 105c, 105d and the runners 119a, 119b, 119c, 119d are arranged in the minimum circumscribed circle C2.

  According to this embodiment, the same effects as those of the first embodiment can be obtained.

  FIG. 4 is a partially enlarged view of a hot runner mold according to a third embodiment of the present invention as viewed from a division surface.

  FIG. 4 shows an example in which four cavities 205a, 205b, 205c, and 205d are arranged in the movable-side unit mold 240.

  Four runners 219a, 219b, 219c, 219d extending in directions different from each other by 90 ° from adjacent cavities 205a, 205b, 205c, 205d are formed.

  The four cavities 205a, 205b, 205c, 205d are arranged in a minimum circumscribed circle C3 in which the hot runner gates 217a, 217b, 217c, 217d of the respective runners 219a, 219b, 219c, 219d circumscribe.

  That is, the hot runner mold of the third embodiment has a configuration in which the cavities 205a, 205b, 205c, 205d and the runners 219a, 219b, 219c, 219d are arranged in the minimum circumscribed circle C3.

  According to this embodiment, the same effects as those of the first embodiment can be obtained.

  FIG. 5 is a partially enlarged view of a hot runner mold according to a fourth embodiment of the present invention, as viewed from a division surface.

  FIG. 5 shows an example in which four cavities 305a, 305b, 305c, 305d are arranged in the movable unit mold 340.

  Runners 319a and 319b extending parallel to each other are formed in the cavities 305a and 305b. Each of the runners 319a and 319b is bent at a right angle on the way, and continues to the hot runner gate 317a.

  Runners 319c and 319d extending in parallel are formed in the cavities 305c and 305d facing the cavities 305a and 305b. Each of the runners 319c and 319d is bent at a right angle on the way, and continues to the hot runner gate 317b.

  The four cavities 305a, 305b, 305c, 305d are arranged in a minimum circumscribed circle C4 that circumscribes the two hot runner gates 317a, 317b.

  That is, the hot runner mold of the fourth embodiment has a configuration in which the cavities 305a, 305b, 305c, 305d and the runners 319a, 319b, 319c, 319d are arranged in the minimum circumscribed circle C4.

  According to this embodiment, the same effects as those of the first embodiment can be obtained.

  FIG. 6 is a partially enlarged view of a hot runner mold according to a fifth embodiment of the present invention as viewed from a division surface.

  FIG. 6 shows an example in which four cavities 405a, 405b, 405c, and 405d are arranged in the movable unit mold 440.

  Runners 419a and 419b extending from adjacent cavities 405a and 405b extend obliquely so as to approach each other and continue to a hot runner gate 417a. The runners 419c and 419d extending from the adjacent cavities 405c and 405d extend obliquely so as to approach each other and continue to the hot runner gate 417b.

  The four cavities 405a, 405b, 405c, and 405d are arranged in a minimum circumscribed circle C5 that circumscribes the two hot runner gates 417a and 417b.

  That is, the hot runner mold of the fifth embodiment has a configuration in which the cavities 405a, 405b, 405c, 405d and the runners 419a, 419b, 419c, 419d are arranged in the minimum circumscribed circle C5.

  According to this embodiment, the same effects as those of the first embodiment can be obtained.

  FIG. 7 is a partially enlarged view of a hot runner mold according to a sixth embodiment of the present invention as viewed from a division surface.

  FIG. 7 shows an example in which six cavities 505a, 505b, 505c, 505d, 505e, and 505f are arranged in a movable unit mold 540.

  Runners 519a, 519b, 519c extending parallel to each other are formed in the cavities 505a, 505b, 505c. Runners 519d, 519e, 519f extending in parallel with each other are formed in cavities 505d, 505e, 505f facing the cavities 505a, 505b, 505c.

  The six cavities 505a, 505b, 505c, 505d, 505e, 505f and the hot runner gates 517b, 517e are in the minimum circumscribed circle C6 circumscribed by the hot runner gates 517a, 517c, 517d, 517f of the runners 519a, 519c, 519d, 519f. Are located in

  That is, the hot runner mold of the sixth embodiment has a configuration in which the cavities 505a, 505b, 505c, 505d, 505e, 505f and the runners 519a, 519b, 519c, 519d, 519e, 519f are arranged in the minimum circumscribed circle C6. It has become.

  According to this embodiment, the same effects as those of the first embodiment can be obtained.

  FIG. 8 is a partially enlarged view of a hot runner mold according to a seventh embodiment of the present invention, as viewed from a division plane.

  FIG. 8 shows an example in which eight cavities 605a, 605b, 605c, 605d, 605e, 605f, 605g, and 605h are arranged in a movable unit mold 640.

  Adjacent cavities 605a, 605b are formed with runners 619a, 619b extending parallel to each other, adjacent cavities 605c, 605d are formed with runners 619c, 619d extending parallel to each other, and adjacent cavities 605e, 605f are parallel to each other. Are formed, and runners 619g and 619h extending parallel to each other are formed in adjacent cavities 605g and 605h.

The runners 619a and 619b are orthogonal to the runners 619c and 619d, the runners 619c and 619d are orthogonal to the runners 619e and 619f, the runners 619e and 619f are orthogonal to the runners 619g and 619h, and the runners 619g, 619h and 619a are orthogonal. 619b.

  The eight cavities 605a, 605b, 605c, 605d, 605e, 605f, 605g, and 605h are hot runner gates 617a, 617b, 617c, 617e, 617e, 617e, 619f, 619g, and 619d of the respective runners 619a, 619b, 619c, 619d. 617f, 617g, and 617h are arranged in the minimum circumscribed circle C7 that circumscribes.

  That is, the hot runner mold of the sixth embodiment has the cavities 605a, 605b, 605c, 605d, 605e, 605f, 605g, 605h and the runners 619a, 619b, 619c, 619d, 619e, 619f in the minimum circumcircle C7. , 619g, and 619h.

  According to this embodiment, the same effects as those of the first embodiment can be obtained.

FIG. 1 is a conceptual diagram showing a cross section of a hot runner mold according to a first embodiment of the present invention. FIG. 2 is a partially enlarged view of the hot runner mold according to the first embodiment of the present invention as viewed from a division surface. FIG. 3 is a partially enlarged view of a hot runner mold according to a second embodiment of the present invention as viewed from a division surface. FIG. 4 is a partially enlarged view of a hot runner mold according to a third embodiment of the present invention as viewed from a division surface. FIG. 5 is a partially enlarged view of a hot runner mold according to a fourth embodiment of the present invention, as viewed from a division surface. FIG. 6 is a partially enlarged view of a hot runner mold according to a fifth embodiment of the present invention as viewed from a division surface. FIG. 7 is a partially enlarged view of a hot runner mold according to a sixth embodiment of the present invention as viewed from a division surface. FIG. 8 is a partially enlarged view of a hot runner mold according to a seventh embodiment of the present invention, as viewed from a division plane.

Explanation of reference numerals

1 Hot runner mold 2 Cooling flow path (fluid piping)
5a, 5b, 50, 105a, 105b, 105c, 105d, 205a, 205b, 205c, 205d, 305a, 305b, 305c, 305d, 405a, 405b, 405c, 405d, 505a, 505b, 505c, 505d, 505e, 505f, 605a, 605b, 605c, 605d, 605e, 605f, 605g, 605h Cavity 10 Fixed main mold 13 Sprue bush 15 Hot runner manifold 16A, 16B Hot runner body 17a, 17b, 117a, 117b, 117c, 117d, 217a, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b, 217b , 217d, 317a, 317b, 317a, 317b, 417a, 417b, 517a, 517b, 517c, 517d, 517e, 517f, 617a, 617b, 617c, 617d, 617e, 617f, 617g, 617h Hot runner gate 18a, 18b Side gate 19a, 19b, 119a, 119b, 119c, 119d, 219a, 219b, 219c, 219d, 319a, 319b, 319c, 319d, 419a, 419b, 419c , 419d, 519a, 519b, 519c, 519d, 519e, 519f, 619a, 619b, 619c, 619d, 619e, 619f, 619g, 619h Runner 20 Movable main mold 30 Fixed-side unit mold 40, 140, 240, 340, 440 , 540, 640 Movable unit type C1, C2, C3, C4, C5, C6, C7 Minimum circumscribed circle

Claims (5)

In a mold having a main mold and a unit part having a cavity that can be separated from the main mold and is injected with a molten resin through a side gate,
A plurality of hot runner gates of a hot runner for feeding the molten resin into the cavity are arranged on the main mold,
The unit section has a plurality of cavities,
A mold wherein all the cavities are arranged in a minimum circumscribed circle set to include the position of the hot runner gate.   2. The mold according to claim 1, wherein a heat insulating means is arranged between the unit and the resin melting part for holding the molten resin in a molten state in the hot runner.   The mold according to claim 1, wherein a fluid pipe is arranged between the resin melting section and the unit section.   The mold according to claim 3, wherein the fluid pipe is disposed between the heat insulating means and the unit portion or between the heat insulating means and the resin melting portion.   The mold according to any one of claims 1 to 4, wherein the optical component is molded.

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