CN115703266A - Sprue cut-off type plastic lens forming device - Google Patents

Abstract

The invention discloses a pouring channel cut-off type plastic lens forming device, which is provided with an upper mold core, wherein the upper mold core is provided with a first cylindrical part extending downwards, an upper mold cavity is formed on the end surface of the first cylindrical part, a lower mold base is provided with a mold core hole and is provided with a pouring channel which is radially communicated with the mold core hole, the first cylindrical part is downwards accommodated in the mold core hole, a lower mold core is arranged in the lower mold base, the lower mold core is provided with a second cylindrical part, a lower mold cavity is formed on the end surface of the second cylindrical part, the first cylindrical part can move along the mold core hole, a lens forming mold cavity is formed between the upper mold cavity and the lower mold cavity, the lower mold base can move between a communication position and a closed position relative to the first cylindrical part or the second cylindrical part, and when the lower mold base is positioned at the communication position, the pouring channel is communicated with the lens forming mold cavity; when the lower die holder is located at the closed position, the peripheral side of the first cylindrical part or the second cylindrical part is opposite to the closed pouring channel, so that the pouring channel is not communicated with the lens forming die cavity.

Description

Sprue cut-off type plastic lens forming device

technical field

The invention relates to a mold for manufacturing lenses, in particular to a runner cut-off type plastic lens forming device.

Background technique

The existing injection molding manufacturing method of optical lenses is mainly to use the molten resin material to be extruded into the forming mold. The forming mold has a mold cavity and a flow channel corresponding to the shape and size of the lens. The mold cavity and the flow channel are connected. The sprue is formed at the joint between the mold cavity and the runner. However, for lenses molded by traditional molding molds, there will be excess and unnecessary chips remaining at the joint between the lens and the gate. Therefore, additional processing is required to remove unnecessary chips. , and there is a problem of poor manufacturing efficiency.

In order to improve the above problems, some operators have developed a cutting structure that can be used to cut off the material head in the mold. For example, the Chinese Patent No. 201821023933 adopts a mold on one side of the molding mold that can be used for cooling and hardening during demoulding. However, this kind of cutting structure will not only complicate the composition of the forming mold, but also cause the cutting action of the cooled and hardened molded object, so it is easy to wear and affect the subsequent cutting. The flatness of the cut, and when the straight shear plate is cut along the periphery of the circular columnar mold, there will still be a little side gate material head remaining, and the purpose of completely removing the gate material head cannot be achieved .

And the cut-off structure provided by Chinese Patent No. 200518909 is to use a shear plate sandwiched between the mold cavity and the runner in the forming mold, and after the molded object in the mold cavity is cooled and hardened, by Pulling the shear piece to slide along the transverse direction can cut off the material head between the mold cavity and the runner. However, this cutting structure also has the disadvantages of complex composition and structure of the forming mold, and the shear plate is prone to wear and tear, and Since the shearing plate is formed by overlapping with the mold, there is a problem that the cut head is not easy to take out. In addition, the cut section must form a plane shape, so it can be used in various occasions. It is greatly restricted, and when cutting the head along the periphery of the circular columnar mold with this cutting structure, there will also be the problem of side gate residue, and the gate head cannot be completely removed.

Another example is the cut-off structure provided by Taiwan Patent No. 201902656, which uses a knife to cut the plastic in the runner upwards. However, this cut-off structure must additionally consider the position of the knife incision during cutting. Therefore, the shape and size of the tool incision must be controlled quite accurately, and in order to control its shape and size easily, the tool incision can only be made straight, so if it is applied to the periphery of a circular columnar mold for When cutting, there will also be a little side gate residue; in addition, when the cutter cuts the plastic in the runner upwards with this cutting structure, it will inevitably push the plastic, causing the density on both sides of the molded product to be the same as Increased stress, if applied to optical lenses, will seriously affect the imaging quality of optical lenses.

In addition, the existing injection molding process of optical lenses is to pour molten and softened plastic into the mold cavity from the outside after the molding mold is closed. However, under the premise that optical lenses are getting smaller and smaller, When the forming mold is closed, the narrow area formed by the concave-convex shape of the cavity surface is easy to restrict and block the flow of plastic, resulting in uneven injection pressure when the plastic is poured into the cavity. The phenomenon occurs, and the finished lens made by it is prone to light streak defects with inconsistent density when it is inspected with polarized light. In addition, in some injection molding situations with a high thickness-to-thin ratio, when the plastic fills the mold cavity from bottom to top, due to the limitation of the mold cavity space after the mold is closed, it will lead to a thinner area in the middle of the optical lens. Packed with air.

Contents of the invention

One of the objectives of the present invention is to provide a sprue cut-off type plastic lens forming device, which has a simple structure and can directly form a lens without a sprue and has a smooth outer contour.

The second object of the present invention is to provide a plastic lens molding device with cut-off runners, which can effectively solve the problem of light streaks on the lens caused by uneven injection pressure stress and easy encapsulation of air during the injection molding process. and other related issues.

In order to achieve the above-mentioned purpose, the present invention provides a plastic lens molding device with cut-off runner, which is characterized in that it includes:

An upper mold base is provided with an upper mold core, the upper mold core has a first cylindrical portion extending downward, and an upper die cavity is formed on the downward end surface of the first cylindrical portion;

The lower mold base is located at the relative lower side of the upper mold base. The upper end of the lower mold base forms a parting surface which is close to the joint mold with the upper mold base. core hole, the first cylindrical portion is downwardly accommodated in the mold core hole, one side of the lower mold base is provided with a runner radially connected to the mold core hole, and the runner is relatively far away from the mold core hole one end of which is formed with an open end;

The lower mold core is arranged in the lower mold seat, the lower mold core has a second cylindrical part located in the hole of the mold core, and a lower mold cavity is formed on the upward end surface of the second cylindrical part. The outer contour shapes of the first cylindrical part and the second cylindrical part conform to the shape of the inner edge of the core hole, and the first cylindrical part can move along the core hole to make the upper mold cavity A lens forming mold cavity is formed in the mold core hole between the lower mold cavity, and the lower mold base can move between a communicating position and a closed position relative to the second cylindrical part, when the lower mold base When located at the communication position, the runner communicates with the lens forming film cavity; and when the lower mold base is at the closed position, the peripheral side of the second cylindrical portion will relatively close the runner, making the runner It is not connected with the lens molding cavity.

In another embodiment, the sprue cut-off type plastic lens molding device provided by the present invention is characterized in that it includes:

An upper mold base is provided with an upper mold core, the upper mold core has a first cylindrical portion extending downward, and an upper mold cavity is formed on the downward end surface of the first cylindrical portion;

The lower mold base is located at the relative lower side of the upper mold base. The lower mold base has a mold core hole that goes deep downward from its upper end. The first cylindrical part is downwardly accommodated in the mold core hole. The lower mold base One side of the mold base is provided with a runner radially connected to the core hole of the mold, and the runner forms an open end at an end relatively far away from the core hole of the mold;

The lower mold core is arranged in the lower mold seat, the lower mold core has a second cylindrical part located in the hole of the mold core, and a lower mold cavity is formed on the upward end surface of the second cylindrical part. The outer contour shapes of the first cylindrical part and the second cylindrical part conform to the shape of the inner edge of the core hole, and the first cylindrical part can move along the core hole to make the upper mold cavity A lens forming mold cavity is formed between the lower mold cavity, and the lower mold base can move between a communication position and a closed position relative to the first cylindrical part. When the lower mold base is in the communication position, The runner communicates with the lens forming film cavity; and when the lower mold base is in the closed position, the peripheral side of the first cylindrical portion will relatively close the runner, so that the runner will not be in contact with the lens forming mold. cavities connected.

Preferably, the runner is in an outwardly expanding shape gradually expanding towards the opening end.

Preferably, there is an injection nozzle that can be relatively close to or retracted from the opening end. The injection nozzle has a feed channel, and the feed channel is formed on the inner edge of the port facing the open end. The conical surface is tapered, and when the injection nozzle is close to the opening end, the feeding channel is connected with the opening end, and the feeding channel is further equipped with a stopper rod, which can be opposite to the opening end. The feeding channel is displaced forward and backward, and the end of the plug rod in the form of a conical surface can be used to correspondingly close the port of the feeding channel.

Preferably, the first cylindrical portion, the second cylindrical portion and the core hole have conical surfaces with the same taper.

Preferably, the lower mold base is arranged in a base, and the lower mold base can move up and down relative to the base.

Beneficial effects of the present invention: the present invention has a simple structure, and can be directly made into a lens without a gate and has a smooth outer contour; it can effectively solve the problem of light streaks on the lens caused by uneven injection pressure during the injection molding process Flaws, and the efficacy of related problems such as easy to wrap air.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

2 to 4 are schematic diagrams showing the action of the first embodiment of the present invention during injection molding.

FIG. 5 is a schematic diagram of the action of the first embodiment of the present invention when the mold is opened.

6 to 8 are schematic diagrams of the second embodiment of the present invention when performing injection molding operations.

FIG. 9 is a schematic diagram of the action of the second embodiment of the present invention during mold opening.

Detailed ways

At first, please refer to Fig. 1 to Fig. 4, the sprue cut-off type plastic lens forming device of the present invention, it comprises an upper mold base 1, an upper mold core 11, a lower mold base 2 and a lower mold core 31, wherein:

The upper mold core 11 is arranged in the upper mold base 1, the upper mold core 11 has a first cylindrical portion 12 extending downward, the outer contour of the first cylindrical portion 12 is cylindrical, and on the first An upper mold cavity 13 is formed on the downward facing end surface of the cylindrical portion 12 .

This lower mold base 2 is arranged in a base 5, and this lower mold base 2 is driven by a driving mechanism (not shown in the figure), so that this lower mold base 2 can move up and down relative to this base 5, and the The lower mold base 2 is arranged on the relative lower side of the upper mold base 1, and the upper end of the lower mold base 2 is formed with a parting surface 21 for engaging the upper mold base 1 with the mold, and the lower mold base 2 has a self- The parting surface 21 goes deep into the mold core hole 22 downwards, and taking the manufacture of circular lenses as an example, the inner edge shape (i.e. cross-sectional shape) of the mold core hole 22 is circular, which is similar to that of the circular lens to be made. The shape of the outer contour conforms, and the shape of the first cylindrical part 12 is correspondingly accommodated downward in the core hole 22, and the upper mold base 1 and the upper mold core 11 are controlled by a transmission mechanism (not shown in the figure). ) are driven synchronously, so that the first cylindrical part 12 can move up and down in the core hole 22 of the die, and a runner 23 radially connected to the core hole 22 is provided on one side of the lower die base 2 The runner 23 is formed with an open end 231 at an end relatively away from the core hole 22 , and the runner 23 is in an outwardly expanding shape gradually expanding toward the open end 231 .

The lower mold core 31 is arranged in the lower mold base 2, the lower mold core 31 has a second cylindrical portion 32 located in the mold core hole 22, and the upper end surface of the second cylindrical portion 32 A lower mold cavity 33 is formed, and the outer contour of the second cylindrical portion 32 is cylindrical, which also conforms to the shape of the inner edge of the mold core hole 22. The lower mold core 31 is subjected to a push mechanism (not shown in the figure). ) transmission, so that the second cylindrical part 32 can also be displaced up and down in the mold core hole 22. In addition, the first cylindrical part 12, the second cylindrical part 32 and the mold core hole 22 can also be made The conical surfaces with the same taper can reduce the relative friction when the first cylindrical part 12 and the second cylindrical part 32 are displaced in the core hole 22 of the mold, and at the same time guide their slippage The effect of the itinerary.

Further, there is an injection nozzle 41 that can be relatively close to or retracted from the opening end 231, the injection nozzle 41 has a feed channel 42, and the feed channel 42 is on the inner edge of the port facing the opening end 231 A conical surface 43 that tapers toward the opening end 231 is formed, and when the injection nozzle 41 abuts against the opening end 231, the feed channel 42 communicates with the opening end 231, making it melt and soften. The plastic can be injected into the sprue 23 through the feed channel 42 and the open end 231 in sequence, and a stopper rod 44 is further pierced in the feed channel 42, and the stopper rod 44 can be driven relative to the The feed channel 42 is displaced forward and backward, and the tapered end of the stopper rod 44 can be used to correspondingly close the port of the feed channel 42 , so as to prevent plastic from continuing to be injected into the sprue 23 . In the present invention, a sprue 23 communicating with the die core hole 22 is directly opened on one side of the lower mold base 2, and connected to the injection nozzle 41, which can effectively shorten the distance between the injection nozzle 41 and the mold core hole. The distance between 22 can greatly reduce the internal pressure loss when the plastic is injected, so it has the effect of accurately measuring the plastic entering the core hole 22 of the mold.

As shown in Figures 2 and 3, the upper mold base 1 will drive the first cylindrical portion 12 of the upper mold core 11 to a first molding position along the mold core hole 22 during the downward mold clamping process. Move between A and a second forming position B. As shown in FIG. 2, when the first cylindrical portion 12 moves to the first molding position A, a plastic mold that communicates with the runner 23 will be formed between the upper mold cavity 13 and the lower mold cavity 33. pouring space S; and as shown in Figure 3, when the upper mold base 1 and the lower mold base 2 are relatively closed, the first cylindrical part 12 will be driven to move to the second molding position B, so that the upper mold cavity 13 and the lower mold cavity 33 form a lens molding cavity P connected with the runner 23 in the mold core hole 22, and the shape of the lens molding cavity P conforms to the shape of the finished lens to be molded , and the side height H where the plastic pouring space S meets the runner 23 is greater than the side height h where the lens molding cavity P meets the runner 23 .

3 and 4, the lower mold base 2 can move up and down between a communication position C on the upper side and a closed position on the lower side relative to the second cylindrical portion 32. As shown in Figure 3, when the lower mold base 2 is located at the communication position C, the runner 23 communicates with the lens molding cavity P, and as shown in Figure 4, when the lower mold base 2 is located at the When the position D is closed, the peripheral side of the second cylindrical portion 32 will relatively close the runner 23 so that the runner 23 is not connected with the cavity P for forming the lens.

And by the sprue cut-off type plastic lens molding device of the present invention, when performing injection molding operations, as shown in Figure 2, before the upper mold base 1 and the lower mold base 2 are closed, the second cylindrical part 32 is in a fixed position that does not block the sprue 23 and remains motionless, while the first cylindrical portion 12 of the upper mold core 11 is located at the first molding position A, and at this time the lower mold base 2 is located at the communicating position C, after the plastic pouring space S connected with the runner 23 is formed between the upper mold cavity 13 and the lower mold cavity 33, a predetermined amount of molten and softened plastic can be injected through the injection nozzle 41 Injected into the plastic pouring space S, since the side height H of the plastic pouring space S is greater than the side height h of the lens molding cavity P, when the plastic is injected into the plastic pouring space S, it is less likely to be affected by the upper mold cavity. 13 and the concave-convex shape of the lower mold cavity 33 are restricted and blocked to ensure the smoothness of pouring plastics, thereby solving the problems of lens light streaks and easy encapsulation of air due to uneven injection pressure stress.

Then as shown in Figure 3, after the operation of above-mentioned pouring plastic is finished, make this first columnar part 12 move down to the second molding position B again, make this upper mold cavity 13 and this lower mold cavity 33 in this mold The lens forming cavity P connected with the sprue 23 is formed in the core hole 22, so that the molten and softened plastic can be filled in the lens forming cavity P, and then the lens forming cavity P can be filled in the lens forming cavity P. In P, a lens with a predetermined size is molded.

Then, as shown in Figure 4, the lower mold base 2 is then moved downwards from the communication position C relative to the second cylindrical portion 32 to the closed position D, because the runner 23 is a part of the lower mold base 2. side, so when the lower mold base 2 moves downward, it will synchronously drive the runner 23 to move downward, so that the peripheral side of the second cylindrical part 32 can gradually close the runner 23, making the runner 23 is not communicated with the lens molding cavity P, and achieves the effect equivalent to shearing the sprue head, and the plastic at this time is molten and softened, so the peripheral side of the second cylindrical portion 32 will not be easily The problem of wear and tear, after the plastic is cooled in the lens forming film cavity P through the upper mold core 11 and the lower mold core 31 in a pressure-holding state, it can be directly made into a lens with no gate and a smooth outer contour . In addition, the present invention directly sets the sprue 23 on one side of the lower mold base 2, which not only cuts off the plastic waste in the sprue 23 through the movement of the lower mold base 2, but also ensures that the plastic waste can be taken out of the sprue later. At 23 o'clock, its plastic waste will not be scraped by the upper and lower dies to produce fine chips, and the outer diameter of the finished product has more precision, and can ensure the accuracy of assembly between the die core hole 22 opening and the upper die core 11.

Finally, as shown in Figure 5, the upper mold base 1 is opened upwards, the first cylindrical part 12 is moved out of the mold core hole 22, and the lower mold core 31 is moved upward relative to the lower mold base 2, so that the lower mold base 2 After the second cylindrical portion 32 of the mold core 31 pushes out of the mold core hole 22 upwards, the finished lens can be taken out from the lower mold cavity 33 .

In addition, it should be particularly noted that when the first cylindrical portion 12 moves to the first molding position A, there will be formed between the upper mold cavity 13 and the lower mold cavity 33 to connect with the sprue 23 The open plastic pouring space S, in addition to injecting a predetermined amount of molten and softened plastic into the plastic pouring space S through the injection nozzle 41 through the above-mentioned method, can also inject a molten and softened plastic through the injection nozzle 41. The plastic is injected to fill the plastic pouring space S, and then, when the first cylindrical part 12 moves to the second molding position B, through the pushing of the first cylindrical part 12, the excess plastic passes through the The sprue 23 is re-discharged into the feed channel 42 of the injection nozzle 41, without the need for precise calculation, the quantitative output of plastic can be simply and easily achieved, and when the excess plastic is discharged, it can be simultaneously Discharging the air in the plastic pouring space S together can further avoid the problem of easy enveloping air, and under the action of pushing and pressing, it can also ensure that the density of the lens made by it remains consistent.

Also as shown in Figures 6 to 9, it is the second embodiment of the present invention, and the difference from the above-mentioned first embodiment is that in this second embodiment, when the cutting operation is performed, the lower mold base is used instead 2 can move up and down relative to the first cylindrical portion 32 between a communication position C on the lower side and a closed position D on the upper side. As shown in Figure 7, when the lower mold base 2 is located at the communication position C, the runner 23 communicates with the lens forming film cavity P, and as shown in Figure 8, when the lower mold base 2 is located at the When the position D is closed, the peripheral side of the first cylindrical portion 12 will relatively close the runner 23 so that the runner 23 will not communicate with the cavity P for forming the lens.

In the second embodiment provided by the present invention, when the injection molding operation is performed, as shown in FIG. The fixed position of the sprue 23 is not blocked and remains still, and the first cylindrical portion 12 of the upper mold core 11 is located at the first molding position A, and at this time the lower mold base 2 is located at the communication position C, so that After the plastic pouring space S connected with the runner 23 is formed between the upper mold cavity 13 and the lower mold cavity 33, a predetermined amount of molten and softened plastic can be injected into the injection nozzle 41. Plastic pouring space S.

Then as shown in Figure 7, after the operation of above-mentioned perfusion plastic is finished, make this first columnar part 12 move down to the second molding position B, make this upper mold cavity 13 and this lower mold cavity 33 can be in this mold A lens molding cavity P communicating with the runner 23 is formed in the core hole 22 .

Then as shown in Figure 8, when the lower mold base 2 moves upwards from the communication position C relative to the first cylindrical portion 32 to the closed position D, since the runner 23 is arranged on one side of the lower mold base 2 , so when the lower mold base 2 moves upward, it will synchronously drive the runner 23 to move upward, so that the peripheral side of the first cylindrical part 12 can gradually close the runner 23, so that the runner 23 is not in contact with the runner 23. The lens molding cavity P is connected, and can also achieve the effect of cutting the sprue head.

Finally, as shown in Figure 9, the upper mold base 1 is opened upwards, the first cylindrical part 12 is moved out of the mold hole 22, and then the lower mold core 31 is moved upwards, and the lower mold base 2 is simultaneously moved. Move down to a pick-up position E, after the second cylindrical portion 32 of the lower mold core 31 is pushed out of the mold core hole 22, the gate-free and molded mold can be taken out from the lower mold cavity 33. The lens with flat outer contour also belongs to the equivalent application of the present invention.

Claims (6)

1. A kind of runner cuts off the plastic lens forming device of the type, characterized by, include:

the upper die holder is provided with an upper die core, the upper die core is provided with a first cylindrical part extending downwards, and an upper die cavity is formed on the downward end face of the first cylindrical part;

a lower die holder arranged relatively below the upper die holder, the upper end of the lower die holder is provided with a die parting surface which is close to the joint die with the upper die holder, the lower die holder is provided with a die core hole which extends downwards from the die parting surface, the first cylindrical part is downwards accommodated in the die core hole, one side of the lower die holder is provided with a pouring channel which is radially communicated with the die core hole, and one end of the pouring channel relatively far away from the die core hole is provided with an opening end;

a lower die core arranged in the lower die base, wherein the lower die core is provided with a second cylindrical part positioned in the die core hole, a lower die cavity is formed on the upward end surface of the second cylindrical part, the outer contour shapes of the first cylindrical part and the second cylindrical part are matched with the inner edge shape of the die core hole, the first cylindrical part can move along the die core hole, so that a lens forming die cavity is formed between the upper die cavity and the lower die cavity, the lower die base can move between a communicating position and a closed position relative to the second cylindrical part, and when the lower die base is positioned at the communicating position, the runner is communicated with the lens forming die cavity; when the lower die holder is located at the closed position, the periphery of the second cylindrical part is opposite to the pouring channel to seal the pouring channel, so that the pouring channel is not communicated with the lens molding cavity.

2. A runner block type plastic lens forming device is characterized in that it comprises:

the upper die base is provided with an upper die core, the upper die core is provided with a first cylindrical part extending downwards, and an upper die cavity is formed on the downward end surface of the first cylindrical part;

a lower die holder arranged relatively below the upper die holder, the lower die holder is provided with a die core hole which extends downwards from the upper end of the lower die holder, the first cylindrical part is downwards accommodated in the die core hole, one side of the lower die holder is provided with a pouring channel which is radially communicated with the die core hole, and an opening end is formed at one end of the pouring channel which is relatively far away from the die core hole;

a lower mould core arranged in the lower mould seat, the lower mould core is provided with a second cylindrical part positioned in the mould core hole, a lower mould cavity is formed on the upward end surface of the second cylindrical part, the outer contour shapes of the first cylindrical part and the second cylindrical part are all consistent with the inner edge shape of the mould core hole, the first cylindrical part can move along the mould core hole, so that a lens forming mould cavity is formed between the upper mould cavity and the lower mould cavity, the lower mould seat can move between a communicating position and a closed position relative to the first cylindrical part, and when the lower mould seat is positioned at the communicating position, the pouring channel is communicated with the lens forming mould cavity; when the lower die base is located at the closed position, the periphery of the first cylindrical part is opposite to the pouring channel so that the pouring channel is not communicated with the lens molding cavity.

3. The gate-shut plastic lens molding apparatus according to claim 1 or 2, wherein the gate is flared toward the open end.

4. The apparatus of claim 1 or 2, further comprising a feeding nozzle capable of moving toward or away from the open end, wherein the feeding nozzle has a feeding channel, the feeding channel has a tapered surface formed at an inner edge of the port facing the open end, the feeding channel is in communication with the open end when the feeding nozzle is moved toward the open end, the feeding channel further has a plug rod passing through the feeding channel, the plug rod can move forward and backward relative to the feeding channel, and the tapered end of the plug rod can be used to correspondingly close the port of the feeding channel.

5. The apparatus of claim 1 or 2, wherein the first cylindrical portion, the second cylindrical portion and the cavity bore have conical surfaces with the same taper.

6. The apparatus of claim 1 or 2, wherein the lower mold base is disposed in a base, and the lower mold base is capable of moving up and down relative to the base.

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