JP3142913B2 - Slow cooling device in gate seal injection molding system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slow cooling device in a gate seal injection molding system, and more particularly to a slow cooling device suitable for a gate seal injection molding system for optical elements such as plastic lenses.

[0002]

2. Description of the Related Art In recent years, various injection moldings utilizing the advantages of molding (molding), for example, injection molding of an optical element such as a plastic lens, have been performed due to the high precision of plastic molding processing. In this type of molding equipment,
Since it is required to reduce the cost by shortening the molding time per molded article, for example, Japanese Patent Application Laid-Open
As described in JP-A-231-231 and JP-A-2-38012, it is possible to use a plurality of mold units so that one mold can be opened to another mold before the mold is opened and a molded product is taken out. Some are

Further, in molding a lens or the like having a large thickness and a large thickness deviation ratio, in order to enhance the shape transfer accuracy by a molding die, an appropriate amount of resin is used just before the filling of the cavity is completed until the filling resin solidifies. It is necessary to keep applying pressure. Therefore, a gate seal molding method as described in, for example, JP-A-64-36421 has been proposed.

Therefore, if a plurality of cavity units are used in the gate seal injection molding system, various molded products can be mixed and produced with high precision (multi-product small-quantity production). Specifically, since the nonuniformity of the resin pressure and the resin temperature due to the orientation and pressure distribution of the resin is eliminated from occurring, and the mold temperature by uniform heating of the mold is raised above the glass metastasis point performs injection filling, stop the flow of the resin by performing a gate seal, then the mold maintained at a temperature above the glass metastasis point performs relaxation of the resin, a uniform pressure and temperature of the resin in the cavity, then Slowly cool slowly until the temperature becomes lower than the heat deformation temperature, and the resin pressure becomes 0 (kgf / cm ² )
Take out the molded product when it becomes.

[0005]

However, in such a gate seal injection molding system, in order to secure a slow cooling time and obtain a certain accuracy, a molding cycle becomes long and productivity is low. There was a problem. For example,
As shown in FIGS. 10 and 11, when the filling resin is polycarbonate (PC), the material of the cavity unit is martensitic stainless steel (equivalent to SUS420), and the size is about 150 mm square, the slow cooling start temperature The slow cooling time from 170 ° C to 130 ° C below the heat distortion temperature is
It takes more than 40 minutes with air cooling (leaving in air).

[0006] In contrast, for example, or increasing the number of the cavity unit, it is conceivable to or the queue Activity units in multiple several up, the case of the,
Not only does the manufacturing cost of the cavity unit increase, but also the dimensions between the cavities tend to vary, and the management and maintenance of the cavity unit on the line are complicated. In addition, in the above case, there is a problem that the size of the cavity unit including the transfer means is increased due to the increase in the size of the cavity unit, which increases the size of the apparatus and the slow cooling time.

[0007] The present invention has been made in view of the above problems, and efficiently performs slow cooling, which requires the longest time in gate seal injection molding, to improve productivity while maintaining multi-product mixed production. It is an object of the present invention to provide a slow cooling device which can be used.

[0008]

In order to achieve the above object, the invention according to claim 1 includes a plurality of cavity units forming cavities therein, and the cavity units are transferred to a predetermined heating station by a transfer means.・
A gradual cooling device in a gate seal injection molding system configured to convey in order of a relaxation station, a gradual cooling station, and a molded product take-out station, wherein air around the cavity unit is subjected to predetermined gradual cooling conditions corresponding to the cavity unit. And a control means for controlling the air recovery means so as to gradually cool different types of cavity units under different conditions in accordance with the slow cooling conditions.

Further, the invention according to claim 2 is characterized in that the air recovery means changes the air recovery direction according to the slow cooling condition, and the invention according to claim 3 is orthogonal to the transport direction of the transport means. 5. The invention according to claim 4, wherein the air recovery means has an air recovery port provided in at least one of the vertical and horizontal directions of the cavity unit. The invention according to claim 5 is characterized in that the air recovery means has a plurality of air recovery ports adjacent to a transfer path of the cavity unit by the transfer means and a plurality of opening and closing means for independently opening and closing each air recovery port. The invention according to claim 6 is characterized in that the control means controls the air recovery means based on the read information of the identification mark attached to the cavity unit. And wherein the Rukoto.

[0010]

According to the first aspect of the invention, the air recovery means for recovering the air around the cavity unit is controlled according to the slow cooling condition of each cavity unit, and the air recovery means performs slow cooling suitable for each cavity unit. You. Therefore, even in the case of multi-mix production, slow cooling is performed efficiently and uniformly for each part of the molded product, thereby improving productivity.

According to the second aspect of the present invention, since the air recovery means changes the air recovery direction according to the slow cooling condition, the slow cooling condition can be set finely, and the slow cooling can be performed more quickly and uniformly. Become. According to the third aspect of the present invention, the air recovery port is provided in at least one of the vertical and horizontal directions of the cavity unit. Therefore, the air recovery port can be easily provided along the cavity transfer path.

[0012] According to the fourth aspect of the present invention, the recovery pump varies its air recovery capability. Therefore, adjustment of the amount of collected air can be facilitated. According to the fifth aspect of the present invention, a plurality of air recovery ports are provided along the transport path of the cavity unit, and these air ports are independently opened and closed by opening and closing means. Therefore, the cuvity unit being conveyed can be gradually cooled.

According to the present invention, the air collecting means is controlled based on the read information of the identification mark attached to each cavity unit. Therefore, optimal slow cooling can be performed for each type of cavity unit.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. 1 to 9 are views showing one embodiment of a slow cooling device in a gate seal injection molding system according to the present invention. First, the configuration will be described.

In FIG. 1, reference numeral 10 denotes a pair of upper and lower molds 11,
There are a plurality of different types of cavity units having 12, and the cavity unit 10 forms a cavity 10a of a predetermined shape corresponding to a strip-shaped molded product 21, for example, as shown in FIGS. Also other cavity units
7 forms a cavity corresponding to the substantially disk-shaped molded product 31 or 32, as shown in FIGS. Still another cavity unit 10 includes, for example, x as shown in FIG.
It has a cavity 10a having a rectangular section on the -y plane and a concave surface on one side.

Although not shown in detail, these various cavity units 10 are conveyed by a conveying means such as a chain, heated at a predetermined heating station, and then filled and filled.
It is sent to the relaxation station, the molten resin is injected and filled into the cavity 10a at this filling / relaxation station, the gate is sealed, and the temperature and pressure are relaxed.
Next, it is conveyed to a slow cooling station, gradually cooled to a temperature lower than the heat deformation temperature, and is opened at a molded product removal station for removal of a molded product.

The cavity unit 10 is provided with a self-holding mechanism (not shown) so that a predetermined mold clamping force can be held by the self-holding mechanism. This self-holding mechanism is used for the upper and lower molds 1 of the cavity unit 10.
A plurality of self-holding bolts for connecting the first and the second by tightening them in the mold clamping direction are provided near the cavity 10a, and the self-holding bolts pass through the mold 11 and are screwed to the mold 12.
By adopting this self-holding mechanism, the injection molding machine is opened with the gate of the cavity unit 10 sealed with a moving valve body after filling / relaxation by the injection molding machine, and the cavity unit 10 is cooled down alone and injected. A predetermined pressure-holding state independent of the molding machine can be maintained.

The slow cooling station is a cavity unit taken out of the injection molding machine by opening the machine.
10 below the heat distortion temperature (solidification temperature)
It has an air-based slow cooling device 41 that gradually cools the air at a cooling rate of less than one minute. As shown in FIGS. 1-3, a pneumatic slow cooling device
41 has a plurality of forced exhaust ducts 44 installed on the mold transfer section 42 and a shielding plate 45 provided in each duct 44. The mold transfer section 42 constitutes a part of the transfer means, and advances by a set count number at a constant speed or stops for a set stop time. Further, it is set so that the time of one molding cycle = the moving time of the mold conveying unit 42 + the stopping time.

The forced exhaust duct 44 is provided for the purpose of causing an air flow in the interior covered with the cover to gradually cool the mold under predetermined slow cooling conditions. for example a ₁ shown in FIG. 3, a _2, B _1, it is formed toward at least one of each collection direction B _2. In FIG. 2, the collection directions A ₁ and A ₂ indicate two directions perpendicular to the transport direction of the cavity unit 10 (the x direction in the figure) and the collection directions B ₁ and B _2. 2 perpendicular to the transport direction (x direction) of the cavity unit 10
One direction is shown. In order to generate airflow in each of these recovery directions, the air recovery port 44 of the forced exhaust duct 44
a is provided in the vicinity of the transport path of the mold transport section 42, and is appropriately arranged above, below, left and right of the cavity unit 10 (only the upper air recovery port 44a is shown in FIG. 1). Illustrated).

A plurality of shielding plates 45 are provided for each exhaust duct.
By changing its inclination in 44, each forced exhaust duct
Opening / closing means for independently opening and closing the 44 air recovery ports, and has a function of varying the air volume passing through each forced exhaust duct 44. 46 is an air volume adjusting means for adjusting the air volume passing through the forced exhaust duct 44 by changing the direction of the shielding plate 45 in each exhaust duct 44, and this adjusting means 46 is, for example, a motor 47 and its output. Gear 48A connected to the shaft and each shielding plate
A gear 48B connected to the gear 45 and meshing with the gear 48A is provided for each forced exhaust duct 44.

The driving of the motors 47 of the plurality of adjusting means 46 is controlled by the controller 50 under different conditions for each type of the cavity unit 10 (particularly for each cavity shape). The amount of air collected from the duct 44 can be changed independently, and the slow cooling rate (cooling rate) of the cavity unit 10 can be changed, and the slow cooling method for each cavity unit 10 can be changed.

That is, in this embodiment, the forced exhaust duct 44, the shielding plate 45 and the air suction pump are
Air recovery means 49 is configured to recover ambient air receiving heat radiation from the cavity unit 10 under predetermined slow cooling conditions based on the shape of the cavity 10a in the cavity unit 10, and is formed inside the cavity unit 10. The direction in which air is collected and the amount of air flow are changed for each general shape (disc, strip, etc.) of the cavity 10a. Further, a shielding plate 45 is provided as an opening / closing means for varying the air recovery capacity, and the opening degree of the air recovery port 44a of the forced exhaust duct 44 (in accordance with a slow cooling condition signal from a controller 50 as a control means). (Corresponding to the ability of the collection pump to collect air). Such an air recovery port 44a
Instead of the adjustment of the number of times, the recovery pump may be of a type in which the air recovery capacity is made variable to cope with a change in the slow cooling condition.

The above-mentioned predetermined slow cooling condition is a condition that differs depending on the type of the cavity unit 10, especially on the shape of the cavity. For example, when a disk-shaped cavity as shown in FIGS. 7 and 8 is arranged at the center as shown in FIG. 5A, the collecting direction is not performed in the collecting directions B ₁ and B ₂ and the collecting direction is not performed. The condition is that the air recovery of A ₁ and A ₂ is executed. Under this slow cooling condition, since the distance from the shape transfer surface of the mold forming the cavity 10a to the side surface of the mold is largely different, if air is collected too much in the collecting directions B ₁ and B ₂ , distortion occurs due to a difference in cooling speed. This is set because it will occur. In this case, by actually collecting the air in the collecting directions B ₁ and B ₂ within a range where the difference in the cooling speed does not actually occur, the cooling speed can be slightly increased. On the other hand, a strip-shaped cavity 10a as shown in FIGS.
As shown in (b), when the air is disposed at the center, the slow cooling condition is a condition that the air is collected in the collecting directions B ₁ and B ₂ . In this case, the distance from the mold side surface to the cavity in the collection directions B ₁ and B ₂ is substantially the same, and by setting such conditions, uniform slow cooling is performed and the element with high accuracy is obtained. Can be obtained. Also in this case, the cooling rate can be slightly increased by performing the air collection in the collection directions A ₁ and A ₂ within a range in which the difference in the cooling rate does not actually occur.

In FIG. 3, reference numeral 51 denotes an ID plate (identification mark).
At a predetermined site. This ID plate
When the cavity unit 10 is conveyed to a predetermined position by the mold conveying unit 42, the information is read facing the ID sensor 52, and based on the read information, the controller (control means) is used. ) Outputs a control signal, for example, the air recovery pump or a plurality of motors 47.
Drive control. In FIG. 3, 53 is an A / D converter, 54 is a CPU, 55 is a D / A converter, and these constitute the controller 50. Reference numeral 56 denotes an actuator such as a motor or a pump. CPU 55
Predetermined control programs and data necessary for controlling the actuator 56 are stored in an internal memory (ROM).

Although not shown in detail, the molded product taking-out station loosens the bolt of the self-holding mechanism of the cavity unit 10 that is conveyed after being gradually cooled in the slow cooling station by a nut runner (not shown), The upper and lower dies 11, 12 are opened by the opening and closing device, and the molded product is taken out. Then, after removing the molded product, the cavity unit 10 is closed again, and the self-holding bolt is tightened by a nut runner.

Next, the operation will be described. First, in the present embodiment, the upper and lower dies 11, 12 of the cavity unit 10 are previously determined.
During this time, for example, the moving valve body is put into the gate forming groove of the lower mold 12, the self-holding bolt is tightened by the mold opening / closing device of the molded product take-out station, and the cavity unit 10 is mold-closed and mold-clamped.

The cavity unit 10 is soaked and heated to a predetermined temperature in a heating station, then transferred to a filling / relaxation station and set (clamped) in an injection molding machine. Receive. At the same time as the mold clamping, the cavity unit 10 is also clamped by the pressing mechanism in a direction orthogonal to the mold clamping direction. In this state, the cavity in the cavity unit 10 is injected and filled with the molten resin. Then, the gate sealed by moving valve element which has received an injection resin pressure of the cavity side when the injection completion, injection molding machine, to maintain a constant temperature above the glass metastasis point a predetermined time in the mold clamped state cavity unit Relieves uneven distribution of pressure and temperature of resin in 10

Next, when the mold of the cavity unit 10 by the injection molding machine is released and the cavity unit 10 is taken out of the injection molding machine by opening the injection molding machine and releasing the clamp of the pressing mechanism, the cavity unit 10 is removed. Is sent to the slow cooling station. At this time, since the cavity unit 10 is tightened by the self-holding bolt, it can hold a predetermined mold clamping force by itself, and a pressure holding state can be obtained without relying on the pressure holding of the injection molding machine.

Next, the cavity unit 10 is gradually cooled in a slow cooling station. During this slow cooling, the shielding plate
45 is an ID plate 51 attached to the cavity unit 10
The rotation is controlled based on the read information, and air is collected in a predetermined direction based on the cavity shape in the cavity unit 10, and the air is gradually cooled in an air-cooling state suitable for the cavity shape. That is, the air recovery means 49 for recovering the air around the cavity unit 10 is controlled according to the slow cooling condition of each cavity unit 10, and the air recovery means 49 performs slow cooling suitable for each cavity unit 10.

[0030] Now, for example, FIG. 7, when the disk-shaped cavity, as shown in FIG. 8 gradually cooling the cavity unit 10 which is arranged in the central portion as shown in FIG. 5 (a), the recovery direction A _1, The air collection of A ₂ is executed, and the collection directions B ₁ , B ₂
Air recovery. Therefore, in the cooling direction (A direction), the distance from the shape transfer surface of the mold forming the cavity 10a to the side surface of the mold is substantially the same, and distortion due to a difference in cooling rate is less likely to occur.

On the other hand, when the rectangular cavity 10a as shown in FIGS. 6 and 9 gradually cools the cavity unit 10 disposed at the center as shown in FIG. 5B, the collecting directions B ₁ and B ₂ Air recovery is performed. Therefore, similar to the above-described slow cooling, uniform slow cooling can be performed,
The shapes of the transfer surfaces (the surfaces forming the cavities 10a) formed on the upper and lower dies 11, 12 of the cavity unit 10 are transferred with high precision.

When the temperature of the resin in the cavity unit 10 decreases due to the slow cooling and the resin solidifies, the cavity unit 10 is conveyed to the molded product removal station. Next, the self-holding bolt is loosened by the nut runner, and the mold of the cavity unit 10 is opened.
Then, the solidified molded product is taken out of the cavity unit 10 by the take-out type take-out device.

Hereinafter, continuous molding is performed with the above series of steps as one cycle. As described above, in the present embodiment, even in the case of multi-mix production in which the cavity shapes are completely different, it is necessary to perform the slow cooling corresponding to each cavity unit 10 efficiently and uniformly for each part of the molded product. And increase productivity. Further, since the air recovery means 49 changes the air recovery direction according to the predetermined slow cooling condition, the slow cooling condition can be set finely, and the slow cooling can be performed more quickly and uniformly.

Further, the air recovery port 44 is directed toward at least one of the vertical and horizontal directions of the cavity unit 10.
is provided, a plurality of air recovery ports 44a can be easily arranged along the transport path of the cavity unit 10, and these can be independently opened and closed by the shielding plate 45, so that the cubicity during transport can be improved. The unit 10 can be gradually cooled as appropriate. Further, based on the read information of the ID plate 51 attached to each cavity unit 10, the air collecting means 49 is provided.
Is controlled, the optimal slow cooling can be performed for each type of the cavity unit 10.

In addition, in this embodiment, during this slow cooling, another cavity unit set in the injection molding machine is used.
The molten resin can be injection-filled into 10, thereby increasing the operation rate of the injection molding machine. As a result, the molding time per piece can be reduced, and the productivity can be improved.

[0036]

According to the first aspect of the present invention, the air collecting means for collecting the air around the cavity unit is controlled according to the slow cooling condition of each cavity unit, and the air collecting means is suitable for each cavity unit. Since the gradual cooling is performed, the gradual cooling can be performed efficiently and uniformly for each part of the molded product even in the case of multi-product mixed production, and the productivity can be improved.

According to the second aspect of the present invention, since the air recovery direction is changed according to the slow cooling condition, the slow cooling condition can be set finely, and the slow cooling can be performed more quickly and uniformly. it can. According to the invention described in claim 3,
At least one of the vertical and horizontal directions of the cavity unit
Since the air recovery ports are provided in two directions, the air recovery ports can be easily arranged along the cavity transfer path.

According to the fourth aspect of the present invention, since the air recovery capacity of the recovery pump is made variable, it is possible to easily adjust the amount of recovered air. According to the fifth aspect of the present invention, a plurality of air recovery ports are provided along the transfer path of the cavity unit, and these are independently opened and closed by the opening and closing means. Slow cooling can be performed appropriately and appropriately.

According to the sixth aspect of the present invention, the air recovery means is controlled based on the read information of the identification mark attached to each cavity unit, so that the optimal slow cooling for each type of cavity unit is achieved. It can be performed.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an embodiment of a slow cooling device of the present invention.

FIG. 2 is a perspective view showing a configuration near the shielding plate.

FIG. 3 is a schematic configuration diagram showing an identification marker and a detecting means thereof.

FIG. 4 is a perspective view showing an air collection direction corresponding to a cavity shape.

FIG. 5 is a sectional view of the cavity unit.

FIG. 6 is a perspective view showing the appearance of the molded product.

FIG. 7 is a perspective view showing a disk-shaped cavity.

FIG. 8 is a perspective view showing another disk-shaped cavity.

FIG. 9 is a perspective view showing a strip-shaped cavity.

FIG. 10 is an explanatory diagram of a position for measuring a temperature change during slow cooling of the conventional slow cooling device.

FIG. 11 is a graph showing the results of measuring the mold temperature of a conventional slow cooling device.

[Explanation of symbols]

 10 Cavity unit 10a Cavity 11, 12 Mold 41 Pneumatic slow cooling device 42 Die transfer unit (conveyance means) 44 Duct for forced exhaust 44a Air recovery port 45 Shield plate (opening / closing means) 46 Air volume adjustment means 49 Air recovery means 50 Controller (control means) 51 ID plate (identification sign) 52 ID sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-139231 (JP, A) JP-A-54-23665 (JP, A) JP-A-52-85257 (JP, A) JP-A-4- 146111 (JP, A) JP-A-61-89019 (JP, A) JP-A-2-38012 (JP, A) JP-B-50-26709 (JP, B1) (58) Fields investigated (Int. ⁷ , DB name) B29C 45/00-45/84

Claims (6)

(57) [Claims] A plurality of cavity units forming cavities therein are provided, and the cavity units are conveyed by a conveying means in the order of a predetermined heating station, a filling / relaxation station, a slow cooling station, and a molded product removal station. A cooling device in the gate seal injection molding system, wherein air collecting means is capable of collecting air around the cavity unit under predetermined cooling conditions corresponding to the cavity unit; Control means for controlling the air recovery means so as to gradually cool the unit under different conditions. A slow cooling device in a gate seal injection molding system, comprising: 2. The slow cooling device in the gate seal injection molding system according to claim 1, wherein said air collecting means changes an air collecting direction according to said slow cooling condition. 3. The air collecting means according to claim 1, wherein said air collecting means has an air collecting port arranged in at least one of the vertical and horizontal directions of a cavity unit orthogonal to the conveying direction of said conveying means. Item 3. An annealing device in the gate seal injection molding system according to Item 1 or 2. 4. The air recovery means according to claim 1, wherein said air recovery means has a recovery pump for varying the air recovery capacity.
The slow cooling device in the gate seal injection molding system according to any one of the above. 5. The air recovery means has a plurality of air recovery ports adjacent to a transfer path of the cavity unit by the transfer means and a plurality of opening and closing means for independently opening and closing each air recovery port. A slow cooling device in the gate seal injection molding system according to claim 1. 6. The gate seal injection according to claim 1, wherein said control means controls said air recovery means based on read information of an identification mark attached to said cavity unit. Slow cooling device in molding system.