JP2021160248A - Mold cooling system, method for manufacturing molded article, and molded article - Google Patents

Abstract

To provide a mold cooling system capable of relatively easily providing a visual display such as a pattern on a surface of a molded article, a method for manufacturing the molded article, and the molded article.SOLUTION: A mold cooling system 101 for cooling a mold device 111 comprises: the mold device 111 having an internal space Si in which a molding material is filled, and a mold inner surface 115 that partitions the internal space Si; and a mold cooling mechanism 121 capable of cooling while generating temperature difference on the mold inner surface 115 so that an inner region Ri with a temperature of a dew point temperature or less and an inner region with a temperature higher than the dew point temperature are included on the mold inner surface 115 of the mold device 111.SELECTED DRAWING: Figure 5

Description

The present invention relates to a mold cooling system in injection molding, a method for manufacturing a molded product, and a molded product.

In order to manufacture a molded product made of resin or the like, a molten molding material injected from an injection molding machine is filled in the internal space of the mold device, and the mold device is cooled to solidify the molding material in the internal space. Let me. As a result, a molded product having a shape corresponding to the internal space of the mold apparatus can be obtained.

Regarding the cooling of the mold device, Patent Document 1 states, "By filling a cavity having a locally narrow portion with a resin, a thin portion corresponding to the narrow portion of the cavity is provided and a fine shape is imparted to the surface. A method for molding a resin product, which comprises, at least when introducing a resin into the cavity, different cooling temperatures between a narrow portion of the cavity and a wide portion different from the narrow portion. A product molding method ”is disclosed. More specifically, it is described that "the cooling temperature in the narrow portion of the cavity is made higher than the cooling temperature in the wide portion".

JP-A-2002-103404

By the way, there are in-mold transfer, in-mold labeling, heat and cool, etc. as techniques for decorating the surface of a molded product such as a pattern or other visual display, but all of them require large-scale equipment and increase the cost. do.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a mold cooling system or a molded product capable of imparting a visual display such as a pattern to the surface of the molded product. The purpose is to provide a manufacturing method and a molded product.

One mold cooling system capable of solving the above problems cools the mold apparatus and has an internal space filled with a molding material and a mold inner surface for partitioning the internal space. The temperature difference on the inner surface of the mold is set so that the mold device and the inner surface of the mold of the mold device include an inner surface region having a temperature equal to or lower than the dew point temperature and an inner surface region having a temperature higher than the dew point temperature. It is provided with a mold cooling mechanism capable of cooling the mold device while generating the mold.

Further, one method for manufacturing a molded product that can solve the above problems is a method of filling the internal space of the mold apparatus with a molding material and solidifying the molding material in the internal space to manufacture the molded product. The liquid adhering step of adhering the liquid onto a part of the inner surface region of the inner surface of the mold for partitioning the inner space of the mold device, and the cooling of the mold device to fill the inner space. In the mold cooling step, the molding material is solidified with the liquid adhering to the inner surface region of the mold apparatus, and the liquid solidifies the molding material, and the inner surface region is solidified by the liquid. The purpose is to visually display a part of the surface of the molded product corresponding to the above.

Further, in one molded product that can solve the above problems, the surface of the molded product has a first surface region and a second surface region having different surface roughness from each other, and the surface of the second surface region. The ratio (Ra / Ra') of the surface roughness Ra of the first surface region to the roughness Ra'is a value larger than 1.4, and the first surface region forms a visual display on the surface. Is what it becomes.

According to the mold cooling system and the method for manufacturing a molded product described above, it is possible to impart a visual display such as a pattern to the surface of the molded product. Further, the above-mentioned molded product is provided with a visual display such as a pattern on the surface.

It is sectional drawing which shows the mold cooling system of one Embodiment of this invention together with an injection molding machine. It is a front view which shows the mold inner surface of the mold apparatus of FIG. 2 is a cross-sectional view taken along the line III-III of FIG. 2 and a cross-sectional view taken along the line bb of FIG. 2 showing the mold apparatus of FIG. FIG. 3 is an enlarged cross-sectional view of the mold apparatus of FIG. 3A. It is the same front view as FIG. 2 which shows the inner surface region which becomes the temperature lower than the dew point temperature on the inner surface of the mold of the mold apparatus of FIG. 2 is a front view showing the surface of a molded product manufactured by using the mold cooling system including the mold apparatus of FIGS. 2 and 3.

Embodiments of the present invention will be described in detail below with reference to the drawings.
As shown in FIG. 1, the mold cooling system 101 according to the embodiment of the present invention includes a mold apparatus 111 and a mold cooling mechanism 121 including a temperature controller for cooling the mold apparatus 111. Is. The mold cooling system 101 can be used in the production of a molded product using the injection molding machine 1 by attaching the mold device 111 to, for example, the injection molding machine 1 illustrated in the figure.

(Molding of molded products)
In order to manufacture a molded product, an injection molding machine 1 injects a molding material, which is a resin material such as a thermoplastic resin, into the internal space Si of the mold apparatus 111 in a molten state. The internal space Si of the mold device 111 has a shape corresponding to the molded product to be manufactured, and by cooling and solidifying the molding material here, the molding material is made into a molded product having a predetermined shape. After that, the molded product is manufactured by taking out the molded product from the mold apparatus 111.

In general, the injection molding machine 1 of FIG. 1 melts the molding material and injects it into the mold apparatus 111 by rotating and advancing the screw 12 arranged inside and heating the heater 13 arranged around the inside. An injection device 11, a moving device 21 for moving the injection device 11 forward and backward with respect to the mold device 111, a mold clamping device 31 for opening and closing the mold device 111 between a mold clamping state and a mold opening state, and a mold clamping device 31. It is provided with an ejector device 41 that takes out a molded product from the mold device 111 in the mold open state.

To describe in more detail an example of manufacturing a molded product using the injection molding machine 1, a predetermined amount of molding material has already been accumulated and arranged inside the injection device 11 in the latter half of the previous molding. , The mold clamping device 31 is used to close the mold apparatus 111 to bring it into the mold clamping state.
Next, the molding material is injected into the mold apparatus 111 by advancing the screw 12, and the filling step of filling the internal space Si in the mold apparatus 111 and the screw 12 are further advanced and injected. A pressure holding step of holding the molding material inside the tip of the device 11 at a predetermined pressure is sequentially performed.

After that, the molding material filled in the internal space Si of the mold apparatus 111 is cooled and solidified, and a cooling step of obtaining a molded product is performed. At this time, the molding material separately charged into the injection device 11 is melted while being fed toward the tip of the injection device 11 by the rotation of the screw 12 under heating by the heater 13, and a predetermined amount of the molding material is melted at the tip. A weighing process is performed.
After that, the mold clamping device 31 is operated to open the mold device 111 to open the mold, the movable member 114 is moved by the ejector device 41, and the molded product is taken out from the mold device 111.

(Mold cooling system)
As described above, the mold cooling system 101 includes a mold device 111 and a mold cooling mechanism 121 for cooling the mold device 111.

In many cases, the mold device 111 is displaced by the fixed mold 112 and the movable mold 113 in which the internal space Si is partitioned inside in the mold clamping state, and the ejector device 41, as shown in FIG. It is configured to include a movable member 114 such as an ejector pin for extruding and taking out a molded product. This mold device 111 can be referred to as a two-plate mold mainly divided into a fixed mold 112 and a movable mold 113, but further has a slide mold, a slide core, or a stripper plate. It is also possible to make a three-plate mold divided into three parts. The mold device 111 can be attached to or replaced with the injection molding machine 1 as appropriate according to the shape of the molded product to be manufactured, and here, the mold device 111 is one of the injection molding machines 1. Not considered a department.

The mold device 111 is provided in each of the internal space Si formed between the fixed mold 112 and the movable mold 113 in the mold-tightened state, and the fixed mold 112 and the movable mold 113, and provides the internal space Si. It has an inner surface of a mold for partitioning. The internal space Si of the mold device 111 is sometimes referred to as a cavity.

FIG. 2 shows, for example, a mold inner surface 115 provided on a fixed mold 112, which is a male mold, as an example of the above-mentioned mold inner surface of the mold device 111. The mold inner surface 115 has a circular shape formed in a substantially central region of the fixed mold 112 in the front view shown in FIG. 2, and is shown in FIG. 3A in a cross section orthogonal to the mold inner surface 115. As described above, it is provided in a convex shape protruding toward the movable mold 113 side (upper side in FIG. 3A) on the facing surface 116 facing the movable mold 113 (not shown here). In this example, although not shown, the movable mold 113, which is a female mold, is provided with a concave mold inner surface that is recessed from the facing surface facing the fixed mold 112. In the mold-tightened state of the mold device 111, the facing surface 116 of the fixed mold 112 and the facing surface of the movable mold 113 approach or come into contact with each other, and the fixed mold 112 and the movable mold 113 are placed between the fixed mold 112 and the movable mold 113. An internal space Si is formed which is partitioned by the inner surface 115 of the mold 112 and the inner surface of the mold 113 of the movable mold 113. Here, as an example, a mold device 111 having such an internal space Si and a mold inner surface 115 is assumed, but the internal space of the mold device and the mold inner surface are appropriately changed according to the shape of the molded product. It is an object to be obtained, and is not limited to the one shown in the figure. Further, the inner surface of the mold is not limited to a flat surface as shown in the drawing, but may include a curved surface or a bent surface at least in a part thereof.

In this example, as shown in FIGS. 3A and 3B, the molding material injected from the injection molding machine 1 is guided to the internal space Si of the mold apparatus 111 inside the fixed mold 112. A sprue 117a is formed. The molding material that has passed through the sprue 117a flows into the internal space Si from the gate 117b provided in the center of the front view of the mold inner surface 115 through the tapered tip of the sprue 117a. A convex portion 115a that rises in a curved shape from the inner surface 115 of the mold is provided at the center of the inner surface 115 of the mold when viewed from the front, and the gate 117b is located at the center of the convex portion 115a. However, the present invention is not limited to such a direct gate method, and can be applied to various gate methods.

The mold cooling mechanism 121 cools the mold inner surface 115 of the mold device 111 as described above. Then, in this embodiment, when the mold cooling mechanism 121 cools the mold apparatus 111, the mold inner surface 115 is cooled to a non-uniform temperature to cause a temperature difference on the mold inner surface 115. Is configured to allow More specifically, in the mold cooling mechanism 121, the mold apparatus 111 is provided so that the mold inner surface 115 includes an inner surface region having a temperature equal to or lower than the dew point temperature and an inner surface region having a temperature higher than the dew point temperature. It is possible to cool.

When a part of the inner surface region of the mold inner surface 115 becomes a temperature equal to or lower than the dew point temperature during cooling by the mold cooling mechanism 121, dew condensation occurs on the inner surface region and liquid water adheres to the inner surface region. In this state, when the molding material injected in the internal space Si of the mold apparatus 111 is solidified to mold the molded product, the surface region of the molded product surface formed in contact with the inner surface region of the mold inner surface 115 ( The first surface region) has properties different from other surface regions (second surface regions) formed in the inner surface region to which water is not attached due to the presence of water. It is presumed that this is because the presence of water in a predetermined inner surface region reduces the transfer rate in the inner surface region. As a result, in the molded product obtained by solidifying the molding material, the surface region (first surface region) can be visually distinguished from other surface regions (second surface region), and the surface region (first surface region) can be visually distinguished. (One surface area) gives a visual display.

Water generated by dew condensation on a part of the inner surface region of the inner surface 115 of the mold may adhere to the surface of the molded product immediately after being formed by the internal space Si, but after that, vaporization or evaporation or other reasons. Is removed by. It is understood that the above-mentioned visual display given to the surface of the molded product appears as visually recognizable as a result of alteration or modification of a part of the surface. That is, a part of the surface itself of the molded product becomes a visual display. Therefore, such a visual indication of the surface of the molded article can maintain its visibility for a long period of time as compared to the label or the like of another member integrally molded by in-mold molding.

In addition, in in-mold molding, which is generally used to decorate the surface of a molded product with a pattern or other visual display, it is necessary to make the developed view of the label into a predetermined shape such as a fan shape, so that the surface can be decorated. Is limited, which limits the design. In addition, productivity is low because an insert process is required. In addition, peculiar defective phenomena such as label misalignment and graining may occur. On the other hand, in the above-described embodiment, it may be possible to prevent inconveniences related to design, productivity and quality in such in-mold molding.

A visual representation means something that is present on a part of the surface of a molded product and is visually recognizable, typically at least selected from the group consisting of patterns, figures, symbols, colors and letters. It is a kind.

The difference between the temperature of the inner surface region where the temperature is lower than the dew point temperature and the temperature of the inner surface region where the temperature is higher than the dew point temperature on the inner surface 115 of the mold by the mold cooling mechanism 121 is 5 ° C. or more. It is preferable that it can be generated. If the mold cooling mechanism 121 can generate such a temperature difference, a visual display can be more clearly and surely given to a part of the surface of the molded product. At this time, the ambient humidity may be, for example, 60% to 70%.

By the way, specifically, the mold cooling mechanism 121 is not limited to this, but in many cases, the internal flow path 122 formed inside the mold apparatus 111 and located close to the inner surface 115 of the mold, and the internal flow. It has a refrigerant 123 such as cold water supplied to the road 122, and a refrigerant supply unit 124 that supplies the refrigerant 123 to the internal flow path 122.

In the illustrated embodiment, as an example, a circle having a cross section parallel to the inner surface 115 of the mold as shown in FIG. The arc-shaped internal flow paths 122a and 122b are formed. Each of the internal flow paths 122a and 122b has a flow path inlet 122c and a flow path outlet 122d that allow the refrigerant 123 to flow in and out of the internal flow path 122a or 122b at each end where the circumference of the arc is interrupted. It is provided. Each of the internal flow paths 122a and 122b is connected to a pipe or the like at the flow path inlet 122c and the flow path outlet 122d and communicates with the refrigerant supply unit 124. However, the internal flow path can be appropriately changed according to the desired shape of the visual display and the like.

The refrigerant supply unit 124 includes, for example, a heat exchanger, a circulation path, and the like. In the circulation path, the refrigerant supply unit 124 passes the refrigerant 123 that has passed through the internal flow paths 122a and 122b and used for cooling the mold apparatus 111 and then returned to cool the refrigerant 123 through a heat exchanger, and cools the refrigerant 123 again. , Supply to the internal flow paths 122a and 122b.

Here, as shown in FIG. 4, the distance Dp between the internal flow path 122 formed inside the mold apparatus 111 and the inner surface 115 of the mold is preferably 3 mm to 10 mm. If the internal flow path 122 is brought close to the inner surface 115 of the mold to some extent and the distance Dp is relatively short, it becomes easier to make a part of the inner surface 115 of the mold into an inner surface region having a temperature equal to or lower than the dew point temperature during cooling. The distance Dp between the inner flow path 122 and the inner surface 115 of the mold is a cross section orthogonal to the inner surface 115 of the mold (a cross section orthogonal to the extending direction of the inner flow path 122) and is a normal line erected on the inner surface 115 of the mold. It means the shortest distance from the mold inner surface 115 to the point on the flow path inner surface closest to the mold inner surface 115 of the inner flow path 122 along the direction of.
Further, when there are internal flow paths 122a and 122b adjacent to each other in a direction substantially parallel to the mold inner surface 115 in a cross section orthogonal to the mold inner surface 115 as shown in FIG. 4, between the internal flow paths 122a and 122b. The interval Sp is preferably smaller than the above distance Dp. If the interval Sp is increased to some extent, even if a relatively low temperature refrigerant 123 is passed through the internal flow path 122, an inner surface region having a temperature higher than the dew point temperature tends to exist on the inner surface 115 of the mold. The distance Sp between the adjacent internal flow paths 122a and 122b is measured along the direction parallel to the inner surface 115 of the mold, and measures the linear distance between the points on the inner surface of the inner flow paths of the internal flow paths 122a and 122b closest to each other. means.

By cooling the mold apparatus 111 using the above-mentioned internal flow path 122 of the mold cooling mechanism 121, a part of the mold inner surface 115 becomes an inner surface having a temperature equal to or lower than the dew point temperature as shown by a broken line in FIG. While the region Ri can be used, the rest can be an inner surface region having a temperature higher than the dew point temperature. That is, the mold apparatus 111 can be cooled while causing a temperature difference on the inner surface 115 of the mold. In the illustrated example, the inner surface region Ri having a temperature equal to or lower than the dew point temperature is the gate 117b in the front view of the mold inner surface 115, depending on the arrangement mode of the internal flow paths 122a and 122b inside the mold apparatus 111. There are two types of arcs, large and small, with different diameters centered on.

According to such a mold cooling system 101, a molded product 201 as shown in FIG. 6 may be manufactured. The molded product 201 includes a surface 202 formed by the mold inner surface 115 of the mold apparatus 111 described above, and the surface 202 has a surface region having different properties such as surface roughness (first). The presence of the surface region and the second surface region) forms the visual display 203.

Since the surface 202 of the molded product 201 is formed by the mold inner surface 115 of the mold device 111, it has a circular shape corresponding to the mold inner surface 115 in the front view shown in FIG. Then, at the time of manufacturing the molded product 201, as described above, the relatively low temperature refrigerant 123 is supplied to the internal flow paths 122a and 122b of the mold cooling mechanism 121, and the mold inner surface 115 is formed with the internal flow paths 122a and 122a. By including the inner surface region Ri cooled to a temperature lower than the dew point temperature in the vicinity of 122b and the inner surface region cooled to a temperature higher than the dew point temperature at a position away from the internal flow paths 122a and 122b. A visual display 203 is formed on the surface 202 of the molded product 201. In this example, on the surface 202 of the molded product 201, there are two types of arc-shaped visual displays 203a and 203b having different diameters corresponding to the internal flow paths 122a and 122b.

When viewed from the front of the surface 202 of the molded product 201, a curved concave portion 202a corresponding to the convex portion 115a of the inner surface 115 of the mold and a gate mark 202b existing in the center of the concave portion 202a are formed in the center of the surface 202. It is formed.
The specific difference in properties between the surface region (first surface region) formed by the visual display 203 of the molded product 201 and the other surface region (second surface region) will be described later.

In order for the mold cooling mechanism 121 to effectively cause dew condensation on a predetermined inner surface region of the mold inner surface 115, the mold cooling mechanism 121 has an internal flow path 122 in the refrigerant supply unit 124 according to the ambient temperature and the ambient humidity. It is preferable that the temperature and / or flow rate of the refrigerant 123 supplied to the water is controlled so as to be adjusted. The ambient temperature and the ambient humidity can be measured by a temperature sensor and a humidity sensor that can be provided in the vicinity of the mold device 111, such as around the refrigerant supply unit 124 as a temperature controller or the like, respectively. For example, the control unit of the injection molding machine 1 or the control unit provided separately from the injection molding machine 1 causes dew condensation on a predetermined inner surface region of the mold inner surface 115 of the mold apparatus 111 according to their ambient temperature and ambient humidity. The mold cooling mechanism 121 can be controlled to adjust the temperature and / or the flow rate of the refrigerant 123 so that the water from the mold adheres.

Depending on the molded product, it may be required to give a visual display of various shapes or modes. In order to meet such a demand, the portion of the mold apparatus 111 including the internal flow path 122 can be made into a replaceable cartridge. Thereby, it is possible to easily impart a visual display of a different shape or mode to a molded product having the same shape by simply replacing the cartridge with an internal flow path having a different shape or mode.

(Manufacturing method of molded products)
The method for manufacturing a molded product includes a mold clamping step, a filling step, a pressure holding step, a cooling step, a weighing step, and the like as described above when viewed from the injection molding machine 1 side. On the other hand, the manufacturing method of this embodiment includes a liquid bonding step of adhering a liquid on a part of the inner surface region of the mold inner surface 115 for partitioning the internal space Si of the mold device 111 on the mold device 111 side. It includes a mold cooling step of cooling the mold apparatus 111 and solidifying the molding material filled in the internal space Si.

In the liquid adhesion step, the molding material is solidified in the internal space Si in the mold cooling step in a state where the liquid is adhered to a part of the inner surface region of the mold inner surface 115, so that the liquid is adhered to the inner surface region. .. As long as it is possible to attach the liquid to a part of the inner surface region of the mold inner surface 115, the method of attaching the liquid is not particularly limited. For example, in a state where a predetermined inner surface region of the mold inner surface 115 is covered with a tape or the like, the liquid is sprayed toward the mold inner surface 115 to attach the liquid to the inner surface region not covered with the tape or the like. Can be done.

Alternatively, as in the mold cooling mechanism 121 of the mold cooling system 101 described above, in the mold cooling step, the mold inner surface 115 is cooled to a temperature equal to or lower than the dew point temperature, and a temperature higher than the dew point temperature. The mold device 111 can be cooled so as to include an inner surface region to be cooled. When cooled in this way, dew condensation occurs on the inner surface region cooled to a temperature equal to or lower than the dew point temperature, whereby water as a liquid adheres to the inner surface region. As a result, the liquid adhesion step can be performed. In this case, at least a part of the liquid adhesion step and the mold cooling step overlap in time. The order of the liquid adhesion step and the mold cooling step is not particularly limited, and either one may be the first, or the mold cooling step may be performed at the same time.

In the mold cooling step, for example, when the mold cooling mechanism 121 described above is used, the refrigerant 123 is supplied to the internal flow path 122 formed inside the mold apparatus 111 at a position close to the mold inner surface 115. As a result, the mold device 111 is cooled, and the liquid can be attached to a part of the inner surface region of the mold inner surface 115 and the molding material filled in the mold device 111 can be solidified.

In this mold cooling step, in order to effectively adhere the liquid to the inner surface region by dew condensation, as described above, the temperature of the refrigerant 123 supplied to the internal flow path 122 and / / according to the ambient temperature and the ambient humidity. Alternatively, it is preferable to adjust the flow rate.

In many cases, the mold apparatus 111 is cooled in the mold cooling step, the liquid is adhered to a part of the inner surface region of the mold inner surface 115 in the liquid adhesion step, and then the molding material is formed in the internal space Si of the mold apparatus 111. Is filled. Then, the molding material filled in the internal space Si is cooled and solidified by the mold device 111 which is continuously cooled with the liquid adhering to the inner surface region. At this time, as described above, the surface region of the surface of the molded product formed in the inner surface region to which the liquid is attached is formed in the inner surface region to which the liquid is not adhered due to the presence of the liquid. The properties are different from the surface area of. In the molded product thus obtained, the surface region can be visually distinguished from other surface regions, and a part of the surface which is the surface region becomes a visual display.

When the molding material flows from the gate 117b into the internal space Si with the liquid adhering to a part of the inner surface region of the mold inner surface 115, the liquid on the inner surface region flows in the flow direction due to the flow of the molding material. It may scatter slightly. In this case, due to the scattering of the liquid, a pattern radiating from the gate mark may be formed on the surface of the molded product as a part of the visual display.

(Molding)
The molded product manufactured as described above has surface regions having different properties on the surface thereof, whereby a visual display is formed.

Explaining this by taking the molded product 201 shown in FIG. 6 as an example, on the surface 202 of the molded product 201, a surface region (first surface region) forming the visual display 203 and another surface region (second surface). The surface roughness may be different from that of the region). Specifically, the ratio (Ra / Ra') of the first surface region Ra to the surface roughness Ra'of the second surface region may be larger than 1.4. In this case, due to such a difference in surface roughness between the first surface region and the second surface region, the visual display 203 formed by the first surface region can be visually sufficiently grasped. .. The surface roughness Ra and Ra'referred to here are arithmetic mean roughness, and can be measured by a contact type or non-contact type surface roughness measuring machine in accordance with JIS B0601-2001 and ISO 25178.

(Injection molding machine)
As described above, the injection molding machine 1 shown as an example in FIG. 1 includes an injection device 11, a moving device 21, a mold clamping device 31, and an ejector device 41. Details of each of these devices are as follows. As described in.

The injection device 11 is mainly a cylinder 14 having a cylindrical shape extending toward the mold device 111, and a screw in which the central axis is arranged in parallel with the cylinder 14 and the flight is spirally provided around the cylinder 14. A band-shaped heater 13 arranged on the outer peripheral side of the cylinder 14 so as to surround the periphery thereof, and a motor box 15 arranged on the rear side of the cylinder 14 and the screw 12 are provided. Although not shown, the motor box 15 approaches a weighing motor that rotates the screw 12 around the central axis and a mold device 111 in order to accumulate a predetermined amount of molding material at the tip of the cylinder 14. An injection motor that moves the screw 12 forward and backward in each direction away from the mold device 111, a pressure detection sensor that detects the pressure that the screw 12 receives from the molding material, and the like are arranged.

Here, the direction of approaching the fixed platen 32a of the mold clamping device 31 to which the fixed mold 112 of the mold device 111 is attached is the front side, and the direction away from the fixed platen 32a is the rear side. Therefore, in FIG. 1, when looking at the injection device 11 located on the right side of the fixed platen 32a, the left direction approaching the fixed platen 32a is the front side, and the right direction away from the fixed platen 32a is the rear side.

The cylinder 14 is provided with a supply port 14a on the rear side in front of the motor box 15 to which a hopper or the like for charging a molding material into the cylinder 14 is attached, and at a tip portion close to the mold device 111. A nozzle 14b having a smaller cross-sectional area is provided on the front side. A water-cooled cylinder 14c by water cooling or the like can be provided in the vicinity of the supply port 14a.
As shown in the figure, the heater 13 arranged around the cylinder 14 including the periphery of the nozzle 14b is divided into a plurality of portions in the axial direction (left-right direction in FIG. 1), and the cylinder 14 inside each heater portion. It is possible to heat the inside of the cylinder at different temperatures.

According to the injection device 11 having such a configuration, the molding material charged into the cylinder 14 from the supply port 14a is driven by the weighing motor under heating by the heater 13 on the outer peripheral side of the cylinder 14 in the weighing process. While being melted based on the rotation of the screw 12, it is sent toward the front side inside the cylinder 14 and is filled in the tip end portion of the cylinder 14. At this time, the screw 12 is displaced backward by the injection motor to form a space filled with the molding material at the tip of the cylinder 14. As described above, this weighing step can be performed at the time of the cooling step at the time of the previous molding or the like.

Then, in the filling step, the screw 12 is displaced forward, so that the molding material at the tip of the cylinder 14 is ejected toward the mold apparatus 111 via the nozzle 14b. Further, in the subsequent pressure holding step, pressure is applied to the molding material filled in the cavity of the mold apparatus 111 through the molding material remaining at the tip end portion of the cylinder 14. At this time, it is possible to replenish the shortage of the molding material due to the cooling shrinkage of the molding material in the cavity of the mold apparatus 111.

Although this injection molding machine 1 is an in-line screw type, it shall be a pre-plastic type injection molding machine in which the plasticized cylinder and the plasticized screw are structurally and functionally separated from each other in terms of structure and function. Is also possible.

The moving device 21 is, for example, an advancing / retreating drive mechanism provided in the lower part of the motor box 15 of the injection device 11 and for moving the injection device 11 forward and backward with respect to the fixed platen 32a described later. Various mechanisms can be adopted as the advancing / retreating drive mechanism constituting the moving device 21, but for example, a double-acting hydraulic cylinder that extrudes / retracts the piston rod 22 whose tip is fixed to the fixed platen 32a. Can be configured to include. The moving device 21 further includes a slide base to which the above-mentioned hydraulic pump and hydraulic cylinder are attached, and a guide 23 laid on the frame Fr to guide the linear motion of the slide base. As a result, the forward / backward displacement of the injection device 11 mounted on the upper part of the slide base is realized.

The moving device 21 separates the injection device 11 from the mold device 111, or brings the injection device 11 closer to the mold device 111 to push the nozzle 14b of the cylinder 14 of the injection device 11 to the mold device at a predetermined pressure. It is possible to perform so-called nozzle touch, which is pressed against 111.

The mold clamping device 31 displaces the movable mold 113 with respect to the fixed mold 112 of the mold apparatus 111 to open and close the mold apparatus 111, and causes the mold apparatus 111 to be in the mold clamping state, the mold closing state, or the mold opening state. And. The mold clamping device 31 of the injection molding machine 1 mainly has a platen 32 arranged so as to sandwich the mold device 111 from both sides, and a platen operating mechanism 33 for moving the platen 32.

Here, the platen 32 is located between the injection device 11 and the mold device 111, and is positioned with the mold device 111 separated between the fixed platen 32a fixed to the frame Fr and the fixed platen 32a. It also includes a movable platen 32b that can be displaced close to or separated from the fixed platen 32a. The fixed mold 112 of the mold device 111 located between the fixed platen 32a and the movable platen 32b is attached to the fixed platen 32a side, and the movable mold 113 is attached to the movable platen 32b side. Further, the mold clamping device 31 is provided with one or a plurality of tie bars 32c extending from the fixed platen 32a toward the rear platen 34, which will be described later, and connecting the fixed platen 32a and the rear platen 34. In this embodiment, the movable platen 32b is guided by the tie bar 32c for the separation / approach displacement with respect to the fixed platen 32a, but the movable platen 32b may not be guided by the tie bar 32c.

At the position where the movable platen 32b is separated from the fixed platen 32a, the movable mold 113 of the mold device 111 is in a mold open state open from the fixed mold 112, and the movable platen 32b is directed toward the fixed platen 32a from this separated position. When the movable mold 113 is brought closer to the fixed mold 112, the movable mold 113 is closed to the fixed mold 112, and the movable platen 32b is further brought closer to the fixed platen 32a to bring the movable mold 113 closer to the fixed mold 112. The mold is pressed against the mold.

Since most of the mold clamping device 31 except for the fixed platen 32a and the ejector device 41 described later are located on the left side of the fixed platen 32a in FIG. 1, most of the mold clamping device 31 and the ejector device 41 can be seen. For example, the rightward direction approaching the fixed platen 32a is the front side, and the leftward direction away from the fixed platen 32a is the rear side.

Further, here, the platen operating mechanism 33 makes a linear motion of the rear platen 34 arranged on the frame Fr, the mold clamping motor 35 provided on the rear platen 34, and the mold clamping motor 35 in the displacement direction of the movable platen 32b. It includes a motion conversion mechanism 36 that converts motion into motion, and a toggle mechanism 37 that increases the force transmitted to the motion conversion mechanism 36 and transmits it to the movable platen 32b.

Of these, the motion conversion mechanism 36 can be various mechanisms capable of converting rotary motion into linear motion. In this example, the screw shaft 36a and the screw shaft 36a that are rotationally driven by the mold clamping motor 35 are used. It is assumed to include a matching nut 36b. It is also possible to use the motion conversion mechanism 36 as a ball screw.

The toggle mechanism 37 that increases the transmission force from the motion conversion mechanism 36 is formed by oscillating a plurality of links 37a to 37c that connect the rear platen 34 and the nut 36b and the movable platen 32b with a joint. be.
The number of links and joints and their shapes can be changed as appropriate, but as shown in FIG. 1, the crosshead 37d connected to the nut 36b and extending in the vertical direction is vertically separated by the crosshead 37d. A pair of links consisting of the located links 37a to 37c are oscillatingly connected to each other.

In addition to the mold clamping motor 35 described above, a mold thickness adjusting motor 38 can also be provided on the rear platen 34. The mold thickness adjusting motor 38 is movably arranged on the fixed platen 32a and the frame Fr by applying a rotational driving force to the screw shaft and the nut connected to the extension portion of each tie bar 32c of the platen 32 described above. It functions to adjust the distance between the rear platen 34 and the rear platen 34. As a result, even when the mold device 111 is replaced or the thickness of the mold device 111 is changed due to a temperature change, the mold device 111 can be provided with the desired mold clamping force. The mold thickness can be adjusted. Although not shown, the mold thickness can be adjusted even if the fixed platen side is movable on the frame Fr and the rear platen side is fixed.

The illustrated mold clamping device 31 is a horizontal type in which the moving direction of the movable platen 32b is parallel to the horizontal direction, but it can also be a vertical type in which the moving direction is the vertical direction.

The ejector device 41 provided on the movable platen 32b extends through the movable platen 32b and is driven forward and backward to press the movable member 114 such as the ejector pin of the mold device 111 from the rear side, and the ejector rod 42 and the ejector. In order to operate the rod 42, it has a rod drive source 43 including a motion conversion mechanism such as a motor and a ball screw.

In the process of taking out the molded product by the ejector device 41, the ejector rod 42 driven by the rod drive source 43 is advanced, the movable member 114 is projected in the mold device 111, and the molded product is taken out from the mold device 111. Becomes possible. After the movable member 114 is projected, the ejector rod 42 can be retracted by the rod drive source 43 to return to the original position.

1 Injection molding machine 11 Injection device 12 Screw 13 Heater 14 Cylinder 14a Supply port 14b Nozzle 14c Water cooling cylinder 15 Motor box 21 Moving device 22 Piston rod 23 Guide 31 Molding device 32 Platen 32a Fixed platen 32b Movable platen 32c Tie bar 33 34 Rear platen 35 Mold tightening motor 36 Motion conversion mechanism 36a Thread shaft 36b Nut 37 Toggle mechanism 37a to 37c Link 37d Cross head 38 type Thickness adjustment motor 41 Ejector device 42 Ejector rod 43 Rod drive source 101 Mold cooling system 111 Mold device 112 Fixed mold 113 Movable mold 114 Movable member 115 Mold inner surface 115a Convex part 116 Opposing surface 117a Sprue 117b Gate 121 Mold cooling mechanism 122, 122a, 122b Internal flow path 123 Refrigerator 124 Refrigerator supply part 201 Molded product 202 Surface 202a Concave 202b Gate trace 203, 203a, 203b Visual display Dp Distance between the inner surface of the mold and the internal flow path Sp Spacing between adjacent internal flow paths Ri Inner surface area where the temperature is below the dew point temperature

Claims (9)

A mold cooling system that cools mold equipment,
A mold device having an internal space filled with a molding material and a mold inner surface for partitioning the internal space.
The mold is provided with a temperature difference on the inner surface of the mold so that the inner surface of the mold of the mold apparatus includes an inner surface region having a temperature lower than the dew point temperature and an inner surface region having a temperature higher than the dew point temperature. A mold cooling system with a mold cooling mechanism capable of cooling the device. The mold cooling mechanism is configured to be capable of causing a temperature difference of 5 ° C. or more between the inner surface region having a temperature equal to or lower than the dew point temperature and the inner surface region having a temperature higher than the dew point temperature. The mold cooling system according to claim 1. The mold cooling mechanism
An internal flow path formed inside the mold device and located close to the inner surface of the mold,
The refrigerant supplied to the internal flow path and
The mold cooling system according to claim 1 or 2, further comprising a refrigerant supply unit that supplies the refrigerant to the internal flow path. The mold cooling mechanism according to claim 3, wherein the mold cooling mechanism adjusts the temperature and / or flow rate of the refrigerant supplied to the internal flow path by the refrigerant supply unit according to the ambient temperature and the ambient humidity. system. It is a method of manufacturing a molded product by filling the internal space of a mold device with a molding material and solidifying the molding material in the internal space.
A liquid adhering step of adhering a liquid onto a part of the inner surface region of the inner surface of the mold for partitioning the internal space of the mold device.
Including a mold cooling step of cooling the mold apparatus and solidifying the molding material filled in the internal space.
In the mold cooling step, the molding material is solidified with the liquid adhering to the inner surface region of the mold apparatus, and the liquid visually displays a part of the surface of the molded product corresponding to the inner surface region. The manufacturing method of the molded product to be displayed. In the mold cooling step, the mold inner surface of the mold apparatus includes an inner surface region cooled to a temperature equal to or lower than the dew point temperature and an inner surface region cooled to a temperature higher than the dew point temperature.
The method for producing a molded product according to claim 5, wherein water as a liquid adheres to the inner surface region in the liquid adhesion step due to dew condensation occurring on the inner surface region cooled to a temperature equal to or lower than the dew point temperature. Claim 5 or 6 in which, in the mold cooling step, a refrigerant is supplied to an internal flow path formed inside the mold apparatus at a position close to the inner surface of the mold to cool the mold apparatus. The method for producing a molded product according to any one of the above. The method for manufacturing a molded product according to claim 7, wherein in the mold cooling step, the temperature and / or flow rate of the refrigerant supplied to the internal flow path is adjusted according to the ambient temperature and the ambient humidity. It is a molded product
The surface of the molded product has a first surface region and a second surface region having different surface roughness from each other.
The ratio (Ra / Ra') of the surface roughness Ra of the first surface region to the surface roughness Ra'of the second surface region is a value larger than 1.4.
A molded product in which a visual display is formed on the surface by the first surface region.

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