JPH09248832A - Heating furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance heat efficiency, to shorten a heating time and to miniaturize a heating furnace by feeding a mold for molding a resin powder in a furnace from the opening part provided to the upper part of the furnace and providing a hot air blowoff part having a hot air control mechanism on the inner bottom surface of the furnace to form the inner structure of the furnace and providing a heat energy recovery part. SOLUTION: A hot air blowoff port 5 and heat energy recovery ports 6, 6a are provided to the inner bottom surface of a heating furnace 1 and hot air blowoff ports 7, 7a are provided to both side surfaces of the furnace and hot air is blown to the whole of a mold to recover heat energy from the heat energy recovery ports 6, 6a of the inner bottom surface of the furnace. The mold 9 is introduced into the furnace from the opening provided to the upper surface part thereof by the arm of a robot by opening a slide door to be placed on mold support members 8, 8a. In this case, hot air is generated by a hot air generator 15 by using the air from an air supply fan 14 and the heat energy recovered from the heat energy recovery ports 6,6a to be supplied to hot air blowoff ports 5, 7, 7a by a hot air circulating fan 16 through main piping 17 and branch pipings 18, 18a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating furnace used for heating a mold in a resin powder molding method (particularly, powder-slush molding method).

More specifically, the present invention has excellent heating characteristics such as the ability to uniformly and uniformly heat a metal mold of any shape (particularly, a complicated three-dimensional shape) in a short time, and can be miniaturized and simplified. The present invention relates to a heating furnace having excellent mechanical structure characteristics such as.

[0003]

2. Description of the Related Art Several methods have been known as a resin powder molding method in which a thermoplastic resin powder is used as a raw material and is processed into a resin molded product having a shape similar to a mold surface. A powder-slush molding method is a typical method of resin powder molding method which is industrially carried out.

In the powder-slash method, thermoplastic resin powder (or powder mainly containing it) is filled in layers on a heated die surface, and the filled resin powder is melted by the heat of the die. Form a resin hot melt on the mold surface,
After that, the hot melt is cooled and solidified to obtain a resin molded product having the same or similar shape as the mold surface.

The powder-slash method is used in the mold heating step,
The process includes a powdering process (resin powder filling process), a mold cooling process, and a demolding process (molded product removing process). A powder-slash method in which a post-heating step is provided after the powdering step is also industrially carried out.

The mold heating step is a step of heating the mold to a high temperature (the temperature at which the thermoplastic resin powder melts), and a large heating furnace is used in industrial practice.

The powdering process is a process performed after the mold heating process, in which a thermoplastic resin powder is filled in layers on a mold heated to a high temperature, and a mold having a desired thickness and a shape similar to the mold surface is formed. This is a step of providing a hot resin melt on the mold surface.

In industrial practice, the thermoplastic resin powder is dropped from above onto the surface of the mold heated to a high temperature (the temperature at which the thermoplastic resin powder is melted by heat) in a large heating furnace in the mold heating step. A layer of thermoplastic resin powder having a certain thickness is filled on the mold surface. This state is maintained for a while (in the range of several tens of seconds), and the high heat of the mold heat-melts the thermoplastic resin powder on the mold surface.

Thereafter, the unmelted resin powder is dropped downward with the mold surface on which the resin powder is placed facing downward, and adhered to a desired thickness (typically, a thickness of about several mm). The layer of the hot melt of the thermoplastic resin is left on the mold surface. It is said that there is a possibility that the layer of the thermoplastic resin hot melt may have a different degree of thermal melting between the inside of the layer that is in direct contact with the mold surface and the outside of the layer.

The layer of the thermoplastic resin hot melt is desired by adjusting various conditions such as the heating temperature of the mold, the time during which the thermoplastic resin powder contacts the mold surface, and the selection of the thermoplastic resin powder. It is controlled by the thickness.

A powdering device in industrial practice is a reserving tank with a connecting end for accommodating a thermoplastic resin powder, and a rotating and integral body of a reserving tank with a releasable tank and a releasable tank. It is equipped with a stationary holding device.

Then, the mobile robot holding the mold frame with the mold attached thereto brings the mold close to the reserve tank from above and closes the connecting surface between the mold surface and the reserve tank (thermoplastic resin). (Powder does not leak to the outside) and connect it into a united body, and then rotate it by the rotating mechanism of the powdering device to position the reserve tank with the opening facing downward on the upper side of the mold. As a result, the thermoplastic resin powder in the reserve tank is naturally dropped on the surface of the heating mold by its own weight to fill the surface of the mold with the thermoplastic resin powder.

After that, the connected unitary product is turned over to return the mold and the reserve tank to the initial upper and lower positions, the connection between them is released, and the mold having the layer of the thermoplastic resin hot melt adhered thereto is removed. It is moved to the next post-heating step by the mobile robot.

In the post-heating step, heating is carried out from the outermost part of the layer of the thermoplastic resin hot melt adhered to the mold surface (that is, the part distant from the mold surface), and the mold surface is heated. It is said to be a step for making the above thermoplastic resin hot melt into a uniform hot melt to obtain a high-quality molded product, which is an essential step in the powder-slush method which is industrially practiced.

In industrial practice, a heating device of the same size as a powdering device or the like is used in the post-heating process.

The mold cooling step is a step of forcibly cooling the mold, thereby solidifying the hot resin melt on the mold surface to form a resin molded product. A mold cooling device that is implemented on an industrial scale uses a device that applies a jet of water to a mold to cool the mold. The demolding step is a step of separating the resin molded product from the mold.

FIG. 7 is an explanatory view of the entire typical powder-slush molding apparatus which is industrially implemented. FIG.
FIG. 8 is a front view of the entire powder-slash molding apparatus shown in FIG. 7. FIG. 9 is an explanatory view of a heating furnace used in the powder-slush molding apparatus shown in FIGS. 7 and 8.

Next, the conventional heating furnace will be described with reference to FIGS. 7 to 9 in relation to the powder-slush molding apparatus in which it is used.

In each of the following drawings, the same reference numerals denote the same or equivalent parts.

The heating furnace 31 of the powder-slush molding apparatus 30 used industrially has a large horizontal oblong box-like structure in which a portion corresponding to the bottom surface is open (generally referred to as a mountain furnace). Are used). A conveyor 32 is provided at a position corresponding to the bottom of the furnace in the open state (see FIG. 9), and the conveyor 32 is provided with a plurality of mold frames 33.

In the following, in order to distinguish the conventional heating furnace 31 from the heating furnace of the embodiment of the present invention, the heating furnace 31 may be referred to as a mountain furnace 31 for convenience.

By the rotation of the conveyor 32, the mold 34 attached to the mold frame 33 is carried into the mountain furnace and moved in the furnace in the lengthwise direction to be heated to a desired temperature. It is carried out of the furnace. Spaces at both ends of the conveyor 32 at the bottom of the Yamagata furnace serve as a carry-in port 35 and a carry-out port 36 of the mold 34. In the carry-in port 35 and the carry-out port 36,
Shutters 37 and 37a that are movable in the lateral direction are provided, and when the mold frame 33 does not pass, the shutter is intermittently closed to prevent the temperature inside the furnace from decreasing.

Incidentally, FIG. 9 shows the shutter 37 of the carry-in port 35.
Is closed and the shutter 37a of the carry-out port 36 is opened.

In the conventional mountain furnace 31, the inside of the furnace is made into a high temperature atmosphere by blowing hot air, the mold 34 is allowed to stay in the high temperature atmosphere for a predetermined time, and the mold 34 is heated by heat conduction from the high temperature atmosphere. Method (that is, a normal heating method in an industrial furnace) is adopted.

In the hot air generator, since a large-capacity furnace needs to have a high-temperature atmosphere, a large-scale device is arranged on the mountain furnace 31 and hot air is supplied into the furnace through a duct.

The powder-slush molding method is generally used for medium to large-sized three-dimensional resin moldings (for example, length of about 30 cm to 2 m, width and depth of about 30 c).
It is used for molding resin molded products of about m to 1 m.

In addition, in the conventional mountain furnace 31, since it takes a long time to heat the mold, it is necessary to increase the productivity of the furnace itself by moving many molds 34 and staying in the furnace. .

Therefore, in the entire powder-slush forming apparatus 30 of the industrial implementation, the mountain furnace 31 is arranged at a position higher than the surface of the earth (for example, a position of about 10 m from the surface) because of its structure, and the powdering device 38 and the post-heating are used. The device 39, the mold cooling device 40, and the demolding device 41 are arranged in a line on the ground surface.

The mold 34 carried out from the carry-out port 36 of the heating furnace 31 to the conveyor 32 is moved to a powdering device 38 by a moving device such as another mobile robot (not shown).
The molded product is operated by each device up to the demolding device 41.

The operation, maintenance, and management of the heating furnace 31 and the hot air generator are performed on a work landing provided at a position corresponding to the height of each of the heating furnace and the hot air generator. .

[0031]

The conventional mountain furnace 31 used in the industrial powder-slush molding apparatus 30 has many problems and is represented by the following (A) to (G). It had many problems. (A) The conventional heating furnace 31 has a structure having a carry-in port 35 and a carry-out port 36 for the mold 34 in the lower part of the furnace from the viewpoint of the mold heating system and the productivity of the mold heating, and a plurality of molds are provided. There was no choice but to adopt a method of moving the 34 in a horizontally long furnace in a row in the horizontally long direction.

For this reason, the conventional mountain furnace 31 has to be arranged at a position higher than the surface of the earth (for example, at a position of about 10 m from the surface of the earth) by arranging it on a large high platform. Had a point.

Therefore, the conventional mountain furnace 31 has the problems that the construction cost and the running cost are high, the downsizing is difficult, and the operation, maintenance and management are complicated. . (B) The conventional mountain furnace 31 employs a heat transfer method in which the inside of the furnace is set to a high temperature atmosphere and heat is transferred from the high temperature atmosphere when the mold 34 moves in the furnace. The overall heat transfer coefficient was not so large, and there was a problem that the temperature of the atmosphere in the furnace had to be increased in order to shorten the heating time of the mold 34.

However, it is practically impossible to raise the temperature of the atmosphere in the furnace to a higher temperature because various negative factors such as deterioration of the economical efficiency of furnace operation and enlargement of the hot-air apparatus increase. Had a problem with. (C) The conventional mountain furnace 31 has a problem that it takes a long time to heat the mold, and also has a problem that the problem is not solved. Therefore, there is a problem that the productivity of the powder-slush molding apparatus 30 as a whole is restricted by the capacity of the mountain furnace 31. (D) The conventional mountain furnace 31 constantly supplies a large amount of hot air, and the shutters 37 and 3 are kept even during the die heating.
Since 7a is opened and closed at short intervals, it has a furnace structure in which heat is dissipated to some extent, and the thermal efficiency of the furnace itself is low. Moreover, the problem is that it is extremely difficult to solve the problem. (E) In the conventional mountain furnace 31, when a plurality of molds 34 (that is, different molds 34) having different shapes or sizes are supplied by the conveyor 32, they are heated under the same conditions in the furnace. Become.

Therefore, if another mold 34 is simultaneously heated in the furnace depending on the heating condition of a specific mold 34, a mold 34 that is underheated or overheated will be generated, and the subsequent steps will be smoothly performed. It had a problem that it could not be done. (F) In the conventional powder-slush molding apparatus 30, there is a constraint that the mountain furnace 31 must be arranged at a position higher than the surface of the earth, so that the structure of the entire molding apparatus becomes complicated and the operation becomes complicated. There was a problem that it was unavoidable. (G) The mold used in the powder-slush molding method is
Generally, they are formed of a metal having the same thickness of several mm, and most of them have a three-dimensional shape.

The temperature at which such a mold is used for powder-slush molding (typically, for example, 200
The method of heating in a high temperature atmosphere was considered to be the best industrial heating technique for heating to ~ 300 ° C.

Therefore, there is a problem that no study has been made on the relationship between the industrially optimum mold heating method and the furnace structure in the heating furnace of the conventional powder-slush molding apparatus. Was there.

Therefore, a furnace structure and a method of heating a mold, which can heat a mold used in the powder-slush molding method with high efficiency in a short time by the inventor of the present invention, are based on trial production and improvement of a furnace on an industrial scale. Examined in detail and found a heating furnace according to the invention.

Here, the first and second inventions are as follows.
It solves the above problems and can be operated on or near the surface of the earth, it is easy to downsize, construction cost and running cost are low, operation, maintenance and management are easy, Construction of the entire powder-slush molding machine that increases thermal efficiency (ie, heat transfer efficiency to the mold), shortens the time required to heat the mold, and can heat molds of different shapes or sizes under optimal conditions. A resin powder molding method (in particular, a powder-slush molding method) having various excellent features such as cost reduction and easy operation of the entire resin powder molding apparatus (in particular, the entire powder-slush molding apparatus). ), It is intended to provide a heating furnace used for heating a mold.

[0040]

Means for Solving the Problems The first invention (claim 1)
The heating furnace according to the invention described in 1) has a structure in which a mold for resin powder molding is carried in and out from the upper opening that can be opened and closed, and the mold is heated in the furnace with the upper opening closed. The furnace main body is configured, and the furnace internal structure is configured to have a hot air blowing part and an energy recovery part having the characteristics defined in (1) and (2) below, and hot air is blown onto the mold. It is used for heating a mold in a resin powder molding method, which is heated by heating.

Inner Structure of Furnace (1) The inner structure of the furnace is characterized in that a hot air blowing section having a hot air control mechanism for blowing hot air from below onto the mold is disposed on the bottom surface of the furnace. (2) The internal structure of the furnace is
A heat energy recovery unit for recovering heat energy in the furnace is provided in the furnace.

In the heating furnace according to the second aspect of the present invention (the invention according to claim 2), a mold for powder slush molding is carried in and out from the upper opening which can be opened and closed, and the upper opening. A furnace body is configured to have a structure for heating a mold in a closed furnace, and the furnace internal structure has the characteristics defined in the following (a) to (c). It is configured to have a hot air control mechanism, and is used for heating a mold in a powder-slush molding method in which hot air is blown onto a mold to heat it.

In- furnace structure (a) The in-furnace structure is characterized in that a hot-air blowing section having a hot-air control mechanism for blowing hot air from below onto the mold is arranged on the bottom surface of the furnace. , (B) The internal structure of the furnace is
The hot-air blowing section is provided on the inner surface of the furnace, and is characterized by a structure in which hot air is blown laterally to the mold. (C) The inner-reactor structure is a heat energy recovery unit for recovering heat energy in the furnace. −
It is configured to have a feature that the recovery part is arranged on the bottom surface of the furnace.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described. 1 is an explanatory view of a specific example of the heating furnace according to the present invention, and FIG. 2 is an explanatory view of the inside of the heating furnace shown in FIG.
FIG. 3 is an explanatory view of a bottom surface portion inside the heating furnace shown in FIGS. 1 and 2.

The heating furnace according to the present invention will be specifically described below mainly with reference to FIGS.

Although the heating furnace shown in FIGS. 1 to 3 is a preferred embodiment of the present invention, it is an example of a wide variety of embodiments included in the present invention.

In FIG. 1, the heating furnace 1 is constructed as one compact device 3 as a whole arranged vertically adjacent to a hot air generating and circulating device 2 for supplying heat energy to the heating furnace 1. The supply of energy and the recovery of heat energy from the heating furnace 1 are facilitated in terms of the arrangement of the device.

The furnace body of the heating furnace 1 is formed into a box-shaped furnace having a flat rectangular shape whose upper surface has an opening that can be opened and closed by a slide door 4, and the upper surface is opened to carry the mold into and out of the furnace. Then, the opening is closed and the mold is heated in the closed furnace. The "furnace body" of the present invention indicates the entire heating furnace 1 shown in Fig. 1.

In the heating furnace of the present invention, the furnace body is typically a plane rectangular box-shaped body shown in FIGS. 1 to 3, but the shape of the furnace body is arbitrary and the mold is It is possible to make the furnace body into a shape suitable for it depending on the shape or the heating efficiency and other conditions. For example, the furnace body may be cylindrical or cubic.

The size of the heating furnace 1 is an internal volume capable of accommodating a large mold used in an industrial powder-slush molding method, that is, one tenth of the size of the conventional mountain furnace 31. The internal volume is.

The height of the heating furnace 1 is also significantly smaller than that of the conventional mountain furnace 31, and the conventional industrial scale powdering device 38, mold cooling device 40, demolding device 41 and heating furnace 1 are used. Even if both of them are arranged side by side on the ground surface, they can be easily operated by a moving device (for example, a transfer robot) (see FIG. 6). Further, the heating furnace of the present invention has excellent heating efficiency such that the volume and height can be significantly reduced and the same productivity can be ensured, regardless of the shape of the furnace body, compared to the conventional mountain furnace 31. Have been found in the present invention.

Inside the heating furnace 1, a hot air outlet 5 and thermal energy recovery ports 6 and 6a are provided on the bottom surface of the furnace, and hot air outlets 7 and 7a are provided on both side surfaces of the furnace so that the hot air blows into the mold. The structure is such that the heat energy is recovered from the periphery of the mold and blown onto the entire mold, and the heat energy is recovered from the heat energy recovery ports 6 and 6a on the bottom surface of the furnace.

In FIG. 1, the lower surface 9a (lower surface in the drawing) of the mold 9 placed on the mold supporting members 8 and 8a arranged on the bottom surface of the furnace of the heating furnace 1 is a hot air outlet on the bottom surface of the furnace. The upper surface 9b of the mold 9 (the upper surface in the drawing) is heated by the hot air blown up from 5
The figure shows a state in which the heat energy is recovered from the heat energy recovery ports 6 and 6a provided on the inner bottom surface of the furnace by heating it with hot air blown from the hot air outlets 7 and 7a on both sides of the furnace.

The mold 9 is mounted on the mold supporting members 8 and 8a arranged on the bottom surface of the furnace in the heating furnace 1 with the mold frame 10 for moving and operating the mold 9 attached. It is placed.
The die 9 is connected to the arm of the robot to which the die 9 is attached, and the arm of the robot is moved when the arm of the robot is moved in each step. Thus, the mold frame 10 is put into the furnace through the opening of the upper surface portion opened by the slide door 4. Mold support member 8, 8a
Has its surface covered with heat insulating material (not shown),
The heat insulating material also serves as a sealing material. Therefore, the contact portion between the mold 7 and the mold supporting members 8 and 8a in FIG. 1 is sealed by the heat insulating material to prevent hot air from passing through (see FIGS. 1 and 3, and FIG. 2). Is not shown for the mold support member).

The die supporting members 8 and 8a are used to position the die 9 to be housed in the furnace for heating and to efficiently apply hot air blown from the hot air outlet 5 on the bottom of the oven to the lower surface of the die 9. In addition, it is for adjusting the height from the hot air outlet 5. Therefore, the mold support members 8 and 8a are arranged at equal intervals with respect to the hot air outlet 5 located at the center of the bottom surface of the furnace in the width direction.

The mold 9 whose cross section is shown in FIG. 1 has a shape similar to or similar to the resin molded product 11 (automobile interior parts) shown in FIGS. 4 and 5. 4 is a perspective view of the back surface of the resin molded product 11, and FIG. 5 is a resin molded product 1.
It is a perspective view of the surface of 1. The hot air outlet 5 is located in the central portion of the bottom surface of the furnace in the width direction, and is formed in a straight line having a length that extends almost in the longitudinal direction of the bottom surface of the furnace. It is formed larger than that of the hot air outlets 7 and 7a (see FIGS. 1 to 3).

Therefore, when the mold 9 is placed on the mold supporting members 8 and 8a, a large amount of hot air is generated on the lower surface 9a of the mold 9.
It will be blown up from the central part or below the central part.

The "hot air blowing section" of the present invention is substantially
The effects of the present invention can be enjoyed by disposing the mold 9 in a region that is always placed in the furnace.

The "hot air blowing section" of the present invention may have a function other than those shown in FIGS. 1 to 3 as long as it has a function of blowing hot air. For example, short linear openings are arranged discontinuously linearly, a plurality of narrow linear openings are arranged in parallel, and a plurality of circular, elliptical, or other shapes are continuously arranged. Etc. It is also possible to form the hot air blowing portion by a convex portion and to provide the hot air blowing portion with a movable part.

Therefore, the "hot air blowing section" of the present invention is
Any form and structure may be used as long as they have a function of blowing hot air. However, the reason why the present invention can easily enjoy the effects and is easy to manufacture is as follows.
For example, it is the hot air blowing part shown in FIGS.

Inside the hot air outlet 5, two hot air control plates 13 and 13a are provided which can be rotated at fulcrums 12 and 12a and controlled and set to their own predetermined opening angles. These hot air control plates are provided. Of the hot air blown from the lower part of the lower surface 9a of the mold 9 by the 13, 13a, or in the vicinity of the central part,
It is possible to control the directionality, spreadability, air flow rate and other factors. The two hot air control plates 13 and 13a are formed to have the entire length in the longitudinal direction of the hot air outlet 5.

Therefore, a large amount of hot air is controlled under optimum conditions that match the heating temperature, the heating time, the size of the mold 9, the shape of the mold 9, etc., and blown up from all over the hot air outlet 5 in the longitudinal direction. Is possible. For example, when the area of the lower surface 9a of the mold 9 is also small, the spreadability of the hot air is reduced by the hot air control plates 13 and 13a to increase the heating efficiency, or a part of the lower surface 9a of the mold 9 has a large uneven shape. In this case, the hot air control plates 13 and 13a can perform various controls such as directing the main stream of hot air to the portion.

The "hot air control mechanism" of the present invention may have any means and structure as long as it has a mechanism for controlling at least the directionality of the hot air blown out. Therefore, various control members and control devices can be used as the hot air control mechanism.

For example, in the case of a hot air control mechanism using a control plate, a plurality of control plates having a short length capable of independently controlling the movement are arranged in the same length as the hot air control plates 13 and 13a shown in FIG. It is possible to use a control mechanism including a short control plate, a control mechanism including a combination of a movable control plate capable of controlling movement and a stationary control plate that is fixed, or a control mechanism including a combination of a plurality of stationary control plates. .

In the heating furnace 1, hot air outlets 7, 7a
Is formed at a position approximately half the height of both sides of the furnace in a straight line extending substantially in the lengthwise direction of the furnace and parallel to the hot air outlets 5 on the bottom surface of the furnace (Fig. 1 and See FIG. 2).

Therefore, the mold 9 is heated by blowing hot air from the downward and lateral directions. When heating a metal mold (typically made of nickel electroforming) having a thickness of several mm used in an industrial molding method, a large amount of metal is blown from the bottom of the mold when heating the mold. When heated by the hot air and the hot air flowing through the die surface by the hot air, various conditions (for example, overall heat transfer coefficient) relating to heat transfer to the entire die 9 are significantly improved, and various excellent effects on heating the die 9 are obtained. The effect will be obtained. The heating furnace of the present invention has a structure in which a mold frame to which a mold is attached is carried into the heating furnace from the opening of the upper surface by a robot, and hot air is blown directly to the mold placed in the furnace to heat the mold. Has become. According to the present invention, the furnace main body of the heating furnace is such that the upper surface of the furnace body has a size capable of loading and unloading the mold frame, and the internal volume of the furnace is a size capable of accommodating the mold and the mold frame. It is possible to enjoy the effect.

Therefore, the size of the furnace body of the heating furnace of the present invention is determined by the relationship with the mold to be heated by the heating furnace, whereby the thermal efficiency of the entire heating furnace becomes excellent. Even if the furnace body is made large, it is sufficient if the opening on the upper surface is about 1.5 times the plane of the mold including the mold frame.

Thermal energy disposed on the bottom of the heating furnace 1
The recovery ports 6 and 6a are arranged in parallel on both sides of the hot air outlet 5 provided on the bottom surface of the furnace, and both die supporting members 8 and 8a.
Is arranged inside. Therefore, the hot air outlet 5 and the thermal energy recovery ports 6 and 6a are disposed in the space formed by the bottom surface of the furnace, the mold supporting members 8 and 8a, and the mold 9, The heat energy from the is easily recovered. "Thermal energy recovery unit" of the present invention
May have any form as long as it has a function of recovering heat energy. For example, it is a heat energy recovery port having various shapes other than the heat energy recovery ports 6 and 6a.

The hot-air generating / circulating device 3 includes an air supply fan 1
4 and the heat energy recovered from the inside of the furnace through the heat energy recovery ports 6 and 6a generate hot air by the hot air generator 15, and the hot air is circulated by the hot air circulation fan 16 into the main pipe 17 and Branch pipes 18, 18
The system is configured to supply the hot air outlets 5, 7, 7a through a.

Moreover, the main pipe 17 has a branch pipe 18,
A pipe having a diameter larger than that of 18a is used, and dampers 19 and 19a are arranged in the middle of the branch pipes 18 and 18a. Therefore, it becomes possible to control the quantitative ratio of the hot air blown out from the hot air outlet 5 on the bottom surface of the furnace and the hot air outlets 7 and 7a on the side surface of the furnace also by the dampers 19 and 19a, and by the dampers 19 and 19a. 18, 18
It is also possible to close a and blow hot air only from the hot air outlet 5 on the bottom of the furnace.

For example, it is effective when the mold 9 is small and the mold 9 is easily heated to a desired temperature within a short time by hot air from the hot air outlet 5 on the bottom surface of the furnace.

Further, the dampers 19 and 19a and the hot air control plate 1
By controlling the combination of 3 and 13a, the mold 9
It is possible to control the hot air blown onto the various states. Furthermore, the pipes 20 and 20 for recovering heat energy from the heat energy recovery ports 6 and 6a to the hot air generator 15 are provided.
The dampers 21 and 21a are also provided in a so that the recovery of heat energy can be controlled.

Then, in the heating furnace 1, the die 9 is heated by transferring the amount of heat of the hot air diffused over the entire inner surface 9a of the die 9 to the die 9. Therefore, the mold 9
Is heated under the condition that the amount of heat supplied into the furnace is not dissipated to the outside of the heating furnace 1, and also under the conditions that the heat transfer efficiency to the entire die 9 is significantly increased (for example, the overall heat transfer coefficient is large. And the like, and even with a remarkably small heating furnace 1 and a hot-air generating / circulating device 3 (that is, a remarkably small mold heating device 1), the productivity is equal to or higher than that of a conventional large-scale heating furnace. Have. The heating furnace 1 shown in FIGS. 1 to 3 includes an entire apparatus 3 including a hot air generating and circulating apparatus 2.
Can be remarkably miniaturized (it can be reduced to a tenth of a size in terms of volume) and has productivity equal to or higher than that of a conventional large heating furnace. Therefore, the entire apparatus 3 and powder Ring device 38, mold cooling device 40, and demolding device 41
And the like can be arranged in a line on the surface of the ground to form a powder-slush molding apparatus with high productivity.

FIG. 6 is an explanatory view showing a powder-slush molding apparatus 22 in which the apparatus for each process including the heating furnace 1 is arranged in a line on the ground surface, that is, the powder-slush molding apparatus 22 according to the present invention.

In the powder-slush molding device 22 shown in FIG. 6, the heating furnace 1, the conventional industrial-scale powdering device 38, and the mold cooling device 40 are arranged in a row adjacent to the surface of the earth, The mold is moved to each device by the mobile robot 23.

The powder-slush molding device 22 is not provided with the post-heating device 39 (that is, the device which is required to be provided in the conventional powder-slush molding device 30), and the heating furnace 1 is used. Is also used for post-heating. For that purpose, the powder-slush molding device 22
In terms of using the heating furnace 1 for post-heating as well, the downsizing of the entire powder-slush molding apparatus has been realized.

In the powder-slush molding device 22, the mold heated in the heating furnace 1 is conveyed by the robot 23 to the powdering device 38, where the layer of the thermoplastic resin hot melt is attached to the mold surface. To be done. Next, the mold to which the layer of the thermoplastic resin hot melt is attached is the robot 2
It is conveyed to a position directly above the heating furnace 1 by 3 and is held stationary for a while (about several tens of seconds) in a state where the layer of the adhered thermoplastic resin hot melt is directed downward. Meanwhile, the sliding door 4 of the heating furnace 1 is in an open state,
The layer of the thermoplastic resin hot melt is heated by the hot air blown from the inside of the furnace (particularly, the hot air outlet 5 at the bottom of the furnace), and the entire layer of the thermoplastic resin heat melt is homogeneously melted in the thickness direction. It becomes a thing.

In the industrial experiment by the industrial heating furnace 1 in the present invention, it was found that the post-heating effect superior to the post-heating effect obtained in the conventional post-heating step is obtained.

The mold post-heated by the heating furnace 1 is conveyed to the mold cooling device 40 by the robot 23 and cooled, and the resin molded product is removed from the mold. The powder-slush molding device 22 has a device for each process including the heating furnace 1 arranged in a line adjacent to the surface of the earth, and the mold is moved by the robot 23. You can get things. Further, when the heating furnace 1 is added, the purpose can be achieved by simply adding the heating furnace 1 to the row.

Therefore, the powder-slush molding method in which the heating furnace of the present invention is used has various modes (typically, for example, a post-heating device is required) which cannot be present in the conventional powder-slush molding method. And not) and operation.

To that end, the term "powder-slush molding process" of the present invention refers to not only conventional powder-slush molding processes but also all powder-slush processes which are possible by using the heating furnace according to the present invention. It is used in the meaning of the molding method. The same applies to the term "for powder-slush molding" of the present invention.

The heating furnace 1 uses any method and means in its control method and control means. A typical control method of the heating furnace 1 is to control the hot air and the heating time in order to uniformly heat the mold 9 in a short time according to its shape with high heating efficiency. Further, when the powder slush molding device 22 is formed by using the heating furnace 1, the powder
It is also possible to set the control method and control means of the heating furnace 1 in relation to the entire slush molding device 22.

In the heating furnace 1 shown in FIGS. 1 to 3, hot air outlets 7 and 7a are arranged on both side surfaces of the furnace in such a length as to extend substantially in the longitudinal direction of the furnace. However, by controlling the shape and thickness of the mold and other conditions of the mold and the control of the hot air blown out from the hot air outlet 5 provided on the bottom surface of the furnace, it is possible to heat the mold by hot air from below. You may be able to enjoy the effect.

In view of this, the first aspect of the present invention provides a heating furnace that requires the hot air outlet to be provided on the bottom surface of the furnace.

Further, in the present invention, the maximum effect of the present invention can be enjoyed when the die used in the powder-slush molding method is heated. However, there are some dies for resin powder molding methods other than the powder-slush molding method, which are made of metal having the same thickness. Therefore, the first aspect of the present invention is directed to a heating furnace used for heating a mold in various resin powder molding methods including a powder-slush molding method.

It is to be noted that the object of the present invention is to meet the following:
Unless the effects of the present invention are particularly impaired, partial alterations and modifications of the present invention or partial additions to the present invention are arbitrary and all are within the scope of the present invention.

[0087]

According to the first aspect of the present invention, the following (1)-
A heating furnace having various excellent characteristics represented by (3) and used for heating a mold in a resin powder molding method can be obtained. (1) The heating furnace according to the first aspect of the present invention has a structure in which hot air can be blown from below to a mold to heat the mold through a hot air blowing portion provided on the bottom surface of the furnace.

Therefore, the mold has hot air flowing on the mold surface,
It is heated by the hot air that collides with the mold surface and the high temperature atmosphere in the closed furnace, and the heat efficiency of the mold heating is greatly improved, so the time required for heating the mold is shortened, and the heating furnace is downsized and simplified. Is realized. Therefore, the construction cost and running cost of the heating furnace and its related equipment will be low,
Operation, maintenance and management of the heating furnace are also easy. (2) In the heating furnace of the first aspect of the present invention, the hot air blown onto the mold from below is supplied through the hot air blowing section having the hot air control mechanism.

Therefore, by controlling the hot air blown from below to the mold so that the heat efficiency of the mold heating becomes extremely large, for example, by controlling the direction of the hot air in such a manner, the mold heating The thermal efficiency is greatly improved, and various benefits are obtained with the improved thermal efficiency. (3) In the heating furnace of the first aspect of the present invention, a heat energy recovery unit for recovering heat energy in the furnace is provided in the furnace.

Therefore, in the heating furnace of the first aspect of the present invention, since the thermal energy supplied as hot air into the closed furnace is recovered, the utilization efficiency of the thermal energy required for the heating furnace is improved.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, various excellent characteristics represented by the following (a) to (c) are added to the powder-slash. The heating furnace used in the molding method is obtained. (A) In the heating furnace according to the second aspect of the present invention, the hot air blowing portion is arranged on the inner surface of the furnace, and the hot air is blown from the lateral direction to the mold in the lateral direction. Thereby, the hot air collides with the mold surface, and the hot air flows on the mold surface to heat the mold.

On the other hand, most of the molds used in the powder-slash molding method are made of a three-dimensional metal having a thickness of several mm. Therefore, the mold used in the powder slush molding method is heated with extremely high thermal efficiency,
Shortening the time required to heat the mold in the slush molding method,
Also, the heating furnace of the powder-slush molding apparatus can be downsized and simplified.

Therefore, by arranging the devices for each step of the powder-slush molding method on the surface of the earth, a powder-slush molding device which is simple and easy to operate and has a low construction cost can be realized. (B) The heating furnace according to the second aspect of the present invention has a structure in which the furnace main body is small and the upper part opens and closes.

Therefore, if the heating furnace of the present invention, the conventional powdering device, the mold cooling device, etc. are arranged side by side adjacent to the surface of the earth and the mold is operated by a robot or the like, The heating furnace can be a new powder-slush molding apparatus which is also used as a heating furnace in the post-heating step. (C) In the powder-slush molding apparatus used in the heating furnace of the second aspect of the present invention, it is easy to expand the heating furnace and add a device other than the heating furnace. Therefore, the capacity or the mode of the entire device is changed. It is possible to obtain a powder-slush molding apparatus that facilitates

[Brief description of drawings]

FIG. 1 is a configuration diagram of a specific example of the present invention.

FIG. 2 is an explanatory view of a part of the specific example of FIG.

FIG. 3 is also an explanatory diagram of a part of the specific example of FIG. 1.

FIG. 4 is a perspective view of a resin molded product.

FIG. 5 is a perspective view of a resin molded product.

FIG. 6 is an explanatory view of the powder-slush molding apparatus of the present invention.

FIG. 7 is an explanatory view of an entire industrial scale powder-slush molding apparatus.

FIG. 8 is a front view of the entire industrial scale powder-slush molding apparatus.

FIG. 9 is an explanatory view of a heating furnace of an industrial-scale powder-slush molding apparatus.

[Explanation of symbols]

 1 Heating Furnace Heat 2 Hot Air Generating and Circulating Device 4 Sliding Door 5 Hot Air Outlet on Bottom of Furnace 6 Heat Energy Recovery Port on Bottom of Furnace 6a Heat Energy Recovery Port on Bottom of Furnace 7 Hot Air Blowout on Side of Furnace 7a Furnace Inner side hot air outlet 8 Mold support member 8a Mold support member 9 Mold 10 Mold frame 11 Resin molded product 12 Support point 12a Support point 13 Hot air control plate 13a Hot air control plate 14 Air supply fan 15 Hot air generator 16 Hot air circulation device Fan 17 Main pipe 18 Branch pipe 18a Branch pipe 19 Damper 19a Damper 20 Pipe 20a Pipe 21 Damper 21a Damper 22 Powder slush molding device 23 Robot

Claims (3)

[Claims] 1. A furnace main body is constructed in such a structure that a mold for molding resin powder is carried in and out of a furnace through an opening that can be opened and closed, and the mold is heated in a furnace with the opening at the top closed. The inner structure of the furnace is configured to have a hot air blowing part and an energy recovery part having the characteristics defined in the following (1) and (2), and hot air is blown onto the mold to be heated.
A heating furnace used to heat the mold in the resin powder molding method. In-furnace structure (1) The in-furnace structure is characterized in that a hot-air blowing section having a hot-air control mechanism for blowing hot air from below onto a mold is arranged on the bottom surface of the furnace. ) The internal structure of the furnace is
A heat energy recovery unit for recovering heat energy in the furnace is provided in the furnace. 2. A furnace main body is structured so that a mold for powder slush molding is carried in and out of a furnace through an opening which can be opened and closed, and the mold is heated in the furnace where the opening at the top is closed. The internal structure of the furnace includes a hot air blowing part and an energy recovery part having the characteristics defined in (a) to (c) below, and the hot air is blown onto the mold to be heated. , A heating furnace used to heat the mold in the powder-slush molding process. In-furnace structure (a) The in-furnace structure is characterized in that a hot-air blowing section having a hot-air control mechanism for blowing hot air from below onto the mold is disposed on the bottom surface of the furnace. ) The internal structure of the furnace is
The hot air blowing section is arranged on the inner surface of the furnace, and has a feature of a structure in which hot air is blown and blown from a lateral direction to the mold,
(C) The in-furnace structure is configured to have a feature that a heat energy recovery section for recovering heat energy in the furnace is arranged on the bottom surface of the furnace. 3. The mold heating furnace according to claim 2, wherein the heating furnace is configured to have any one or more of the following features (i) to (iv). (I) The hot-air blowing section disposed on the bottom surface of the furnace is arranged in a region below the mold housed in the furnace, and (ii) the mold housed in the furnace is mounted on the bottom surface of the furnace. A mold supporting member is provided in a position in which the hot air blowing portion on the bottom surface of the furnace is located, (i
ii) The thermal energy recovery unit is provided in an arrangement located between a plurality of mold supporting units for mounting the molds to be housed in the furnace, and (iv) the hot-air control mechanism included in the hot-air blowing unit is at least It is characterized in that it is configured to control the directionality of hot air.