JPH04355108A - Molding mold temperature control method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold temperature control method for controlling the mold temperature of a mold for slush molding.

0002

2. Description of the Related Art For example, a skin body (molded body) formed by slush molding using a resin material is used as an interior body in which an automobile instrument panel or the like is incorporated. In this case, the slush molding includes a step of preheating the mold, a step of charging a molding material such as vinyl chloride plastisol or powder into the heated mold, and discharging the excess molding material. a step of further heating the mold; a step of cooling the heated mold;
There are steps such as taking out the skin from the mold, and the mold is sequentially conveyed between the above steps to form the skin.

[0003] By the way, in the heating step, one method of heating a slush molding mold is conventionally known by using a hot air oven. This hot air oven heats the mold for a set time or more through hot air in the furnace while maintaining the temperature inside the furnace at a desired constant temperature, thereby bringing the mold to a desired temperature.

0004

[Problems to be Solved by the Invention] However, the above-mentioned heating method using a hot air stove has the disadvantage that heating takes a long time because the temperature inside the furnace is constant.

[0005] Therefore, in order to shorten the heating time of the mold, it is conceivable to control the amount of heat applied to the mold. However, it is difficult to continuously control the heating output of the heat generating source and the amount of air blown, and it also costs a lot of money.

[0006] Furthermore, when the temperature is raised in such a short time, there is a problem that, for example, due to the characteristics of the mold made of nickel electroforming, the temperature tends to vary even when heated under the same conditions. In this case, it is also possible to control the heating time to eliminate variations. however,
In order to efficiently transfer between work stations,
It is necessary to keep the processing time of each station constant. This is because if the processing time changes and the waiting time until the mold is transferred to the next station changes, the temperature of the mold, which is maintained uniformly, will vary.

Furthermore, when using the same slush molding device to cast multiple types of molds with different sizes and shapes (for example, so-called molds for instrument panels, door interiors, etc.), the above-mentioned constant heating time is maintained. In order to raise the temperature to the desired temperature while maintaining the temperature, it is necessary to control the amount of heat over a wide range.

The present invention solves this kind of problem by calculating the heating output switching time or air blowing amount switching time of the mold and controlling the heating output or air blowing amount in multiple stages. It is an object of the present invention to provide a temperature control method for a mold that can efficiently adjust the temperature to a desired temperature within a certain heating time without being affected by differences in mold characteristics or the type and size of the mold used. purpose.

[0009]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a mold for molding a molded article from a resin-based molding material by being transferred between work stations so that the heating output of the heat generating source is A method of controlling the temperature to a desired temperature by heating through a hot air heating furnace that can be controlled in multiple stages,
Setting the temperature at which the mold is discharged from the hot air heating furnace provided in the heating station, setting the heating time of the mold, detecting the temperature of the mold before being carried into the hot air heating furnace, and before carrying the mold into the hot air heating furnace. From the process of detecting the temperature in the hot air heating furnace, the set temperature for unloading the mold and the heating time, and the detected temperature of the mold before being brought in and the temperature in the hot air heating furnace, The method is characterized by comprising a step of calculating a heating output switching time of the hot air heating furnace.

[0010]Furthermore, the present invention heats the mold, which is transferred between each work station and forms a molded article from a resin molding material, through a hot air heating furnace whose air flow rate can be controlled in multiple stages. , a method of controlling the temperature to a desired temperature, the method comprising: setting the temperature at which the mold is discharged from the hot air heating furnace provided in the heating station; setting the heating time of the mold;
A step of detecting the temperature of the mold before being carried into the hot air heating furnace, and detecting the temperature in the hot air heating furnace before carrying the mold into the hot air heating furnace, and the set furnace temperature and heating time of the mold, The present invention is characterized by comprising the step of calculating an air flow rate switching time of the hot air heating furnace from the detected temperature of the mold before being carried in and the temperature inside the hot air heating furnace.

[0011]

[Function]■ In the above mold temperature control method according to the present invention, the mold temperature is determined based on the preset mold temperature and heating time, the mold temperature before the mold is brought in, and the temperature in the hot air heating furnace. Since the heating output switching time in a hot air heating furnace is calculated, the efficiency of this mold within a fixed heating time is not affected by differences in the characteristics of the mold or the type and size of the mold used. can be heated to the desired temperature.

Furthermore, when the type, size, etc. of the mold changes, the amount of air blown in the hot air stove is switched under the control of the heating output to efficiently heat the mold to the desired temperature within a fixed heating time. can do.

[0013] In the mold temperature control method according to the present invention, hot air is Since the air flow switching time in the heating furnace is calculated, the mold can be heated efficiently within a certain heating time without being affected by differences in the characteristics of the mold or the type and size of the mold used. It can be heated to the desired temperature.

Furthermore, when the type, size, etc. of the mold changes, the heating output of the heat generating source is switched under the control of the air flow rate to efficiently heat the mold to the desired temperature within a fixed heating time. can do.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of a mold temperature control method according to the present invention in conjunction with a molding apparatus for carrying out the method will be described in detail with reference to the accompanying drawings.

In FIG. 2, reference numeral 10 indicates a molding apparatus for carrying out the method for controlling the temperature of a mold according to this embodiment. This molding device 10 includes a first heating station 14 that heats a mold 12 fixed on a conveyor table 11 to a desired temperature, and a resin molding material that is supplied to the heated mold 12 and welded thereto. A welding station 16 discharges unnecessary molding material after cooling, a second heating station 18 heats the welded molding material, a cooling station 20 cools the mold, and a skin body (molding a take-out station 22 for taking out the body), first and second lifting stations 24 and 26 for making the first heating station 14, welding station 16 and second heating station 18 into a two-stage structure; A transport mechanism 28 capable of circulating the mold 12 between the molds 12 and 26 is provided. Each of these stations is driven and controlled by a control device 29.

As shown in FIG. 3, the first heating station 14 has a hot air heating furnace 30, and within this hot air heating furnace 30, there is a hot air generating means consisting of burners 31a, 31b which are heat sources and a blowing air generating means 32. 33 are arranged. A plurality of hot air outlets 34 supply the hot air generated by the hot air generating means 33 to the mold 12, a plurality of hot air recovery ports 36 collect the hot air, and the collected hot air is circulated to the hot air generating means 33. A passage 38 is provided to allow the passage. The hot air heating furnace 30 is provided with a driving means 41 for rotating (swinging) the mold 12, and a temperature detection sensor (not shown) is provided to detect the temperature inside the hot air heating furnace 30. The temperature detection sensor supplies temperature information of the hot air heating furnace 30 to the control device 29 .

The welding station 16 includes a resin supply mechanism 37 for forming a skin layer in the molding cavity of the mold 12, a foamable resin supply mechanism 39 for molding a foam layer on the skin layer, and a foam resin supply mechanism 39 for molding a foam layer on the skin layer. A driving means 40 for rotating the mold 12 is provided.

The second heating station 18 includes a heating furnace 42
In addition, a driving means 44 is provided to swing the mold 12 within a predetermined angular range within the heating furnace 42.

At the entrances and exits of the first heating station 14, welding station 16, and second heating station 18, there are shutters 48a that engage the cylinders 46a to 46d.
48d to 48d are provided.

The cooling station 20 has a cooling chamber 52 in which a cooling water supply means 50 is housed, and a driving means 5 for inverting the mold 12 within the cooling chamber 52.
4. Air blowing means 56 is arranged between the cooling station 20 and the second heating station 18 to slowly cool the skin.

The take-out station 22 is provided outside the circulating conveyance path of the molding device 10, and has a driving means 5 for swinging the mold 12 in order to take out the skin body from the mold 12.
It has 8.

First and second lifting stations 24, 2
6 includes a lifting platform 62 that engages with a motor 60, and a conveyor belt 64 that constitutes the conveyance mechanism 28 and is disposed vertically in parallel.
, 66 and the elevating table 62 form an annular conveyance path. This conveyance mechanism 28 has a conveyance path 68 arranged at the take-out station 22, and this conveyance path 68 is connected to the mold 1.
2 is advanced and retreated between the take-out station 22 and the lifting platform 62.

A radiation thermometer (not shown) is disposed immediately before the cooling station 20 and at the first lifting station 24 to detect the temperature of the mold 12. The information is supplied to the control device 29.

Next, the molding apparatus 1 constructed as described above
0 and the operation of the control device 29 will be explained below with reference to the flowchart shown in FIG. 1 in relation to the temperature control method according to the present embodiment. ■ 1st heating station 14
The unloading temperature T1 of the mold 12 from the hot air heating furnace 30 provided in the hot air heating furnace 30 is set based on characteristic data such as the material and shape of the mold 12, and is supplied to the control device 29. ■
The temperature T2 of the mold 12 before being carried into the hot air heating furnace 30 is
It is detected by a radiation thermometer (not shown) disposed at the first lifting station 24 and is supplied to the control device 29 . (2) The temperature T3 inside the hot air heating furnace 30 before the mold 12 is carried in is detected via a temperature detection sensor (not shown) and supplied to the control device 29. (2) Judging from the material, shape, etc. of the mold 12, a desired heating time S (seconds) for the mold 12 is set and supplied to the control device 29. ■
In this way, temperature information regarding the set unloading temperature T1 of the mold 12, the detected temperature T2 of the mold 12 before being carried in, and the temperature T3 in the hot air heating furnace 30, and the set heating time S (seconds) is input to the control device 29. This control device 29 calculates the heating output switching time P or the air blowing amount switching time P (seconds) based on the above information. Said heating output switching time P or air blowing amount switching time P (seconds)
is determined by the following formula.

P=α×T2+β×T3+γ×T1+S+K However, α,
β, γ and K are constants, T1, T2, T3,
A set of S and P is collected many times, and based on this data, the most appropriate value is selected using a statistical method. Therefore, these values vary depending on conditions such as the type of mold, the heating output, and the switching stage of the air blow rate.

After the control device starts timing, the heating output switching time P or the air blowing amount switching time P obtained from the above formula
(seconds) later, the heating output or air blowing amount is switched.

[0028] As a result, even if the temperature T2 of the mold 12 immediately before being carried into the hot air heating furnace 30 and the temperature T3 inside this hot air heating furnace 30 change due to fluctuations in various external conditions, the preset constant temperature can be maintained. Always the desired furnace temperature T1 with heating time S
It can be heated to. Therefore, it is possible to efficiently mold a high-quality skin body through the molding operation described below.

To explain this using FIG. 4, this graph shows radiation heating due to two-stage heating output switching between Hi and Low of the burners 31a and 31b, and the amount of air blown by the air blowing means 32. The figure shows a state in which the mold 12 is heated with hot air by changing the amount of air blown. Note that the heating time S is set to 80 seconds.

[0030] Here, the total heat amount curve D1 is
, 31b is set to Low, and the ventilation generating means 3
The total heat amount curve D2 shows the hot air heating state when the air flow rate of No. 2 is switched to a small amount. The state and total heat curve D3 are:
The hot air heating state and total heat amount curve D4 in the state where the heating output of the burners 31a, 31b is set to Low and the air flow rate of the air blow generation means 32 is switched to high is the total heat amount curve D4.
The hot air heating state is shown in which the heating output of b is set to Hi and the amount of air blown by the air blown generating means 32 is switched to high. In the total heat amount after 80 seconds of heating time in the total heat amount curves D1 to D4, the total heat amount curve D3
A low heating output control range whose upper limit is the total heat amount of the total heat amount curve D1 and a lower limit of the total heat amount of the total heat amount curve D1, and a high heating output control range whose upper limit is the total heat amount of the total heat amount curve D4 and the lower limit is the total heat amount of the total heat amount curve D2. is stipulated. Therefore, in order to control within the desired high and low heating output range within the above range,
The control device 29 calculates the air flow rate switching time P as shown in FIG. By switching the amount of air blown by the air blown generation means 32 from high to low, it is possible to control the total amount of heat to a desired amount within the high heating output control range (see total amount of heat curve D6). Similarly, based on the calculation result in the control device 29, the heating output of the burners 31a and 31b is set to Low during the air flow switching time P2 in the total heat amount curve D3.
By switching the amount of air blown from the air blown generation means 32 from high to low while maintaining the temperature at
(see 5).

In FIG. 4, the air blowing amount of the air blowing generating means 32 is switched based on the air blowing amount switching time, but on the contrary, the burner 31a is switched based on the heating output switching time.
, 31b is shown in FIG.

In FIG. 5, settings are made under the same conditions as in FIG.
Switching the heating output in two stages by changing the heating output by increasing or decreasing the amount of air blown by the air blowing generating means 32, and changing the heating time S by 8
It is set to 0 seconds. In the figure, P3, P4, P
5 indicates the heating output switching time, and the P3, P4,
By switching the heating output of the burners 31a and 31b from Hi to Low at P5 seconds, the desired amount of heat of the mold can be obtained from the total heat amount curves D11 to D16.

[0033] Next, the forming operation of this skin body will be schematically explained.

Hot air heating furnace 3 of first heating station 14
When the mold 12 is carried into the hot air generating means 33, the mold 12 and the conveyor table 11 are integrally rotated (swung) via the driving means 41, and the hot air generating means 33 is driven. This hot air generating means 33 can generate hot air by driving the air blowing generating means 32 under the heat radiation action of the burners 31a and 31b. This hot air is supplied to the mold 12 from the hot air outlet 34, and the supplied hot air is circulated from the hot air recovery port 36 to the hot air generating means 33 via the passage 38, and the hot air generating means 33 generates the hot air. It is heated and guided into the mold 12.

At this time, the burners 31a, 31b and the air blow generating means 32 are configured to be switchable in two stages. That is, the burners 31a and 31b can switch the heating output between high and low levels (Hi, Low), and the air blowing means 32 can switch the air blowing amount between high and low. The heating output of such burners 31a and 31b is high and low (
(Hi, Low) and the amount of air blown by the air blown generating means 32,
This is done under the control of the heating output switching time or the air blowing amount switching time in the control device 29. As described above, time measurement is started by the control device 29, and the mold 12 is heated with hot air for a preset fixed heating time.

After the hot air heating, the mold 12 is transported to the welding station 16 via the transport mechanism 28, and first, a non-foaming powder in the form of a powder is placed inside the molding cavity under the action of the resin supply mechanism 37. A resin is added to form a skin layer. Furthermore, after powdered foamable resin is supplied to the skin layer under the action of the foamable resin supply mechanism 39 and welded, the conveyor table 11 is rotated 360° under the action of the drive means 40 to enter the mold 12. Unnecessary foamed resin is discharged to the outside.

The mold 12 transported to the second heating station 18 is oscillated within a predetermined angle range by the driving means 44, and the foamable resin is foamed to form a skin body.

[0038] The conveyance table 11 is moved to the second elevating station 26.
is conveyed to a lifting platform 62 and lowered under the action of a motor 60. At this time, the air blowing means 56 is driven to supply cooling air to the mold 12, and the mold 12 and the skin are gradually cooled.

Cooling station 2 via transport mechanism 28
The conveyance table 11 conveyed to 0 is reversed under the action of the driving means 54, and cooling water is supplied to the outer surface of the mold 12 via the cooling water supply means 50, so that the mold 12 is rapidly cooled. Ru.

The conveyance table 11 conveyed from the cooling station 20 to the first elevating station 24 is raised to the same height as the conveyance path 68 via the elevating table 62, and then moved to the take-out station 22 via this conveyance path 68. It is transported and swung by the driving means 58 to perform the work of removing the skin body.

[0041] Here, three molds 12 are circulated and conveyed to the molding apparatus 10, and the skin body is sequentially molded by these molds 12.

[0042] In this embodiment, the heating output is set to Hi, L.
Although the explanation is given by switching the air flow rate to two stages (low and high), the invention is not limited thereto, and it goes without saying that the heating output and the air flow rate can be controlled by switching in multiple stages.

[0043]

[Effects of the Invention] According to the method for controlling the temperature of a mold according to the present invention, the following effects can be obtained.

That is, the heating output switching time for heating the mold based on the preset furnace temperature and heating time of the mold and the detected temperature of the mold before being carried in and the temperature of the hot air heating furnace, or The air flow switching time of the hot air heating furnace is calculated. As a result, the heating output or airflow rate can be changed in multiple stages based on the heating output switching time or airflow rate switching time of the forming mold, without being affected by differences in mold characteristics or the type and size of the mold. By controlling the switching, it becomes possible to efficiently adjust the heating temperature to a desired temperature within a certain heating time.

[Brief explanation of drawings]

FIG. 1 is a flowchart for explaining a method for controlling the temperature of a mold according to the present invention.

FIG. 2 is an explanatory front view of a molding device and a control device for implementing the mold temperature control method according to the present invention.

FIG. 3 is a side view of a first heating station that constitutes the molding apparatus in FIG. 2;

FIG. 4 is a diagram showing the relationship between the total amount of heat and heating time for explaining the temperature control method for a mold according to the present invention.

FIG. 5 is a diagram showing the relationship between the total amount of heat and the heating time to explain the temperature control method for a mold according to the present invention.

[Explanation of symbols]

10... Molding device 11...Transportation platform 12...Molding mold 14, 18...Heating station 16...Welding station 20...Cooling station 22...Removal station 30...Hot air heating furnace 31a, 31b...Burner 32...Air blow generation means 33...Hot air generation means

Claims (4)

[Claims] [Claim 1] A mold that is transferred between work stations to form a molded article from a resin-based molding material is heated through a hot air heating furnace in which the heating output of a heat source can be controlled in multiple stages. A method of controlling the temperature to a desired temperature, the method comprising: setting the temperature at which the mold is discharged from the hot-air heating furnace provided in a heating station, setting the heating time of the mold, and setting the mold before being carried into the hot-air heating furnace. and detecting the temperature in the hot air heating furnace before carrying the mold into the mold;
a step of calculating a heating output switching time of the hot air heating furnace from the set mold exit temperature and heating time, and the detected temperature of the mold before being carried in and the temperature inside the hot air heating furnace; A method for controlling the temperature of a mold, comprising: 2. In the method according to claim 1, before carrying the mold into the hot air heating furnace, the type of the mold is determined, and the amount of air blown in the hot air heating furnace is adjusted according to the type of the mold. A mold temperature control method characterized by switching. 3. The desired temperature is achieved by heating the mold, which is transferred between each work station and used to mold a molded product from a resin-based molding material, through a hot air heating furnace whose air flow rate can be controlled in multiple stages. The method includes: setting the temperature at which the mold is discharged from the hot air heating furnace provided in the heating station, setting the heating time of the mold, and controlling the temperature of the mold before being carried into the hot air heating furnace. and the process of detecting the temperature in the hot air heating furnace before carrying in the mold, the set unloading temperature and heating time of the mold, and the detected temperature and hot air heating of the mold before carrying in the mold. A method for controlling the temperature of a mold, comprising the step of calculating an air blowing amount switching time of the hot air heating furnace from the temperature inside the furnace. 4. In the method according to claim 3, the type of mold is determined before the mold is carried into the hot air heating furnace, and the heating output of the heat source is switched in accordance with the type of mold. A mold temperature control method characterized by: