JP2001001339A - Preheater for mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to efficiently preheat a mold by forming a spacer incorporating a heating element into almost such a rectangular shape as to keep away from the form engraving part for the mold and a guide pin and inserting the spacer into a parting gap between the top force and the bottom force of the mold from the opposed directions of the gap. SOLUTION: A preheater 1 is structured of a heating element 12 of an electrical resistance type inserted into a spacer 11 and each of two pieces of the preheater 1 is connected to a controller for temperature setting and control by means of a lead wire 13. A mold 2 comprises a top force 21 and a bottom force 22 which are two split upper and lower parts of the mold 2, each having an internal form engraving part 23 formed and, if necessary, guide pins 24 provided. In addition, the spacer 11 of the preheater 1 is made of an efficiently heat conductive metal and is shaped into a projecting form which appears to be a combination of two rectangles. Further, the spacer 11 is inserted into a parting gap between the top force 21 and the bottom force 22 of the mold 2 from the opposed directions of the gap and the mold 2 is closed to preheat the mold 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold preheating heater for raising a mold to near a temperature required for molding conditions before performing resin molding or die casting.

[0002]

2. Description of the Related Art Usually, a mold is used when performing resin molding or die casting. However, since this mold has a large heat capacity, it is necessary to set the molding machine and then start heating until the temperature reaches the molding conditions. And the time required to operate the molding machine is wasted. If the temperature of the mold has not reached the set temperature due to insufficient heating of the mold, or if the temperature is not uniform due to rapid heating, the flow of hot water into the mold will be poor and the temperature condition will be stable. In addition, there is a problem that a defect occurs in a product. For this reason, it is common practice to preheat the mold temperature to near the molding conditions before attaching the mold to the molding machine prior to operation.

Conventionally, as a preheating means, a furnace capable of storing a mold is provided, a mold is placed in the furnace for heating, or a gas burner is inserted from a gap between the molds (between the parts).
A direct fire method of directly applying a flame to a heated portion to heat it is used.

[0004]

However, according to the preheating means using a furnace, there is a problem in that the furnace is large and thus takes up space, and the furnace itself is costly. Further, since indirect heating is performed using air as a medium, there is also a problem that the heating efficiency is poor, the temperature rise takes time, and the energy loss is large. On the other hand, direct heating by a gas burner or the like has a problem that it is difficult to uniformly heat the temperature over the entire mold, and it is dangerous because a flame is used. is there.
Furthermore, the place for preheating the mold by any of the above means is a place where the furnace is installed, or a limited place such as near a gas cylinder, so that a preheating place must always be secured, There is a problem that the mold must be moved at least from the mold storage place to the preheating place and further to the molding machine.

Accordingly, the present invention is to provide a mold preheating heater which can efficiently and safely preheat a mold by direct heating, and has a simple structure which does not require a large or special place for preheating. Was an issue.

[0006]

Means for Solving the Problems In the mold preheating heater of the present invention, a spacer serving as a heating portion having a heating element incorporated therein is formed in a substantially rectangular parallelepiped shape avoiding the die engraving portion and the guide pin. Then, the upper and lower molds are heated by holding the upper mold by its own weight by sandwiching the mold from the opposing two or four directions between the upper and lower mold parts and closing the mold. It adopts the configuration that is performed.

[0007]

According to this means, the heating efficiency is high because of direct heating, and no special stationary device such as a furnace or a gas cylinder is required just by sandwiching the heater having the above configuration between the molds.
The preheating work can be performed at a place where the mold is placed, such as a mold storage place or a molding machine, without requiring a large space. Also,
Since a simple structure in which a heater serving as a heating element is inserted into a substantially rectangular parallelepiped spacer is employed, manufacture is easy. Furthermore, since no flame is used, a mold preheating operation which is safe and does not need to be constantly monitored can be performed.

[0008]

An embodiment of a mold preheating heater according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of the present invention, and is a configuration diagram showing a state before a preheater is mounted on a mold. The preheater 1 includes a heating element 12 having electric resistance inside a spacer 11 serving as a heating surface. The preheaters 1 and 2 are connected by lead wires 13 to one controller 3 for temperature setting and temperature control, respectively.
On the other hand, 2 is the upper and lower 2 corresponding to the preheater 1 of the present invention.
The upper mold 21 and the lower mold 22 are separated from each other, and a mold engraved portion 23 is formed in each of the molds, and a guide pin 24 is provided as necessary.

The spacer 11 serving as the heating surface of the preheater 1 is made of a metal having good heat conductivity.
It is preferable to adopt a shape that is easy to manufacture, such as a substantially rectangular parallelepiped or a combination of rectangular parallelepipeds, but is not particularly limited as long as the surface that contacts between the mold parts is a flat surface.
In the present embodiment, a convex shape such as a combination of two rectangular parallelepipeds, which is heated while avoiding the engraved portion 23 and the guide pin 24 of the mold 2 and in contact with the peripheral edge of the molding surface of the mold 2. I made it big.

On the other hand, the heating element 12 is provided by being inserted into an insertion hole penetrated through the spacer 11, and has a shape and a structure inside a metal cylindrical outer cylinder, which is made of insulating material at the center of the cylinder. An electric heater called a sheath heater was used in which a heating wire was wound around the core, filled with an insulating material so that the heating wire did not contact the outer cylinder, and the end of the outer cylinder was sealed.

The preheating heaters 1 and 2 combining the spacer 11 and the heating element 12 are positioned between two parts of the mold 2 so as to be inserted from two opposing directions. 13 was connected to one controller so that the temperature could be controlled. Although not shown, a temperature sensor is attached to one or both of the mold 2 and the preheater.

FIG. 2 is a structural view showing a state in which the mold preheating heater 1 according to one embodiment of the present invention is installed in the mold 2. The upper die 21 of the mold 2 is placed on the preheater 1 at a corresponding position on the preheater 1 at the edge of the lower die 22 on the upper surface avoiding the engraved portion 23 (see FIG. 1) and the guide pin 24. The preheater 1 is held between the upper mold 21 and the lower mold 22 and is held by the weight of the upper mold 21.

FIG. 3 shows a mold preheating heater according to another embodiment of the present invention, in which a heating element 12 having the same structure is inserted into a simple rectangular parallelepiped spacer 11 by the above-described means. What is sandwiched between the upper and lower mold partings from four directions is shown. As described above, the shape, size, and number corresponding to the preheating conditions such as the size, shape, and preheating time of the mold may be selected.

[0015]

According to the mold preheating heater of the present invention,
Good heating efficiency by direct heating as described above,
The preheating operation can be performed comprehensively at a low cost due to effects such as a manufacturing cost due to the simplicity of the structure, and the need for a monitor to be constantly provided due to the high safety due to electric heating. Further, since the work place is not limited, the work of moving the mold can be reduced by performing the work in, for example, the mold storage place, and the preheating work can be simplified because the work is safe because no flame is used. it can. Furthermore, since large equipment such as a furnace is not required, the cost can be reduced, and preheating work that requires no space can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a state before a mold is installed according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a mold installation state according to an embodiment of the present invention.

FIG. 3 is a schematic view showing another embodiment of the present invention.

[Explanation of symbols]

 1. Preheating heater 11. Spacer 12. Heating element 13. Lead wire 2. Mold 21. Upper mold 22. Lower mold 23. Engraving part 24. Guide pin 7. controller

Claims (1)

[Claims] 1. A substantially rectangular parallelepiped for preheating a mold by arranging it between two parts or four directions facing each other between two parts of the mold which are vertically separated from each other so as to be sandwiched by the weight of the upper mold. A mold preheater characterized by incorporating an electric resistance heating element inside the spacer.