JPH0438885Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention is an extrusion molding device in which a flow guide, a die, and a backer are arranged adjacent to each other on the same axis. The present invention relates to an extrusion molding device that is suitable for preheating both materials at the same time using an induction heater, and is used, for example, as an extrusion molding device for aluminum sash.

(Prior Art) As a conventional device related to the present invention, one in which the sheets 2 and 4 of FIG. 1, which shows an embodiment of the present invention, are not interposed is known. That is, a die extrusion tool consisting of a flow guide 1, a die 3, and a backer 5 was arranged in sequence, and both sides of the die 3 were brought into contact with one side of the flow guide 1 and the backer 5, respectively.

Such conventional equipment requires preheating to a predetermined temperature before extrusion, but this is done by generating eddy currents in the surface layers of the flow guide 1, die 3, and bucker 5 using the magnetic force generated by the electric coil. It used an induction heater that generates heat using its electrical resistance.

(Problems to be Solved by the Present Invention) The above-mentioned conventional device uses the principle that an eddy current is generated in the extrusion tool by the magnetic force generated by the use of an electric coil, and heat is generated by the electric resistance of the surface layer of the extrusion tool. Take advantage of. These eddy currents tend to flow not only within each extrusion tool but also between the extrusion tools, but it is difficult to bring the contact surfaces of each extrusion tool, which are originally processed separately, into complete surface contact, and it is usually localized. There is a point of contact. Therefore, due to the contact resistance that exists at each contact point of this extrusion tool, these contact parts generate abnormal heat (local heat) compared to non-contact parts.
This heat generation causes the extrusion tool to melt locally and form uneven stripes, and the pressure during extrusion distorts the shape of the molded product introduction hole of the extrusion tool, causing the extrusion molded product to have a defective shape. There was a problem that the strength of the steel was reduced.

Therefore, it is possible to reduce the occurrence of local heat by polishing the contact surface of each extrusion tool, but this is extremely troublesome and increases the number of work steps.Moreover, the extrusion tool used for extrusion once has a large extrusion force. Because of this deformation, the surface needs to be polished every time it is extruded, which has the disadvantage of reducing the thickness of the extrusion tool.

Therefore, the present invention has developed a technology that can significantly reduce the local heat observed in conventional equipment without causing any adverse effects when an extrusion tool consisting of a flow guide, die, and backer is preheated at the same time using an induction heater. This will be a major issue.

[Structure of the idea]

(Means for solving the problem) The technical means taken to solve the above technical problem is to provide electrical insulation between the flow guide and the die, and between the die and the backer under normal conditions. In addition, paper that carbonizes when heated with an induction heating type heater is interposed in each case.

(effect) The above technical means works as follows.

The paper interposed between the flow guide and the die, and between the die and the backer has electrical insulating properties, so during the preheating process by the induction heater, the flow guide and the die are separated at the beginning of the preheating process. No eddy currents flow between the die and the bucker, and therefore no local heat is generated.

The paper burns out due to the rise in temperature of the flow guide, die, and backer, but the burnt out paper, that is, the carbide of the paper, is an electrical conductor, and the burnt out paper causes the flow guide, the die, and the backer of the die to By making surface contact with each other, the flow guide, the die, and the backer of the die are electrically in surface contact with each other.
No local heat is generated, and the flow guide, die, and backer are heated evenly.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

In FIG. 1, an extrusion tool is composed of a flow guide 1, a die 3, and a backer 5, and the flow guide 1 has an introduction hole 6 for, for example, an aluminum billet.
However, a die hole 7 is formed in the die 3, and a hole 8 is formed in the backer 5. Therefore, the aluminum billet introduced into the introduction hole 6 is pressed against the die hole 7 by a piston, etc.
It is molded into a molded product with the shape and dimensions of the hole 8.
taken out. Papers 2 and 4 are interposed between the corresponding contact surfaces of the flow guide 1 and the die 3, and between the die 3 and the backer 5, respectively. The papers 2 and 4 are commonly used papers, have a thickness of about 0.1 mm, and are donut-shaped.

Papers 2 and 4 were originally flow guide 1 and die 3.
The contact surfaces of the die 3 and the backer 5 are electrically insulated. Therefore, when preheating the extrusion tool with the induction heater, no eddy current flows between the contact surfaces of the flow guide 1 and the die 3 and between the contact surfaces of the die 3 and the bucker 5 at the beginning of the preheating process, resulting in local heat generation. is significantly reduced. As the preheating process progresses, the temperature of the extrusion tool increases, and the papers 2 and 4 eventually burn out. The burnt out paper, that is, the carbide of the paper, is an electrical conductor, and when the papers 2 and 4 are burnt out, there is a gap between the flow guide 1 and the die 3, and between the die 3 and the backer 5.
Since there is a surface contact between the flow guide 1 and the die 3 and between the die 3 and the backer 5, there is an electrical surface contact between the flow guide 1 and the die 3 and the backer 5. Therefore, local heat is greatly reduced, flow guide 1, dice 3, backer 5
is heated evenly.

2 to 4 show modifications of the sheets 2 and 4 of FIG. 1, and as shown in FIG.
As shown in FIG. 3, it may be a frame-shaped paper 11, and as shown in FIG. 4, it may be a donut-shaped uneven paper 12.

[Effect of idea]

According to the present invention, even if the extrusion tool is preheated by the induction heater, the local heat is suppressed and the extrusion tool is not damaged, thereby significantly reducing the number of defects in molded products. In addition, since ordinary paper only needs to be inserted between the flow guide, die, and backer, there is little increase in work man-hours, and after extrusion molding, the carbide from the paper can be easily removed by ordinary die cleaning. , the increase in costs is also extremely small.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of an extrusion molding apparatus according to an embodiment of the present invention, and FIGS. 2 to 4 are perspective views showing modifications of the paper shown in FIG. 1, respectively. 1... Flow guide, 2... Paper, 3... Dice, 4... Paper, 5... Backer, 10... Paper, 1
1... paper, 12... paper.

Claims (1)

[Scope of utility model registration request] In an extrusion molding apparatus in which a flow guide, a die, and a backer are arranged coaxially and adjacent to each other, electrical insulation is normally provided between the flow guide and the die and between the die and the backer, and the flow guide , an extrusion molding device in which the die and the backer are each interposed with paper that carbonizes when heated simultaneously with an induction heater.