JPH0217862Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a magnetic field injection molding machine for molding a magnetic plastic product into a desired shape by mixing a powdered magnet into a thermoplastic resin.

[Technical background of the invention and its problems]

Recently, many magnetic plastic products are being used, which are made by mixing powdered magnets into thermoplastic resin and molding them into desired shapes, such as door sealing magnets that are attached to the opening edges of refrigerators, and self-adhesive buttons for various display purposes. It's starting to become easier.

The above-mentioned powder magnets usually contain about 90% by weight of thermoplastic resin, but when injection molded with a general injection molding machine, the arrangement of the powder magnets becomes uneven in the thermoplastic resin press-fitted into the mold. , after becoming a magnetic plastic product, its function as a magnet will not be fully demonstrated.

Therefore, when molding the thermoplastic resin containing the powdered magnet, a magnetic field is applied to the mold to align the polarity of the powdered magnet while the resin injected into the mold is in a molten state, and then solidified. When taking out the magnet, the direction of the magnetic field is reversed to demagnetize it.

As schematically shown in FIG. 4, the conventional magnetic field forming means described above has a plurality of tie bars 2, 2... Coils 7,
8 is provided, and by energizing the coils 7 and 8, a magnetic field is formed in the mold sandwiched between the movable plate 6 and the fixed plate 4 through the tie bars 2, 2, .

By the way, in the above-mentioned conventional magnetic field injection molding machine, the configuration of the carp mounting part is as shown in FIG.
The coils 7 and 8 are supported by the fixed plate 4 and the movable plate 6 by holding members 9 and 10.

However, it is inevitable that the coils 7 and 8 will have a large variation in the A dimension due to restrictions on product accuracy during manufacturing. For this reason, in the past, the above-mentioned A dimension was made slightly smaller and installed, but according to this, each time the coils 7 and 8 are excited, the fixed plate 4, the movable plate 6, 4a surface, 6a This has the disadvantage that the coil life is significantly shortened due to the strong collision with the surface and wear of the sliding surface.

[Purpose of invention]

In view of this, the present invention was developed with the aim of eliminating the above-mentioned drawbacks of the prior art, and is designed to prevent coil movement, eliminate damage caused by coil collisions, and always form a predetermined magnetic field. The present invention provides a magnetic field injection molding machine.

[Summary of the idea]

In order to achieve the above object, the present invention connects fixed plates fixed at intervals on a base with tie bars, and a mold clamping cylinder is connected to the tie bar between these fixed plates to connect the mold to one fixed plate. In an injection molding machine, a movable plate is movably provided to clamp and hold the coil, and a coil for forming a magnetic field is wound around the movable plate and the fixed plate. It is characterized by a heat-resistant packing interposed between the coil holder and the coil holder made of material.

[Example of idea]

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 3.
The same reference numerals are given to the same members as those in the figure and FIG. 5 for explanation.

FIG. 1 shows a partially sectional front view of an embodiment of the present invention, in which a fixing plate 3 is mounted on a base 1.
is fixed on the base 1, and another fixed plate 4 is fixed on the support seat 11 fixed on the base 1 at a distance from this fixed plate 3, and these fixed plates 3,
Multiple pieces between 4 (usually 4 pieces, 2 pieces above and below each side)
Tie bars 2, 2... are fixed.

A movable plate 6 and a mold mounting plate 12 are slidably supported by the tie bars 2, 2, . fixed plate 4 by driving the mold clamping cylinder 5.
The mold is held under pressure between the movable plate 6 and the movable plate 6.

Coils 7 and 8 are wound around the coil mounting portions 4b and 6b of the fixed plate 4 and the movable plate 6, and on the outer side of these coils 7 and 8, there is a coil made of a non-magnetic material and forming a mold mounting surface. Presser foot 9,1
0 is appended.

In the present invention, a heat-resistant packing 13 is interposed between the coil 7 and the coil retainer 9, as shown in FIG. 3, which is an enlarged cross-sectional view of the fixing plate 4 side. The moving plate 6 side is similarly configured.

In addition, in Fig. 1 and Fig. 2, 14, 14
is a magnetic member made of a material with high magnetic permeability that magnetically connects the left and right upper portions of the fixed plate 4 and the movable plate 6;
4 and 14 are fixed to the fixed plate 4, and can be slid on the movable plate 6 on the movable plate 6 side. Further, in order to more securely support the magnetic members 14, 14, a gate-shaped or horse-clamped support frame 15 is established on the base 1 as shown in the second figure, and this support frame 1
The magnetic members 14, 14 can be insulated and supported by the magnetic members 14, 14.

The support seat 11 is also made of a magnetic material, and the lower part of the movable plate 6 is slidably moved on the support seat 11. Numerals 17, 17, and 17 are dowel pins for extruding the product from inside the mold, and 18 is an injection port for supplying molten resin into the mold.

Next, the effect will be explained.

A mold is inserted between the fixed plate 4 and the movable plate 6, the mold is clamped by the movable plate 6 by driving the mold clamping cylinder 5, and then the powder magnet is introduced into the mold from the injection port 17. The molten resin is press-fitted by an appropriate supply means.

At the same time, when the coils 7 and 8 are energized, the magnetic members 13 and 13 connecting the fixed plate 4 and the movable plate 6 and the support seat 9 made of magnetic material
A magnetic field is formed through the mold, and when this magnetic field passes through the mold, a magnetic field is formed, which aligns the powder magnets in the molten resin in the mold in a certain direction and magnetizes them.

After the molten resin has solidified, the moving plate 6 is returned and the product is protruded by the dowel pin 16 and collected. This results in a magnetic plastic product in which the polarity of the powder magnets is aligned.

In the above action, when the coils 7 and 8 are energized and excited, even if the coils 7 and 8 try to move,
Since heat-resistant gaskets 13 and 13 are interposed between the coil holders 9 and 10 and the coils 7 and 8, they are held down without moving, so that the coils 7 and 8 do not collide with the fixed plate 4 or the movable plate 6. The coils 7 and 8 are prevented from being damaged and the coil life can be greatly extended, and a strong magnetic field can always be generated.

Note that, as in the illustrated embodiment, if the fixed plate 4 and the moving plate 6 are connected by magnetic members 14, 14 and the support seat 11 is made of a magnetic material, the magnetic field is transmitted to the magnetic member 1 with high magnetic permeability when the magnetic field is formed.
4, 14 and the support seat 11, a strong magnetic field is formed and the alignment of the powder magnets can be further improved.

[Effect of idea]

As explained above, the present invention connects fixing plates fixed at intervals on a base using tie bars, and uses a mold clamping cylinder between the tie bars between these fixing plates to connect the mold to one of the fixing plates. In an injection molding machine, a movable plate is movably provided to clamp and hold the coil, and a coil for forming a magnetic field is wound around the movable plate and the fixed plate. Since a heat-resistant gasket is interposed between the coil holder made of aluminum, the coil does not vibrate and collide with the fixed plate or moving plate when electricity is applied to the coil, preventing damage to the coil and extending the life of the coil. It can be extended to a wide width.
Furthermore, since the packing is made of a heat-resistant material, it has the advantage that the heat generated by the coil does not cause wear and tear due to the heat of the mold.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view showing an embodiment of a magnetic field injection molding machine to which the present invention is applied, Fig. 2 is a side view of the same, Fig. 3 is an enlarged sectional view of the main parts, and Fig. 4. 5 is a schematic front view of a conventional magnetic field injection molding machine, and FIG. 5 is an enlarged view of the coil section thereof. 1... Base, 2... Tie bar, 3, 4... Fixed plate, 5... Mold clamping cylinder, 6... Moving plate, 7, 8... Coil, 9, 10... Coil holder, 11... Support Seat, 13...Heat-resistant patchkin.

Claims (1)

[Scope of utility model registration request] Fixed plates fixed at intervals on the base are connected by tie bars, and a movable plate that clamps and holds the mold between one of the fixed plates can be moved to the tie bar between these fixed plates using a mold clamping cylinder. In an injection molding machine in which a coil for forming a magnetic field is wound around the movable plate and the fixed plate, there is a heat-resistant coil between the coil and a coil holder made of a non-magnetic material that presses the coil. A magnetic field injection molding machine characterized by interposing a magnetic seal.