JPS6324811B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous extrusion molding apparatus for hollow products using a thermosetting resin as a molding material.

Conventionally, in plunger-type extrusion molding equipment for thermosetting resin, molding material powder supplied from a hopper is extruded by a plunger into a die that is externally heated by a heating device, and the hardened resin is chrome-plated or nickel-plated. The material is extruded by pressure that overcomes the frictional resistance between the inner surface of the die and the resin. Since the plunger is fed into the die while having an internal cross-sectional area that is approximately the same as that of This has caused problems such as the supply amount of molding material becoming unstable and continuous piston movement of the plunger being obstructed.

For this reason, in Japanese Patent Publication No. 52-17057,
In order to solve this problem, we have developed a cylinder in which a thermosetting resin material is extruded using a plunger, and a cylinder that is connected to the tip of the cylinder, has an internal cross-sectional area smaller than the cross-sectional area of the plunger, and has an inner cross-sectional area at the inlet. and a die with a heating means that gives a predetermined product outer shape with a tapered surface formed thereon, and the predetermined product is continuously extruded from the die while heating and hardening the resin material by the extrusion action of the plunger. A device for molding has been disclosed. By adopting such a structure, the molding material is not only compressed and hardened only in the axial direction of the cylinder, but also the cross section suddenly becomes smaller after exiting the cylinder and at the entrance to the die. , the material pushed by the plunger will be compressed in the radial direction, thus creating a shearing action that will separate the molding material stuck to the tip of the plunger, making the supply of said molding material unstable. This made it possible to effectively solve the problem.

However, even in a device with such a structure,
There are still some problems to be solved when extruding hollow products. That is, such equipment generally adopts a horizontal equipment configuration in which a die and a cylinder are connected horizontally, and a mandrel or the like for forming a hollow product extending from the cylinder side into the die is concentric. The mandrel has a structure in which the extrusion molding operation of a predetermined thermosetting resin powder is carried out, but such a mandrel cannot be supported at both ends, and is simply supported at the end on the cylinder side. Because of the holding structure, it is very difficult to set such a mandrel horizontally and concentrically with the die, and this causes uneven thickness of the product due to the eccentric arrangement of the mandrel. It has inherent problems.

In addition, the hollow product extruded from the die is pulled out horizontally, but gravity acts on such horizontal parts, and this tendency exists even if the extruded product is supported by guide rollers in front of the die. However, this was one of the causes of deteriorating the dimensional accuracy of the product.

Furthermore, in an apparatus having such a structure, since the resin material is simply melted by heating from the outside of the die, there is an uneven flow of molten resin between the mandrel side and the inner side of the die. This caused uneven curing on the inner and outer surfaces of molded hollow products, and the fluidity of the molten resin was also poor, making it difficult to quickly and stably obtain hollow products of uniform quality. This was difficult.

The present invention has been made against this background, and its purpose is to produce hollow products of uniform quality and excellent dimensional stability at high speed and in a stable manner. An object of the present invention is to provide an apparatus capable of extrusion molding.

In order to achieve such an object, the present invention provides a cylinder configured to extrude a thermosetting resin material using a plunger, and a cylinder that is connected to the lower end of the cylinder and has an inner cross-sectional area smaller than the cross-sectional area of the plunger. and a die with a heating means that gives a predetermined product external shape and has a tapered surface formed at the inlet part, and are coaxially connected and arranged so that their axes are substantially perpendicular, and A mandrel is provided that extends concentrically from the cylinder into the die, and by the extrusion action of the plunger, the resin material is heated and cured while a predetermined hollow product is continuously formed through the gap between the die and the mandrel. In the extrusion molding apparatus, a predetermined second heating means is provided in the mandrel, and the second heating means is located at least in a portion corresponding to the tapered surface forming portion of the die entrance portion. It was placed in the

As described above, according to the present invention, the extrusion device has a vertical structure in which the cylinder and the die are arranged in a substantially vertical direction, and the second heating means is provided in the mandrel, and the heating means around the die is heated. They work together to heat the resin material, and as a result, the resin material pushed from the cylinder into the die is heated from the outside as well as from the inside, so it is heated from the inside. This makes it possible to easily melt and fluidize the resin material, and to make the flow of the molten resin a laminar flow (relative flow). As a result, it was possible to effectively suppress the occurrence of curing unevenness on the inner and outer surfaces of the obtained hollow product, and it became possible to extrude a homogeneous hollow product at high speed. Since the product is also taken out in the downward direction, it is easy to achieve straightness, and problems such as uneven thickness and curvature of the product caused by the action of gravity or eccentricity of the mandrel can be effectively suppressed. This made it possible to improve accuracy.

Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail based on the drawings.

First, in FIG. 1 showing one embodiment of the present invention, a press lower plate 12 mounted on a base 10 is shown.
A die (die cone) 16 having a heating device 14 around it is disposed so as to have a substantially vertical axis, and a cylinder 18 is concentrically disposed above the die 16, and its flange portion is connected to the die 16 by tightening the bolt 20. Note that the inner cross-sectional area (inner diameter) of the cylinder 18 is the same as that of the die 16.
The inner cross-sectional area (inner diameter) of the molding cylinder 18 is larger than the inner cross-sectional area (inner diameter) of the molding cylinder 18, and a tapered surface 22 is formed at the die inlet that becomes the connecting part with the cylinder 18. Dice 1
It is configured so that the diameter changes smoothly to the inner diameter of 6. Further, the cylinder 18 includes a fluid chamber 24 in the circumferential direction inside the wall thereof, and a predetermined temperature regulating fluid is supplied through the temperature regulating pipe 26 and circulated and distributed within the fluid chamber 24. The resin material supplied into the cylinder 18 can be cooled or preheated.

A plunger 28 is fitted into the cylinder 18 so as to be slidable in the vertical direction.
Further, the upper end of the plunger 28 is attached to a mounting frame 32 that is moved up and down by a hydraulic cylinder 30.
It is attached to the plunger mounting board 34 of. The vertical movement of the plunger mounting plate 34, in other words, the mounting frame 32, is performed by the press lower plate 1.
2 and the press upper plate 36
It is adapted to be guided by a guide member 39 that slides at 8.

Further, the mandrel 40 is attached to and hangs down from a support frame 42 whose upper end is fixed to the press upper plate 36 fixed to the upper part of the post 38, and the plunger mounting plate 34 and the plunger 28 are arranged concentrically. slidably penetrate through the
Extends into the mold. That is, the mandrel 40 extends concentrically from within the cylinder 18 into the die 16 and extends forward a predetermined distance through the outlet of the die 16.

Further, the mandrel 40 has a hollow structure, and a heating device (second) is installed at a predetermined position inside the mandrel 40.
44 are provided. That is, the heating device 44 is disposed within the mandrel 40 with a predetermined length so as to include a portion corresponding to the tapered surface 22 formed at the entrance of the die 16 and extend from there to the die exit side. External power supply 4
By heating the mandrel 40 from the inside by supplying power from the die 16, heat can be supplied from the inside to the resin material that is compressed and melted at the inlet of the die 16.

In order to supply a thermosetting resin (usually used in pellet form) 48 as a molding material into the cylinder 18, such as phenol resin, melamine resin, urea resin, epoxy resin, diallyl phthalate resin, etc. At the top of the cylinder 18, two material input devices 50 are arranged facing each other. This material input device 50 includes a hopper 52
, a supply cylinder 54 and a piston 56 , and the thermosetting resin 48 in the supply cylinder 54 dropped and supplied from the hopper 52 is extruded by the piston 56 , which is caused to reciprocate and slide within the supply cylinder 54 . By the action,
It is adapted to be charged into the cylinder 18 through an input port 58 at the top of the cylinder 18 (formed oppositely around the cylinder 18 in correspondence with the material input device 50).

The hollow product 60, which is formed by being melted and hardened between the die 16 and the mandrel 40, and is pulled out downward from the outlet located at the lower part of the die 16, is cut into a predetermined shape by a cutter or the like (not shown). cut to length and taken out device 6
It is designed to be taken out by 2.

Therefore, in the extrusion device having such a configuration, a predetermined thermosetting resin 48 is supplied into the cylinder 18 from the material input device 50, and the hydraulic cylinder 3
The resin material 48 is compressed and fed into the die 16 by the extrusion action of the plunger 28 operated by the 0. The heat from the heating device 14 is applied to the resin material 48.
, and the tapered surface 22 at the entrance of the die 16
An internal heating device 44 disposed within the mandrel 40 corresponding to the forming section provides effective internal heating of the resin material 48 being compressed in the compression zone at the entrance of the die 16. This effectively causes such resin material 48 to be melted, fluidized, and cured while traveling through die 16 so that a given hollow article 60 can be bonded between die 16 and mandrel 40. It ends up being pushed out through the gap between the two.

According to this configuration, the resin material 48 compressed at the inlet of the die 16 can be accessed from the outside by the heating device 1 provided on the die 16.
4 and from inside the mandrel 40
By the heating device (second) 44 provided inside,
By heating, the resin material 48 located inside the mandrel 40 is effectively melted and fluidized, and the flow of the molten resin is made into a laminar flow (inside and out) as shown in FIG. This made it possible to effectively eliminate the curing unevenness on the inner and outer surfaces of the resulting hollow product 60, thereby making it possible to mold a homogeneous hollow product.

FIG. 3 also shows the resin surface temperature on the die 16 side when extrusion is performed in the case (A) where the heating device 44 is provided in the mandrel 40 and the case (B) where it is not provided. The results of the resin surface temperature on the mandrel 40 side are shown.
In the case where the heating device 44 is disposed inside 0,
The resin temperature on the mandrel 40 side is significantly raised (see solid line A), which effectively increases the fluidity of the molten resin and therefore enables high-speed molding. Incidentally, according to the inventor's experiments, the mandrel 40
In the case where the heating device 44 is not provided in the interior, the extrusion molding speed is approximately 2.0 to 2.5 m/Hr at most, whereas in the case where the heating device 44 is provided,
Extrusion speeds of 5.0-7.0 m/Hr could be achieved. In addition, when performing such high-speed molding, in order to improve the dimensional accuracy of the hollow product 60 obtained, the axial length of the die 16 is increased to maintain a dimensional stability range compatible with the high speed. It is recommended to provide one.

Further, according to this configuration, the mandrel 40
The mandrel 40 and the die 16 are not arranged in a horizontal cantilevered structure as in the past, but only need to be hung down, so that the concentricity between the mandrel 40 and the die 16 is maintained well, and the die 16 and the mandrel 40 are The hardened hollow product 60 extruded from between the holes does not have uneven thickness, and furthermore, the hollow product 60 to be molded does not fit into the die 16.
Since the hollow product 60 naturally comes out downward and is taken up by a take-up roller or the like, gravity that causes bending does not act on the hollow product 60, thereby effectively maintaining its straightness. It became possible. Incidentally, the hollow product obtained by the apparatus according to the present invention has a roundness of 0.02 and a cylindricity of 0.02.
0.05, and the straightness was obtained as a result of 0.05mm/500.

In this exemplary device, the thermosetting resin 48 is supplied into the cylinder 18 by two material input devices 50 and 50 provided around the cylinder 18 at an equal distance. The resin material 48 is spread more evenly around the mandrel 40 within the cylinder 18 as it is designed to be done.
There is an advantage that the resin material 48 can be thrown in, and moreover, during such charging, the falling of the resin material 48 is caused by the mandrel 40.
There is nothing that can prevent you from doing so.
The resin material 48 charged in this way and evenly accumulated in the cylinder 18 from below is evenly distributed into the die 16 by the extrusion action of the plunger 28.
It becomes pushed to the side.

Next, another embodiment of the present invention will be described based on FIG. 4, in which the same parts as in the previous example are given the same numbers and detailed explanation will be omitted.

The apparatus shown in FIG.
There is a significant difference in shape from the previous model. That is, the mandrel 66 is the die 1
At a position corresponding to the tapered surface 22 forming portion of the inlet portion of the die 1, the portion transitioning from the small diameter portion on the cylinder 18 side to the large diameter portion on the die 16 side is
A heating device (second) 44 is disposed within the mandrel 66 corresponding to the position where the tapered surface 68 is formed.

According to the structure of the mandrel 66 of this embodiment, the resin material 4 pushed in by the plunger 28
8 is compressed from the outside by the tapered surface 22 at the entrance of the die 16, and is also compressed from the inside on the mandrel 66 side by the tapered surface 68 provided on the mandrel 66. At the same time, it is melted and fluidized by the heating action from the outer heating device 14 and the inner heating device 44, but by forming the tapered surface 68 on the inside in this way, the melting along the mandrel 66 is This effectively eliminates the delay in resin flow, or in other words, effectively improves the flow unevenness on the resin surface, resulting in uniform curing and even higher quality. It becomes possible to obtain a good hollow product.

In the devices of these embodiments, the inner heating device 44 is disposed within the mandrel 40 or 66 at a portion corresponding to the portion where the tapered surface 22 is formed at the entrance portion of the die 16;
It is also arranged to extend a predetermined length from the inlet portion of the die 16 toward the outlet portion thereof, so that the melting, curing, and molding operations of the resin material 48 can be performed more effectively. Although it is most common to insert an electric heating device as illustrated in the mandrel as the heating device 44, it is also possible to arrange a heating means of other structure in place of this. There is no harm in trying to force him to do so.

Furthermore, the material input device 50 provided around the cylinder 18 may be provided in one or more than two pieces as in the above example; 50 are arranged around the cylinder 18 at equal intervals, there is an advantage that the predetermined resin material 48 can be evenly charged into the cylinder 18, and the structure of the material charging device 50 also has the advantage that: It is possible to adopt various material charging structures in addition to the above example.

In addition, various modifications, changes, improvements, etc. may be made to the present invention based on the knowledge of those skilled in the art without departing from the spirit of the present invention, and such forms may also be modified. It goes without saying that the present invention is included within its scope.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an example of an apparatus according to the present invention, FIG. 2 is an enlarged sectional view of the main part illustrating the flow of resin material in such an apparatus, and FIG. 3 is an extrusion It is a graph showing the temperature on the die side and the mandrel side of the resin material to be molded, and FIG. 4 is a front main part sectional view showing another example of the apparatus according to the present invention. 12: Press lower plate, 14: Heating device, 16: Dice, 18: Cylinder, 22: Tapered surface, 28:
Plunger, 30: Hydraulic cylinder, 36: Press upper plate, 40: Mandrel, 44: Heating device, 4
8: Thermosetting resin, 50: Material input device, 52:
Hopper, 54: Supply tube, 56: Piston, 58:
Inlet port, 60: Hollow product, 62: Removal device, 6
6: Mandrel, 68: Tapered surface.

Claims (1)

[Scope of Claims] 1. A cylinder configured to extrude a thermosetting resin material using a plunger, which is connected to the lower end of the cylinder, has an inner cross-sectional area smaller than the cross-sectional area of the plunger, and has an inlet portion. A die with a heating means, which has a tapered surface and which gives a predetermined product outer shape, is coaxially connected and arranged so that their axes are substantially perpendicular, and a die is concentrically arranged from the cylinder into the die. The apparatus is provided with a mandrel extending from the plunger, and is configured to continuously extrude a predetermined hollow product through a gap between the die and the mandrel while heating and hardening the resin material by the extrusion action of the plunger. A predetermined second heating means is provided within the mandrel, and the second heating means is located at least in a portion corresponding to the tapered surface forming portion of the die entrance portion. Extrusion molding equipment for hollow products. 2. A portion of the mandrel located within the die has a larger diameter than a portion located within the cylinder, and a portion of the mandrel corresponding to the tapered surface forming portion of the die inlet has a smaller diameter portion on the cylinder side. 2. The device according to claim 1, wherein a tapered surface connecting the large diameter portion on the die side is formed. 3. The apparatus according to claim 1 or 2, wherein a plurality of material input means are provided around the cylinder, and the resin material is input into the cylinder through the plurality of material input means.