KR19990077295A - Press apparatus heating device, press using the same and product manufacturing method using the press - Google Patents

Abstract

The heating device of the press mechanism 4 mounted in a press 3 for producing a product made entirely or partly of plastics or composites comprises a core 1 made of an electrical steel sheet, a coil arrangement disposed around the core 1 (9, 10, 11) and the voltage source 12. The voltage source 12 is connected to the coil arrangement 9, 10, 11 to generate a magnetic field inside and around the core 1. The coil 1 comprises two poles 8a, 8b, which receive the press mechanism 4 between the two poles and apply pressure to the press mechanism 4 and press the press mechanism 4. The inner cells are removably positioned relative to each other to induce the generated magnetic field. The press 3 comprises such a heating device, and is used in the manufacturing method in which the press mechanism 4 is heated by a magnetic field to which it is applied.

Description

Press mechanism heating device, press using the same and product manufacturing method using the press

When producing a product made entirely or partially of plastic or composite, a press is used and the press mechanism of the press must be heated. This operation normally occurs by removing the press mechanism from the press and placing the press mechanism in a preheated device such as a furnace to heat it. Such preheated devices are disclosed, for example, in US Pat. No. 5,023,419. Manipulating this press mechanism is very time consuming, which means that the number of finished products per hour is small.

In view of reducing time consumption, a press using a hot plate has been provided, by which the press mechanism is heated in situ within the press. This takes about 10 minutes to heat the 1 Kg press mechanism to a temperature of 200 ° C. by heat conduction from the hot plate to the press mechanism. This is an economically too long time for producing large quantities of parts made entirely or partly of composites.

After heating, the apparatus must be cooled. Such cooling is normally carried out using water, or in the case of instrument inserts made of silicified material, using carbon dioxide which is vaporized to achieve a temperature of about -60 ° C, or using liquid nitrogen. If the cooling operation is slow or difficult to control and the chemical treatment of the composition is not precisely controlled, it is impossible to obtain a quality finished product that meets the criteria.

In the manufacture of products made entirely or partly of composites, current savings have only been possible in the manufacture of expensive parts, because current technology allows only a small part per hour to be produced.

It is an object of the present invention to solve the above-mentioned disadvantages of the prior art, and to provide an apparatus for rapidly and uniformly heating a press mechanism mounted in a press, for example, without having to remove the press mechanism from the press. The heating device must have a simple design, have high manufacturing performance and produce a final product of high and uniform quality.

The present invention also allows for fast, reproducible and economical cooling of the press mechanism mounted in the press after the above-described heating operation.

Another object of the present invention is to provide an energy saving heating device which can be driven using a general circuit voltage.

It would also be desirable to provide a press for producing a product, wholly or partly made of plastic or composites, and a product manufacturing method that satisfies the above-mentioned objects.

According to the invention, the above objects, which become clearer in the detailed description below, can be achieved by the apparatus, the press and the manufacturing method according to claims 1, 10, 11 and 12. Preferred embodiments of the invention are defined in the dependent claims.

The above techniques of the present invention can be easily understood in view of the following detailed description with reference to the drawings. The same parts in the drawings have the same reference numerals.

The present invention relates to heating a press mechanism mounted on a press. More specifically, the present invention relates to an apparatus for magnetically heating a press mechanism directly in a press and for rapidly cooling the press mechanism continuously in the press. The present invention relates to a press and a method for producing a product of plastics or composites in whole or in part.

1 is a cross sectional view of a first embodiment of the present invention in which a pole of a core is recessed in a press mechanism;

FIG. 2A is a cross-sectional view of a second embodiment of the present invention in which the press mechanism comprises a plate having an instrument insert; FIG.

FIG. 2B is a cross sectional view taken along line B-B in FIG. 2A;

3 shows a third embodiment in which the press mechanism has an instrument insert made of a gas penetrating material;

4 shows a fourth embodiment in which the magnetic core consists of two movable horizontal plates in contact with two fixed vertical plates.

FIG. 5 shows a fifth embodiment of the present invention using two pole coils each surrounding a pole arranged in the instrument; FIG.

1 shows a heating device according to the present invention, in which the heating device comprises a core 1 of any suitable magnetic material, such as a thin piece of package made of electrical sheet steel as used in a transformer core. ). The core 1 is mounted between the mutually movable jaws 2a and 2b in the press 3 and is positioned against them. A press mechanism 4 consisting of two half halves is located within the periphery of the core 1. Each bisected half comprises at least a clamshell portion 5a made of metal and an outer layer 5b made of an electrically nonconductive ceramic material. The instrument 4 is suitable for receiving the workpiece 6, which is made of a material arranged in the instrument or injected under pressure.

The core 1 is in the form of a box with an open end and consists of two parts 7a and 7b which are joined together and movable with respect to each other. The core 1 has two opposing protrusions 8a and 8b therein, which protrude into half of the mechanism and form a magnetic pole when the heating device is activated. The first coil 9 is arranged around one narrow side of the core 1, and the second coil 10 is arranged around the other narrow side facing the core 1. The third coil 11 is arranged inside the coil 1 around the mechanism 4. The coils 9-11 are connected in series and are connected to a voltage source 12, the voltage warp being single phase and operating using zero electrical mains, for example providing 200 V at 50 Hz. . Alternatively two or three phases can be used, which are described in detail below.

The press mechanism 4 has a cooling duct 13 in the outer layer, which cooling duct is designed to pass through a liquid or gaseous utility medium having a lower temperature than the mechanism 4. Heat is conducted from the apparatus 4 by heat conduction, and the apparatus 4 is cooled. Preferably, a heat exchanger 14 is used, on the first side of the heat exchanger a coolant such as, for example, gaseous carbon dioxide having a temperature of −65 ° C. is delivered, and on the second side, for example, lubricant and The same utility medium is delivered.

The press 3 of the present invention operates in the following types. A first material, such as a polymeric material, preferably a thermoplastic, so-called glass fiber tissue impregnated with a resin prepreg, is applied into the press mechanism 4, and the fastening devices 2a, 2b are then pressed against each other. do. As a result, parts 7a and 7b of the core 1, poles 8a and 8b and half of the instrument are also activated by applying a voltage to the coils 9-11, which coils are internal to the core 1 The magnetic field is induced into the circuit formed by the vortex mechanism 4 and also appears in a predetermined region outside the core 1. The magnetic field generated by the coil 9-11 and induced through the core 1 is induced into the apparatus 4, where it cooperates for heating due to the magnetic field. The magnetic field outside the coil 1 heats many of the peripheral metal parts of the appliance 4 using induction. Since high frequencies tend to cause large losses in the core, using a relatively low frequency, preferably an applied voltage at a frequency of 16 to 500 Hz, satisfactory penetration depth and therefore uniformity of the instrument inside the instrument One heating is obtained. The frequency shall be adapted to the thickness of the apparatus. If a transmission depth of about 2 cm is required, a frequency of about 25 Hz is used. As described below with reference to FIGS. 2A-2B, if the instrument has an insert made of silicified material for the purpose of passing a gas formed during processing of a workpiece or used for cooling the instrument The frequency should be adjusted appropriately so that the negative degree is also heated to a uniform temperature.

The apparatus of the present invention can be used for heating and pressing treatment of a plurality of composition materials. In addition to the above-mentioned resin penetration processing agent, the workpiece 4 consists of a combination of a thin film made of, for example, a fiber fiber and a polymer material or a compound of ground fiber, a thermoplastic material and a filler. Alternatively, the workpiece may comprise a prefabricated fibrous body, which is placed in the instrument, on top of which the liquid plastic material of thermosetting plastic, such as polyurethane or epoxy, is injected into the instrument. In this case, the workpiece is generally not cooled immediately after the treatment in the pressurization but is postcure in a separate furnace.

For example, compared to a heating time of about 60 minutes under the same conditions using conventional techniques of heating through a hot plate mounted in a press, for example, the environment shown in FIG. It can be heated to 200 ° C. in about 5 minutes. With the apparatus of the present invention, the apparatus can then be cooled to 40 ° C. in about 2 minutes. Since a processing time of about 2 minutes is used per workpiece, eight workpieces per hour can be fabricated by the present invention.

As a result, an embodiment is constructed using a 1 Kg press mechanism constituting a clamshell portion having a wall thickness of about 2 cm. The poles of the core are recessed in an electrically nonconductive ceramic outer layer into the connection with the clamshell portion. Cooling The outer layer consists of a cooling coil. A thin film of polypropylene-infused glass fiber tissue is positioned between the clamshell halves, which are adjacent the half halves. By using the apparatus of the present invention, the appliance can be heated in about 5 seconds directly to about 200 ° C. in a press, and the plastic material melts to form a surface layer for the appliance surface coated with a suitable release agent. After about 20 seconds have elapsed at the treatment temperature, the instrument is cooled to 40 ° C. within 10 seconds through a cooling coil with carbon dioxide. As a result, the final product is removed and new material is provided to the instrument. Thus, up to 120 workpieces per hour can be processed. Using conventional techniques, only about six workpieces per hour can be processed in the same instrument.

According to the second embodiment shown in FIG. 2A, the instrument 4 comprises two plates 15a, 15b coupled to the non-conductive ceramic outer layer 5b. The poles 8a, 8b of the core 1 extend through the outer layer 5b and are in contact with the plates 15a, 15b. The magnetic field induced through the core 1 is also induced through the plates 15a and 15b. Since each plate 15a, 15b forms a second winding of one turn each, the plates 15a, 15b are also heated by the magnetic field. The external magnetic field from the coil 11 heats the peripheral portion of the instrument 4 and the plates 15a and 15b by induction response.

Each of the plates 15a, 15b has an insert for instrument inserts 16a, 16b made of a material that allows gas to pass from the workpiece, and the instrument inserts 16a, 16b and the workpiece 6 to cool. Gas is used. The plates 15a, 15b are provided with cooling ducts (not shown) for fast and reproducible cooling of the plates 15a, 15b and thus the workpiece 6.

If the outer layer 5b is made of a conductive material, only the plates 15a and 15b are heated, not the outer layer, when the coil 9-11 is activated. This can be accomplished by designing each outer layer 5b so as not to form a second winding, as shown in FIG. 2B.

FIG. 3 shows a third embodiment comprising gas-penetrating instrument inserts 16a, 16b mounted recessedly within the instrument half. The poles 8a, 8b of the core 1 extend in contact with the instrument inserts 16a, 16b through half of the instrument half. When the coils 9-11 are activated, the instrument inserts 16a, 16b are heated to processing temperatures quickly and uniformly.

4 shows a fourth embodiment of the present invention, wherein the core 1 consists of four plates 17a, 17b, 17c, 17d, of which two plates 17a, 17b are presses It is arranged to be movable in contact with the fixing device 2a, 2b of (3), and the two plates 17c and 17d are arranged to be fixed perpendicularly to the movable plates 17a and 17b. Thus, the instrument half halves can be pressed against each other by the press 3 during the work of the workpiece, while the magnetic field is induced in the core 1 independent of the thickness of the workpiece 6.

In the above-described embodiment, the pawls 8a and 8b protrude into the mechanism 4 and are preferred in most cases because the height of the heating device is minimized. 5 shows a fifth embodiment in which the pawls 8a and 8b are arranged opposite the outside of the instrument 4. This arrangement can be used, for example, when the instrument 4 is relatively thick and includes the clamshell instrument part 5a without any ceramic outer layer.

The coil arrangement of FIG. 5 further comprises two pole coils 11a, 11b arranged around the poles 8a, 8b, respectively. This coil arrangement allows the pole coils 11a and 11b to be adjacent to the instrument 4 for optimized heating of the instrument 4. The range of coils 11a and 11b should be suitable for the range of the instrument 4. It can be seen that the coils 11a and 11b are arranged adjacent to the press mechanism 4, preferably at a distance of a predetermined centimeter or less. If the coils 11a and 11b are arranged in the connection with the press mechanism 4, the loss is drastically reduced.

It should be emphasized that the present invention generally has the additional advantage of allowing rational fabrication of structures made of plastic or composites including metal inserts, such as reinforcing tubes. The metal insert is heated by an applied magnetic field. This is rarely achieved using conventional techniques.

A further advantage of the present invention is that the magnetic field generates vibrations in the press mechanism and the vibrations result in increased heat transfer, thereby reducing the occurrence of bubbles in the workpiece.

In all the embodiments described above, the core 1 surrounds the press mechanism 4. This is useful because the enclosed core 1 forms a cage which holds most of the generated magnetic field, which is concentrated adjacent to the press mechanism 4 by means of a pole to heat the press mechanism. It is also to be considered to design the core 1 so as to surround only part of the press mechanism 4. However, in this case, power consumption increases, and loss also increases.

The press mechanism 4 is heated by a magnetic field concentrated therein. In addition, the pole coil 11 inductively heats the periphery of the press mechanism 4. Eddy currents around the contact surface between the poles 8a, 8b and the instrument 4 also result in some heating of the instrument.

In the illustrated embodiment, the protrusions or pawls 8a, 8b are in direct contact with the clamshell portion 5a, the plates 15a, 15b or the instrument inserts 16a, 16b. This forms a mutual short-circuit consisting of a thin piece of steel sheet in the core, which causes loss and high power consumption. Thus, the instrument 4 comprises a thin insulating material arranged between the poles 8a, 8b and the shell portion 5a, between the plates 15a, 15b or the instrument inserts 16a, 16b. desirable.

It is contemplated that the coil arrangement 9-11 can be varied within the scope of the present invention. For example, the core coils 9, 10 may be arranged around the core 1 in slightly different forms. Multiple core coils may be used. Furthermore, multiple pole coils 11a and 11b can be used, for example, around each pole 8a and 8b of the core 1. It is also conceivable to use only pole coils or alternatively only core coils.

The relative arrangement of the poles 8a, 8b can be made in a somewhat different way. For example, the protrusions forming the pawl may be movably positioned with respect to the remaining core 1 and may be in contact with the fixing devices 2a, 2b of the press 3. The pressure exerted by the fixing devices 2a, 2b is thus transmitted directly to the press mechanism 4 via the pawls 8a, 8b.

According to a preferred embodiment (not shown), the press has three heating devices connected to a common voltage source and each using a single phase. It is also conceivable to arrange an optional number of individually controllable heating devices in one same press, each of which heats a portion of one or more of the press mechanisms extending through the heating device.

It is also possible to provide a core to a heating device having a plurality of protrusions or poles arranged in pairs, and to arrange one or more pole coils around each pair of poles. For example, a core may have three pairs of poles associated with a pole coil, each using a single phase common voltage source.

It is understood by those skilled in the art that the present invention is illustrated and described with reference to the preferred embodiments, and that various changes and modifications can be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (14)

Apparatus for heating a press mechanism (4) mounted on a press (3) for producing a product made in whole or in part made of plastic or composites, Cores 1 made of electrical steel, coil devices 9, 10 and 11 located around the core and coil devices 9, 10 and 11 for generating a magnetic field in and around the core 1. Includes a voltage source 12 connected to The coil 1 has two poles 8a, 8b, which receive the press mechanism 4 at least partially between themselves and apply pressure to the press mechanism 4 and the magnetic field. Apparatus characterized in that they are detachable from one another in order to direct the generated magnetic field into the press mechanism (4) in such a way as to heat the press mechanism (4). Device according to claim 1, characterized in that the core (1) surrounds the press mechanism (4). 3. The method according to claim 1 or 2, comprising two core coils (9, 10), the core coils (9, 10) wherein the magnetic field generated by the core coils (9, 10) is the press mechanism. Arrangements around each part of the core (1) in such a way that they cooperatively act in the region of (4). Apparatus according to one of the preceding claims, characterized in that the pawls (8a, 8b) are recessed in the press mechanism (4). 5. The device according to claim 1, comprising at least one pole coil (11) arranged around the poles (8a, 8b). 6. Device according to one of the preceding claims, characterized in that the press mechanism (4) has at least one instrument insert (16a, 16b) made of a gas-penetrating material. 7. Device according to claim 6, characterized in that the instrument insert (16a, 16b) contacts at least one of the pawls (8a, 8b). Device according to one of the preceding claims, characterized in that a cooling duct (13) is formed in the press mechanism (4) for the coolant to pass through. 9. The core (1) according to any one of the preceding claims, wherein the core (1) comprises four additional poles (8a, 8b) formed in pairs and at least one connected to a voltage source (12) of separate phases. Device, characterized in that a pole coil is assigned to each pair of poles (8a, 8b). Press for producing a product made entirely or partially of plastic or composite, comprising the heating device according to claim 1. 10. A press for producing a product made entirely or partially of plastics or composites comprising the three heating devices according to claim 1. The heating devices are each characterized by using a single-phase common voltage source (12). Providing the initial material to the press mechanism 4 arranged in the press, Applying pressure to the press mechanism 4 using the press 3, Heating the press mechanism and A method for producing a product made entirely or partially of plastic or composite, comprising cooling the press mechanism 4 after a processing time, And wherein said heating occurs by introducing a magnetic field into said press mechanism. 13. A magnetic field as claimed in claim 12, characterized in that the magnetic field is generated by applying a voltage across the coil arrangement (9, 10, 11) arranged around the core (1) made of a magnetic material surrounding the press mechanism (4). Device. Apparatus according to claim 12 or 13, characterized in that the initial material consists of a prefabricated fiber body arranged in the press mechanism (4) and a plastic material injected into the press mechanism (4).