DE102013220097B4 - Forming tool and forming process for this purpose - Google Patents

Abstract

A method for foaming in the heated state foamable and volume-increasing semifinished product (2) in a molding apparatus (1) for producing molded articles, the molding apparatus (1) having a shape with a first mold element (8) and a second mold element (16) and an opening device for opening or closing the mold, wherein the first mold element (8) has a first mold side (10) with a mold shell (12) formed therein for receiving semifinished product (2) or plate material, and one of the first mold side (10). and wherein the second mold element (16) has a second mold side (14) for receiving semifinished product (2) or plate material which is directed towards the first mold side (10) and connected to the first mold side (10 ) defines a mold space (28) when the mold is closed, wherein the first and second mold members (8, 16) are made of quartz glass and the mold apparatus (1) first radiator system (4) having at least one halogen lamp, which is arranged adjacent to the irradiation side (6) of the first emissive element (8), directed to the irradiation side (6) of the first emissive element (8), the method comprising the following steps: a) introducing the semifinished product (2) to be foamed into the mold shell of the first mold element (8) and closing the mold, b) heating the semifinished product (2) to be foamed with the at least one halogen lamp of the first radiator system (4) until the foamed product has melted Semi-finished product (2) completely fills the mold space (28) c) ending the heating, d) opening the mold and removing the foamed semifinished product (2).

Description

The present invention relates to a method of forming semifinished or sheetable material formable in a heated state according to claim 14, and to a method of foaming in the heated state foamable and volume-increasing semifinished product according to claim 1.

Forming devices, also referred to as forming devices, forming tools or forming tools, are commonly used to make shaped articles. They are therefore also referred to as tools or as molds. Such a molding apparatus usually comprises a mold having two mold halves forming a mold top and a mold bottom. In between, a cavity, the so-called mold cavity, is formed in closed mold devices.

To mold the article, the material to be molded is placed between the two mold halves. Then, the mold top formed in the one mold half and the mold bottom formed in the other mold half are moved against each other with a lock mechanism, and the mold is closed. The material, for example a granulate, which is located in the resulting mold cavity is converted by means of chemical and / or thermal and / or printing processes so that its surface assumes the shape of the mold top and the mold bottom of the mold apparatus.

The material may be, for example, a foamable plastic granules, or even a plastic plate, such as a plastic foam plate. Other materials, such as metals, metal granules or melts can also be accommodated and shaped in such molding devices.

Semifinished products made of foam systems cool quickly after being heated. Forming is therefore often possible only with additional tools. Foam granules, such as Rohacell, which is used for "in situ" foaming in a mold, for example, must be heated during forming. In the known forming tools, such heating takes place only from the tool surface. Since the heat conduction in foam materials is often very small, it may therefore happen that a part of the material to be formed on the mold wall already burns while another part of the material to be formed, which is locally further away from the mold wall, does not even reach the temperature has, at which a transformation can take place.

A method and apparatus for making contact lenses discloses the EP 637 490 B1 , The DE 197 05 303 A1 describes a process for the production of small and micro parts from a molding compound. A photopolymerization molding apparatus discloses DE 691 05 306 T2 , The DE 201 05 063 U1 describes an apparatus for producing molded parts and the DE 16 29 283 A describes a method of forming a molded foam article.

The object of the invention is therefore to provide a method which overcomes this disadvantage and ensures a more uniform heating of the material to be formed.

This object is achieved by a method for foaming in the heated state foamable and the volume-increasing semifinished product in a molding apparatus according to claim 1, and by a method for molding in the heated state formable semi-finished or sheet material according to claim 14. Advantageous embodiments are in the dependent claims disclosed.

According to the invention, the molding apparatus for producing molded articles has a mold with a first and a second mold element, as well as an opening device for opening and closing the mold. The first mold element has a first mold side with a mold shell formed therein for receiving semifinished product or plate material, as well as one of the first mold side opposite arranged irradiation side. The second mold member has a second mold side for receiving semifinished or sheet material directed toward the first mold side and defining a mold space with the first mold side when the mold is closed.

The first mold element is made of quartz glass and the molding device has a first radiator system, which is arranged adjacent to the irradiation side of the first mold element, directed to the irradiation side of the first mold element. A material received in the mold space of such a shaping device, such as, for example, granules or plastic particles, can thus be heated directly by radiation emitted by the emitter system and penetrating the quartz glass, without the mold space wall having to be hot. The material to be reshaped can therefore directly absorb the radiation and thereby heat up.

As is known, quartz glass is transparent to radiation between 300 nm and about 2000 nm, so that radiator systems which emit radiation in this wavelength range are advantageously used for heating. The first radiator system therefore has at least one Halogen lamp, which is advantageously designed rod-shaped to illuminate the tool shape in length and to illuminate the material to be formed as completely and uniformly as possible.

The majority of the halogen lamp radiation can, if the halogen lamp is operated at a sufficiently high color temperature, be transmitted through the quartz glass on the material to be formed and thus contributes only slightly to the heating of the mold elements. The thickness of the first element element is therefore advantageously selected such that the predominant part of the energy emitted between 300 nm and about 2000 nm by the first emitter system through the quartz glass of the first emissive element in the direction of the molding space reaches the mold space. The advantage of rod-shaped halogen lamps is that the molding apparatus or the mold is irradiated over its entire length range and therefore the material to be formed is uniformly heated along the mold.

In a preferred embodiment, the first radiator system has a reflector, which reflects at least a part of the radiation of the first radiator system, which impinges on the reflector, on the irradiation side of the first element. In this way, the part of the radiation of the radiator system can be used to heat the material to be formed, which does not hit directly on the irradiation side of the first element element. As a result, a larger part of the radiant energy radiated by the radiator system can be utilized. When using halogen lamps, this means that the material to be heated can be heated with halogen lamps of lower power.

A reflector is to be understood in this document to mean an object which has a reflective material or a reflective coating, wherein a reflective material / a reflective coating is to be understood as a material / coating. A material is said to be reflective when at least 40% of the radiation incident on the material is reflected between 300 nm and 2000 nm. Reflective materials include, for example, highly polished metals or metal coatings of, for example, gold or aluminum.

In one embodiment, the mold shell is milled into the first mold element, wherein the surface of the mold shell is preferably polished. Smooth, polished surfaces typically reflect the radiation impinging thereon more than rough, matte surfaces of the same material. Therefore, when the surface of the shell mold is polished, a greater part of the radiation reaching the mold cavity can be reflected back from the surface of the mold shell back into the mold cavity and thus additionally contribute to the heating of the material to be formed.

On the other hand, in order for the irradiation side of the first element element to reflect only a very small part of the radiation emitted by the first radiator system in the direction of this irradiation side, the first irradiation side is advantageously antireflected and / or has an antireflection coating.

In one embodiment, the shape of the molding device is designed as a pressing tool. As a result, parts of, for example, plastic plates or foam plates can be reshaped.

In order to ensure a more uniform heating or heating of the material to be formed, for example, the second mold element may consist of a radiation-absorbing material, while the first mold element consists of quartz glass. During the heating of the material to be reshaped, on the one hand, the material is heated by the radiation emitted by the first radiation system, on the other hand, the second form element is heated by this radiation at the same time as it absorbs the radiation, which can lead to the heating of the material to be reshaped supported by the radiator system side, as well as from the side of the second element element ago. In this embodiment, the material to be formed is expediently arranged on the second mold element or contacted with the second mold element.

On the other hand, the second form element can also have a side which preferably opposes the second form side and which reflects the radiation of the first emitter system in the direction of the mold cavity in order to reflect radiation which penetrates both mold elements back into the mold space. The second form element is made of quartz glass. However, the reflective side may also be directly on the surface of the second feature.

In a further embodiment, a second emitter system is arranged opposite the first emitter system such that the two mold elements, with their two mold sides facing each other, are arranged between the first and the second emitter system, wherein the two emitter systems are aligned facing each other. Advantageously, in this embodiment, the second form element is made of quartz glass or another transparent material. By using two spotlight systems, where a Radiator system heats the material to be formed from one side and the other radiator system heats the material to be formed from the one side opposite the other side, it is possible to heat the material to be formed more effectively and faster from both sides.

The second radiator system has for this purpose at least one, preferably rod-shaped, halogen lamp.

In a particularly preferred embodiment, the two emitter systems and the two form elements are arranged in a housing which has reflective inner walls which reflect part of the radiation emitted by the two emitter systems onto the inner walls. In this way, a large part of the radiation generated can be used to heat the material to be formed.

Advantageously, at least one of the radiator systems has a plurality of mutually parallel, rod-shaped halogen lamps, in order to ensure a uniform surface heating of the material to be formed.

In one embodiment, the mold cavity formed by the closed mold may have at least one pressure equalization channel for equalizing pressure differences between the mold cavity and the outer space surrounding the mold. The molding apparatus may additionally comprise a mold insert, preferably formed of quartz glass and preferably easily replaceable. By an easily replaceable mold insert, it is possible to produce with a single mold device, or with a mold differently shaped moldings.

The method of forming thermoformable semifinished or plate material in the apparatus may comprise the following method steps: First, the semifinished product or plate material to be formed is introduced between the first and second mold elements. Then the mold is closed, or the two mold elements are pressed against each other and optionally against the semi-finished or sheet material so that the semi-finished or sheet material is formed by the two mold sides when it is heated and malleable. Subsequently, the semi-finished product or plate material introduced between the first and second mold elements is heated and shaped. Finally, the mold is opened again and the molded semi-finished or sheet material removed.

With the shaping device, the method according to the invention for foaming foamable in the heated state and the volume-increasing semifinished product can be performed. For this purpose, the semifinished product to be foamed is first introduced into the mold shell of the first molded part and the mold is closed. The semifinished product to be foamed is heated with the first and / or second emitter system until it foams and completely fills the mold space. Then the heating process can be ended. The mold is now opened again to remove the foamed semi-finished product.

In a preferred method, the semifinished product or sheet material is heated to 100 ° C to 400 ° C, preferably 150 ° C to 400 ° C. Methods are also possible in which the semifinished product or plate material is heated under overpressure, for example a pressure of at least 3 bar, preferably at pressures between 5 bar and 200 bar.

The semifinished or plate material or the material to be formed may be, for example, PMI (polymethacrylimide), PET (polyester), EPP (expanded polypropylene) or EPA (expanded polystyrene). It may, for example, be in the form of foam granules or in the form of beads or in the form of foam sheets, preferably up to 60 mm thick. The semifinished product may have thermoplastic GRP cover layers, such as polypropylene. The cover layers advantageously have a melting temperature of less than 190 ° C. The semifinished product may, for example, also have nonwoven cover layers of polypropylene, polyethylene or mixed nonwovens. Also compact semifinished product as a starting material is conceivable.

By the device heating of plastics and semi-finished directly above the tool is possible. The forming process can be extremely fast, which reduces cooling and shortens cycle times.

The invention will be explained in more detail with reference to drawings. The terms used herein, such as top, bottom, left or right and the like, refer to embodiments and are not intended to be limiting in any way, even if they relate to preferred embodiments. Show it:

1 a quartz glass tool for plate-shaped material,

2 a quartz glass tool for foamable granules.

1 shows a mold or a molding device 1 for forming semi-finished products 2 , which is present as a plate-shaped material. The molding device 1 has a first radiator system 4 on, on an irradiation side 6 of the first form element 8th is directed. The first form element 8th consists of quartz and has one of the irradiation side 6 opposite first form side 10 on. The first form side 10 is on an optional mold insert 12 directed, on the second form side 14 a second formula element 16 is arranged. The second form element 16 is also made of quartz glass.

The first form side 10 of the first formula element 8th is the second form side 14 of the second formula element 16 pointing above the mold insert 12 arranged. A second spotlight system 18 pointing to an irradiation site 20 of the second formula element is below the second formula element 16 arranged. Between the first form element 8th and the second mold element 16 is the semi-finished product 2 arranged in the form of a plate-shaped material. The mold insert 12 is in one on the second form side 14 of the second formula element 16 arranged mold shell (not shown) arranged. In the first form element 8th and in the second form element 16 are each Halterungsausnehmungen 22 for an opening device (not shown), with which the shape 8th . 16 can be opened or closed. The spotlight systems 4 . 18 each have reflectors 24 . 26 on.

The processing of the plate-shaped semi-finished product 2 in the molding device 1 is done as follows:
First, the semifinished product in the form of plate-shaped material 2 between the first mold element 8th and the second mold element 16 arranged. Then the two form elements 8th . 16 moved toward each other with the opening device and optionally on the semi-finished product 2 pressed. Here comes the first form page 10 on the optional mold insert 12 or on the second form side 14 or on the semi-finished product 2 to lie. Now in the first spotlight system 4 and in the second radiator system 18 arranged spotlights, such as halogen lamps turned on.

The of the radiator systems 4 . 18 emitted radiation hits either directly, or indirectly through the reflectors 24 . 26 on the treatment sites 6 and 20 , The radiation is transmitted through the first mold element 8th or the second form element 16 in the direction of the first form side 10 or second form side 14 emitted, passes through the form sides 10 . 14 through and from the plate-shaped semi-finished product 2 absorbed. As a result, the plate-shaped semi-finished product heats up 2 and becomes plastically deformable. During this deformability, the two form elements 8th . 16 pressed together until the semifinished product 2 the space between the first form element 8th and the second mold element 16 completely filled out. Then the two spotlight systems 4 . 18 turned off, the two mold halves by means of the Halterungsausnehmungen 22 engaging opening device opened and removed the molded semi-finished product.

2 shows a mold for foaming in the heated state foamable and volume-increasing semi-finished in a molding apparatus 1 , The molding device 1 in 2 has a first radiator system 4 , a second spotlight system 18 , as well as a first form element 8th and a second mold element 16 on. The first spotlight system 4 is, as well as in the example of 1 on the first irradiation page 6 of the first formula element 8th directed and above the first formula element 8th arranged. The second emitter system 18 is on the second radiation side 20 of the second formula element 16 directed and below the second radiator system 18 arranged. In the second form side 14 of the second formula element 16 a mold shell is formed, on which the mold insert 12 is arranged. In the mold insert 12 is a semi-finished product in the form of granules 2 added. If the form 8th . 16 is closed, in the form of a mold space 28 defines in which the granules 2 is included.

After the granules 2 in the mold insert 12 is included, becomes the first form element 8th in the direction of the second mold element 16 moves and the shape 8th . 16 is closed with the opening device. Then the foamable granules will be with the radiator systems 4 . 18 heated until the foamed semi-finished the mold space 28 completely filled out. Between the form space 28 and the molding device 1 surrounding outer space can thereby, either in the first form element 8th or in the second form element 16 , or between the two form elements 8th . 16 a pressure equalization channel may be formed, one possibly in the mold space 28 during this process resulting pressure difference between the mold space 28 and balances the outside space. Once the foamable semi-finished product 2 the shape space 28 has completely filled, the heating process is completed and the radiator systems 4 . 18 will be switched off. After an optional cooling of the semifinished product, the mold is opened and the foamed semifinished product is removed.

The invention has been explained with reference to two preferred embodiments, without being limited to these embodiments. For example, the mold insert 12 be made of a transparent material such as quartz glass, but also of an absorbent material. Is the mold insert of an absorbent material that of the second radiator system 18 emitted radiation, for example, by the second mold element, which consists of quartz glass, on the mold insert 12 blasted and from the mold insert 12 absorbed. This heats the mold insert 12 on, so in addition to the irradiation and heating of the granules with radiation coming from the first emitter system 4 is emitted and which impinges on the top of the granules, a heating of the granules by heat conduction from the mold insert 12 on the granules 2 done from the bottom of the granules ago.

The mold insert 12 is optional. The in the second form side 14 Trained shell mold could be the desired surface structure for the semifinished product 2 and record it directly. Many other ways of building such a molding device 1 are conceivable without leaving the inventive concept.

LIST OF REFERENCE NUMBERS

1

Forming device, molding tool

2

Semi-finished products, plates, granules

4

first radiator system

6

Irradiation side of the first element element

8th

first form element

10

first form side

12

mold insert

14

second form side

16

second form element

18

second radiator system

20

Irradiation side of the second formula element

22

retaining recess

24

reflector

26

reflector

28

cavity

Claims (16)

Process for foaming semifinished products which can be foamed in the heated state and increase in volume ( 2 ) in a molding apparatus ( 1 ) for producing shaped articles, wherein the molding device ( 1 ) a mold having a first mold element ( 8th ) and a second shaped element ( 16 ) and an opening device for opening or closing the mold, wherein the first mold element ( 8th ) a first form side ( 10 ) with a molded shell formed therein ( 12 ) for receiving semi-finished products ( 2 ) or plate material, and one of the first form side ( 10 ) disposed opposite irradiation side ( 6 ), and wherein the second shaped element ( 16 ) a second form side ( 14 ) for receiving semi-finished products ( 2 ) or plate material, which leads to the first mold side ( 10 ) and with the first form side ( 10 ) a form space ( 28 ) defined when the mold is closed, wherein the first and the second mold element ( 8th . 16 ) consists of quartz glass and the shaping device ( 1 ) a first radiator system ( 4 ) with at least one halogen lamp which is adjacent to the irradiation side ( 6 ) of the first formula element ( 8th ), on the irradiation side ( 6 ) of the first formula element ( 8th ), the method comprising the following steps: a) introducing the semifinished product to be foamed ( 2 ) in the shell of the first part of the formula ( 8th ) and closing the mold, b) heating the semifinished product to be foamed ( 2 ) with the at least one halogen lamp of the first radiator system ( 4 ) until the foamed semifinished product ( 2 ) the shape space ( 28 ) completely fills c) ending the heating, d) opening the mold and removing the foamed semi-finished product ( 2 ). A method according to claim 1, characterized in that the at least one halogen lamp is rod-shaped. Method according to one of the preceding claims, characterized in that the first radiator system ( 4 ) a reflector ( 24 ), the at least a portion of the radiation of the first radiator system ( 4 ) pointing to the reflector ( 24 ), on the irradiation side ( 6 ) of the first formula element ( 8th ) reflected. Method according to one of the preceding claims, characterized in that the mold shell in the first mold element ( 8th ) is milled, wherein the surface of the shell mold is preferably polished. Method according to one of the preceding claims, characterized in that the molding device ( 1 ) is designed as a pressing tool. Method according to one of the preceding claims, characterized in that the second shaped element ( 16 ) consists of a radiation-absorbing material. Method according to one of the preceding claims, characterized in that the second shaped element ( 16 ) one, preferably the second form side ( 14 ) opposite, in the direction of form space ( 28 ) the radiation of the first radiator system ( 4 ) has reflective side. Method according to one of the preceding claims, characterized in that the first radiator system ( 4 ) opposite a second radiator system ( 18 ) is arranged so that the two form elements ( 8th . 16 ), with its two form sides ( 10 . 14 ) facing each other between the first radiator system ( 4 ) and the second radiator system ( 18 ) are arranged, wherein the two radiator systems ( 4 . 18 ) are aligned facing each other. Method according to claim 8, characterized in that the second emitter system ( 18 ) has at least one, preferably rod-shaped, halogen lamp. Method according to claim 8 or 9, characterized in that the two emitter systems ( 4 . 18 ) and the two form elements ( 8th . 16 ), are arranged in a housing, the radiation of the two radiator systems ( 4 . 18 ) has reflective inner walls. Method according to one of the preceding claims, characterized in that at least one of the radiator systems ( 4 . 18 ) has a plurality of mutually parallel, rod-shaped halogen lamps. Method according to one of the preceding claims, characterized in that the molding space formed by the closed mold ( 28 ) at least one pressure equalization channel for equalizing pressure differences between the mold space ( 28 ) and the outer space surrounding the mold. Method according to one of the preceding claims, characterized in that the molding space formed by the closed mold ( 28 ) a mold insert ( 12 ), preferably of quartz glass. Method for molding semifinished products which can be shaped in a heated state ( 2 ) or plate material in a molding device ( 1 ) according to one of the preceding claims, comprising the following method steps: a) introduction of the semifinished product to be molded ( 2 ) or plate material between the first mold element ( 8th ) and second form element ( 16 ), b) closing the molding device ( 1 ), or pressing the two form elements ( 8th . 16 ) against each other and against the semi-finished product ( 2 ) or plate material such that the semifinished product ( 2 ) or plate material through the two mold sides ( 10 . 14 ) is heated when it is heated, c) heating the between the first and second form element ( 8th . 16 ) semi-finished product ( 2 ) or plate material with the at least one halogen lamp of the first emitter system ( 4 ) and forms of the semifinished product ( 2 ) or plate material, d) opening the molding device ( 1 ) and removing the shaped semifinished product ( 2 ) or plate material. Method according to one of the preceding claims, characterized in that the semifinished product ( 2 ) or the plate material is heated to 100 to 400 degrees Celsius, preferably 150 to 400 degrees Celsius. Method according to one of the preceding claims, characterized in that the semifinished product ( 2 ) or the plate material is heated at a pressure of at least 3 bar, preferably a pressure between 5 and 200 bar.

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