AT506097B1 - HEATING DEVICE FOR A TOOLING TOOL - Google Patents

Abstract

Heating device for heating at least a portion of a cavity forming a cavity for receiving plastic melt forming mold (7, 8), wherein the mold (7, 8) between mold platens (5, 6) is clamped, with an outside of the mold (7, 8) can be arranged or arranged heating station (2) and with a transport device (3) through which at least the part to be heated (9, 10, 13) of the molding tool (7, 8) to the heating station (2) is transported back and forth, wherein the transport device (3) has a rotating device to which the part to be heated (9, 10, 13) is connected so that the part to be heated (9, 10, 13) in its state connected to the rotating device is rotated toward the heating station (2) and transportable back, wherein at least two parts to be heated (9, 10, 13) are connected to the transport device (3) such that one of the at least two parts to be heated (9, 10, 13) can be heated by the heating station (2) is while de Other of the at least two parts to be heated (9, 10, 13) can be used as a preheated part in a manufacturing process of a plastic part.

Description

Austrian Patent Office AT506 097B1 2010-03-15

The present invention relates to a heating device for heating at least a portion of a cavity forming a cavity for receiving molten plastic, wherein the mold is clamped between mold platens, with an outside of the mold can be arranged or arranged heating station and with a transport device through which at least the part of the mold to be heated can be transported back and forth to the heating station, the transport device having a rotating device to which the part to be heated is connected, so that the part to be heated in its connected to the rotating device state by rotation to the heating station back and forth is transportable.

Generic heaters are used for (dynamic) tempering a molding tool, wherein usually in each cycle prior to the introduction of plastic melt heating the surface to a temperature preferably between glass transition or. Melting temperature and melt temperature of the plastic takes place. After heating is usually cooled again. Ideally, only the surface of the cavity which comes in contact with the melt is heated. The lower the masses to be heated, the more economical and energy-efficient the dynamic temperature control can be carried out.

[0003] In the applicant's Austrian patent application A 877/2007 entitled "Tool temperature control by means of IR radiator". A solution was presented in which the cavity is placed in an insert formed by a thin spring-lifting plate. The heating takes place externally via an infrared radiation source. During heating, this thin plate is lifted off the cooled base of the mold, thus heating only a small mass. The air gap created by the lifting serves as an insulator to the cooled tool. This has a favorable effect both on the heating time and on the cooling time.

However, this method, like all heating methods based on external heating stations (i.e., not installed in the mold), has the disadvantage that heating can not take place in parallel with mold opening, mold closing, and closing force build-up. Only the time it takes for a part removal robot can be used to heat the opposite cavity in parallel. If the heating time lasts longer than the removal, this inevitably leads to a cycle time extension. This problem could be countered with the development of correspondingly fast heating methods, but it has been shown that particularly rapid heating often involves poor reproducibility of the temperature reached.

Known heaters have the disadvantage that massive bearings and strong drives for sometimes very heavy heating stations must be provided.

Publications DE 10 2007 013 596 A1, KR 2004-0026865 A, JP 04-077221 A, JP 04-175123 A, JP 10-067019 A and US 2004/099995 A1 relate to a heating device, wherein the to be heated Part from the field of mold platens to a heating station and back is transportable.

A heating device with all features of the preamble of claim 1 is disclosed in JP 2002-052588 A.

The object of the invention is to develop a generic heater such that at least one of the problems discussed above is resolved.

This object is achieved with a heating device with the features of claim 1.

According to the invention, the heating of the part to be heated (eg the cavity) takes place outside of the molding tool. This has several advantages: sometimes heavy heating stations (IR emitters, induction coils, etc.) do not need to be manipulated, so are driven into the mold area, but are preferably 1/13 Austrian Patent Office AT506 097B1 2010-03-15 fix mounted outside of the mold. Optionally provided cooling devices (hoses for water cooling, fans, etc.) do not have to be transported, but are also preferably mounted fixed outside of the mold, where more space is available. When the heating stations including their optionally provided cooling must therefore be paid no attention to a space and weight-saving design.

Further advantageous embodiments of this are defined in the corresponding dependent claims.

The present invention provided heating outside the range of the mold allows heating in the embodiment of the part to be heated as a removable insert, a part to be heated in the heating station, while an already preheated part in a manufacturing process of a plastic part (eg an injection molding ) is used. For this purpose, the insert to be heated is made double, and moved from the tool area in a heating area with methods known from multi-component injection molding. The heating process takes place here parallel to the manufacturing process, so it comes - apart from the rotational movements - to any extension of the cycle. There is thus sufficient time for heating, this time generally does not extend the cycle. The heating rate can be selected so that an exact reproducibility of the maximum temperature reached is ensured. Local temperature differences can be compensated for by slower heating or by a soaking time following the heating process. Instead of a timed heating operation, temperature control is possible by measuring the actual temperature at the insert to be heated (e.g., by pyrometer) and, upon reaching the desired set temperature, heating is stopped.

The removal of the finished moldings can be done in the heating station. In this case, the finished part remains in the cavity after opening the mold (e.g., in the movable insert). While the molded part outside the mold is removed from the cavity, the next cycle can already begin.

Further advantageous embodiments of the invention are defined in the dependent claims.

Protection is also desired for an arrangement with the features of claim 24 and an injection molding machine with the features of claim 34.

Further advantageous embodiments are defined in the corresponding dependent claims.

Further advantages and details of the invention will become apparent from the figures and the associated description of the figures.

[0025] [0025]

Showing:

1 shows a first embodiment of the invention,

2 shows a second embodiment of the invention in two different views,

3 shows a third embodiment of the invention,

4 shows a fourth embodiment of the invention,

Fig. 5 shows a fifth embodiment of the invention and

Fig. 6 is a replaceable in all embodiments advantageous detail of the invention.

The preferred embodiment of the invention is shown in Fig. 1. On preferably cooled base body of the movable mold half 7 is releasably secured to a relatively thin insert 10, which includes the cavity. This insert 10 is fastened together with a second, identical insert 9 to a respective rotating arm of the transport device 3 together with a second, identical insert 9. To change the inserts 9, 10 is first a small stroke in the direction of the machine axis (lifting the cavity from the cooled mold 7, 8), followed by a rotational movement of 180 °. Parallel to the injection molding process with one insert 10, the other insert 9 is heated by a heating station 2, for example an IR radiation source (see indicated rays 2 '). (IR is an abbreviation for "infrared" throughout the disclosure).

The insert 9, 10 can be heated from the rear side (preferred), from the front side, or from both sides. For the infrared heater, a coating may be provided, wherein the coating should have the property to absorb IR rays well. Such a coating can now be easily arranged on the rear side of the insert (9, 10). This is then not in connection with the injected plastic, so it does not need to be well polishable. It also does not have to be taken into account for an undesirable adhesion tendency to the plastic. Furthermore, the surface can be made rough, which in turn causes an increase in the absorption. It only needs to be made twice the insert (in contrast to the turntable solution of FIG. 2, where two movable mold halves 7 are necessary). TO THE EMBODIMENT OF FIG. 2, the entire movable mold half 7 is mounted here in duplicate on a turntable (rotatable about a horizontal axis 12) of a transport device 3; while the one movable mold half 7 is in the machine, the other with the external heating station 2, z. B of an IR radiation source, heated. In Fig. 2, a feather-lifting thin plate is shown, which includes the cavity and represents the part to be heated 13, although in this embodiment by an air gap from the main body of the mold half 7 spaced, but is permanently connected thereto.

The embodiments of FIGS. 1 and 2 are particularly suitable - but not only - for tie-bar injection molding machines. TO THE EMBODIMENT ACCORDING TO FIG. In Fig. 3, a machine with two injection units is schematically indicated by the respective injection nozzle 11. In a rotatable cube (insert), which forms the mold center part and at the same time the transport device 3, four cavities are carried out in the parts 13. The two outer heating stations 2 are each used for heating parallel (ie during) to the injection molding process. With the two injection units either the same or different moldings can be injected. Similarly, two components can be sprayed over each other (two-component process), where either only in an external heating station 2, the cavity is heated, or the pre-molded part is rotated outwards, and is heated before over-molding. This heating can e.g. be used to improve the adhesion, or to reduce the stress in the parting surfaces. TO THE EMBODIMENT ACCORDING TO FIG. FIG. 4 illustrates a solution for spar machines which functions similarly to an index plate method. Here, one of the upper spars 14 forms the center for the rotational movement of the parts 9, 10 to be heated by the transport device 3. THE EMBODIMENT OF FIG. As mentioned above, have tool-integrated heating devices (induction coil, resistance heaters), which are not the subject of the invention, the advantage that they can be operated in parallel with machine movements. The disadvantage, however, is that they are tool-bound, so that the investment costs for design and manufacture must be credited in full to the one product to be produced. In the case of the heating device 1 according to the invention, this is in principle also the case if the contour of the radiation source is adapted to the part 9, 10 (of the cavity) to be heated.

Instead of the illustrated in Fig. 1, adapted in size of the cavity or the use of radiation source is proposed in this embodiment, to remedy this disadvantage, to arrange a plurality of 2a, 2b of separately controllable radiation sources above the tool area. These are components of the injection molding machine in the sense that they can be used for various molds 7, 8.

Depending on the size of each part to be heated 9, 10 only those radiation sources 2a are used, which are necessary for the heating of the same. The remaining radiation sources 2b remain inactive.

In order to ensure an ideal temperature distribution, the power of the individual radiation sources 2a, 2b can be controlled individually. The temporal performance curve in the heating phase can also be specified individually. With suitable temperature measuring devices can also be a location / time-dependent control.

The control of the radiation sources can be done via a separate control device, but preferably this is integrated into the machine control of an injection molding machine. Thus, the operating parameters of the radiation sources can be stored in the tool data record.

Optionally, the individual radiation sources can be displaced in the direction of the machine axis in order to achieve a better adaptation to the contour of the surface to be heated. This shift can be done manually or via suitable drives. In the latter case, the positions of the individual radiators can also be stored in the tool data set.

The region of the radiation sources and the transport device 2 (at least in the region of the part 9, 10 to be heated) can be provided with an enclosure in each of the embodiments discussed in order to minimize the heat emission to the environment. This housing can be cooled or the waste heat can be extracted via heat exchangers and used elsewhere.

The described embodiments of the possible control or regulation of the heating station, the provision of position measuring devices or the provision of temperature measuring devices are of course advantageously used in all discussed embodiments. TO THE EMBODIMENT ACCORDING TO FIG. The part to be heated 9, 10 is not moved by a rotary motion from the mold 7, 8, but taken from a handling robot 15 and placed in a heating station 2 (not visible in Fig. 6). An already warmed insert is inserted with the handling robot 15 into the mold 7, 8, and fastened by suitable means (for example mounted on guide bolts).

The handling robot 15 has a movable arm via a non-illustrated arm 16, to which two holding devices 17 are fixed, which in this embodiment by means of brackets 18 (the brackets 18 are in Fig. 6 at the upper holding device 17 in two different Operating positions shown), which can access to heating parts 9, 10. 6 shows the situation in which a part 10 to be heated is removed from the area of the forming tool 7, 8 by the handling robot 15 and an already preheated part 9 is inserted by the handling robot 15 into the area of the forming tool 7, 8. 4.13

Claims (34)

Austrian Patent Office AT506 097B1 2010-03-15 Claims 1. Heating device for heating at least a part of a molding tool (7, 8) forming a cavity for receiving plastic melt, the molding tool (7, 8) being clamped between platens (5, 6) with a heating station (2) which can be arranged or arranged outside the molding tool (7, 8) and with a transport device (3), through which at least the part (9, 10, 13) of the molding tool (7, 8) to be heated to the heating station (2) is transportable back and forth, wherein the transport device (3) has a rotating device, with which the part to be heated (9, 10, 13) is connected, so that the part to be heated (9,10,13) in his with the rotating device connected state by rotation to the heating station (2) is transported back and forth, characterized in that with the transport device (3) at least two parts to be heated (9, 10, 13) are connected so that one of the we at least two parts to be heated (9, 10, 13) are heatable by the heating station (2), while the other of the at least two parts to be heated (9, 10, 13) is usable as a preheated part in a manufacturing process of a plastic part. 2. Heating device according to claim 1, characterized in that the heating station (2) on a movable platen (7) can be arranged or arranged. 3. Heating device according to claim 1 or 2, characterized in that the heating station (2) for heating the at least one part to be heated (9, 10, 13) of the molding tool (7, 8) at least one radiation source, preferably at least one IR radiation source , having. 4. Heating device according to claim 1 or 2, characterized in that the heating station (2) for heating the at least one part to be heated (9, 10, 13) of the molding tool (7, 8) at least one induction coil or to the part to be heated (9, 10, 13) contactable contact surface heating or an electrically conductive ceramic or a hot air gun or a closed furnace. 5. Heating device according to claim 3, characterized in that the contour of the radiation source is adapted to the part to be heated (9,10,13). 6. Heating device according to claim 3, characterized in that the heating station (2) has a plurality (2a, 2b) of separately controllable or controllable radiation sources. 7. A heating device according to claim 6, characterized in that the plurality (2a, 2b) of separately controllable or controllable radiation sources are timed differently controlled or regulated. 8. Heating device according to claim 6 or 7, characterized in that the radiation sources are arranged in the form of a grid. 9. Heating device according to one of claims 6 to 8, characterized in that at least a part of the radiation sources is slidably mounted. 10. Heating device according to claim 9, characterized in that the mounting of the displaceable radiation sources allows a shift in the direction of the machine axis of an injection molding machine. 11. Heating device according to claim 9 or 10, characterized in that the displaceable radiation sources are manually displaceable. 12. Heating device according to claim 9 or 10, characterized in that a drive for displacing the displaceable radiation sources is provided. 13. Heating device according to one of claims 9 to 12, characterized in that a position-measuring device is provided for detecting the position of the displaceable radiation sources. 5/13 Austrian Patent Office AT506 097B1 2010-03-15 14. Heating device according to one of claims 1 to 13, characterized in that a control device for controlling the heating station (2) is provided. 15. Heating device according to claim 14, characterized in that the control device can be integrated or integrated into a machine control of an injection molding machine. 16. Heating device according to one of claims 1 to 15, characterized in that a drive for driving the transport device (3) is provided. 17. Heating device according to one of claims 1 to 16, characterized in that the heating station (2) is arranged completely in the area outside the platens (5, 6). 18. Heating device according to one of claims 1 to 17, characterized in that the rotating device is designed as a turntable for a half of at least one molding tool (7). 19. A heating device according to claim 18, characterized in that on the turntable, the halves of two molds (7) can be arranged or arranged. 20. Heating device according to one of claims 1 to 17, characterized in that the rotating device is designed as a turning plate for the at least one part to be heated (9, 10, 13). 21. Heating device according to claim 20, characterized in that at least two, preferably four, parts to be heated (9, 10, 13) can be arranged or arranged on the insert. 22. Heating device according to one of claims 1 to 17, characterized in that the rotating device has a rotary arm for supporting the at least one part to be heated (9, 10, 13). 23. Heating device according to claim 22, characterized in that the rotary arm on a spar (14) of an injection molding machine can be stored or stored. 24. Arrangement comprising: a molding tool (7, 8) and a heating device for heating at least part of a mold cavity (7, 8) forming a cavity for receiving plastic melt, the molding tool (7, 8) being arranged between platens (5, 6) is clamped, with an outside of the mold (7, 8) can be arranged or arranged heating station (2) and with a transport device (3) through which at least the part to be heated (9, 10, 13) of the molding tool (7, 8) to the heating station (2) is transportable back and forth, wherein the heating station (2) is arranged so that the part to be heated (9, 10 13) is heated from its rear side, characterized in that with the transport device (3 ) at least two parts to be heated (9, 10, 13) are connected so that one of the at least two parts to be heated (9, 10, 13) is heated by the heating station (2), while the other of the at least two parts to be heated (9,10,13) as a preheated part in egg a manufacturing method of a plastic part is usable. 25. Arrangement with a heating device according to one of claims 1 to 23 and a molding tool (7, 8), characterized in that the cavity is at least partially secured by at least one insert (9, 10) attached to a base body of the molding tool (7, 8). is formed, which represents the at least one part to be heated (9,10,13). 26. Arrangement according to claim 24 or 25, characterized in that the at least one insert (9, 10) by springs from the main body of the molding tool (7, 8) can be pressed away. 27. Arrangement according to claim 25 or 26, characterized in that the to-be-heated Austrian Patent Office AT506 097 B1 2010-03-15 part (9, 10, 13) in the form of two inserts (9, 10) is executed, so that one insert (9, 10) can be heated, while the other insert (9, 10) is located in the molding tool (7, 8). 28. Arrangement according to one of claims 25 to 27, characterized in that the insert (9, 10) or the inserts (9, 10) has a surface-treated, preferably roughened or coated area, which in the IR region has an increased degree of absorption having. 29. Arrangement according to claim 28, characterized in that the surface-treated area is arranged on the side facing the main body of the molding tool (7, 8) side of the insert (9,10). 30. Arrangement according to one of claims 24 to 29, characterized in that a cooling device for cooling the base body of the molding tool (7, 8) is provided. 31. A heating device according to any one of claims 1 to 23 or arrangement according to one of claims 24 to 30, characterized in that a preferably cooled housing for the heating station (2) and / or the transport device (3) is provided. 32. Heating device according to one of claims 1 to 23 or arrangement according to one of claims 24 to 30, characterized in that a temperature measuring device for detecting the temperature of the heating station (2) and / or the at least one part to be heated (9,10,13 ) is provided. 33. Heating device or arrangement according to claim 32, characterized in that the signals of the temperature measuring device of a control device for controlling the measured temperature can be fed. 34. Injection molding machine with a heating device according to one of claims 1 to 23 or claims 31 to 33 or with an arrangement according to one of claims 24 to 30 or claims 31 to 33. For this 6-sheet drawings 7/13