Hot-runner distribution system having a frame element, for filling mold cavities with polymer melts

Abstract

A hot-runner distribution system for polymer melts for filling mold cavities, wherein heating tube elements are connected to each other and held together by a frame element.

Description

[0001] HOT DUCT DISTRIBUTION SYSTEM WITH FRAME ELEMENT FOR FILLING MOLDING CAVITIES WITH POLYMER MELTS

[0002] Description:

[0003] The present invention relates to a hot runner distribution system for polymer melts for filling mold cavities with a frame element.

[0004] In modern polymer processing, hot runner systems are frequently used, with a distribution system for the polymer melt comprising several components. The core component is a distribution plate that is heated uniformly. Heated hot runner nozzles are positioned beneath this plate. Furthermore, a priming nozzle is screwed onto the distribution plate to connect to the injection unit of the injection molding machine. The polymer melt is distributed to the hot runner nozzles via the priming nozzle and the distribution channels in the distribution plate. From the hot runner nozzles, the melt is directed into the cavities of the injection mold. The distribution plate expands accordingly due to the heating. Therefore, the distribution plate must be able to move above the hot runner nozzles.At the same time, the hot runner nozzles also expand in length, so these hot runner systems must be designed and installed in the mold very precisely with regard to thermal expansion, especially since the outer mold structure must be much cooler so that the molded parts made of polymer can cool down quickly enough after the injection process and be demoldable.

[0005] The processing pressures in polymer injection molding are considerable and can exceed 1000 bar. Simultaneously, the tightness between the hot runner nozzle and the manifold plate, with its movable contact surfaces, must be achieved through precise surface machining and clean integration of the hot runner nozzle, ensuring the correct length of the heated nozzle. Even when switching between polymers with different melting temperatures, leaks or deformation of the hot runner components can occur due to differing thermal expansion of the manifold plate and hot runner nozzle. In every hot runner system, energy or material is saved because there is no cold gate spider. Hot runner molds are cooled and heated simultaneously.

[0006] 5. However, this still consumes a considerable amount of energy and puts a strain on the climate.

[0007] The consistently large surface area of ​​the hot runner manifold and the contact points between the hot runner manifold and the mold, combined with the aforementioned high sealing forces, result in significant energy loss. This necessitates considerable effort.

[0008] A hot runner system also consists of a large number of heating points with the required temperature sensors. Due to the different masses of conventional hot runner components, light hot runner nozzles and heavy hot runner manifold plates must be heated at different rates, necessitating complex control technology, which in turn increases costs.

[0009] 15

[0010] A needle valve system for molds for hot and cold filling materials would be desirable, which is more economically feasible and reduces the aforementioned disadvantages of the systems mentioned.

[0011] Needle valve systems typically require only smaller strokes, which

[0012] 20 can be easily managed with the membrane cylinder system proposed here. In contrast to a piston cylinder system, the complexity of the cylinder is considerably reduced by integrating the various functions and elements of a piston cylinder system into the membrane section.

[0013] This task is accomplished using the characteristics of the defining part of the An¬

[0014] 25. Proposition 1 is resolved. Further developments and advantageous embodiments of the invention are included in the further claims.

[0015] According to the invention, a hot runner distribution system for polymer melts is provided for the

[0016] Filling of mold cavities, whereby the hot tube elements are connected to each other and held together by a frame element.

[0017] 30 28-08-2025-43502301 -Hau p vpqst-0080 PCT / DE2025 / 000089 A hot runner manifold system is proposed that reduces energy input compared to conventional systems and high efficiency. Preferably, the system is designed with novel hot runner nozzles with needle valves, preferably with a novel diaphragm cylinder, rather than with simple, complicated-to-control standard hot runner nozzles. The proposed nozzles are attached to the mold plate. At contact point 59, the hot runner nozzle 35 is heated by a type of cooling element in the melt channel area. Hot runner nozzles 35 have needle shaft seals 22 at contact points on the mold plate. The hot runner nozzle 35 with needle valve is sealed to the diaphragm cylinder by suitable winding of the heating wire 44 in the upper area of ​​the melt channel, ensuring minimal heat transfer to the mold plate and further reduced by the needle shaft seal 22. This is especially important when the hot runner nozzle 35 is not yet fully attached to the mold plate due to thermal expansion. The temperature at contact point 59 is also reduced by heat transfer brakes 58 in front of the contact point.Thin areas are molded in. This is also made possible by the fact that, in contrast to conventional systems, less system pressure is required and no nozzle needs to be sealed. The hot runner system is mechanically combined with a seal. Hot runner nozzle 35 with torpedo union nut 57 56 without torpedo union nut 57 creates two injection points 36 and thus two between the two hot runner nozzles 35 and the injection nozzle 34. The connection between 37 and injection nozzle 34 and hot runner nozzle 35 is achieved through press fits 38 and / or seals, which can compensate for thermal expansion 37. The press fit at the stub pipe is achieved by a suitable wall thickness of between 28-08-2025-43502301-Haufl Host-005 PCT / DE2025 / 000089. By appropriately selecting the wall thickness of the stub pipe, the system's high pressure ensures that the stub pipe expands to its outer diameter, creating a seal. The heated hot runner system 33 should have as few gaps 42 as possible at the connection points of the hot tube elements 39.To avoid this, a different color change is possible. Hot runner nozzle body, injection nozzle 34 and 37, hot tube elements 39 are designated. In order for the hot tube elements 39 to be forced apart by the injection pressure, they are held together by frame elements 40. Frame element 40 consists of two half-shells 53 connected to each other. Between two frame elements, threaded connectors 54 press two pressure elements, preferably in the form of pressure screws 41, onto the frame element 40 or onto the threaded connector 54. Here, two pressure elements, preferably in the form of pressure screws 41, always press the hot tube elements 39 together. The hot runner nozzle body 43 and injection nozzle 34 only contact the frame elements at contact points. On one side, the hot runner system can be formed in the assembled state, and on the other side, there are few contact points 52 between the hot tube elements 39 and the frame elements, thus keeping heat loss low. The frame element 40 has a different thermal conductivity. The injection nozzle 34 has a 55 with contact points on its upper edge, whichpreferably from and nozzle shape The heating of hot runner elements 39 with heating wires, whereby several hot runner elements 39 are heated by one or more wound heating wires 44, thereby creating several heating zones compared to conventional hot runner systems. In hot runner systems 33 with two hot runner nozzles 35, only one heating zone is proposed by providing the injection nozzle 34 with a double wire helix 45 and the heating wire end 46 37 and hot runner nozzle 35. For this purpose, only a temperature sensor 47 is attached to a suitable surface. In hot runner manifold systems with hot runner nozzles 35, heating zones are proposed, wherein two hot runner nozzles 35 are equipped with one 37 and the injection nozzle 34 with two 37. The system is based on the number of hot runner nozzles 35. The heating wire windings of the hot runner elements 39 can be used for protection. either completely or with sheathing tubes 48. The sheathing tubes 48 also serve as a pressure plate for the heating wire 44 on hot tube elements 39 and also as a reflector of the energy to the hot tube elements 39.Heating wires 44 can be made with fiberglass or metal tubes (tubular heating elements). The frame elements 40 preferably form a closed frame box, which also provides contact protection. A component 49 can be inserted between the hot tube elements and the frame box. This further protects the hot tube elements from the mold. Here, the needle valve nozzle 29 is attached to the mold plate, connecting to the hot runner distributor. The upper seals 30, hot runner nozzle 35, and the diaphragm cylinder can also be used. The system is compatible not only with needle valve nozzles 29 and diaphragm cylinders, but also with conventional needle actuation systems and hot runner nozzles without needle valves. With the proposed system, large mold assemblies can be used. This lung two-component application with hot runner to and on molds of other 28-08-2025-43502301-HauPtPos t-0063 PCT / DE2025 / 000089 This requires rotating the hot runner nozzle and injection nozzle alignment, which this system accomplishes. The invention is described in more detail below with reference to drawings.described, showing a view from below of a needle valve hot runner system 28 with two needle valve nozzles and next to the gate nozzle and a frame element such as above the needle valve nozzle 29 upper diaphragm piston stiffener, diaphragm part with the diaphragm sealing edge and diaphragm piston stiffener. The needle is arranged between the diaphragm piston stiffener and the hot runner nozzle. 2 a through needle valve hot runner system with two needle valve nozzles and next to the gate nozzle. Above the needle valve nozzle of the diaphragm cylinder shape of upper diaphragm part with diaphragm sealing edge and diaphragm piston stiffener. View from above of a slant needle valve hot runner system with 2 needle valve nozzles and next to the gate nozzle. Above the needle valve nozzle upper diaphragm piston stiffener, diaphragm with the diaphragm sealing edge and sealing screw. 4 Shows needle valve hot runner system with clamping housing installed in longitudinal section nozzle side shape. Top mold spacer plate. The diaphragm part 2 from diaphragm piston wall diaphragm side wall4 and membrane sealing edge. 28-08-2025-4350230 "Main Post "0064 PCT / DE2025 / 000089 Hot runner manifold system illustration with hot runner nozzle and injection nozzle rotated 90° relative to each other 6 Hot runner manifold system illustration with hot runner nozzle and injection nozzle rotated 90° relative to each other Fig7 Hot runner manifold system with hot runner nozzle and injection nozzle rotated 90° relative to each other After preferred embodiments of the invention have been described with reference to the accompanying drawings, the invention is limited to precise embodiments and various changes and modifications thereto can be made by a person skilled in the art without deviating from the scope of the invention as defined in the accompanying claims.

[0018] 28-08-2025-43502301 - Main Item t“0065 PCT / DE2025 / 000089 Diaphragm cylinder Diaphragm part Needle Mold plate Needle shaft seal Needle valve hot runner system with clamping housing. Hot runner nozzle with needle valve Upper seals of the needle valve nozzle Needle shaft Injection nozzle Hot runner nozzle Injection point Press fit Hot runner elements Frame element Pressure screw Intervals Hot runner nozzle body Heating wire Double wire coil Heating wire end Temperature sensor Sheathing tube Hot runner mold Tube stub. Contact points Half shell Threaded connector Spacer ring 28-08-2025-4350230 i-Main Item -0066 PCT / DE2025 / 000089 56 Lower 57 Torpedo union nut 58 Heat transfer brake 59 Contact point 60 Melt channel Mold cavity 62 Mold Nozzle side

Claims

10 Claims 1. Hot runner distribution system for polymer melts for filling mold cavities (61) 5 characterized in that hot tube elements (39) are connected to each other and held together by a frame element (40). 10 2. Hot runner distribution system for polymer melts for filling mold cavities (61) according to claim 1 characterized in that several different hot tube elements (39) are heated with only one insulated heating wire (44) or tubular heating element. 15 3. Hot runner distribution system for polymer melts for filling mold cavities (61) according to claim 1, characterized in that 20 that the system has hot runner nozzles with needle valve (29) and the needles (13) are preferably moved by a diaphragm cylinder (1).

4. Hot runner distribution system for polymer melts for filling mold cavities 25 would be characterized according to claim 1 in that the hot tube elements (39) are joined to each other by press fit. 30 5. Hot runner distribution system for polymer melts for filling mold cavities according to claims 1 and 4, characterized in that 28-08"2025-4350230 "HauP i-0069 PCT / DE2025 / 000089 that press fit through pipe stub, wherein wall pipe stub 0.5mm-3mm hot runner distribution system polymer melts filling mold cavity according to claim characterized in that the frame element is preferably constructed with half-shells, pressure screws and / or threaded connectors hot runner distribution system polymer melts filling mold cavity according to claim characterized in that hot runner nozzle with or without needle valve on the mold plate nozzle direction and hot runner nozzle at the contact point at least 50°C temperature in the melt channel hot runner distribution system polymer melts filling mold cavity according to claim characterized in that melt channel hot runner nozzle with the melt channel of the approached hot runner distribution system polymer melts filling mold cavity according to claim characterized in thatthat the angle of approach to the injection nozzle and hot runner nozzle is 180° but preferably 90° or another angle,

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