A hot distribution structure of a part molding tool

Abstract

The utility model discloses a kind of part mould pressing tool heat distribution structures, including mould, at least two leading temperature measuring holes for inserting temperature measuring thermocouple rod are equipped on the mould, the hole diameter of the leading temperature measuring hole is 0.1~0.5mm larger than the diameter of temperature measuring thermocouple rod inserted therein, and the leading temperature measuring hole is 5~35mm from the heated surface of mould;At least two lags temperature measuring holes for inserting temperature measuring thermocouple rod are also equipped on the mould, the hole diameter of the lag temperature measuring hole is 1~5mm larger than the diameter of temperature measuring thermocouple rod inserted therein;The lag temperature measuring hole is away from mould pressing heat source and close to the heat dissipation edge of the mould.This part mould pressing tool heat distribution structure can quickly obtain part leading thermocouple equivalent point and part lag thermocouple equivalent point on mould without affecting mould pressing function.

Description

Technical Field

[0001] This utility model relates to the field of composite material parts manufacturing technology, and in particular to a heat distribution structure for part molding tooling. Background Technology

[0002] In the manufacturing process of composite material parts for aircraft, due to pre-airworthiness compliance requirements, special processes in part production need to be monitored. Curing is one such special process, requiring systematic collection of curing data to ensure that all areas of the composite material part reach and remain within the temperature range required by the process specifications for a sufficient duration during curing. Specifically, it cannot exceed the temperature limit (too fast / too high): the material may degrade, blister, or deform; nor can it be too low (too slow / too low): the resin will not cure sufficiently (insufficient curing degree), and the part's strength, durability, and other properties will not meet requirements. However, directly measuring the curing data of the part often damages it. Therefore, an indirect method is used to monitor the heating and cooling rates of the mold, identifying the locations on the mold that accurately reflect the fastest heating point (the most dangerous point) and the slowest heating point (the most likely point of under-curing). During the heating phase, the simulated thermocouple positioned at the mold location where the temperature rises fastest (reaching the set temperature first) and can match or conservatively represent the fastest heating rate of the part is designated as the leading thermocouple. Conversely, the simulated thermocouple positioned at the mold location where the temperature rises slowest (reaching the set temperature last) and can match or conservatively represent the slowest heating rate of the part is designated as the lagging thermocouple. Based on the equivalent substitution relationship between the part and mold temperatures, the thermocouple measurement temperatures at various locations are analyzed to identify the simulated thermocouple temperature measurement positions on the mold that can replace the leading and lagging thermocouples for the part. By analyzing the temperatures fed back by the leading and lagging thermocouples, the fastest and slowest heating rates of the part during curing are determined, ensuring that the part does not overheat during curing while meeting the minimum curing temperature requirement, thus guaranteeing sufficient curing degree.

[0003] In practice, it is difficult to find suitable leading and lagging thermocouple positions on the mold to replace the parts in one go. Repeated adjustments are required during operation to simulate the heating and cooling processes of the parts. Due to the structure of the parts and mold, as well as the heating method, the temperature in different areas of the parts may vary significantly.

[0004] Compression molding is an important method in composite material manufacturing, especially suitable for high-precision, high-volume production of aerospace composite parts. This process uses upper and lower hot plates to directly pressurize and heat the mold, causing the prepreg to cure under high temperature and pressure.

[0005] In compression molding, heat is conducted rigidly through upper and lower hot plates. The high thermal conductivity of the metal mold (150–400 W / mK) causes it to heat up much faster than that of composite materials with low thermal conductivity (0.5–5 W / mK). This makes it difficult for a slow heating point to naturally form on the mold to match the hysteresis zones (such as thick walls and dead corners) inside the part. In contrast, autoclave molding heats the part uniformly through gas convection. The mold surface has hysteresis zones formed by natural heat dissipation (such as below the vacuum bag). The single heat source direction and solid conduction path of compression molding mask the actual hysteresis effect of the part by the rapid heat transfer of the metal mold, making it difficult to accurately monitor the slowest heating zone of the part using simulated thermocouples. Utility Model Content

[0006] To solve the above-mentioned technical problems, the purpose of this utility model is to provide a heat distribution structure for part molding tooling; this heat distribution structure for part molding tooling can quickly obtain the leading thermocouple equivalent point and the lagging thermocouple equivalent point of the part on the mold without affecting the molding function.

[0007] To achieve the above-mentioned technical objectives and effects, this utility model is implemented through the following technical solution:

[0008] This utility model provides a heat distribution structure for a part molding tooling, including a mold. The mold is provided with at least two leading temperature measuring holes for inserting a temperature measuring thermocouple rod. The diameter of the leading temperature measuring hole is 0.1 to 0.5 mm larger than the diameter of the temperature measuring thermocouple rod inserted therein, and the leading temperature measuring hole is 5 to 35 mm away from the heated surface of the mold.

[0009] The mold is also provided with at least two hysteresis sensing holes for inserting thermocouple rods. The diameter of the hysteresis sensing holes is 1 to 5 mm larger than the diameter of the thermocouple rods inserted therein. The hysteresis sensing holes are far away from the molding heat source and close to the heat dissipation edge of the mold.

[0010] Furthermore, the hysteresis temperature measuring hole is filled with an insulating layer that wraps around the temperature measuring thermocouple rod.

[0011] Furthermore, the insulation layer is one of the following: a foam layer, a heat-resistant plastic layer, and a ceramic wool layer, or a mixture of two or more of the following materials: foam, heat-resistant plastic, and ceramic wool.

[0012] Furthermore, the region of the mold with slow heat conduction is provided with a resistance heating rod mounting hole for mounting a resistance heating rod.

[0013] Furthermore, the areas of the mold with slow heat conduction are mold weight reduction grooves, reinforcing ribs, or structural areas with a wall thickness exceeding 40mm.

[0014] Furthermore, the leading temperature measuring hole is located in the central region of the mold.

[0015] Furthermore, the aperture of the leading temperature measuring hole is 10.2-10.5 mm, which is compatible with a PT100 temperature measuring thermocouple rod with a diameter of 10 mm; the aperture of the lagging temperature measuring hole is 12 mm, which is compatible with a PT100 temperature measuring thermocouple rod with a diameter of 6 mm.

[0016] The technical effects of this utility model are as follows:

[0017] This invention uses a small-diameter leading temperature measuring hole (5-35mm from the heated surface) to directly and accurately capture the fastest heating area of ​​the mold, monitor the most dangerous overheating point of the part, and avoid material degradation or deformation in actual production. By using a large-diameter lag temperature measuring hole (combined with proximity to the heat dissipation edge and can also be combined with the design of the insulation layer), a delayed heating area is artificially created to simulate the lag effect caused by the low thermal conductivity of composite materials. This solves the problem of metal molds masking the actual slow heating of parts in the molding process, thereby ensuring that the resin is fully cured in actual production by accurately monitoring the molding process temperature.

[0018] This invention, through pre-arranged leading / retarding temperature measuring holes and combined with a structured design featuring adjustable insulation layer thickness and resistance heating compensation, transforms the positioning of equivalent temperature measuring points on the mold from the traditional experience-dependent "blind testing-adjustment" to an engineered process of "structured pre-arrangement + dynamic convergence." Thus, the fastest / slowest heating equivalent point of the part can be locked through 2-3 parameter fine-tunings, reducing the testing workload by more than 80% compared to traditional methods, and shortening the temperature control verification cycle for the molding and curing of composite parts from several weeks to several hours. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the heat distribution structure of the part molding tooling of this utility model.

[0020] In the diagram, 1: mold; 11: upper mold; 12: lower mold; 2: leading temperature measuring hole; 3: lagging temperature measuring hole; 4: resistance heating rod mounting hole. Detailed Implementation

[0021] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the scope of protection of the present invention.

[0022] like Figure 1 As shown, this utility model provides a heat distribution structure for a part molding tooling, including a mold 1, which includes an upper mold 11 and a lower mold 12.

[0023] The mold 1 has at least two leading temperature sensing holes 2. The diameter of the leading temperature sensing hole 2 is 0.1-0.5 mm larger than the diameter of the thermocouple rod inserted into it, and the leading temperature sensing hole 2 is 5-35 mm away from the heated surface of the mold 1. Through shallow embedding and precise hole diameter matching, the thermocouple rod is ensured to be in close contact with the mold, quickly conduct heat from the molding heat source (hot plate), and accurately capture the fastest heating point (most prone to overheating) of the part. The leading temperature sensing hole 2 is preferably located in the middle area of ​​the mold. The diameter of the leading temperature sensing hole 2 is preferably 10.2-10.5 mm, which can be used to fit a PT100 thermocouple rod with a diameter of 10 mm.

[0024] The mold 1 is also provided with at least two hysteresis sensing holes 3. The diameter of the hysteresis sensing holes 3 is 1-5 mm larger than the diameter of the thermocouple rod inserted therein. The hysteresis sensing holes 3 are far from the molding heat source and close to the heat dissipation edge of the mold. The diameter of the hysteresis sensing holes 3 is preferably 12 mm, which is suitable for PT100 thermocouple rods with a diameter of 6 mm. The hysteresis sensing holes 3 can also be filled with an insulating layer that wraps around the thermocouple rod. When the insulating layer is not filled, an air insulating layer is formed in the large-diameter hysteresis sensing hole, which increases the thermal resistance. After filling with the insulating layer, the heating rate is further reduced, the accuracy of hysteresis simulation is enhanced, and the thermal response efficiency of the hysteresis sensing hole can be adjusted by adjusting the thickness of the insulating layer. Therefore, when the temperature deviation is >5%, there is no need to change the hole position; the insulating layer can be directly adjusted to match the measured value of the part, which greatly reduces the trial and error cost.

[0025] Furthermore, the insulation layer is one of the following: a foam layer, a heat-resistant plastic layer, and a ceramic wool layer, or a mixture of two or more of the following materials: foam, heat-resistant plastic, and ceramic wool.

[0026] For the hysteresis temperature measuring hole 3, this utility model artificially creates a "thermal resistance-heat dissipation" composite environment to forcibly slow down the heating rate of the measuring point and accurately simulate the slowest heating point of the part.

[0027] The mold 1 has a slow-heating area with a resistance heating rod mounting hole 4 for mounting a resistance heating rod. Specifically, the slow-heating area of ​​the mold 1 is the mold weight reduction groove, reinforcing rib, or structural area with a wall thickness exceeding 40mm. The resistance heating rod mounting hole 4 extends to the surface of the mold cavity. The resistance heating rod mounting hole 4 can be set within a 15mm circumferential range of the hysteresis temperature measuring hole. The electric heating rod plays a core role in active thermal compensation in the heat distribution structure of the molding tooling. When a specific area of ​​the mold (such as the weight reduction groove or thick rib) has excessive thermal resistance, resulting in a heating rate of the part in that area being less than the lower limit of the specification (e.g., less than 1.5℃ / min), and the temperature value measured by the hysteresis hole is significantly lower than that of other areas (temperature difference > 10℃), the electric heating rod generates Joule heat when energized. The heat is conducted to the hysteresis area of ​​the mold to compensate for the heat loss from the environment, thereby increasing the heating rate of the slowest heating area of ​​the part and raising the temperature of the coldest point of the part. Together with the hysteresis temperature measuring hole 3, it forms a monitoring-compensation closed loop to ensure that the coldest point of the part meets the curing temperature requirements.

[0028] The temperature measurement arrangement method based on the heat distribution structure of the part molding tooling described above includes the following steps:

[0029] (1) Selection of candidate pore sites

[0030] At least two leading temperature measuring holes 2 are selected as leading candidate holes on mold 1; at least two lagging temperature measuring holes 3 are selected as lagging candidate holes.

[0031] (2) Thermocouple installation

[0032] Insert the corresponding thermocouple rods into the leading candidate hole 2 and the lagging candidate hole 3;

[0033] The hysteresis candidate hole 3 can be selectively filled with an insulation layer; specifically, before installing the temperature measuring thermocouple rod in the hysteresis candidate hole 3, the insulation layer is filled in the hysteresis candidate hole 3 first, and then the temperature measuring thermocouple rod is inserted.

[0034] (3) Heat distribution test

[0035] Start the molding heating program and simultaneously record the temperature profiles of all candidate holes;

[0036] (4) Equivalent point confirmation

[0037] The leading candidate hole with the fastest temperature rise was identified as the leading thermocouple equivalent point of the part.

[0038] The candidate hole with the slowest temperature rise was identified as the equivalent point of the component's hysteresis thermocouple.

[0039] When the deviation between the tested candidate hole heating rate and the measured value of the part is greater than 5%, the candidate hole is moved to an adjacent candidate hole for retesting. For the hysteresis temperature measuring hole 3, the candidate hole position can be changed instead of retesting, and the insulation layer thickness can be adjusted before retesting.

[0040] Among them, the measured values ​​of the parts (the fastest measured heating rate and the slowest measured heating rate of the parts) are obtained in advance by setting thermocouples on a certain process specimen in the molding process.

[0041] Example

[0042] like Figure 1 As shown, this embodiment provides a heat distribution structure for molding tooling used to manufacture carbon fiber composite parts for aerospace applications. It includes a mold 1, which includes an upper mold 11 and a lower mold 12. The mold 1 is heated by heating with upper and lower hot plates (mold heat source) of a press.

[0043] The upper mold 11 and lower mold 12 of mold 1 are respectively provided with multiple leading temperature measuring holes 2. The diameter of the leading temperature measuring holes 2 is 10.2-10.5 mm. A PT100 thermocouple rod with a diameter of 10 mm is inserted into the leading temperature measuring hole 2. The leading temperature measuring hole 2 is 15-25 mm away from the heated surface of the mold (the outer surface of the mold).

[0044] The upper mold 11 and lower mold 12 of mold 1 are respectively provided with multiple hysteresis temperature sensing holes 3. The diameter of the hysteresis temperature sensing hole 3 is 12mm, and a PT100 temperature sensing thermocouple rod with a diameter of 6mm is inserted into it. The hysteresis temperature sensing hole 3 is located away from the molding heat source and close to the heat dissipation edge of the mold. In addition, the hysteresis temperature sensing hole 3 is filled with an insulation layer that wraps the temperature sensing thermocouple rod. The insulation layer is foam.

[0045] The area of ​​mold 1 with slow heat conduction is provided with a resistance heating rod mounting hole 4 for mounting a resistance heating rod. The resistance heating rod mounting hole 4 extends through to the surface of the mold cavity.

[0046] The temperature measurement arrangement method based on the heat distribution structure of the part molding tooling described above includes the following steps:

[0047] (1) Selection of candidate pore sites

[0048] At least two leading temperature measuring holes 2 are selected as leading candidate holes on mold 1; at least two lagging temperature measuring holes 3 are selected as lagging candidate holes.

[0049] (2) Thermocouple installation

[0050] Insert the corresponding thermocouple rods into the insulation layer in the leading candidate hole and the lagging candidate hole.

[0051] (3) Heat distribution test

[0052] Start the molding heating program and simultaneously record the temperature profiles of all candidate holes;

[0053] (4) Equivalent point confirmation

[0054] The leading candidate hole with the fastest temperature rise was identified as the component's leading thermocouple equivalent point.

[0055] The candidate hole with the slowest temperature rise was identified as the equivalent point of the component's hysteresis thermocouple.

[0056] When the deviation between the test-obtained candidate hole heating rate and the actual measured value of the part is greater than 5%, the hole is moved to another candidate hole for retesting. For the hysteresis temperature measuring hole 3, the candidate hole position can be changed instead of retesting, and the insulation layer thickness can be adjusted before retesting.

[0057] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention.

[0058] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A heat distribution structure for a part molding tooling, comprising a mold, characterized in that, The mold is provided with at least two leading temperature measuring holes for inserting temperature measuring thermocouple rods. The diameter of the leading temperature measuring hole is 0.1 to 0.5 mm larger than the diameter of the temperature measuring thermocouple rod inserted therein, and the leading temperature measuring hole is 5 to 35 mm away from the heated surface of the mold. The mold is also provided with at least two hysteresis sensing holes for inserting thermocouple rods. The diameter of the hysteresis sensing holes is 1 to 5 mm larger than the diameter of the thermocouple rods inserted therein. The hysteresis sensing holes are far away from the molding heat source and close to the heat dissipation edge of the mold.

2. The heat distribution structure of a part molding tooling according to claim 1, characterized in that, The hysteresis temperature measuring hole is filled with an insulating layer that wraps around the temperature measuring thermocouple rod.

3. The heat distribution structure of a part molding tooling according to claim 2, characterized in that, The insulation layer is one of the following: a foam layer, a heat-resistant plastic layer, and a ceramic wool layer, or a mixture of two or more of the following materials: foam, heat-resistant plastic, and ceramic wool.

4. The heat distribution structure of a part molding tooling according to claim 1, characterized in that, The mold has a resistance heating rod mounting hole in the slow heat conduction area for mounting resistance heating rods.

5. The heat distribution structure of a part molding tooling according to claim 4, characterized in that, The areas of the mold with slow heat conduction are the mold weight reduction grooves, reinforcing ribs, or structural areas with a wall thickness exceeding 40mm.

6. The heat distribution structure of a part molding tooling according to claim 1, characterized in that, The leading temperature measuring hole is located in the middle area of ​​the mold.

7. The heat distribution structure of a part molding tooling according to claim 1, characterized in that, The leading temperature measuring orifice has a diameter of 10.2–10.5 mm and is compatible with a PT100 temperature measuring thermocouple rod with a diameter of 10 mm; the lagging temperature measuring orifice has a diameter of 12 mm and is compatible with a PT100 temperature measuring thermocouple rod with a diameter of 6 mm.

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