Manufacture of members by molding or extrusion and systems

Abstract

The present invention shows a method for manufacturing a member by shaping and curing a raw material, the method comprising: a step of manufacturing a batch of the raw material; a step of determining at least one curing characteristic of a sample of the raw material; a step of shaping the raw material; a step of determining the time required for the shaped raw material to cure taking into account at least one curing characteristic; and a step of curing the shaped raw material until the determined time has elapsed. The present invention also shows a database and a system for manufacturing such a member.

Description

Technical Field

[0001] The present invention relates to the manufacture of a member by molding and curing a raw material. The molding can be performed, for example, by injection molding, compression molding, drawing, or extrusion. The raw material is injected into a mold for the manufacture of the member or is otherwise molded. The molded raw material is cured. The finished member can be removed from the mold after curing or, in the case of extrusion, can be obtained directly. The present invention also relates to a database and a system for manufacturing such members.

Background Art

[0002] The raw material needs to remain in the mold until it is sufficiently cured. To ensure the required curing is achieved, the raw material is usually retained in the mold for a longer time than the time required for curing. This reduces the productivity of the manufacturing process.

[0003] The paper "Framework of a Smart Injection Molding System Based on Real-Time Data" by Hwaseop Lee, Kwangyeol Ryu, and Youngju Cho, Elsevier, Procedia Manufacturing 11, 2017, 1004 - 1011, https: / / doi.org / 10.1016 / j.promfg.2017.07.206 is directed towards improving productivity in the field of injection molding. The paper "Prediction and Verification of Optimal Curing Conditions for Rubber Compositions" by Albrecht Becker and Roy Ovink, Rubber & Plastic News, March 23, 2020, pages 16 - 19, deals with improving curing conditions.

Summary of the Invention

[0004] An object of the present invention is to improve the manufacture of a member made, for example, from a raw material cured in a mold.

[0005] The problem of the present invention is solved by a method and a database including the features of claim 1, and a system including the features of the other independent claims. The dependent claims indicate preferred embodiments of the present invention.

[0006] The process of solving the problem of the present invention includes the following steps. A batch of raw materials is created. The raw materials are capable of being cured. At least one curing characteristic of the raw materials of this sample is required. The raw materials from the batch are injected into a mold or formed in another way. The time required for the formed raw materials to cure is determined taking into account one or more curing characteristics. The formed raw materials are cured until the determined time has elapsed.

[0007] A member is a piece created from raw materials by curing. Examples of members include: springs for keyboards, catheters, ventilator masks, hoses, cable insulators, seals, baby pacifiers, insulators for high-voltage wires, tires, electrical switches, household power outlets, conveyor belts, bellows, adjustment rings, pushers, handles for pots and frying pans, connectors and sensor housings, printed circuit boards, reflectors for vehicle headlights, and relays. These examples can be made from silicone rubber. Further examples of members include: adjustment rings, pushers, and handles for pots and frying pans. These examples can be made from phenolic resin. Further examples of members include: connectors and sensor housings, or printed circuit boards. These examples can be made from epoxy resin, melamine resin, or polyester resin. A further example is a reflector for a vehicle headlight, which can be made from BMC (bulk molding compound).

[0008] The raw materials cure based on a chemical reaction. The raw materials are materials that can be cured by crosslinking. The raw materials can consist of two or more components, which are mixed together and cured. At this time, these components can be manufactured separately from each other. These components are mixed immediately before manufacturing the members.

[0009] A batch of raw materials is a predetermined quantity of raw materials that is processed in one process or a series of processes and can be assumed to be uniform. In this case, there is no difference or at least little difference in the curing rate. For example, one or more raw material properties of the batch can be measured regularly. Thus, it is possible to determine whether one or more raw material properties have changed. If it is clearly determined that one or more raw material properties have changed, a new batch exists. For example, one or more thresholds can be specified for changes in one or more material properties. If one or more material properties change in such a way that they exceed at least one predetermined threshold, a new batch exists.

[0010] Within the scope of the present invention, a batch does not exist if the raw materials are always manufactured by the same processing unit in the same way without observing a predetermined quantitative limit such that if exceeded, one or more curing properties of the raw materials are redetermined. For example, if the raw materials or components of the raw materials are not continuously manufactured in a mixer and are thus batchwise, the quantity of raw materials manufactured in the mixer is a regular batch of raw materials, each a batch of components of the raw materials within the scope of the present invention. The weight of a batch manufactured in this way is typically up to 3 tons, or up to 10 tons especially in the case of LSR, or up to 20 tons especially in the case of EPDM. The weight of a batch manufactured in this way is typically at least 1 ton or 2 tons. Thus, if the raw materials contain several components, there may be one batch for each component, typically weighing up to 3 tons, or at least 1 ton or 2 tons.

[0011] The weight of the batch can be between 40 kg and 100 kg. This applies, for example, to LSR (liquid silicone rubber). The batch can weigh up to 250 kg. This is typical, for example, for car tires.

[0012] For example, when 3 tons are produced discontinuously in a mixer, then one or more curing properties can be measured and the curing time can be determined for it. Thereafter, when the same 3 tons of raw material or the same raw material components are produced again in a discontinuous manner in the mixer, one or more curing properties that enable the determination of the relevant curing time are measured again. In this case, 3 tons is a predetermined quantity within the scope of the present invention. Since the material is produced in the same way in the same mixer, it is uniform, and there is no possibility of variation in the curing properties due to different material properties of the starting material. Therefore, this is a batch within the scope of the present invention. If instead, the raw material or the components of the raw material are produced continuously without re-measuring one or more curing properties at regular intervals, then it is not a batch within the scope of the present invention.

[0013] A batch of raw material may be produced from two or more starting materials. In practice, a batch can be obtained as follows. As soon as a new batch of starting material is processed, it is treated as a new batch of raw material. Thus, the curing properties are then determined again.

[0014] In practice, the production period may be specified. When the production period ends, the subsequently produced raw material is treated as a new batch of raw material. At this time, the production period is selected to be short enough to ensure that the properties of the batch of raw material do not change or at least do not change significantly. In practice, quantitative aspects may be fixed. When a predetermined amount of raw material is produced, the subsequently produced raw material is treated as a new batch of raw material. The amount selected at this time is small so that the properties of the batch of raw material do not change or at least do not change significantly. And the maximum weight or maximum volume may be defined as the amount. When the production volume of the raw material reaches the maximum weight or maximum volume, the subsequently produced raw material is treated as a new batch of raw material.

[0015] One or more curing characteristics are characteristics of the raw material, and the curing time of the raw material of the sample is based thereon. The curing characteristics are material characteristics of the raw material of the batch and are used to determine the optimal curing time. If the raw material consists of more than one component, the curing characteristics of each component can be determined alternatively or additionally. According to the present invention, the curing characteristics are determined anew for each batch.

[0016] The formed raw material does not need to be fully cured in order to be removed from the mold or further processed. Typically, it is sufficient that the raw material in the mold, each formed raw material, has reached the desired degree of curing.

[0017] The determined time is the time at which the desired degree of curing is achieved. Then the cured member can be removed from the mold. This applies in particular also to raw materials that cure at room temperature. However, it is also possible to wait for a predetermined time to ensure that the desired degree of curing has been achieved.

[0018] The mold is a formed piece and includes a cavity for forming a liquid or flexible raw material. The mold may consist of two shells. One or more openings may extend into the cavity. This opening can be closed. The cavity can be cylindrical, for example, to produce a hose. The cavity can be in the shape of a baby's pacifier to produce a baby's pacifier. The cavity can be in the shape of a spring to produce a spring. The cavity can be in the shape of a ring to produce an annular seal.

[0019] The formed raw material may also be one created, for example, by a screen printing, dip coating, or inkjet printing process. A mold with cavities is not absolutely necessary to form the raw material. For example, to form the raw material, the raw material can be applied as a layer to a substrate. At this time, the raw material has the shape of a layer and is a formed material within the scope of the present invention.

[0020] The solution according to the present invention can significantly reduce the time required for curing. This is particularly applicable when manufacturing relatively large members, for example, weighing at least 1 kg. Overall, the measurement effort and / or calculation effort required to determine the curing characteristics is very large, and even if the measurement effort and / or calculation effort have to be repeated for each batch, a significant productivity benefit can be achieved. Further, if a new batch has new curing characteristics, it is necessary to immediately re-determine the time required to cure the formed raw material. It has been found that the amount of testing and calculation can increase by more than 50% for each batch of raw materials and for each component of the batch compared to what is normally done. However, it has been found that this can result in a saving of up to 30% in the curing time compared to the case where the curing time is not determined for each batch of raw materials and for each component of the batch. Overall, productivity can be greatly improved despite the initial additional effort. Surprisingly, the productivity benefit is very large and more than offsets the initial additional effort. Overall, the technical effort required to manufacture the member can be significantly reduced.

[0021] When the formed raw material is heated for curing, the supply of heat is stopped when a determined time has elapsed. When the formed raw material is irradiated for curing, the irradiation is stopped when a specified time has elapsed.

[0022] The raw material to be cured in the mold is taken out of the mold when a predetermined required time has elapsed. When the mold is heated to cure the raw material in the mold, the supply of heat can be stopped by immediately taking out the finished member when the determined time has elapsed. Therefore, the raw material stays in the mold only until a predetermined required time elapses using a batch sample. When the raw material is formed in some other way, the member can be taken out when a predetermined required time has elapsed using a batch sample. Thereafter, the next member can be manufactured at the same location.

[0023] The raw material can be one that manufactures a member made of an elastomer, a thermosetting resin, or other plastic by curing. Curing can result in a member made of, for example, silicone, rubber, or a thermosetting plastic. The curing process can include heating the raw material in the mold and heating the shaped raw material. The curing process can include irradiating the raw material with UV light.

[0024] LSR (Liquid Silicone Rubber), HCR (Mirable High Viscosity Rubber Silicone Solid Rubber), EPDM (Ethylene Propylene Diene Rubber), SBR (Styrene Butadiene Rubber), EPDM (Ethylene Propylene Diene Rubber), FKM (Fluororubber) are examples of raw materials.

[0025] EPDM (Ethylene Propylene Diene Rubber) is used to create window seals, cable sleeves, and insulators. SBR (Styrene Butadiene Rubber) is a component of tire mixtures added to NR (Natural Rubber). HNBR (High Density Nitrile Butadiene Rubber) is a typical material for dampers and bellows. FKM (Fluororubber) is a typical material for fuel lines.

[0026] Epoxy resin (Bakelite) for electronic components, ignition coils in ICE (Deutsche Bahn) are examples of raw materials.

[0027] The volume of the cavity of the mold can be several milliliters, for example at least 1 milliliter. The volume of the cavity can be several liters. Generally, the volume is less than 10 liters. However, volumes up to, for example, 60 liters, 100 liters, or 500 liters are possible. For example, the weight of a baby's pacifier can be 15 g. The corresponding volume of the cavity is just a few cubic centimeters. The weight of a high-voltage insulator can be from 5 to 8 kg. The corresponding volume of the cavity is several liters. For example, the weight of a single-contact connector can be from 0.1 to 0.2 g. The corresponding volume of the cavity is less than 1 milliliter.

[0028] The processing unit used to cure the raw material can include a plurality of cavities, whereby a plurality of members can be manufactured simultaneously.

[0029] In one embodiment of the present invention, a sample is taken from a batch. Then, one or more curing characteristics of the raw material of the sample are determined.

[0030] The sample is a very small portion taken from a batch. The volume and respective weight of the sample are selected to be large enough to determine at least one or more desired curing characteristics.

[0031] However, advantageously, the volume and respective weight of the sample are larger than the volume and respective weight necessary to determine the required curing characteristics. And the raw material of the sample can be stored so that the curing characteristics of the raw material can be re-determined at a later date. At this time, for example, if an error is detected, one or more stored curing characteristics can be corrected at a later date. The weight of such a sample is thus typically from 0.5 kg to 5 kg. The weight of such a sample can be 1 kg.

[0032] When the raw material contains several components, samples of each component are taken from each batch. At this time, the weight of each sample of each component is typically from 0.5 kg to 5 kg.

[0033] Generally, the time required to cure the formed raw material is calculated by a computer. There may be at least one mathematical formula that can calculate the time required to cure the formed raw material. Alternatively, the time required to cure the formed raw material can be determined by computer simulation. The calculation can be performed by a computer of the processing unit. Computer simulation may require a very high-performance computer. Therefore, computer simulation is preferably performed by a computer other than the computer of the processing unit.

[0034] The calculation can be performed using the Deng-Isayev model, the Sestak-Berggren model, or the Kamal model. All of these models describe the reaction kinetics of the vulcanization reaction in terms of a mathematical model and are capable of predicting the curing behavior for different thermal histories. Other mathematical models can also be used.

[0035] The time required for curing is preferably determined as a function of the processing unit used. If different processing units are used, one or more equations may be changed or the computer simulation may be adjusted. Two processing units are not constructed in the same way and thus are different if there are design differences. Adapting one or more equations and their respective computer simulations to the processing unit can further improve productivity. If the mold is changed within the processing unit, it will already have to re-determine the time required for curing. This is especially true if the mold cavities are different or the material from which the mold is made is different. However, once the time required for curing the molded raw material has been determined, there is no need to re-determine this time to manufacture the same member again. The same member means a member having the same shape and made by the same mold from the same batch of the same raw material. However, when manufacturing other members or using raw materials from a different batch, the curing time for manufacturing the members is re-determined. Thus, if the cavities of the processing unit are replaced with new cavities and their volumes and / or shapes are different, there are two different processing units within the scope of the meaning of the present invention.

[0036] Preferably, the processing unit includes a computer, which determines by calculation the time required for curing. The computer of the processing unit controls only that processing unit and / or performs calculations only for that processing unit. Thus, there is not one computer accessible via the Internet by a plurality of processing units, with that computer controlling the plurality of processing units and / or performing calculations for the plurality of processing units. It has been found that the computational effort for determining the time required for curing is small enough that the computer of the processing unit does not become overloaded. Since the processing unit always has its own computer, in this embodiment there is no need to provide a separate computer. This embodiment can also ensure that the software used to determine the required time is appropriate software adapted to the processing unit.

[0037] In one embodiment of the present invention, there is a database that stores one or more curing characteristics determined for each batch. The one or more curing characteristics are also stored for other batches. The database thus stores data that can be used to identify each batch. Thus, the data for identifying each batch is stored to find the batch to be searched and the associated one or more curing characteristics. The computer for determining the time required for curing is connected to or configured to be connected to the database. In particular, the computer can be connected to the database via the Internet. Each computer is set to search for the desired batch and obtain the associated curing characteristics. Each computer belongs to a processing unit that includes at least one mold or other means for shaping the raw material. This means that many different processing units can manufacture parts without requiring separate databases, and the curing characteristics are stored in the database for each processing unit. This further improves productivity.

[0038] According to the present invention, i.e., according to the system of the present invention, the curing time can be calculated in an automatic manner. Thus, in one embodiment of the present invention, the time for curing is not specified, and only the desired degree of curing is specified. Thereafter, the system according to the present invention automatically calculates the time required to achieve the desired degree of curing. Curing is then carried out by the processing unit according to the calculated time. The quality of the manufactured member can thus be improved and / or homogenized.

[0039] In one embodiment, each batch contains a code that can be used to identify that batch. This code, or information based on the code, can be transferred by a computer to a database. The computer can then obtain the curing characteristics belonging to that batch in such a manner. In particular, any of the computers described above can do this.

[0040] In one embodiment, the code contains the address of a database. For example, by reading the code, it is possible to automatically connect to the database.

[0041] In one embodiment, each batch contains information regarding the determined curing characteristics. Thus, by reading the determined curing characteristics or the corresponding code, the curing characteristics required for the manufacture of the member are obtained. In this case, a database is not necessary.

[0042] The determined curing characteristics or the corresponding code may be printed on the package of the batch. The determined curing characteristics or the corresponding code may be printed in the accompanying document of the batch. However, the determined curing characteristics or the corresponding code can also be electronically stored on a computer-readable storage medium. The storage medium may be an RFID chip.

[0043] The code can be a number or a combination of numbers and characters. The computer may include an input device through which a number or a combination of numbers and characters may be input. The code can be a barcode or a QR code. The computer can be connected to a code reader and thus, for example, to a barcode reader or a QR code reader. This connection can be a wireless connection. This connection can be a cable connection. The computer can read the code with the assistance of a barcode reader or a QR code reader. If the computer receives the code, the computer can obtain one or more curing characteristics via a database. If the computer receives one or more curing characteristics, the computer can determine the time required to cure the shaped raw material. Data exchange can be performed using a known interface such as the EUROMAP interface.

[0044] Alternatively, the code reader may be configured to connect to the database after reading the code. The code reader can be configured to receive the batch curing characteristics from the database after the connection is established. The code reader may be configured to send the obtained curing characteristics to the computer, and the computer determines the time required for curing.

[0045] In one embodiment, the code includes an electronic address through which the database can be accessed. This can be an internet address. Thus, it is ensured that the computer contacts the exact database for obtaining the curing characteristics.

[0046] In one embodiment, the code contains access data for its database. The access data may include, for example, a username and / or a user password. The database can thus be protected from unauthorized access.

[0047] A code reader can be a scanner or a mobile phone equipped with software that can be used to read codes. Preferably, to minimize the number of required devices, the mobile phone is the code reader. This is because virtually everyone owns a mobile phone with a camera function, and thus an existing mobile phone can be used. For this embodiment, it is only necessary to provide software that can be installed on a general mobile phone.

[0048] For the manufacture of a member, a feeding device can be provided, and using it, the raw material is sent from a container to a mold. The container may be coded. The feeding device may include a camera and can be used to read the code. Thus, the feeding device may include a code reader. When the material is liquid, such a feeding device can be a pump.

[0049] The curing characteristics of the material that can be used to optimize the manufacture of a member from the raw material formed by curing are heat capacity, thermal conductivity, and heat transfer rate. This is applied to the raw material that is heated to rapidly cure the formed raw material.

[0050] Other material properties that can help determine the curing time for the formed raw material are density and viscosity. In fact, by injecting the raw material into the mold, the raw material is heated. Material properties that can determine this effect can be a matter of concern so that this can be taken into account. Density or viscosity, when used to determine the curing time, are curing characteristics within the scope of the meaning of the present invention.

[0051] In one embodiment of the present invention, when the raw material is heated for rapid curing in a mold, one or more curing characteristics of each of the batches and batch samples are determined at several different temperatures and stored in a database. Preferably, one or more curing characteristics are determined at at least three different temperatures. Measuring at three different temperatures is sufficient to predict the curing behavior at another temperature. For this reason, it is advantageous to measure at three different temperatures.

[0052] To further increase the accuracy of the prediction, the curing characteristics can be measured at more than three temperatures. However, in that case, the prediction accuracy is not significantly improved. Therefore, technically, it is reasonable to measure the curing characteristics only at three different temperatures.

[0053] When the curing characteristics are measured only at three different temperatures, the difference between two adjacent different temperatures is preferably at least 10°C. The difference between two adjacent temperatures preferably does not exceed 20°C.

[0054] This temperature range is preferably selected in such a way that the temperature predicted to be applied to the curing of the shaped raw material is within the selected temperature range.

[0055] For example, the temperature predicted to be applied to the curing of the formed raw material is 130°C. In this case, a temperature range of 120°C to 150°C can be selected. Also at this time, 150°C can be selected as the first temperature of the temperature range. Then 135°C can be selected as the second temperature of the temperature range. Then 120°C can be selected as the third temperature of the temperature range. Then the temperature difference between two adjacent temperatures is 15°C, and thus is at least 10°C and does not exceed 20°C. Then, at least one curing characteristic is measured at three different temperatures: 150°C, 135°C, and 120°C. However, the temperature predicted to be applied for curing can be lower. For example, in the case of silicone, the maximum temperature must not exceed 130°C, preferably 120°C. Then at least one curing characteristic may be measured at the following three different temperatures: 120°C, 110°C, and 100°C, or 120°C, 100°C, and 80°C.

[0056] For example, the curing characteristics may be measured at the following three different temperatures: room temperature, 35°C, and 50°C.

[0057] Thus, one or more curing characteristics of the sample are determined at a plurality of different temperatures and stored in a database, and the productivity in one embodiment of the present invention is further improved. Therefore, the first predetermined temperature can be, for example, between 110°C and 170°C. The second predetermined temperature can thus be, for example, between 110°C and 160°C. Thus, the third predetermined temperature can be, for example, between 90°C and 150°C. Thus, the first temperature can be 110°C, the second temperature can be 100°C, and the third temperature can be 90°C. However, the first temperature can be 170°C, the second temperature can be 160°C, and the third temperature can be 150°C. Thus, the first temperature can be 150°C, the second temperature can be 130°C, and the third temperature can be 110°C.

[0058] The first predetermined temperature can be between 100°C and 130°C. The second predetermined temperature can be between 110°C and 80°C. The third predetermined temperature can be between 100°C and 70°C. This applies in particular to silicone.

[0059] Preferably, the determination of one or more curing characteristics includes determining the curing state at a given temperature as a function of time. It can be a curve that is determined and stored in a database. Such a curve may show the degree of curing as a function of time at a given temperature. The degree of curing may be represented by torque or curing state. The curing state as a function of time t (also called "SoC") is given by the equation: SoC(t)=(M(t)-ML) / (MH-ML) where ML is the measured minimum torque, MH is the measured maximum torque, and M(t) is the torque measured as a function of time.

[0060] However, the determination of the curing characteristics may also include that only some typical curing characteristics are determined. As a curing characteristic, a time tX may be determined at a given temperature. tX is the time required to reach MX at a given temperature, where MX=(MH-ML)×0.X+ML. For example, X may be 90. Then t90 is the time required to reach M90, where M90=(MH-ML)×0.9+ML. t90 is considered to be the optimal curing time for high-quality production in many processes.

[0061] Another typical time of particular interest is the time t50. t50 is the time required to reach M50 at a given temperature, where M50=(MH-ML)×0.5+ML.

[0062] Another typical time of particular interest is time t60. t60 is the time required to reach M60 at a given temperature, where M60 = (MH - ML) × 0.6 + ML.

[0063] Thus, time t90, t60 and / or t50 may be determined as curing characteristics for the sample at one or more predetermined temperatures.

[0064] In one embodiment of the present invention, time t0.2 and / or t10 may be determined as curing characteristics for the sample at one or more predetermined temperatures. t0.2 can be the time at the end of the incubation stage. The torque then increases gradually and curing is initiated. t10 often represents the first stage of curing. Thus, it can be useful to determine times t0.2 and t10.

[0065] Torque can be measured by a rheometer test on a moving die rheometer at a constant temperature. The moving die rheometer is also known as an MDR. Another measuring device that can be used to determine appropriate curing characteristics is a rubber processing tester, also known as an RPA. The RPA can be used to perform a rheology test procedure for analyzing raw material elastomers. The RPA operates, for example, in the range up to 230 °C.

[0066] In one embodiment of the present invention, not only are the curing characteristics of the raw material of the sample determined and stored in a database, but other material characteristics that are not used to determine the curing time of the shaped raw material are also determined and stored. When the raw material is heated in a mold, the material expands within the mold. It may be necessary to take this expansion into account in order to produce a member without defects. Thus, one or more material characteristics regarding the coefficient of expansion of the raw material or the components of the raw material may be determined and stored in the database. Thus, for improving the manufacture of the member, yet another material characteristic can be stored in the database in a retrievable manner.

[0067] From the stored curing characteristics, it is necessary to calculate how the formed raw material cures. This is because the curing rate of the formed raw material also depends on the characteristics or type of the mold. This is based on the fact that, for example, the volume inside the formed raw material is heated at different rates.

[0068] For example, the computer can use simulation software called Sigma 3D as an example. The computer may first determine how quickly, completely or 90% the formed raw material cures at a temperature that may be between two of the three temperatures stored in the database.

[0069] In the mold, the heat applied from the outside is transferred at different rates. Therefore, the regions and volumes inside the mold are cured at different rates. Computer simulation can be used to determine the volume part that cures most slowly inside the formed raw material. The simulation software determines how much time is required for the raw material in the volume part to cure in a desired manner, that is, to reach the desired degree of curing. When this determined time has elapsed, the thus finished member can be taken out of the mold.

[0070] The formed raw material may cure particularly rapidly at a temperature of, for example, 220°C. However, this does not mean that it is preferable to cure at this temperature of 220°C. The reason is that a very high temperature causes significant expansion of the material and may cause problems. In addition, high temperatures can have a negative impact on the filling process, because the material may cure in a narrow cross-section part during the injection stage. Therefore, the temperature for curing must be selected so that no excessive problems occur. During heating, the formed raw material cures. Therefore, the time of the heating process should not be too long. Also for this reason, it is not preferable to cure the formed raw material at a temperature that maximally accelerates curing.

[0071] In order to cure such materials at a desired temperature within the mold, it is preferable to set the mold to the desired temperature. Heat is then transferred from the mold to the raw material being molded. Thus, the mold is preferably made of a metal that transfers heat well.

[0072] The temperature of the mold is preferably kept constant and not changed even when the batch of raw material is changed and the curing characteristics change. In this embodiment, when the curing characteristics are changed, then a new time for filling / hardening the molded raw material within the mold is determined. Alternatively or complementarily, the raw material can be given a different initial temperature when it is placed in the mold.

[0073] For example, the temperature of the mold is set at a constant 140 °C. Based on the curing characteristics, it has been determined that the raw material within the mold must be cured for 5 seconds to achieve the desired degree of curing. For example, the desired degree of curing may be full curing. At this time, the initial temperature of the raw material is, for example, 20 °C. The initial temperature is the temperature of the raw material when it is still outside the mold but is in a state where it can be placed in the mold in an appropriate manner. Since the raw material is from a different batch, the curing characteristics are changed here. Then a new curing time is determined by a computer and / or a new initial temperature of the raw material is determined. Then, for example, it may be determined that due to the batch change, the curing time has become 6 seconds at 140 °C.

[0074] In one embodiment of the present invention, one or more curing characteristics are also used to predict the technical effort required to manufacture the member. According to the present invention, for a specified raw material batch and mold shape, it is possible to predict how long the curing time will be. Since the curing time can be predicted very accurately, for example, it is possible to very accurately predict how many members can be manufactured per unit time, for example, per hour. Thus, the delivery time can be predicted very accurately. This enables, for example, optimizing subsequent manufacturing processes. This is particularly the case when the manufactured member is required for the manufacture of other items. Other stored material characteristics can also be advantageously used in this way.

[0075] In one embodiment of the present invention, there is a control unit that completely automatically controls the curing process. In this case, there is no need to manually input the changed curing time into the processing unit. Instead, the control unit completely automatically registers, for example, when the curing characteristics of the raw material are changed, and automatically adjusts the curing time. After the curing time has elapsed, the processing unit may completely automatically eject the manufactured member from the mold. The computer of the processing unit configured to shape the raw material and also configured to cure the shaped raw material may be the control unit.

[0076] In one embodiment of the present invention, the processing unit used to shape the raw material and then cure the shaped raw material is assigned a processing unit code. Through this processing unit code, the processing unit can be identified. The processing unit code applied to the processing unit is then read by a code reader.

[0077] In one embodiment, when the control unit is not a computer of the processing unit, the code reader is configured to transmit the read processing unit code of the processing unit to the control unit. In this way, the control unit knows which processing unit is being used. This makes it particularly easy to perform fully automated manufacturing.

[0078] In one embodiment, the code reader is configured to establish a data connection to the computer of the processing unit after reading the code of the processing unit. This data connection can be a wireless data connection, such as a Bluetooth connection or a Wi-Fi connection. Subsequently, the code reader can send the necessary information to the computer so that the member can be automatically manufactured. For example, the curing characteristics obtained by the code reader from the database can be sent to the computer.

[0079] The processing unit code can be a code similar to the codes described above. For example, it can be a barcode or a QR code.

[0080] In one embodiment of the present invention, the manufactured article is marked and made uniquely identifiable. Thus, batches (raw materials) can be clearly assigned. This means that the manufacturing time, processing unit, and cavity can be clearly assigned to the manufactured article. This mark may be, for example, a number or a combination of numbers and letters. This mark may be, for example, generated by a laser. Thus, fully automated manufacturing will be traceable. For this purpose, the control unit stores at least when, by which processing unit, and in which cavity of the processing unit the member was manufactured. Preferably, manufacturing conditions such as the curing time and / or curing characteristics of the raw material are also stored. For example, if it is later found that the manufactured member has a defect, it can be determined how and by which processing unit the member was manufactured. Then, it can be analyzed why the defect occurred. Defects found in this way can be avoided in the future.

[0081] The present invention enables an automated method for shortening the curing time caused by batch-to-batch variations in the molding and extrusion processes of crosslinkable materials such as rubber or duroplastics by using simulation software that predicts the slowest curing rate in rubber or duroplastic members or profiles.

Brief Description of the Drawings

[0082] A schematic diagram explaining the principle of the present invention is shown in FIG. 1.

[0083] Batches of curable raw materials are being manufactured. Sample 1 is taken from the batch by the supplier of the batch of raw materials. The supplier determines the curing characteristics 2 of the raw material of Sample 1 at three different temperatures. The supplier stores the curing characteristics 2 as data in the database 3. The supplier generates a QR code 4 and attaches the QR code 4 to the package of the batch of raw materials.

[0084] The manufacturer of the component receives a batch of raw materials that already does not contain samples. The manufacturer's code reader 5 reads the QR code on the package of the raw materials. The code reader 5 sends the code to the database 3. In response, the database 3 sends the stored curing characteristics 2 belonging to that batch of raw materials to the code reader 5. The code reader 5 sends the received curing characteristics 2 to the processing unit 6, and the processing unit manufactures the component from the batch of raw materials by molding and curing. The processing unit 6 includes a computer 7. The computer 7 calculates three different curing curves 8, 9, 10 for three different temperatures T1, T2, T3 from the received material characteristics. The temperature of the cavity of the processing unit is T0. T0 is a temperature between the temperatures T2 and T3. Based on the three different curing curves 8, 9, 10, the computer 7 calculates a curing curve 11 for the temperature T0. The computer 7 knows how much time is required to fully cure the raw materials in the mold based on the calculated curing curve 11. And the computer controls the curing process in such a way that the curing time is as short as possible to optimize productivity.

[0085] In this example, the computer 7 can be a computer that uses a Sigma 3D or other simulation program to generate the "master equation", i.e., the equation used to calculate the volume portion that cures the slowest. The volume portion of the cavity that cures the slowest is the volume portion where the curing time is the longest.

[0086] This equation can take into account the kinetic characteristics of the reaction of the material and can be transferred to the processing unit 6 (e.g., via USB or WLAN). This equation then describes the shape or geometric boundary conditions of the component to be manufactured, and they are assigned to the processing unit 6 after the equation is transferred to the processing unit 6. The relationship between the batch of material (having different curing kinetic properties for each batch) and the master equation can then be implemented in the processing unit 6.

[0087] A schematic diagram of the processing unit 12 (as an example of the processing unit 6 in FIG. 1) is shown in FIG. 2. The processing unit 12 may include a mixing unit. The mixing unit may include two containers 13 for storing batch materials and mixing equipment for mixing the batch materials. The processing unit includes a cavity 14 and a feeding system 15. The feeding system 15 can feed the mixed batch materials into the cavity 14.

[0088] The processing unit may include a plurality of cavities 14.

[0089] To investigate the influence of batch-to-batch variations in the material, one economically relevant grade of liquid silicone rubber was selected for investigation. During such investigations, variations in the curing behavior were tracked for 93 batches, particularly at times t10, t60, and t90, to identify the slowest and fastest curing batches. For time t90, the difference between the slowest curing LSR and the fastest curing LSR, measured on a rubber processing tester, was 100% (1.5 minutes and 3.0 minutes). The difference in time t60 between the slowest curing LSR and the fastest curing LSR was 1.1 minutes and 1.6 minutes, measured on a rubber processing tester. The difference in time t10 between the slowest curing LSR and the fastest curing LSR was 1.0 minute and 1.1 minutes, measured on a rubber processing tester.

[0090] For these data, curves were manually fitted using the Isayev-Deng mathematical model, thus generating a data package for the Sigma 3D material library and known 3D simulation software. Figure 3 shows the fitting of the slowest curing batch material (black squares) and the fastest curing batch material (white squares) based on the values of times t10, t60, and t90. In Figure 3, the degree of crosslinking D is plotted against the time t in seconds. For the Isayev-Deng model, the following values were determined: for the slowest curing batch material, T0 = 32500, t = 4.80E-36, n = 3.2, k0 = 3.12E+24, E0 = 1.522, R = 8.31448; and for the fastest curing batch material, T0 = 30000, t = 3.84E-33, n = 4.05, k0 = 3.21E+24, E0 = 1.520, R = 8.31448. Using these data, it is possible to simulate the heating time of a representative mold (a mold for a 2 mm test sheet and also usable for trial molding), and also to identify the curing times of the slowest and fastest curing batch materials, thus identifying the productivity differences between these two batches. This simulation shows a reduction in heating time between the slowest and fastest curing batches, which was between 10 and 60% based on the mold temperature. Figure 4 shows a temperature curve comparing the theoretical temperature on the vertical axis and the measured temperature on the horizontal axis, where T is the mold temperature, C-R means cold runner, and R-M means the actual mold. In Figure 4, the top curve shows the set temperature of the device (set [°C]). The other two curves show the temperatures measured at two different positions within the mold. The middle curve "actual mold [°C]" shows the position inside the mold. The bottom curve "cold runner [°C]" shows the position of the cold runner section. The cold runner means the passage to the actively cooled cavity. R 2 means the correlation factor determined by curve fitting.

[0091] To verify the simulation results, in actual molding trials, the trials were repeated on comparable molds. In these trials, molds for 2 mm test sheets as described above were used. Based on calculations, the coldest and thus slowest curing part is the gate area. This area is also the interface between the cold runner and the hot mold surface. As a result, this interface is significantly colder than the rest of the mold, thus resulting in the slowest curing of the material (confirmed by actual mold measurements).

[0092] This effect provides an excellent opportunity to investigate the actual curing process. Since the surface of each molded member warps easily in case of insufficient curing, the gate area was used as an indicator of the curing time.

[0093] The simulation results were confirmed by this molding test, and a large difference was also confirmed between the fastest curing material batch and the slowest curing material batch. Figure 5 shows the curing times plotted against the set mold temperature for the slowest curing batch material (upper curve) and the fastest curing batch material (lower curve). Figure 5 shows that there is a significant saving in time, especially in the low temperature region.

[0094] At low temperatures (up to 140 °C), the curing time reduction is approximately 60%, and considering the off - times of processes such as mold opening and closing times and demolding, a productivity improvement of > 50% is achieved. At higher temperatures, the process advantages are smaller (about 10% reduction in curing time at 170 °C).

[0095] For members with a small surface - to - volume ratio (high - voltage LSR insulators) molded at low temperatures due to long filling times, the predicted productivity benefits are significant.

Claims

1. A method for manufacturing a component by molding and curing raw materials: The process of manufacturing batches of raw materials; A step of determining at least one curing property of the raw material of a sample; The process of molding raw materials; A step of determining the time required for a molded raw material to harden, taking into account at least one hardening characteristic; and A method comprising the step of curing molded raw materials until a determined time has elapsed.

2. The method according to claim 1, wherein the molded raw material is heated to harden, and the heat supply is stopped when a predetermined time has elapsed, or the molded raw material is irradiated to harden, and the irradiation is stopped when a predetermined time has elapsed.

3. The method according to claim 1, wherein raw materials are placed in a mold, and the molded raw materials are hardened by heating the mold.

4. The method according to claim 3, wherein the finished component is removed from the mold immediately after a predetermined time has elapsed.

5. The method according to claim 1, wherein a processing unit (6) for molding raw materials and curing the molded raw materials includes a computer (7) that calculates the time required for curing.

6. The method according to claim 1, comprising processing a database (3) storing one or more curing properties (2) of each batch.

7. The method according to claim 1, wherein each batch includes a code (4) that can be used to identify the batch, and the code may be attached to the batch package.

8. The method according to claim 7, wherein a code reader (5) reads a code (4), connects to a database (3) after reading the code (4), receives the curing characteristics of a batch from the database (3) after the connection is established, and sends the acquired curing characteristics (2) to a computer (7) that determines the time required for curing.

9. The method according to claim 8, wherein the mobile phone is a code reader (5).

10. The method according to claim 1, wherein the curing properties (2) of one or more batches of raw materials are determined at several different temperatures.

11. The method according to claim 1, wherein a processing unit configured to mold raw materials and to cure molded raw materials includes a code (4), and a code reader (5) establishes a wireless data connection to a computer (7) of the processing unit after reading the code (4).

12. A database (3) for performing the method according to claim 1, which stores one or more curing properties (2) of each batch and is accessible via the Internet.

13. The curing characteristics for each batch are determined and stored at three different temperatures in the database (3) according to claim 12.

14. A system comprising a database (3) according to claim 12, and a processing unit for performing a method according to one of claims 1 to 11.

15. The system according to claim 14, wherein the processing unit includes a mold and a heating means for heating the mold.

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