Method for Controlling a Casting Plant
A method for controlling a casting plant has at least one mould for receiving a fluid material, the fluid material solidifying in the mould during a solidifying time, at least one process parameter being detected during the production process and the solidifying time being determined in accordance with the process parameter detected.
The invention relates to a method for controlling a casting plant having at least one mould for receiving a fluid material, the fluid material solidifying in the mould during a solidifying time. The invention further relates to a casting plant having at least one mould, a casting plant system comprising this casting plant, a computer programme and a computer programme product.
Motor components but also other components are nowadays produced by a casting process in casting plants. During the casting process, a solid member having a specific shape in accordance with the shape of the mould is produced from a fluid material after the material has solidified. In this instance, a constant concern is to configure the production process in an efficient manner and in particular to improve the production speed in addition to reducing incorrectly produced components.
During casting, the efficiency of the production process is particularly dependent on the solidifying time, that is to say, the time during which the initially fluid material cools and solidifies in a mould of the casting plant so that it can be removed from the mould. The solidifying time also significantly determines the cycle time and consequently the production rate of the production process.
In conventional methods for controlling a casting plant of the prior art, the solidifying time is a constant time period. In other words, a cast component is always removed from the mould after the same time. In this instance, the solidifying time is generally configured at maximum load with regard to the operation of the casting plant in order to increase production.
However, a problem in the prior art is that, on the one hand, the casting process is subjected to a plurality of non-constant factors which can be influenced only to a limited extent or not at all. This includes, for example, the ambient temperature of the casting plant or the temperature of the materials used.
On the other hand, undesirable and unavoidable interruptions to the casting process occur again and again, for example, as a result of defective components, maintenance work, technical errors, etc. After an interruption, the casting plant has to be re-started once more and the mould in particular has to be brought back to temperature. However, since the solidifying time is configured to be constant and for operation at maximum load, interruptions and unavoidable influences with respect to the casting process result in defective components. On the other hand, a constant solidifying time may also result in a component remaining in the mould for longer than is necessary.
Therefore, an object of the present invention is to provide a method for controlling at least one casting plant, which method allows more efficient production of components, particularly even under non-optimum conditions.
The object which is previously derived and set out is achieved according to a first aspect of the invention by a method for controlling a casting plant having at least one mould for receiving a fluid material, the fluid material solidifying in the mould during a solidifying time. The method comprises the steps that at least one process parameter is detected during the production process and the solidifying time is determined in accordance with the process parameter detected.
Unlike the prior art, the solidifying time is not predetermined as a constant time according to the invention but instead it is variable and is determined during the production process in accordance with at least one process parameter. In other words, the solidifying time may change during the production process in accordance with a detected process parameter.
A casting plant having at least one mould is controlled with the method according to the invention. A mould which may in principle have any shape in accordance with the set shape of the component to be produced is filled with a fluid material. The initial material may preferably be a fluid metal. In order to fluidise a metal, it is heated accordingly.
The fluid and hot material introduced into the mould cools in the mould and solidifies to form a solid member. The solidifying time, that is to say, the time period between the mould being filled and the time of removal of the cast component, is determined according to the invention in accordance with a process parameter detected during the production process.
The term process parameter is intended to be understood to be a parameter which is characteristic of the casting process or which influences it directly or indirectly. In particular, the process parameter is a parameter which is characteristic of the solidifying time or which influences it directly or indirectly.
By the solidifying time being determined (automatically) according to the invention in accordance with a parameter detected during the production process, the reject rate can be reduced. The production rate and the efficiency of the production method can also be significantly increased even under non-optimum operating conditions. In particular, interruptions to the production process and unavoidable influences may be taken into consideration by the method according to the invention. Even small reductions in the cycle time in the order of seconds result in significantly higher production rates.
In principle, the at least one process parameter can be detected at any times. According to a first embodiment of the method according to the invention, a current process parameter can be detected during a casting process of a component to be produced. The term casting process is intended to be understood to be an individual casting operation of a component during the production process of a large number of components. In particular, at least one current process parameter can be detected for each component to be cast during the casting process of the corresponding component. The solidifying time for the component (currently) to be produced can preferably be determined in accordance with the detected current process parameter. In other words, the solidifying time of the component to be cast may depend (directly) on a current process parameter. Current influences and particularly changes with respect to the casting process can be taken into consideration (in a timely manner). In particular (automatic) real-time control of the solidifying time is possible. The cycle time and quality can be improved.
According to a preferred embodiment of the method according to the invention, the at least one process parameter can be detected continuously. Continuous detection of a process parameter at least during the casting process of a component (currently) to be cast results in exact and (constantly) current measurement values. Alternatively, the process parameter may be detected at predeterminable time intervals, in particular at periodic time intervals. The time intervals may particularly be selected so that the measurement values are sufficiently current to be able to take into consideration, for example, influences which act on the casting process in an adequate and timely manner. For example, a value may be detected every second, preferably every half second.
It will be understood that a plurality of different process parameters of the production process, in particular the casting process, can be detected. Different process parameters can also be detected in different manners, that is to say, continuously or at predeterminable time intervals.
Furthermore, the determination of the solidifying time can be carried out according to another embodiment of the method according to the invention in accordance with a comparison of the detected process parameter with at least one set process parameter. A set process parameter, such as a limit value, may be predetermined. By comparing the (current) process parameter with a suitable set process parameter, the solidifying time can readily be determined. For example, the set process parameter can be predetermined so that, when the current process parameter exceeds or falls below the set process parameter, this indicates the time from which the mould can be opened. In other words, at least one condition can be predetermined so that, when the condition is fulfilled, adequate solidifying of the material has been carried out and the cast component can be removed.
At least two set process parameters may preferably be provided for a process parameter. An upper and a lower limit value which define a permitted range may further be predetermined. Only if the current process parameter is in this range can the mould be opened. Furthermore, additional set criteria can be predetermined. For example, it may be considered in a continuously changing process parameter whether it is (currently) changing in an increasing or decreasing manner.
In principle, different process parameters of the production process are suitable for determining the solidifying time.
Process parameters which characterise or influence the solidifying time may preferably be detected. It has been recognised that the temperature of the mould or the temperature of the material located in the mould is particularly suitable for determining the solidifying time. In particular, it is possible to derive from the temperature of the material in the mould whether the initially fluid material has solidified (sufficiently) and whether the mould can be opened. A set value temperature may preferably be predetermined, at which it is ensured that the fluid material used has solidified to such an extent that a cast component can be removed. In other words, the optimum removal time can be determined for each component. The removal time, that is to say, the variable solidifying time, may particularly depend on the current temperature of the material or component. On the one hand, an excessively early removal time at which adequate solidifying has not yet begun can be prevented. On the other hand, unnecessarily long solidifying times can be prevented. The cycle time can be improved with a simultaneous reduction in the number of defective components.
As already described, additional criteria may be predetermined. For example, it may be considered whether the temperature of the mould or the temperature of the material in the mould is increasing or decreasing. For instance, when the mould is filled, the detected temperature may initially increase and accordingly initially be below a set value. In order to nevertheless ensure that the material has solidified, the temperature progression can be taken into consideration. It is possible to conclude from a decreasing temperature progression that the material is cooling and solidifying. In addition to reaching, falling below or exceeding a set temperature, there may be provision for the temperature progression to be decreasing in addition to determining the solidifying time.
It will be understood that the temperatures of the mould and the material in the mould can be detected according to other variants of the invention.
Furthermore, according to another embodiment of the method, the solidifying time of the component to be produced can be determined in accordance with the solidifying time of at least one previously produced component. In Particular, results from previous casting processes may be stored and considered. For example, it is possible to conclude a defective measurement from an unusual discrepancy between the current solidifying time and the solidifying time of the previously cast component.
In order to prevent excessively early opening of the mould in the event of incorrect detection of the (current) process parameter, at least one set solidifying time may preferably be predetermined. For example, at least one minimum set solidifying time may be predetermined. The minimum set solidifying time may particularly be selected so that at least adequate solidifying of the material has begun, which solidifying prevents fluid material from flowing out of the mould when the mould is opened and resulting in damage to the casting plant or other devices. Furthermore, a maximum set solidifying time may be predetermined. Incorrect measurement of the at least one process parameter may result not only in a condition, such as a set process parameter being reached, being achieved too early, but also in a condition not being achieved or being achieved too late. In order also to allow removal in this instance, a maximum set solidifying time may be predetermined, the mould being able to be opened and the component being able to be removed (always) when the maximum set solidifying time has been reached. It will be understood that corresponding errors can be displayed for a user.
According to a particularly preferred embodiment of the method according to the invention, the above-described criteria, in accordance with which the solidifying time, that is to say, the removal time of the cast component, can be determined, may be taken into consideration in a formula. For example, different conditions can be associated with each other logically in a formula. In particular, a set value temperature being reached may be associated with the conditions that the temperature progression is decreasing and a minimum solidifying time has been exceeded.
According to another embodiment of the method, the at least one set process parameter may further be determined before the production process. All the set values, in particular a previously described formula, may preferably be determined before the production process. In particular, the at least one set solidifying time can be established before the production process.
According to another preferred embodiment, the at least one set process parameter can be determined in accordance with the fluid material, the casting plant, the state of the casting plant and/or the shape of the mould. For example, different fluid materials may have different solidifying temperatures. Therefore, the at least one set temperature may be different for different materials. Similarly, the mould shape used, for example, the size, diameter thereof, etcetera, may require different set process parameters in order to achieve optimum results. However, different casting plant types and the state of the casting plant may also have some influence on an optimum solidifying time. It will be understood that other criteria may be used for determining the set process parameter. It will also be understood that a set solidifying time can also be determined in a similar manner in addition to a set process parameter.
There may further be provision for the at least one set value parameter also to be able to be determined (again) during the production process at predeterminable time intervals.
Another aspect of the invention is a casting plant having at least one mould for receiving a fluid material. In the casting plant, there is provided at least one sensor device which is configured to detect at least one process parameter during the production process and there is provided at least one control device which is configured to determine the solidifying time in accordance with the detected process parameter.
The casting plant is particularly constructed to carry out the above-described method.
The casting plant further comprises at least one mould having a predeterminable shape. The shape is particularly dependent on the component to be produced. The mould may be filled with a fluid material, such as a metal or the like. After the material has solidified, the mould may be opened and the solidified component may be removed.
At least one suitable sensor device is further provided in order to detect at least one previously mentioned process parameter during the production process and in particular during a casting process.
A control device is further provided. The control device, for example, a microcomputer, a Digital Signal Processor (DSP) or the like, is configured to process the detected process parameter and to determine the optimum solidifying time, that is to say, the removal time, for the cast component in accordance with the process parameter.
The production rate and the efficiency of the production method can be significantly increased even under non-optimum operating conditions.
According to a first embodiment of the casting plant according to the invention, the sensor device may be a temperature sensor. The temperature sensor may particularly be arranged on or in the mould. A process parameter which is significant for the casting process can be detected by means of a suitable temperature sensor.
According to a preferred embodiment of the casting plant according to the invention, the temperature sensor may be arranged in such a manner that the temperature of the material in the mould can be detected. As already described, the solidifying time actually required is dependent (inter alia) on the temperature of the material in the mould. For example, the temperature of the mould can be measured. The temperature of the material in the mould can be derived from this temperature.
In principle, the temperature of the material in the mould may be detected in a contactless manner or with contact. In a particularly preferable manner, the at least one temperature sensor may be arranged in such a manner that the temperature sensor directly contacts the material in the mould. The temperature can be detected in a particularly precise manner. The at least one set temperature value can thereby be set practically without any tolerance as a result of measurement inaccuracies. The cycle time may be significantly reduced without any loss of quality.
Another aspect of the invention is a casting system comprising at least one above-described casting plant and a central control unit configured to determine at least one set process parameter.
The casting system may also have two or more casting plants which can communicate with the central control unit. The central control unit, in particular a central processing device having a database, may be in the form of a superordinate control unit. For example, information concerning the casting plant, such as the state of the casting plant, the shape of the mould, etcetera, and concerning the components to be produced and initial materials, can be stored in the database. At least one optimum set process parameter, preferably a previously described formula for determining the solidifying time, can be derived from that information. Information from a plurality of casting plants which are connected to the central control unit can further advantageously be used in order to determine an optimum set process parameter, preferably a formula for determining the solidifying time.
Another aspect of the invention is a computer programme having instructions which can be carried out on a processor in such a manner that a casting plant is controlled by means of the above-described method.
Yet another aspect of the invention is a computer programme product comprising an above-described computer programme having instructions which can be carried out on a processor in such a manner that a casting plant is controlled by means of the above-described method.
According to another embodiment, there is provided a method for controlling a casting plant having at least one mould for receiving a fluid material, the fluid material solidifying in the mould during a solidifying time, at least one process parameter being detected during the production process and the solidifying time being determined in accordance with the detected process parameter.
According to another embodiment, a current process parameter is detected during a casting process of a component to be produced and the solidifying time for the component to be produced is determined in accordance with the detected, current process parameter.
According to another embodiment, the process parameter is detected continuously or at predeterminable time intervals.
According to another embodiment, the determination of the solidifying time is carried out in accordance with a comparison of the detected process parameter with at least one set process parameter.
According to another embodiment, the process parameter is the temperature of the mould or the process parameter is the temperature of the material in the mould.
According to another embodiment, the solidifying time of the component to be produced is determined in accordance with the solidifying time of at least one previously produced component.
According to another embodiment, at least one set solidifying time is predetermined.
According to another embodiment, at least the set process parameter is determined before the production process.
According to another embodiment, the set process parameter is determined in accordance with the material, the casting plant, the state of the casting plant and/or the mould shape.
According to another embodiment, a casting plant having at least one mould for receiving a fluid material is provided, there being provided at least one sensor device configured to detect at least one process parameter during the production process and there being provided at least one control device configured to determine the solidifying time in accordance with the detected process parameter.
According to another embodiment, the sensor device is a temperature sensor, the temperature sensor particularly being arranged on or in the mould.
According to another embodiment, the temperature sensor is arranged in such a manner that the temperature of the material in the mould can be detected.
There are now a large number of possibilities of configuring and developing the method according to the invention for controlling at least one casting plant, the casting plant according to the invention, the casting plant system according to the invention, the computer programme according to the invention and the computer programme product according to the invention. To this end, reference may be made, on the one hand, to the patent claims which arc subordinate with respect to the independent patent claims and, on the other hand, to the description of embodiments in conjunction with the drawings, in which:
The casting plant 4 illustrated is configured to produce, in particular to cast, components 6. For example, motor components or the like can be cast. To this end, a fluid material 8, such as a fluid metal, is provided. The metal may be in particular aluminium or an aluminium alloy.
The fluid material 8 is introduced into a mould 10, also referred to as a casting mould 8. In order to produce components 6 having cavities, it is further possible to provide mould substances 12. Cores can, for example, be formed with the mould substances 12 in order to produce subsequent cavities in the components 6. For example, suitable sands are used as mould substances 12 for a core.
The casting plant 4 further has a control device 14. The control device 14 may be configured to control the casting plant 4 or the casting process. The control device 14 may have suitable processing means 16, such as a processor, storage means, interfaces, etcetera, in order to predetermine different control parameters for the casting process. For example, it is possible to predetermine cooling parameters, heating parameters for heating mould portions of the tool mould and/or suitable cutting and supply parameters.
The control device 14 is particularly configured to determine the solidifying time, that is to say, the removal time, as will be set out in greater detail below.
In the present embodiment, the casting plant 4 further comprises a sensor device 18. The sensor device 18 is in particular a temperature sensor 18 for detecting the temperature of the mould 10 and/or the material in the mould 10.
The temperature of the material in the mould 10 can preferably be detected directly. For example, a temperature sensor 18 can be arranged in such a manner that it directly contacts the material in the mould 10. Alternatively or additionally, the temperature of the mould 10 can be measured. For example, the temperature of the material in the mould 10 can be derived from that temperature.
The temperature sensor 18 detects at predeterminable time intervals or continuously at least one of the above-mentioned temperatures. The temperature values detected can be provided for the control device 14 in a suitable form for further processing.
It will be understood that, according to other variants of the present invention, a plurality of temperature sensors 18 may be provided in order to detect the temperature of the mould 10 and/or the material in the mould at different locations. It will further be understood that additional detection devices may be provided, for example, in order to detect the ambient temperature and the like.
The casting plant 4 may further be in communication connection with a central control unit 20. In principle, a wireless or wired communication connection may be provided.
The central control unit 20 may comprise processing means (not illustrated) and a database. The central control unit 20 may further be connected to additional casting plants (not illustrated).
The operation of the casting plant 4 according to
In a first step 201, initially before the beginning of the production process, that is to say, before the casting process of a first component 4, at least a first set process parameter can be determined. The determination of the set process parameter may be dependent in particular on the material 8, the casting plant 4, the state of the casting plant 4, the mould shape, the component 6 to be produced, etcetera.
It will be understood that a plurality of set process parameters may be determined. In particular at least one limit value for at least one process parameter may be determined. Furthermore, at least one set solidifying time may be predetermined. At least one minimum set solidifying time and one maximum set solidifying time may preferably be determined.
Furthermore, not only set parameters but also a formula for determining the optimum solidifying time may preferably be determined, in particular in accordance with the above-mentioned criteria, the formula preferably being able to be dependent on a set solidifying time, set process parameter and detected process parameters. For example, individual conditions can be associated with each other logically.
According to the embodiment explained in greater detail below, there may be predetermined a minimum set temperature, a minimum set solidifying time, a maximum set solidifying time and the condition that the temperature progression is decreasing, the individual connections being able to be associated with each other logically.
The set temperature value may be, for example, in the range between 350° C. and 600° C. in the case of aluminium as the material. The minimum set solidifying time may be in the range between 80 seconds and 180 seconds. The maximum set solidifying time may be in the range between 100 seconds and 250 seconds.
The determination of the at least one set process parameter or a formula may be determined by the control device 14 of the casting plant 4. However, a superordinate control device 20, for example, a central control unit 20 having a database for determining the at least one set process parameter may preferably be provided. The superordinate control device 20 may particularly be configured to monitor and control a plurality of casting plants.
In a subsequent step 202, the fluid material can be introduced into the mould 10. At the same time, a time measuring device can be started. For example, the time measuring device may be started when the filling operation is started or when the filling operation finishes.
In a subsequent step 203, the fluid material can cool and solidify. At least one process parameter may be detected during the casting process. In the present embodiment, the temperature of the material in the mould 10 is continuously detected by a sensor device 18. It will be understood that the temperature can be detected continuously during the entire production process and not only during the casting operation.
The control device 14 can particularly be configured to compare the currently detected temperature of the material with the optimum set temperature.
If the control device 14 establishes that the optimum set temperature has been reached or the value has fallen below it, it can initially further be investigated whether the temperature progression is decreasing. Furthermore, it can additionally be investigated whether the minimum set solidifying time has already been exceeded. To this end, the value of the time measuring device can be compared with the minimum set solidifying time.
If the conditions are complied with, the control unit 14 can cause the mould 10 to be opened and the component 6 to be removed in a step 204. After the component 6 has been removed, the mould 10 can be closed again, the time measuring device can be reset and the method can be continued in accordance with step 202.
An alternative removal condition may be reaching the maximum set solidifying time. The value of the time measuring device may be compared, preferably continuously, with at least the maximum set solidifying time. Even if the temperature of the material has not yet reached the set temperature, it is nevertheless possible for the cast component 6 to be removed. In this instance, there is a measurement error in all probability.
However, the mould 10 is not opened if, although the current temperature of the material is below the set temperature, the temperature progression is increasing. In the present embodiment, the mould 10 is also not opened if, although the current temperature of the material is below the set temperature, the minimum set solidifying time has not yet been reached.
The last instances mentioned indicate a technical error. For example, the detection device 18 may be defective. In this instance, the mould 10 may initially be opened in step 204 after the minimum or maximum set solidifying time has expired. Subsequently, the production process may be interrupted or ended (step 205). Suitable measures for eliminating the technical error may be taken.
Claims
1. A method for controlling a casting plant comprising at least one mould for receiving a fluid material,
- the fluid material solidifying in the mould during a solidifying time,
- at least one process parameter being detected during the production process,
- the process parameter being the temperature of the material in the mould,
- the solidifying time being determined in accordance with the process parameter detected, and
- the determination of the solidifying time being carried out in accordance with a comparison of the process parameter detected with at least one set process parameter,
- wherein
- at least the at least one set process parameter is determined before the production process and
- at least one set process parameter is determined again during the production process at predeterminable time intervals.
2. The method according to claim 1, wherein the process parameter is detected continuously or at predeterminable time intervals.
3. The method according to claim 1, wherein the solidifying time of the component to be produced is determined in accordance with the solidifying time of at least one previously produced component.
4. The method according to claim 1, wherein at least one set solidifying time is predetermined.
5. The method according to claim 4, wherein the set process parameter is determined in accordance with the material, the casting plant, the state of the casting plant and/or the shape of the mould.
6. A casting plant having at least one mould for receiving a fluid material, the casting plant being formed to carry out the method according to claim 1,
- wherein
- at least one sensor device is configured to detect at least one process parameter during the production process and
- at least one control device is configured to determine the solidifying time in accordance with the detected process parameter.
7. The casting plant according to claim 6, wherein the sensor device is a temperature sensor, the temperature sensor being arranged on or in the mould.
8. The casting plant according to claim 7, wherein the temperature sensor is arranged in such a manner that the temperature of the material in the mould can be detected.
9. The casting system comprising at least one casting plant according to claim 6 and a central control unit configured to determine the at least one set process parameter.
10. A computer program having instructions which can be carried out on a processor in such a manner that a casting plant is controlled by the method according to claim 1.
11. The computer program product comprising a computer program having instructions which can be carried out on a processor in such a manner that a casting plant is controlled by the method according to claim 1.
Type: Application
Filed: Sep 17, 2012
Publication Date: Dec 25, 2014
Inventors: Martin Schickmair (Allhaming), Andre Groeschel (Niederneukirchen)
Application Number: 14/349,844
International Classification: B22D 2/00 (20060101);
