Device and method for monitoring a tablet press by means of a measuring device attached to a punch

Abstract

The present invention relates to a pressing punch for a tablet press. The pressing punch preferably comprises a measuring device which can be operated electrically autonomously from a power supply for the tablet press. The present invention also relates to a tablet press comprising the pressing punch and a method for monitoring a tablet press during continuous operation using the pressing punch according to the present invention.

Description

Technical Field

[0001] The invention preferably relates to a punch for a tablet press. The punch preferably has a measuring device which can be operated independently of the power supply for the tablet press.

[0002] Furthermore, the present invention preferably relates to a tablet pressing machine and a system comprising the above-mentioned punch.

[0003] In addition, the present invention relates to a method for monitoring a tablet press during operation using a punch according to the present invention. The measuring device of the punch preferably comprises a sensor, a computing unit and a communication unit as well as a memory unit. The sensor of the measuring device records physical or chemical measured values. Subsequently, the communication unit of the measuring device preferably transmits the recorded measured values ​​of the sensor to a programmable logic controller of the tablet press and / or to a data processing unit, and / or the recorded measured values ​​of the sensor are preferably stored on the memory unit of the measuring device. Background Art

[0004] Tablet presses are mainly used to produce tablets on an industrial scale. Tablet presses are based on the following principle: In a first step, a die is filled with the powder mixture to be tableted. This mixture is then pressed into tablets by the interaction of an upper punch and a lower punch. Modern tablet presses can produce several million tablets per hour with multi-tip tools.

[0005] A large amount of compacting processes cause the wear and tear on the tool, and also can produce wear and tear on the various parts of the tablet press.In addition, in the operating process, for example due to temperature changes and / or vibrations in the machine environment, fixed machine parameters may be proved to be no longer optimally suitable for the compacting process.Therefore, wear and tear and inappropriate operating parameters can cause defective compacting processes and the damage of the components of the tablet press as a whole.In the prior art, various types of measuring equipment are used to monitor these defects.The basic component of the measuring device is a sensor.

[0006] A sensor (also detector or transducer or probe) is a technical component and preferably the first element of a measuring chain in a measuring device. A sensor can qualitatively or quantitatively determine the material composition and / or physical (e.g. heat, temperature, humidity, pressure, sound field parameters, brightness, acceleration) or chemical (e.g. pH value, ionic strength, electrochemical potential) properties of its environment as measured variables. These variables are detected by physical or chemical effects and converted into electrical signals that can be further processed. Sensors in machine tools, in particular forming machines such as presses or punches, are well known.

[0007] DE 10 2006 002 359 B4 discloses a tablet press in the form of a rotary tablet press having a temperature sensor in close proximity to its mould. The sensor is fixed and does not rotate with the turntable, for example attached to the machine frame. In particular, the sensor records the temperature value of the tablets being produced to monitor the production process.

[0008] The shortcoming of this tablet press is that only one physical property can be recorded, namely the temperature in the compression zone. In addition, the temperature can only be measured at rest at one point in the compression zone.

[0009] DE 10 2005 051 567 B4 discloses a tablet press (rotary tablet press) and a method for measuring the displacement of a punch. Here, the punch of the rotary tablet press is equipped with markers. The rotary movement of the punch causes them to pass through a fixed sensor (mounted outside the turntable). The sensor records the change in the position of the marker, which is then evaluated.

[0010] Document DE 195 02 596 C2 describes sensors and measuring devices for monitoring the tableting process. Here, force sensors are attached to both the upper and lower pressure rollers in order to determine the pressure force values ​​of a pair of punches. In conjunction with the turntable position, the measurement and previously determined machine parameters are used to measure and calculate the displacement-pressure force distribution.

[0011] The disadvantage of this arrangement is that the contact force is not measured directly at the punch. There are components with different strengths and stiffnesses between the sensor and the punch (contact roller, contact roller bearing, contact station). These components influence the quality of the force measurement. Another disadvantage is that only one physical property can be recorded using this sensor arrangement, namely the force acting on the contact roller via the punch.

[0012] An essential component for the functioning of a tablet press is the punch, which is why monitoring the punch is particularly important. In the prior art, some forming machines, especially tablet presses, are known to include sensors for monitoring the pressing force on the punch. However, the known designs for monitoring the pressing force on the punch have significant disadvantages, as described below.

[0013] Document DD 294 457 A5 describes a sensor for force measurement on a tablet press. Here, the force sensor is installed in the piston body. The punch is attached to the piston body so that the force sensor is arranged above the punch (in the case of an upper punch) or below (in the case of a lower punch). The force sensor is wired to a power supply via a corresponding hole in the piston body.

[0014] The disadvantage of force measurement with such an arrangement is that it cannot be actually implemented in a tablet press designed as a rotary tablet press. The punch in a rotary tablet press is directly guided by a control cam. It is not feasible to install each punch in a piston body and also ensure an external power supply for the punch. In addition, this arrangement of the sensor in DD 294 457 A5 is specifically provided for determining force during the compaction process. The detection of the force generated in the punch that may occur before or after the compaction process is not detected by the arrangement described in this document. In addition, due to the position of the sensor, the acceleration or temperature of the punch is also impossible to be unique.

[0015] This arrangement also has the disadvantages of an eccentric tablet press. For example, the punch must be mounted in a specially designed piston body, whereby, among other things, different loads occurring partially in the punch cannot be measured. Disadvantageously, these problems arise, for example, if the punch is not perpendicular to the powder material to be compacted.

[0016] Document DE 101 35 283 C2 discloses a method for compacting powdered materials. The deformation of the die table is measured or calculated for different compaction forces. The sensor for force measurement is directly connected to the punch and is installed above the punch (above the upper punch) and below the punch (below the lower punch). The sensor is installed on the contact surface of the punch head of the punch.

[0017] From a practical point of view, this method is also not feasible for tablet presses designed as rotary tablet presses, because in rotary tablet presses, the punches are guided via control cams. The punches are in direct contact with the pressure rollers of the rotary tablet press with their punch heads, so it is impractical to mount the sensor on the punch heads.

[0018] Therefore, there is a need for improvements to provide measurement technology that can be easily and reliably integrated into a tablet pressing machine or tableting process, thereby allowing continuous measurement and monitoring of process parameters.

[0019] Purpose of the Invention

[0020] The object of the present invention is to eliminate the disadvantages of the prior art and to provide a device and a method for determining physical and / or chemical properties directly and continuously on and / or in a punch for a tablet press. In particular, the object of the present invention is to provide a device for integrating a measuring device into a tablet press, which is characterized by a high degree of flexibility and precision in order to achieve continuous measurement and / or monitoring of various process parameters with respect to the punch during the tableting process. Summary of the invention

[0021] The objects of the invention are solved by the features of the independent claim. Advantageous embodiments of the invention are described in the dependent claims.

[0022] In a preferred embodiment, the invention relates to a punch for a tablet press, characterized in that the punch has a measuring device that can be operated independently of the power supply for the tablet press.

[0023] Since the punch of the tablet press has a measuring device, it is possible to record the measured variables directly related to the punch without considering the influence of other components. In addition, it is possible to install in a simple manner without being connected to the power supply of the tablet press. In addition, due to the rotating punch in the case of the rotary tablet press, the measuring device is advantageously not fixed in a fixed position at a position in the tablet press. Therefore, physical or chemical properties (e.g., temperature measurement) can be continuously recorded during the entire rotation process of the turntable of the rotary tablet press. Therefore, compared with known prior art devices, the present invention advantageously enables to record measured values ​​before, during and after the compaction process.

[0024] According to the invention, the tablet press is preferably a rotary tablet press or an eccentric tablet press.

[0025] According to the invention, the punch is preferably designed in such a way that the punch has a punch head, a punch barrel and a punch tip. The terms punch head, punch barrel and punch tip are familiar to a person skilled in the art. The measuring device is preferably included in the punch shaft or integrated therein.

[0026] In another preferred embodiment, the punch is characterized in that the measuring device has a sensor for recording physical and / or chemical properties of the punch and / or its environment. The physical properties are defined, for example, by heat, temperature, humidity, pressure, sound field parameters, brightness, acceleration. Chemical properties are, for example, pH value, ionic strength, electrochemical potential. The properties can be recorded qualitatively or quantitatively as measured variables.

[0027] Particularly preferably, the measuring device comprises a plurality of different sensors which simultaneously and in parallel record different physical or chemical properties (of the punch and / or its environment). The combination of a plurality of different measured values ​​recorded advantageously improves the accuracy of the description of the condition of the tablet press components or the conditions of the production process.

[0028] In a preferred embodiment of the invention, the punch is characterized in that the measuring device has sensors, in particular for recording forces, temperatures or accelerations of the punch and / or its environment. By recording these values, a general description of the wear and function of the punch and / or the tablet press can advantageously be made.

[0029] In another preferred embodiment of the invention, the punch is characterized in that the measuring device has a plurality of sensors for measuring the pressing force, the temperature of the punch and the punch tip, and for measuring the linear acceleration and the rotational acceleration of the punch. By measuring these values, it is advantageously possible to make general statements about the pressing process, the function and the wear of the punch.

[0030] In a preferred embodiment, the measuring device comprises an active sensor. An active sensor generates a voltage due to its measuring principle and does not require any auxiliary power supply. An active sensor can be, for example, a thermocouple, a light sensor or a pressure sensor. The installation of an active sensor advantageously requires lower energy consumption.

[0031] In another embodiment, the sensor of the measuring device is designed as a passive sensor. Passive sensors contain passive components whose parameters are changed by the measured variable. These parameters are converted into electrical signals by the main electronics. This requires an externally supplied auxiliary power supply. Passive sensors are, for example: strain gauge load sensors, resistance thermometers, strain gauges, magnetic field sensors (Hall probes). Passive sensors have the advantage of providing particularly accurate measurement results.

[0032] In a preferred embodiment of the measuring device, the sensor is a temperature sensor. By detecting the temperature, conclusions can be drawn about the function of the punch guide and the lubricant, which can provide information about wear. By recording the temperature and the temperature curve at the punch tip, corresponding conclusions can be drawn about the pressing process.

[0033] Furthermore, by monitoring the temperature of the punch and / or its environment, conclusions can preferably be drawn about the temperature value of the pressed material. This is highly relevant during the tableting of temperature-sensitive pressed materials. The compaction of temperature-sensitive pressed materials can only be accomplished within a certain temperature range. Therefore, the compaction process can be adjusted by the recorded values ​​and / or also aborted if these values ​​exceed or fall below threshold values.

[0034] Furthermore, the recorded temperature values ​​of the punch can advantageously be used to monitor or check compression or expansion of the punch due to temperature fluctuations.

[0035] Preferably, the temperature can be recorded in many ways using different sensors and measuring devices. Preferred sensors for recording temperature are listed below. However, the present invention is not limited to general sensors, general sensor operation methods or construction methods.

[0036] Preferred temperature sensors include NTC thermistors, i.e. hot conductors. This has a negative temperature coefficient, so that when the temperature rises, the resistance drops and a higher current flows. However, it is also preferred to use PTC thermistors, i.e. cold conductors with a positive temperature coefficient, so that when the temperature increases, the resistance increases and a lower current flows.

[0037] In another preferred embodiment, the temperature sensor is designed as a semiconductor temperature sensor, which generates an electrical variable proportional to the absolute temperature, which can preferably be represented in analog or digital form.

[0038] In another preferred embodiment, the temperature sensor comprises a temperature probe having an oscillating quartz as a measuring element. The resonant frequency of the oscillating quartz varies depending on the temperature and can be measured very accurately. According to the invention, the temperature probe is preferably distributed on the outer surface of the punch body, particularly preferably distributed inside the punch body.

[0039] In another preferred embodiment, the temperature sensor is implemented as a thermocouple. A thermocouple is a pair of metal conductors made of different materials connected at one end. They convert temperature differences into voltage (Seebeck effect).

[0040] Other temperature sensor alternatives according to the present invention may include ferromagnetic temperature sensors.

[0041] In a preferred embodiment of the measuring device, the sensor is a displacement sensor or a gap sensor. Advantageously, the displacement sensor is able to accurately determine the position of the punch in the tablet press so that position anomalies can be noticed immediately. Geometric changes of individual elements of the tablet press can also be identified.

[0042] In the compression process of the tablet press, the upper punch and the lower punch preferably cover a distance that converges toward each other. By measuring this distance via a displacement sensor or a gap sensor, it is preferably possible (in combination with a force sensor) to determine the ratio between the compression force and the displacement, so that the properties of the compressed material such as elasticity, plasticity and porosity can advantageously be derived from this ratio.

[0043] The determination of the position, distance or displacement can be achieved by a variety of measuring principles and thus a variety of sensor arrangements. The invention is therefore not limited to the displacement sensors or gap sensors listed in this document.

[0044] Preferably, the measuring device includes direct and indirect measuring principles for determining position, distance or displacement. In addition, the measured values ​​can also be preferably obtained by integrating all conceivable linear displacement measuring systems in the punch.

[0045] In another preferred embodiment, the measurements can be linked together to improve the description and accuracy of the conditions. For example, the precise position of the turntable in a rotary tablet press helps improve the displacement measurement using an acceleration sensor.

[0046] In a preferred embodiment of the displacement sensor a potentiometric transducer is used. A potentiometric transducer is a resistive element, the resistance value of which can be changed mechanically (by rotation or displacement). According to the invention, the potentiometric transducer is incorporated into the punch in such a way that it changes its resistance with each rotation of the entire punch.

[0047] Next, the strain gauge, also in a similar principle, is used in an alternative embodiment of the displacement sensor according to the invention. The strain gauge changes its resistance by changing its length and cross section. A bridge circuit is preferably used to measure the resistance. The bridge circuit can be used to determine the absolute resistance or to determine the relative change in resistance. When measuring with a strain gauge, the relative change in resistance is measured, as already mentioned. In this case, the design of the bridge circuit associated with the measurement of the change in resistance of the strain gauge is well known to those skilled in the art as a quarter bridge, half bridge and full bridge. The strain gauge can preferably be used to detect the displacement in the longitudinal direction of the punch.

[0048] Another preferred displacement sensor comprises a capacitive sensor. A capacitive sensor consists of two metal parts insulated from each other. Together with the object to be measured, it forms a capacitor with variable capacitance. The measuring effect is based on a geometric change in the distance between the two capacitor surfaces or a lateral displacement of the two capacitor surfaces, which results in a change in the effective capacitor area.

[0049] Another embodiment of the displacement sensor may be, for example, preferably an inductive sensor. An inductive sensor essentially works with an inductor (open coil), generating a magnetic field that is changed by the object. This measuring principle makes it possible to measure angles, distances and speeds without contact or wear. Preferably, a plurality of coils are used according to the invention.

[0050] In another preferred embodiment, the measuring device comprises a force sensor. The invention is not limited to sensors for recording the forces shown below. Any force measurement that can reasonably be integrated into the punch is conceivable so as to enable the clamping force measurement. Preferably, the force sensor is designed as a pressure sensor.

[0051] In a preferred embodiment of the measuring device, the sensor comprises a pressure sensor. It has been shown that a pressure sensor in the measuring device provides good information about the wear of the punch. In addition, the pressure sensor can be used to determine, for example, a maximum force that is forbidden to be exceeded in order to avoid overloading.

[0052] The present invention can preferably aim at determining the pressing force and the pressing force curve. This can focus on the forces in the punch, for example, which have already occurred before the punch hits the pressing roller.

[0053] Depending on the powder and filling to be compacted, compaction already occurs in the descending track cam of the rotary tablet press. This is not desired, but is unavoidable. In addition, if the setting is not correct, the upper punch can be pressed against the upper compaction roller or lifting cam of the rotary tablet press by the lower punch.

[0054] Based on the measurement of the impact force curve during a complete rotation of a tablet press designed as a rotary tablet press, effects / forces that were previously not measurable in the prior art can be detected. This makes it possible, among other things, to detect wear on the punch and cam path, which otherwise could not be detected from the measurement. However, such a measurement can show which forces are generated when striking the impact roller and how the impact force is generated with different pressed materials, since it can be measured directly.

[0055] Continuous information about possible wear of the punch or cam path can ensure significantly improved quality control. On the one hand, early replacement can be indicated. On the other hand, operating parameters can be adjusted to minimize gradual wear.

[0056] Another preferred pressure sensor is a piezoresistive pressure sensor. Piezoresistive pressure sensors use metal strain gauges or pressure-sensitive semiconductor chips. Those skilled in the art are familiar with the following piezoresistive sensor technologies: ceramic thick film sensors, metal thin film sensors, silicon pressure sensors, and piezoresistive silicon sensors.

[0057] Another preferred pressure sensor is a piezoelectric pressure sensor. In a piezoelectric sensor, a voltage is generated in a crystal by means of pressure through charge separation (piezoelectric effect). The pressure causes ions to move inside the crystal, thereby generating a charge on the surface that is proportional to the force. The charge is converted into a proportional voltage by a charge amplifier. Any pressure can be set to the zero point of the charge amplifier by deriving the charge (shorting it out), so that the pressure change can be directly measured.

[0058] In another preferred embodiment, the pressure sensor comprises a Hall element.The pressure sensor operates according to the Hall effect, whereby the magnetic field around the Hall element changes when pressure is applied.

[0059] In an alternative preferred embodiment of the present invention, the pressure sensor is a capacitive pressure sensor. A capacitive pressure sensor contains two capacitors dispersed into a silicon chip. When pressure is applied, the distance between the diaphragm and the two capacitor plates facing each other changes in opposite directions, causing the capacitance to change accordingly. Preferably, the capacitor is part of an internal amplifier whose output signal depends on the difference between the capacitances.

[0060] In another preferred embodiment, the sensor comprises an inductive pressure sensor. The inductive pressure sensor works with an iron core connected to a membrane. Pressure changes generate a force on the membrane and cause it to move. This causes the position of the iron core to change in opposite directions in the two coils: in one coil, the inductance increases, in the other coil, the inductance decreases. This difference can advantageously be determined very accurately electrically.

[0061] In a preferred embodiment of the invention, the sensor of the measuring device is designed as an acceleration sensor.In a preferred embodiment, some of the sensors already mentioned can also envisage the intended use of acceleration sensors.

[0062] The invention is not limited to the acceleration sensors specified below and may well comprise other or different sensors for recording accelerations.

[0063] The displacement of the punch can preferably be detected by means of a preferred measuring device comprising an acceleration sensor. The use of an acceleration sensor is advantageously suitable for this purpose, since it does not have to have a basis as a zero point or reference. Instead, the displacement is determined indirectly by integrating the measured acceleration. However, sufficiently accurate information about the position displacement of the punch can be determined, which information can be used both for quality control of the compacted product and for process optimization.

[0064] Furthermore, the association of these measured values ​​with one or more further measured values, preferably recorded by other measuring devices and / or sensors, is preferred. This leads to an increase in precision and information value. For example, in the case of a rotary tablet press, the precise position of the turntable can help improve the displacement measurement using an acceleration sensor.

[0065] Additionally, acceleration sensors can be used in conjunction with force measurements to provide information about wear.

[0066] In another preferred embodiment, a measuring device comprising an acceleration sensor is used to measure the impact of the punch. In addition, the punch can preferably be used to determine a force-displacement graph. In particular, the displacement can be calculated based on the linear acceleration and the rotational acceleration.

[0067] In the sense of the present invention, piezoelectric acceleration sensors are preferably used. Here, a piezoelectric ceramic sensor plate converts dynamic pressure fluctuations into electrical signals that can be processed accordingly. The pressure fluctuations are generated by a (seismic) mass attached to the piezoelectric ceramic and act on the piezoelectric ceramic when the entire system is accelerated.

[0068] The acceleration sensor can also preferably be formed by a micro-electromechanical system (MEMS). The sensor is a spring-mass system, wherein the "spring" is preferably a silicon rod only a few micrometers (μm) wide. In addition, the mass is preferably also made of silicon. Due to the deflection during the acceleration of the punch in the tablet press (for example, during the start-up of the turntable or due to the change in the direction of the up and down movement of the punch), the change in capacitance can be measured very sensitively between the spring suspension part and the fixed reference electrode. The electronics for evaluating this small change in capacitance are preferably accommodated on the same integrated circuit.

[0069] In a preferred embodiment of the MEMS, a piezoresistive resistor is attached to the bending beam by ion implantation, changes its resistance according to the bending and thus allows conclusions to be drawn about the acceleration. Ion implantation is known to those skilled in the art and is preferably used in semiconductor technology to change the electrical properties of a substrate material (here: the bending beam).

[0070] In another preferred embodiment, the acceleration sensor comprises a strain gauge. The force on the test mass is determined by determining the deformation of the fixture (e.g. a rod) using the strain gauge. For the purposes of the present invention, a punch may preferably be defined as a test mass. However, the test mass may also preferably be a mass other than a punch, which test mass comprises the measuring device.

[0071] In another preferred embodiment of the acceleration sensor, the acceleration is determined by magnetic induction. When a test mass suspended on a spring moves, a voltage is induced by a magnet in the coil. The test mass is preferably a mass different from the punch, which test mass comprises the measuring device.

[0072] In a preferred embodiment, the acceleration sensor is a Ferraris sensor. This sensor measures relative acceleration without a test mass using eddy currents.

[0073] In another particularly preferred embodiment, the measuring device comprises a strain gauge full bridge, an integrated MEMS sensor and a temperature sensor.

[0074] In the sense of the present invention, the communication unit in the measuring device is preferably used for the wireless transmission of the recorded data of the sensor. Therefore, the communication unit is preferably a transmission unit. In another embodiment, the communication unit is in particular a transmission unit and / or a receiving unit. The transmission is preferably performed by directional or non-directional electromagnetic waves, whereby the frequency band used can range from a few hertz (low frequency) to hundreds of terahertz (visible light), depending on the application and the technology used. According to the present invention, the following data transmission methods are preferably used: Bluetooth, WLAN, ZigBee, NFC, Wibree or WiMax in the radio frequency range, and IrDA and optical directional radio (FSO) in the infrared and optical frequency ranges, respectively. Advantageously, it has been shown that by transmitting via such a transmission unit, data can be transmitted wirelessly during the compaction process of the tablet press without losing information, while a sufficient data transmission rate can be obtained. In another embodiment, the transmission unit and / or the receiving unit comprises an antenna.

[0075] In one embodiment, in addition to wireless data transmission or as a substitute for wireless data transmission, wired transmission can be provided. In one embodiment, the measuring device includes analog and digital outputs (USB, RS232, field bus) for transmitting data via signal conductors. On the one hand, the signal conductors preferably transmit the recorded measurement data to a programmable logic controller and / or a data processing unit of a tablet press, and on the other hand, control commands are preferably transmitted to the output of the measuring device via signal conductors.

[0076] In a preferred embodiment, the punch is characterized in that the measuring device comprises a sensor, a communication unit, a memory unit, an energy storage unit and a computing unit, whereby the measured values ​​obtained as raw data can be processed by the computing unit. Advantageously, the data (high-resolution measurement) can be saved via the memory unit so that the data can be used at a later time.

[0077] In the sense of the invention, the memory unit of the measuring device is used in particular for saving or storing data. According to the invention, the recorded measurement data of the sensor are preferably saved in the memory unit. The memory unit is preferably an electronic data carrier. Flash memory is particularly suitable for tightly integrating the electronic data carrier in the measuring device, but other data carriers may also be preferred.

[0078] In another preferred embodiment, the measuring device comprises a computing unit. According to the present invention, the computing unit of the measuring device preferably comprises a processor unit. The processor unit thus preferably comprises in particular a graphics processing unit (GPU) and / or a central processing unit (CPU). Both processors are known to those skilled in the art. Therefore, many calculation operations of the raw data can preferably have been performed in a decentralized manner on the measuring device. For example, the measurement signal can be sampled at a high frequency. The average value and the minimum / maximum value can be determined from the raw data by the computing unit, and the average value and the minimum / maximum value are transmitted to the programmable logic controller of the data processing unit and / or the tablet press via the communication unit. Advantageously, this saves energy and bandwidth.

[0079] In another preferred embodiment, the measuring device is adapted to process the recorded measured values ​​as raw data by means of a calculation unit, then store them in a memory of the measuring device and / or transmit them to a data processing unit and / or a programmable logic controller of the tablet press by means of a communication unit (preferably via Bluetooth). The processing of the raw data can be represented, for example, in a conversion of the measured data into a desired format or reduced to a particularly relevant description (see above average value, exceedance of defined threshold values ​​of force / acceleration / temperature / distance, etc.).

[0080] Preferably, the measuring device comprises a cable output at which the pre-processed measurement signal is output as a universal analog or digital signal (eg 0-10 V, serial port).

[0081] In a preferred embodiment of the invention, various trigger options for the memory unit and the computing unit of the measuring device can be used to control the acquisition of the measured data, for example, in particular after a specific time interval or when a threshold value (force / acceleration / temperature) is exceeded. This ensures that the data logger stores data only when certain events (such as in particular high loads) occur. In this way, the cumulative collection (collectives) of stress factors has been recorded in the stressed component. The stored measured values ​​can be read out, for example, after completing the measurement, by a data processing unit (e.g., PC) and / or a programmable logic controller of a tablet press via a simple USB connection.

[0082] In another preferred embodiment of the present invention, the measuring device (preferably, its computing unit) is suitable for controlling and / or accessing data by a data processing unit and / or a programmable logic controller of a tablet press. For this purpose, for example, control parameters for performing the measurement can be sent to the measuring device. The control parameters can, for example, relate to the type of measurement or the selection of active sensors (in the case of multiple sensors), the timing of the measurement, or instructions for the preparation or pre-evaluation of raw data.

[0083] The data processing unit may be, for example, a tablet computer, a smartphone or a PC, preferably having installed thereon a computer program product (application / "app") for controlling and / or accessing data.

[0084] Preferably, the communication unit of the measuring device ensures the exchange of data between the app and the measuring device, whereby the app preferably transmits control commands to the measuring device, which can be processed by a computing unit included in the measuring device.

[0085] In addition to controlling the measuring device, the app is preferably adapted to access data from the measuring device (or to transfer [processed] measured values ​​using the communication unit of the measuring device to a communication unit of a tablet or smartphone) and to visualize and / or store the data.

[0086] Further preferably, the measuring device has different transmission modes, preferably two or more, which differ in bandwidth and power consumption.

[0087] The first transmission mode is preferably defined by direct communication between the measuring device and the external device (smart phone, tablet PC or programmable logic controller of the tablet press). In the sense of the present invention, this transmission mode is called streaming transmission. In particular, this transmission mode is characterized by a high data rate.

[0088] In the second transmission mode, the measured values ​​of the measuring device are preferably transmitted to the distribution unit. The distribution unit is connected to various external devices (smart phone, tablet PC or programmable logic controller of the tablet press), whereby these external devices can access the data of the distribution unit. This transmission mode is preferably called broadcast, whereby a high internal sampling rate (500Hz) is used to obtain the measured variables and form real-time average values, as well as minimum / maximum values, so that a high data rate is not necessary. The distribution unit can also preferably be a data processing unit. DETAILED DESCRIPTION

[0089] In the following, a specific embodiment and a preferred application of the measuring device are described. The invention is not limited to this embodiment.

[0090] The preferred measuring device enables time-synchronous transmission and storage of the recorded measured values ​​of the two sensors with a strain gauge measuring bridge. In addition, the integrated MEMS sensor preferably measures the rotational speed and the three-axis acceleration. The integrated processor unit preferably processes the sensor data already on the measuring device and thus advantageously significantly reduces the amount of data to be transmitted. The measuring device preferably enables simple and continuous monitoring of the processing. The recorded measurement data and the interpretation conditions are preferably transmitted to the distribution unit via Bluetooth, preferably Bluetooth Low Energy 4.2. Preferably, a large number of measuring devices can be connected to the distribution unit in a time-synchronous manner.

[0091] Under ideal conditions, the transmission range is up to 30 meters, and more than 50 devices can be connected to the distribution unit. At the same time, all measurement data are displayed and optionally stored in an application on a tablet or smartphone. The application is preferably used to set the calibration values ​​of the measuring devices and configure the outputs of the gateway. The measuring devices are also preferably powered by lithium-ion batteries and charged by a USB power supply. The measuring devices also preferably have external dimensions of 50 mm×13 mm×9 mm. In addition, the measuring devices preferably have up to 8 GB of flash memory.

[0092] In a preferred embodiment, the measuring device has a strain gauge sensor in addition to the MEMS sensor, so that in addition to the force measurement, acceleration and rotational speed as well as orientation can also be recorded. Modern MEMS sensors include an integrated temperature sensor, which means that the temperature can also be measured by the measuring device.

[0093] In a preferred embodiment of the invention, the measuring device can be operated in an energy-autonomous manner. With regard to the invention, the measuring device can therefore be used independently of the power supply of the tablet press. It has been found that an energy-autonomous measuring device can be used particularly easily in tablet presses that operate according to the rotary principle. In addition, if the power supply of one sensor fails, only one sensor is affected, so that all sensors are independent of each other.

[0094] Preferably, the measuring device comprises a battery and / or an accumulator as energy storage device, which makes the measuring device energy self-sufficient in the sense of the invention. Preferably, the battery and / or the accumulator provides the communication unit with sufficient energy to transmit data.

[0095] In another embodiment, a battery or accumulator preferably provides the energy for operating the measuring device. In particular, the computing unit, the communication unit and the sensor are simultaneously supplied with sufficient energy. Preferably, the measuring device comprises an output for a charging connection for charging the accumulator.

[0096] In a further preferred embodiment, an integrated overcharge and discharge protection of the battery is included in the measuring device for safe operation of the measuring device.

[0097] In a further preferred embodiment, the battery is designed as a Li-ion or Li-Po battery.In addition, the measuring device can comprise an LED display.

[0098] In another preferred embodiment, the measuring device is energy self-sufficient with respect to the power supply of the tablet press by providing an induced current / induction. In a preferred embodiment, there is an electric conductor in the punch that moves in the magnetic field. The magnetic field can preferably be generated by a coil mounted inside and / or outside the turntable. The movement of this conductor causes a current for the operation of the measuring device.

[0099] In a preferred embodiment, the measuring device comprises a photovoltaic cell (solar cell), which also reacts well to artificial light in the plant. By means of the photoelectric effect, light energy is converted into electrical energy, and the measuring device can be operated in an energy-self-sufficient manner according to the invention. The generated electricity is preferably used directly for the measuring operation.

[0100] In another preferred embodiment, the generated electricity is stored in the above-mentioned battery.

[0101] In another preferred embodiment, the measuring device of the punch is connected to at least one second measuring device of the second punch. In a preferred embodiment, the connection is formed by a signal conductor. In another preferred embodiment of the invention, the connection is wireless via the communication unit. Preferably, power and / or data can be transmitted via the connection of the measuring devices. Further preferably, all measuring devices can be connected to the distribution unit.

[0102] In a preferred embodiment of the invention, the punch is characterized in that the measuring device is integrated in the punch body. According to the invention, the punch body is preferably defined by a punch barrel, a punch tip and a punch head, whereby the punch body is preferably designed as a thick-walled hollow body or a solid body. The advantage of the integrated measuring device is that the external geometry of the punch does not change, so that the geometric parameters of the tablet press do not have to be changed due to the punch.

[0103] In another preferred embodiment, the measuring device is precisely fitted into a punch designed as a solid body. The punch is machined by a separate manufacturing process in such a way that the measuring device can be inserted into the punch in a subsequent assembly process. Preferably, a connecting device can also be used here. Thus, the measuring device can preferably be inserted into the punch in a material-locked, force-locked and / or form-locked manner.

[0104] In a preferred alternative according to the invention the measuring device is attached to the inner wall of the thick-walled hollow body of the punch. Preferably access to the measuring device can be provided via a transverse hole to the longitudinal axis of the punch in order to be able to connect a signal line or a feed antenna.

[0105] In an exemplary embodiment, the measuring device is inserted into a punch having a shell diameter of 25.4 mm or into a punch having a shell diameter of 19 mm.

[0106] In a preferred embodiment, the computing unit of the measuring device is connected to one or more data processing units and / or a programmable logic controller of the tablet press.

[0107] In a preferred embodiment, the data processing unit is provided as a component external to the tablet press and is designed as a stand-alone device independent of the tablet press.

[0108] In another preferred embodiment, the data processing unit exists as an internal data processing unit. Preferably, the internal data processing unit can be a component of the tablet press and can be integrated in the frame of the tablet press, for example. The internal data processing unit is preferably also designed as a programmable logic controller of the tablet press and is preferably also referred to as a machine controller.

[0109] In a preferred embodiment, the measuring device can communicate with one or more data processing units (eg externally: PC, smartphone, tablet; or internally: machine control system).

[0110] Direct communication between the measuring device and the machine control system allows rapid adjustment of the operating parameters of the tablet press based on the measurement results. For example, in order to avoid wear when a predetermined force limit is exceeded, the machine control system can adjust the operating parameters based on the transmitted information.

[0111] However, communication of the measuring device with an (external) data processing unit (e.g. PC, tablet computer, smartphone) is particularly preferred. The data processing unit can therefore also be designed as an external component (e.g. tablet computer, smartphone). Preferably, the external component communicates with both the measuring device and the machine control system.

[0112] For example, the (preprocessed) measurement results of the measuring unit can first be transferred to a data processing unit in the form of a PC, tablet computer, etc. or a computer program installed thereon. With the help of external components, a more extensive evaluation of the measurement results can be performed, for example, for monitoring and / or recording the tableting process.

[0113] Based on the evaluation and verification by the personnel, the operating parameters can then be adjusted, for example by sending corresponding control instructions to the machine control system.

[0114] However, the possibility of acquiring and recording the data of the measuring device on a data processing system already offers numerous advantages independent of a possible adjustment of the operating parameters. In particular, recording the measuring data can ensure the recording and therefore the quality control of the production process. If predetermined tolerance limits of the pressing force are exceeded, for example, the corresponding pressed product can be marked for further inspection. As mentioned above, the recording of the measuring data also allows early wear detection. Based on this information, the repair or replacement of the corresponding components can be indicated or the maintenance intervals can be adjusted.

[0115] The invention also relates to a tablet pressing machine comprising a punch of the above type.

[0116] In another preferred embodiment, the present invention relates to a tablet press comprising a programmable logic controller, the programmable logic controller comprising at least a computing unit, a communication unit and a memory unit, and the measuring device of the punch comprises a communication unit, characterized in that the communication unit of the programmable logic controller is compatible with the communication unit of the measuring device of the punch. According to the invention, the communication unit of the programmable logic controller can be designed as a transmission unit and / or a receiving unit. The advantage of integrating the punch according to the invention into the tablet press is that in particular the tablet press can be monitored during operation and / or when idle.

[0117] Compatibility of communication units in the sense of the present invention means that the communication units can communicate with each other. In the sense of the present invention, two communication units use the same data transmission method already mentioned above so that data can be sent or transmitted to each other.

[0118] In another preferred embodiment, the tablet press is designed as a rotary tablet press or an eccentric tablet press. The rotary tablet press preferably comprises a punch of the above type, a rotary table, a die table, a punch guide for receiving the punch, a power supply and upper and lower pressure rollers.

[0119] The eccentric tablet press preferably comprises a punch, a die and a power supply of the type described above.

[0120] In a further preferred embodiment, the data processing unit, such as a smart phone or a tablet computer, comprises a computing unit, a communication unit and a memory unit. According to the present invention, the communication unit of the data processing unit is also used to receive data (and / or send data) from (and / or to) a communication unit of a programmable logic controller of a measuring device and / or a tablet press. The communication unit can receive / send data via a cable, but in particular wireless transmission of data occurs.

[0121] In a preferred embodiment, the data processing unit and / or the communication unit of the programmable logic controller of the tablet press preferably sends the data for controlling the measuring device to the communication unit of the measuring device.

[0122] For example, a data processing unit and / or a communication unit of a programmable logic controller of a tablet press can send control parameters to the measuring device to perform the measurement. The control parameters can, for example, relate to the type of measurement or the selection of active sensors (in the case of multiple sensors). Moreover, the timing of the measurement, the preferred transmission mode or even instructions for the preparation or pre-evaluation of raw data can be defined.

[0123] In a preferred embodiment, the communication unit of the measuring device sends data, preferably processed (prepared) measurement data, to a communication unit of an (external) data processing unit and / or a programmable logic controller of the tablet press.

[0124] The data transmitted by the measuring device are preferably stored in a memory unit of a data processing unit and / or a programmable logic controller of a tablet press. In the sense of the present invention, the memory unit of a data processing unit and / or a programmable logic controller of a tablet press is preferably used to save or store data. According to the present invention, preferably, the measurement data of the recorded sensor are stored in a memory unit. This relates to the analysis results of the data directly obtained via the measuring device and the programmable logic controller of the data processing unit and / or the tablet press itself. Preferably, software programs and, among others, command sequences, mathematical and statistical models are also stored in a memory unit, which can be provided as described for controlling the measuring device and / or for accessing (reading out) the data of the measuring device. The memory unit is preferably an electronic data carrier.

[0125] The data processing unit and / or the computing unit of the programmable logic controller of the tablet press preferably comprises a processor unit. The processor unit therefore preferably comprises a graphics processing unit (GPU) and / or a central processing unit (CPU).

[0126] In another preferred embodiment of the present invention, at least one measuring device is attached to at least one arbitrary element of the tablet press. Preferably, the arbitrary element refers to the punch, the turret, the die plate, the punch guide for receiving the punch, the power supply, and the upper and lower hold-down rollers of the rotary tablet press.

[0127] In another preferred embodiment, the invention relates to a system comprising a data processing unit and a tablet press of the above-described type, wherein the measuring device of the punch comprises a communication unit and the tablet press comprises a programmable logic controller, characterised in that the data processing unit and / or the programmable logic controller of the tablet press are suitable for

[0128] - receiving and further processing of measured values ​​from a measuring device, preferably processed (prepared) raw data, and / or

[0129] - Transmitting control commands to the measuring device.

[0130] Such a system is advantageously suitable for monitoring the tableting process, because the measured data can be processed (visualized and / or analyzed) on a device external to the measuring device with increased storage space and computing power, while the measuring device can remain very compact and only needs to include a few components. This requires a situation where the evaluation of the data can preferably occur online (directly) without manually removing or reading the measuring device. In addition, the measuring device advantageously records the measured values ​​directly at the punch, so that a particularly accurate and detailed description of the compacting process can be made. In addition, the measuring device can receive control commands from the user (or automatically) via an external device (a data processing unit or a programmable logic controller of a tablet press), so that certain parameters (e.g., sampling rate) can be set from a remote location.

[0131] In another preferred embodiment, the invention relates to a method for monitoring a tablet press using a punch of the above-described type, wherein the measuring device of the punch comprises a sensor, a computing unit, a communication unit and a memory unit, and the tablet press comprises a programmable logic controller with a communication unit, characterized in that

[0132] - the sensors of the measuring device record physical and / or chemical properties;

[0133] - processing (preparation) of the measured values ​​recorded as raw data by a computing unit of the measuring device;

[0134] The processed (prepared) measured values ​​are sent via the communication unit of the measuring device to a programmable logic controller and / or a data processing unit of the tablet press and / or the processed (prepared) measured values ​​are saved on a memory unit of the measuring device.

[0135] An advantage of the method according to the invention is that the condition of the tablet pressing machine can be monitored and analyzed during operation and / or when idle.

[0136] In another preferred embodiment, the monitoring of the tablet press is preferably technical monitoring. On the one hand, this monitoring is designed to prevent failures and enables timely measurement or repair. On the other hand, further development of technology and prevention of environmental damage are practical possibilities.

[0137] In a preferred embodiment, the method is characterized in that the sensors of the measuring device register forces, temperatures or accelerations, in particular of the punch and / or its surroundings and / or the speed of the turntable.

[0138] In a further preferred embodiment, the recorded measured values ​​are stored in a memory unit of the data processing unit and / or in a memory unit of the programmable logic controller and / or in a memory unit of the measuring device.

[0139] In a further preferred embodiment, the method is characterized in that the programmable logic controller and / or the data processing unit of the tablet press (preferably a tablet computer and / or a smartphone) can transmit control commands to the measuring device, preferably by means of a computer program product (application / app) installed on these devices.

[0140] In a further preferred embodiment of the invention, the stored measurement data are analyzed, preferably by means of an algorithm.

[0141] In a preferred embodiment of the invention, the memory unit of the measuring device is detachably fastened so that a user of the machine can manually connect the data to be evaluated to the programmable logic controller and / or the data processing unit of the tablet press.

[0142] In another preferred embodiment of the invention, the computing unit of the data processing unit and / or the programmable logic controller directly accesses the measurement data stored in the memory unit of the data processing unit and / or in the memory unit of the programmable logic controller and executes an algorithm for analyzing the measurement data also stored in the memory unit.

[0143] By analyzing the measurement data with the help of algorithms, errors, wear and malfunctions of punches and / or other components of the tablet press can be detected at a very early stage.

[0144] In a further preferred embodiment of the invention, the method is characterized in that the recorded measured values ​​of the measuring device are analyzed by means of a machine learning algorithm.

[0145] In another preferred embodiment, external parameters and / or measured values ​​from the punch are incorporated into the analysis of the method for monitoring the tablet press. These can be determined by a measuring device independent of the measuring device according to the invention. For example, in the case of a rotary tablet press, the recorded measurement data of the pressing roller (e.g., pressing force), the turntable (e.g., rotation), the die table or in a simple case, the ambient temperature of the tablet press can also be stored in a memory unit of the data processing unit of the tablet press and subsequently analyzed by the following algorithm. A large number of different recorded data allow a comprehensive analysis with few errors.

[0146] In a further preferred embodiment, the method is characterized in that the recorded measured values ​​of the measuring device are analyzed by means of an algorithm, preferably a machine learning algorithm, in combination with externally recorded and / or provided measured values.

[0147] In the sense of the present invention, machine learning algorithms are a sub-area of ​​artificial intelligence. Machine learning uses mathematical and statistical models to "learn" from a data set. In general, machine learning algorithms have the following advantages: information that is too complex for a human observer can be automatically extracted from a large data set. There are various machine learning algorithms that can be roughly classified into three different learning methods: supervised learning, unsupervised learning, and reinforcement learning.

[0148] In a preferred embodiment, supervised learning is used to analyze or process the stored measurement data. In a supervised learning method, a so-called training process is first performed. Here, training data are provided in the form of input data together with corresponding target data. The purpose of training is usually in machine learning methods to adjust the parameters of the function so that the function can then determine the target value with high accuracy from the corresponding input value. The adjusted function is then used after the training process to predict the target data for previously unseen input data. The function is described by a mathematical and / or statistical model.

[0149] In a preferred embodiment, the function is designed by a support vector machine, a Bayesian network and / or a decision tree. Particularly preferably, the function is described by an artificial neural network. According to the invention, the artificial neural network can have different architectures.

[0150] In the sense of the invention, the input data are preferably defined by machine parameters, environmental parameters and / or measurement data of a measuring device. The machine parameters are preferably the rotation speed of the turntable, various material properties and / or key values ​​of the components, the run time or operating time, the life of the machine, the number of punches or other components, etc. The environmental parameters are preferably the ambient temperature, humidity, etc.

[0151] Preferably, measurement data from different measuring devices equipped with different sensors for measuring different physical and / or chemical properties are used as input data.

[0152] According to the invention, the target data are preferably adapted to display the probability of occurrence of damage, failure of a component or faulty execution of a pressing process.

[0153] In another preferred embodiment, an unsupervised learning method is used to analyze or process the stored measurement data. In unsupervised learning, the algorithm attempts to detect patterns in the input data that deviate from the unstructured background noise. The function in the training process is oriented only on the similarity of the input data and adjusts its parameters accordingly, so that no output data is used for the training process.

[0154] In a preferred embodiment, an unsupervised learning method is used to segment or cluster the input data, or preferably, to compress the input data.

[0155] In a preferred embodiment, the unsupervised learning algorithm preferably comprises principal component analysis (PCA) and / or a K-Means algorithm and / or at least one neural network.

[0156] As already described, in both methods described above, a so-called training process is performed in a first step to determine the optimal parameters of the above-mentioned machine learning function. Based on the adapted function, various statements are made after training on previously unknown input data.

[0157] In another preferred embodiment, a reinforcement learning method is used to analyze or process the stored measurement data. On the other hand, in the reinforcement learning method, the training process is continued even after the parameters of the function have been adjusted. Through "trial and error", the impact of different instructions is observed and evaluated using an adaptation function to previously unknown input data. In response to these instructions, the algorithm receives feedback that is abstractly represented in the form of rewards or penalties. The algorithm then further optimizes the function based on its parameters. Therefore, the algorithm continuously adjusts or modifies the function of the machine learning process. Preferably, reinforcement learning can use Q-learning methods and / or the above-mentioned neural networks and / or other neural networks and other algorithms known to those skilled in the art.

Claims

1. A punch for a tablet press, It is characterized in that The punch has a measuring device which is energy self-sufficient and can operate independently of the power supply for the tablet press, Therein, the measuring device is integrated inside the punch body and comprises a sensor for recording physical and / or chemical properties, wherein the sensor comprises a communication unit, a memory unit, an energy storage unit and a computing unit, wherein the measured values ​​obtained as raw data can be processed by the computing unit.

2. A punch according to the preceding claim, It is characterized in that in, The measuring device fits precisely into a solid punch body, or wherein the measuring device is attached to the inner wall of a hollow punch body.

3. A punch according to any one of the preceding claims, It is characterized in that Among the sensors for recording physical and / or chemical properties are sensors for recording force, temperature and / or acceleration of the punch and / or its environment.

4. The punch according to claim 1 or 2, It is characterized in that The tablet press is a rotary tablet press or an eccentric tablet press.

5. A tablet pressing machine comprising a punch according to any one of the preceding claims.

6. A system comprising a. a tablet press comprising a punch according to any one of claims 1 to 3, b. Data processing unit, in, The measuring device of the punch comprises a communication unit, and the tablet press comprises a programmable logic controller, It is characterized in that The data processing unit and / or the programmable logic controller of the tablet press are used to - receiving and further processing the measured values ​​from the measuring device, and / or - Transmitting control commands to the measuring device.

7. The system according to claim 6, It is characterized in that The measured values ​​are processed raw data.

8. A method for monitoring a tablet press using a punch according to any one of claims 1 to 4, - wherein the tablet press comprises a programmable logic controller having a communication unit, It is characterized in that The measured values ​​recorded as raw data by the measuring device of the punch are processed by the computing unit of the measuring device to generate processed measured values, The processed measured values ​​are sent via the communication unit of the measuring device to the programmable logic controller and / or the data processing unit of the tablet press and / or the processed measured values ​​are saved on the memory unit of the measuring device.

9. The method according to claim 8, It is characterized in that The sensors of the measuring device record forces, temperatures or accelerations of the punch and / or its environment.

10. The method according to any one of the preceding claims 8 to 9, It is characterized in that The programmable logic controller and / or the data processing unit of the tablet press can transmit control commands to the measuring device by means of a computer program product installed on these devices.

11. The method according to claim 10, It is characterized in that The data processing unit is a tablet computer and / or a smartphone.

12. The method according to any one of the preceding claims 8 to 9, It is characterized in that The recorded measured values ​​of the measuring device are evaluated.