DE102015000618B4 - Clamping unit, forming machine and method of monitoring a clamping unit - Google Patents

Abstract

Closing unit of a molding machine, comprising- two clamping plates (2) each for assembling parts of a molding tool (3),- at least one drive (4, 5) which is suitable for moving at least one of the clamping plates (2) and closing it with a clamping force - at least one measuring device (6, 7) for measuring at least one clamping force value and/or at least one position value of at least one of the clamping plates (2) and - a control or regulating unit (9) which is connected to the at least one drive (4, 5 ) and the at least one measuring device (6, 7), characterized in that - at least one reference force application point of at least one clamping plate (2) can be stored in a memory (11) of the control or regulation unit (9) and - a processor (12 ) the control or regulating unit (9) is designed to interrupt, prevent or interrupt a closing movement of the clamping plates (2) to be carried out by the at least one drive (4, 5). r to reverse and/or to interrupt or prevent the application of closing force by the at least one drive (4, 5) if at least one calculated force application point and the at least one reference force application point do not essentially match.

Description

The present invention relates to a clamping unit of a molding machine according to the features of the preamble of claim 1 and a method for monitoring a clamping unit of a molding machine according to the features of the preamble of claim 17. The present invention also relates to a molding machine.

A process scheme frequently used in transfer molding involves placing a semi-finished product in a mold, closing the mold and introducing and curing a reactive liquid mixture, after which the mold can be opened and the resulting component can be removed.

For example, fiber fabrics or the like can be used as semi-finished products.

Exact positioning and the nature of the semi-finished product are essential for the quality of the resulting component. In the case of non-rigid semi-finished products in particular, however, this exact positioning poses a certain challenge for the automation of the process. As a result, if the semi-finished product is incorrectly positioned, either a costly quality control must be carried out or the incorrect positioning of the semi-finished product will result in reinforcement faulty components come into circulation.

In the worst case, such components end up in circulation and cause consequential damage, costs and possibly even personal injury.

In any case, material costs arise for produced components, which may not be brought into circulation.

the DE 10 2012 209 066 A1 discloses a molding machine comprising a stationary platen provided with a stationary mold, a movable platen provided with a movable mold, a lock driving mechanism for moving the movable platen forward or backward and for locking the movable mold to the stationary mold , a detection section for detecting information on a locking state, an injector and a control unit to monitor the information obtained by the detection section in an injection process, and to calculate an injection pressure of the injector based on a value derived from the information was obtained to control.

US 2011/0052742 A1 discloses a mold clamping device that can prevent a molding material from spurting out of a gap surface of a mold even if the resin pressure in the cavity causes offset of the mold opening force and can extend the life of the mold. The mold clamping device includes a controller that estimates a mold opening force by mold cavity pressure for molding with a mold cavity pressure that is asymmetrical with respect to a center of a mold block, determines a hydraulic mold closing value that is applied to each time bar corresponding to the estimated mold opening force, and the hydraulic Pressure applied to each time bar distributed to achieve the specified hydraulic mold closure value.

the U.S. 5,582,845 A discloses a system for detecting the presence and absence of inserts at various stages in a molding system comprising at least a first insert loading station, an insert changing plate, an insert shifting device and a molding station with mold cores.

The system includes a device for detecting the presence and absence of inserts on the insert changing plate as the inserts are moved from the first station via the insert changing plate to the insert shifting device. If one of the enclosures is found to be absent, an indicator for it is actuated. The device also serves to determine the presence and absence of the supplements on the supplement changing plate after the supplements have been removed from the supplement changing plate via the transfer device. If the presence of one of the inserts is detected, an indicator for it is activated.

the U.S. 5,928,578 A discloses a skip eject system for an injection molding machine having an electronic camera for capturing an actual image of an open mold after a part ejector has been actuated and a controller for comparing such actual image to an ideal open mold image which does not have a Part is in the open mold. When a comparison of the actual image with the ideal image indicates that there is no longer a part in the open mould, the controller issues a signal to close the mould. However, if the comparison indicates that the part is still in the open mold, the controller will issue an ejector signal to actuate the ejector for a new cycle. This sequence continues until a comparison of an actual image of the open mold with the ideal image indicates that the part is no longer in the open mold. In an alternative implementation the ejector continues to cycle until a comparison of an actual image of the open mold with the ideal image indicates that the part has been ejected, whereupon the controller issues a signal to stop the ejector cycle and close the mold for injection of a new part conclude. If a certain number of ejector cycles are exceeded after opening the mold, an alarm will be triggered and the machine will stop.

the DE 10 2004 043 300 A1 relates to a method for operating an injection molding machine, with a force being measured during an opening and/or closing movement of a mold half along a travel path and the force being compared with a maximum permissible force and/or a minimum permissible force, with the fact that when the maximum allowable force and/or when falling below the minimum allowable force, a time measurement is started, with a drive of the tool half being switched off when exceeding the maximum allowable force and/or falling below the minimum allowable force exceeds a predetermined period of time.

US 2004/0 080 067 A1 relates to a method for detecting a malfunction during a mold closing process in an injection molding machine. A reference pattern showing a relationship between a mold clamping force and a position of a movable platen when mold clamping is performed is picked up. One or more monitor sections are set in advance with respect to that position based on the reference pattern, and an allowable limit value of a mold clamping force in the respective monitor sections is also set in advance in terms of a linear function of the position. The die clamping force is monitored in each monitor section during each die clamping step, and when its value exceeds the allowable limit, an alarm is issued.

the DE 10 2004 005 686 B4 discloses a drive unit, in particular for injection molding machines, with a pressure chamber filled with a fluid, into which a displacement body can be inserted. The displacement body is actuated by a linear motor.

the DE 696 03 693 T2 relates to a system for manufacturing multilayer preforms with inserts.

the AT 007 859 U1 discloses a method for monitoring the closing force of an injection molding machine, in which two mold halves enclosing at least one cavity are pressed together with their end faces by the closing force, with the pressure applied to the end faces or their distance from one another at at least one point of the end faces being determined by means of at least is determined by a sensor, a reaction being triggered if there is a distance between the end faces or if the pressure limits between the touching end faces exceed or fall below predetermined limits.

WO 2013/026 610 A1 proposes detecting deviations in the positioning of the semi-finished product using a camera and then adjusting the position of the other tool part, known as the upper tool, accordingly.

The disadvantage here is that the upper tool must be able to be moved in a plane perpendicular to the closing direction of the mold, which is very complex in terms of construction.

Furthermore, it is disadvantageous that a deviation with regard to the lower tool cannot be compensated for.

The object of the invention is to provide a closing unit for a shaping machine and a method for operating such a closing unit, in which it is possible to prevent in a simple manner that components with incorrectly positioned semi-finished products are manufactured.

This object is achieved by the features of claim 1 with regard to the device and by the features of claim 17 with regard to the method.

A basic idea of the invention is to detect incorrect positioning of the semi-finished product before the completion of the component and in particular before the semi-finished product comes into contact with a fluid material, such as a reactive mixture. If incorrect positioning is detected, the shaping cycle can be interrupted and, for example, the semi-finished product can be repositioned, or a new semi-finished product can be used.

Various alternatives are proposed for detecting incorrect positioning. These are the measurement of at least one clamping force value and/or at least one position value of at least one of the clamping plates and/or the measurement of a position of a semi-finished product located in the mold. In addition, at least one reference closing force and/or at least one reference position and/or at least one reference force application point of the platens and/or a reference position for the semi-finished product. This makes it possible for the closing movement of the clamping plates to be interrupted, prevented or reversed and/or the application of clamping force to be interrupted or prevented if the at least one clamping force value and the at least one reference clamping force and/or the at least one position value and the at least one reference position and /or at least one calculated force application point and the at least one reference force application point and/or the detected position and the reference position of the semi-finished product do not essentially match.

The force application point can be defined as the mean of all positions at which a force is introduced into the mold clamping plates or into a mold clamping plate, with each position being weighted with the force acting there. In other words, the force application point corresponds to the end point of the resulting torque vector of the force application that took place via the individual force application positions (usually bars) in the movable mold platen.

In a particularly preferred embodiment of the invention, the shaping cycle is interrupted if the at least one clamping force value and the at least one reference clamping force and/or the at least one position value and the at least one reference position on the one hand and the detected position and the reference position of the semi-finished product on the other hand do not essentially match. With this combination, almost all relevant incorrect positioning that occurs in practice can be prevented. In this regard, reference is made to the figures and the associated description of the figures.

Further advantageous embodiments of the invention are defined in the dependent claims.

A particularly preferred embodiment of a closing unit according to the invention can comprise at least one express stroke drive and at least one power stroke drive as at least one drive. This makes it possible to have the two tasks “opening and closing the mold” and “applying the closing force” carried out by independent drives that are specialized for each task.

An embodiment can also be preferred in which the at least one measuring device is designed to measure a large number of closing force values and/or position values and/or force application points of the clamping plates and/or layers of a semi-finished product in the mold for each molding cycle. By measuring a large number of measured values - for example a closing force curve or a position curve - various advantages can be achieved depending on the situation. On the one hand, it is possible to document in a time-resolved manner when incorrect positioning of the semi-finished product occurs, which means that conclusions can be drawn about frequently occurring errors. Furthermore, it may be possible to react more quickly as soon as the semi-finished product is incorrectly positioned.

It can particularly preferably be provided in this embodiment that a large number of reference closing forces and/or a large number of reference positions are also stored or can be stored in the memory of the control or regulation unit. The mentioned advantage of a time-resolved detection of an incorrect positioning can be increased by a constant comparison of the corresponding measured values and references.

In an embodiment that is particularly easy to carry out, it can be provided that the at least one reference clamping force is designed as at least one limit value, with the processor of the control or regulation unit (9) being designed to interrupt a closing movement of the clamping plates to be carried out by the at least one drive , to prevent or reverse and / or to interrupt or prevent the application of closing force by the at least one drive if the at least one closing force value exceeds the at least one limit value.

It can be used as a criterion for a measured value not essentially matching a reference, but also for exceeding a limit value due to the deviation between the measured value and the reference.

In a particularly preferred embodiment, it can be provided that the at least one measuring device is designed to detect a position of the semi-finished product and/or a shape of the semi-finished product and/or a surface condition of the semi-finished product when measuring the position of a semi-finished product located in the mold . Several different types of incorrect positioning of a semi-finished product can be detected in this way.

In a likewise particularly preferred embodiment, it can be provided that the at least one measuring device for measuring the position of a semi-finished product located in the mold comprises an optical sensor, in particular a camera. It is up to experts to decide where the optical sensor is to be arranged. On the one hand, this can be outside of the mold be in order. In this regard, reference is made to the figures and the associated description of the figures. In a somewhat more complex embodiment, the optical sensor can also be arranged inside the mold. A particularly accurate and particularly reliable detection of incorrect positioning can be achieved in this way.

The use of a camera as an optical sensor can offer the advantage that further details of the semi-finished product (color, folds and the like) can be recorded.

Provision can furthermore be made for the processor to be designed to prevent and/or interrupt an introduction process of liquid or plastic material - preferably by injection using positive pressure and/or drawing in using negative pressure - if the at least one closing force value and the at least one Reference closing force and/or the at least one position value and the at least one reference position and/or the measured position and the reference position of the semi-finished product do not essentially match. In some cases this means that the semi-finished product can continue to be used. Furthermore, this measure makes it possible to keep the cycle time as short as possible, even in a shaping cycle in which incorrect positioning occurs.

It can preferably be provided that the mold clamping plates can be aligned at an angle to one another by means of the at least one drive. It can furthermore be particularly preferred that the extent of the inclination of the mold clamping plates relative to each other can be predetermined by changing the position of the at least one force application point. This makes it possible to implement control or regulation of the skew.

In a very particularly preferred way, it can be provided that the processor is designed to calculate a distance between the at least one calculated force application point and the force application reference profile and to interrupt, prevent or reverse a closing movement of the clamping plates to be carried out by the at least one drive and/or or to interrupt or prevent the application of closing force by the at least one drive if the distance between the at least one calculated force application point and the at least one reference force application point exceeds a distance limit value. This enables a reliable detection of incorrectly positioned semi-finished products without significantly increasing the number of false trips.

Furthermore, protection is sought for a molding machine, in particular an injection press, with a clamping unit according to the invention. Of course, the invention can also be used with molding machines other than an injection press. Examples would be presses or injection molding machines.

For a simple determination of the reference clamping force and/or the reference position and/or the reference position, it can be provided that at least one reference production cycle is carried out in which at least one clamping force value prevailing between the clamping plates and/or at least one position value of at least one of the clamping plates and/or a position of the semi-finished product is measured, and the closing force value is defined as the reference closing force and/or the position value as the reference position and/or the position of the semi-finished product as the reference position.

The invention can be used with semi-finished products that contain fibers and/or textiles and/or plastics and/or metals and/or an organic sheet. For example, fiber fabrics can be used.

• 1a und 1b zwei Verfahrensschritte eines Formgebungszyklus, wobei keine Fehlpositionierung des Halbzeugs auftritt,
• 2a und 2b zwei Verfahrensschritte in einem Formgebungszyklus, bei dem eine erste Fehlpositionierung des Halbzeugs auftritt,
• 3a und 3b zwei Verfahrensschritte in einem Formgebungszyklus, bei dem eine zweite Fehlpositionierung des Halbzeugs auftritt,
• 4a und 4b zwei Schließkraftverläufe in Formgebungszyklen,
• 5a und 5b zwei weitere Schließkraftverläufe in Formgebungszyklen,
• 6a und 6b zwei Darstellungen von Verläufen eines Krafteinleitungspunktes sowie
• 7a und 7b zwei Spritzpressen mit erfindungsgemäßer Schließeinheit.

Further advantages and details of the invention result from the figures and the associated description of the figures. show:

• 1a and 1b two process steps of a forming cycle, whereby no incorrect positioning of the semi-finished product occurs,
• 2a and 2 B two process steps in a forming cycle, in which a first incorrect positioning of the semi-finished product occurs,
• 3a and 3b two process steps in a forming cycle, in which a second incorrect positioning of the semi-finished product occurs,
• 4a and 4b two clamping force curves in forming cycles,
• 5a and 5b two further clamping force curves in forming cycles,
• 6a and 6b two representations of curves of a force application point as well as
• 7a and 7b two transfer presses with a clamping unit according to the invention.

In the 1a and 1b a closing unit 1 is shown. It has two platens 2, on each of which parts of the mold 3 are mounted. In addition, there are two express stroke drives 4 and four power stroke drives 5, which allow high pressing forces to be exerted on the tool 3. (Because of the manner of representation, only two of the four power lifting drives 5 can be seen.) The precise structural design direction of the closing unit 1 is not essential for the invention. The hydraulic clamping unit 1 with four beams shown here is only to be understood as an example. Clamping units with frames, such as an electric toggle-joint machine or other mixed forms, could also be used. In addition, it is not essential for the invention whether horizontally or vertically closing closing units are used.

1a shows the closing unit 1 after the semi-finished product 8 - in this case a fiber fabric - has been placed in the tool 3. The closing unit is then closed by the express stroke drives 4.

The control or regulating device 9 is connected to the force sensors 7 on the one hand. A force sensor 7 is provided for each hydraulic drive, only two force sensors 7 being shown and provided with reference symbols for the sake of clarity. The control or regulating device 9 is also connected to the camera 6 . In this embodiment, several images of the semi-finished product 8 located in the mold 3 are created by the camera 6 and transmitted to the control or regulating device 9 . The processor 12 compares these images with reference images stored in the memory 11 . Since in this case the semi-finished product 8 is correctly positioned, the images essentially do not differ from the reference images, as a result of which the closing of the clamping unit 1 is not interrupted or prevented.

At the end of the closing movement, the situation is over 1b in front. In this state, the processor 12 of the control or regulation unit 9 compares the measured values of the force sensors 7 with reference closing forces stored in the memory 11 . In this exemplary embodiment, the large number of measured values reflects a course of the closing force, which is compared with a course of the reference closing force. Since there is no incorrect positioning of the semi-finished product 8 here, the application of the closing force is not interrupted either. A reactive mixture can be introduced into the cavity of the tool 3 as the following method step. After the mixture has hardened, the finished component can be demolded.

In this case, the force sensors 7 are designed as pressure sensors in the hydraulic cylinders. Appropriate sensors are to be used with electrical locking units. In addition to force sensors 7, position sensors can of course also be used.

In the 2a and 2 B are analogous representations to the 1a and 1b shown, in which case the semi-finished product 8 is incorrectly positioned.

In relation to 2a the camera 6 creates images of the incorrectly positioned semi-finished product 8. The closing of the closing unit 1 is then interrupted or prevented by the processor 12 of the control or regulation unit 9, since the image of the semi-finished product 8 does not correspond to that stored in the memory 11 of the control or regulation unit 9 reference image matches. Subsequently, the position of the semi-finished product 8 can be improved or a new semi-finished product 8 can be inserted and production can be continued.

In 2 B the situation is shown if the camera 6 fails to detect the position of the incorrectly positioned tool 8 . Even in this case, the force sensors detect a closing force curve that deviates from the reference closing force curve, since the semi-finished product 8 is clamped between the boundary surfaces of the tool 3 . The processor determines this deviation and interrupts the application of closing force because the deviation has exceeded a limit value.

3a and 3b are also analogous to the previous figures, with the semi-finished product 8 being incorrectly positioned in a different way or being in an incorrect position due to its nature. In this case, the positional deviation is such that it cannot be captured by an image from the camera 6 . The closing of the closing unit 1 is thus not interrupted or prevented due to the position detection, whereby the state in 3b will be produced.

Nevertheless, a closing force curve deviating from the reference closing force curve is also detected by the force sensors 7 . As already below 2 B described, the processor 12 determines this deviation and prevents the application of the closing force since the limit value has been exceeded. The introduction of a liquid mixture, which reacts and hardens during the normal course of the cycle, is also prevented.

In the 4a and 4b Closing force curves F and limit values G are plotted against time t. In 4a a clamping force curve is shown as it would occur if the shaping cycle was carried out without errors - i.e. as in connection with the figure in 1a and 1b described - occurs. At any point in time, the course of the closing force F remains below the limit value or the course of the limit value G. Now occurs as in FIGS 2a and 2 B and 3a and 3b, incorrect positioning of the semi-finished product 8 changes the course of the closing force and leads to the course of the closing force F exceeding the course of the limit value G. This is in 4b marked by a circle. At this point in time, the control or regulation unit 9 takes effect into the molding cycle to prevent the production of a defective part.

In this case, the reference closing force is given by the values below the limit value curve G.

The closing force curve F off 4a can also be used as a reference closing force curve. In the simplest case, the limit value G results from an offset to the closing force curve F.

A problem can arise when it is necessary to maintain a target positioning of the semi-finished product 8 very precisely. Then limit curves G must be selected relatively restrictively. Examples are in the 5a and 5b shown. In fact, lower limit curves can also be provided in these cases, which is also in the 5a and 5b is shown. The problem addressed arises from erroneous triggering of the monitoring of the positioning of the semi-finished products 8, which becomes more likely due to the restrictive selection of the limit values. In other words, the separation of correctly positioned semi-finished products 8 from incorrectly positioned ones due to restrictive limit values cannot be good enough to produce economically.

In this case, a variable derived from position and closing force values can be used to differentiate between correctly and incorrectly positioned semi-finished products 8 . Specifically, it is proposed to use the so-called force application point L. This is determined as the average of the positions at which forces are exerted on the movable platen 2 weighted by the forces exerted at the respective positions.

In order to calculate the force application point L, it may be necessary to use position sensors on both the high-speed hoist drives and the power hoist drives. Whether this is actually necessary depends in practice on how precise the determination of the force application point must be and whether the inclined position of the movable platen 2 should also be monitored during the closing of the clamping unit by means of the rapid stroke.

In the 6a and 6b are each shown the movable platen 2 in a plan view. A vertical clamping unit with four bars is used as an example. In this case the positions at which forces are exerted on the platen 2 are essentially given by the bars (it is assumed that no monitoring is undertaken while the fast stroke is activated).

During the power stroke, the movable platen 2 is locked to the bars, therefore the positions at which forces are applied to the movable platen 2 can be measured as (vertical) positions P1 to P4 of the bars. (That's why the spars are in the 6a and 6b symbolically provided with the reference symbols P1 to P4.)

Assuming that the clamping plates 2 are aligned completely parallel, as a result of which the force application point L is in the center of the movable clamping plate 2, it may happen that a semi-finished product in the illustration in 6a the upper right quadrant has less resistance than the rest of the plate. In the course of further movement, the movable platen 2 will be inclined or inclined, as a result of which the force application point L will be shifted to the upper right quadrant.

This skewing can be intentional—for example, because the semifinished product 8 has a special shape or is intended. In fact, a control of the power stroke drives 5 can fall back on the force application point L in order to follow a target course of the force application point L.

In the situation at 6a the course of the force application point L lies exactly (within the scope of the representation accuracy) on the target course. An area B is also drawn in, which is characterized by a maximum distance from the desired course of the force application point L. If the force application point L leaves the area B, the closing movement of the clamping plates 2 is interrupted, prevented or reversed, or the application of the closing force by the at least one drive 4, 5 is interrupted or prevented.

The monitoring of the force application point L can also be carried out in a time-resolved manner. Then the entire area B is not available, but only an environment—given by a distance limit value—around the reference force introduction point associated with the respective point in time.

In the 7a and 7b Injection presses are shown, each of which has a closing unit 1 according to the invention. Exemplary and schematic is in 7a a resin injector 13 is shown. In 7b an injection device for thermoplastics 14 is shown. It is not essential to the invention in which way the material to be cast is introduced into the cavity of the molding machine.

Claims (21)

Closing unit of a molding machine, comprising - two clamping plates (2), each for assembling parts of a molding tool (3), - at least one drive (4, 5), which is suitable for moving at least one of the clamping plates (2) and closing it with a clamping force - at least one measuring device (6, 7) for measuring at least one clamping force value and/or at least one position value of at least one of the clamping plates (2) and - a control or regulating unit (9) which is connected to the at least one drive (4, 5 ) and the at least one measuring device (6, 7), characterized in that - at least one reference force application point of at least one clamping plate (2) can be stored in a memory (11) of the control or regulation unit (9) and - a processor (12 ) the control or regulating unit (9) is designed to interrupt a closing movement of the clamping plates (2) to be carried out by the at least one drive (4, 5), to prevent to correct or reverse and/or to interrupt or prevent the application of closing force by the at least one drive (4, 5) if at least one calculated force application point and the at least one reference force application point do not essentially match. locking unit after claim 1 , characterized in that the at least one measuring device (6, 7) is also designed to measure a position of a semi-finished product (8) located in the mold (3), a reference position for the semi-finished product (8) can be stored in the memory (11) and the Processor (12) of the control or regulation unit (9) is designed to interrupt, prevent or reverse a closing movement of the clamping plates (2) to be carried out by the at least one drive (4, 5) and/or the application of the closing force by the interrupting or preventing at least one drive (4, 5) if the measured position and the reference position of the semi-finished product (8) do not essentially match. locking unit after claim 1 or 2 , characterized in that at least one reference clamping force and/or at least one reference position of at least one clamping plate (2) can be stored in a memory (11) of the control or regulation unit (9) and the processor (12) of the control or regulation unit (9) designed to interrupt, prevent or reverse a closing movement of the clamping plates (2) to be carried out by the at least one drive (4, 5) and/or to interrupt or close the application of closing force by the at least one drive (4, 5). prevent if the at least one closing force value and the at least one reference closing force and/or the at least one position value and the at least one reference position do not essentially match. Locking unit according to one of Claims 1 until 3 , characterized in that the at least one drive (4, 5) comprises at least one express stroke drive (4) and at least one power stroke drive (5). Locking unit according to one of Claims 1 until 4 , characterized in that the at least one measuring device (6, 7) is designed to measure a large number of closing force values and/or position values and/or force application points (L) and/or positions of a semi-finished product (8) located in the mold (3) for each molding cycle. to measure and/or calculate. locking unit after claim 3 , characterized in that the at least one reference closing force is designed as at least one limit value (G), the processor (12) of the control or regulating unit (9) being designed to carry out a closing movement by the at least one drive (4, 5). of the clamping plates (2) and/or to interrupt or prevent the application of clamping force by the at least one drive (4, 5) if the at least one clamping force value exceeds the at least one limit value (G). locking unit after claim 3 , characterized in that the processor (12) of the control or regulating unit (9) is designed to determine a deviation of the at least one closing force value from the at least one reference closing force and/or the at least one position value from the at least one reference position and a to interrupt, prevent or reverse the closing movement of the clamping plates (2) to be carried out by the at least one drive (4, 5) and/or to interrupt or prevent the application of clamping force by the at least one drive (4, 5) if the deviation is at least exceeds a limit. locking unit after claim 2 , characterized in that the at least one measuring device (6, 7) is designed to measure the position of a mold (3) located in the semi-finished product (8) a position of the half zeugs (8) and / or a shape of the semi-finished product (8) and / or a surface finish of the semi-finished product (8) to detect. locking unit after claim 2 , characterized in that the at least one measuring device (6, 7) for measuring the position of a semi-finished product (8) located in the mold (3) comprises an optical sensor, in particular a camera (6). locking unit after claim 9 , characterized in that the optical sensor, in particular the camera (6), is designed to create at least one image of the semi-finished product (8), and the processor (12) is designed to the image of the semi-finished product (8) with the to compare the reference position in the form of a reference image and to interrupt, prevent or reverse a closing movement of the clamping plates (2) to be carried out by the at least one drive (4, 5) and/or the application of the closing force by the at least one drive (4, 5) to interrupt or prevent if the image of the semi-finished product (8) and the reference image do not essentially match. Locking unit according to one of Claims 1 until 10 , characterized in that the processor (12) is designed to prevent and/or interrupt an introduction process of liquid or plastic material - preferably by injection using excess pressure and/or drawing in using negative pressure - if the at least one closing force value and the at least a reference closing force and/or the at least one position value and the at least one reference position and/or the measured position and the reference position of the semi-finished product (8) do not essentially match. Locking unit according to one of Claims 1 until 11 , characterized in that the mold mounting plates (2) can be aligned at an angle to one another by means of the at least one drive (4, 5). locking unit after claim 12 , characterized in that the extent of the inclination of the mold mounting plates (2) to each other by changing the position (x, y) of the at least one force application point (L) can be predetermined. Locking unit according to one of Claims 1 until 13 , characterized in that the processor (12) is designed to calculate the position (x, y) of the at least one force application point (L) based on the measurement of at least one clamping force value and at least one position value of at least one of the clamping plates (2). Locking unit according to one of Claims 1 until 14 , characterized in that the processor (12) is designed to calculate a distance between the at least one calculated force application point and the at least one reference force application point and to interrupt a closing movement of the clamping plates (2) to be carried out by the at least one drive (4, 5). , prevent or reverse and/or interrupt or prevent the application of closing force by the at least one drive (4, 5) if the distance between the at least one calculated force application point and the at least one reference force application point exceeds a distance limit value. Shaping machine, in particular an injection press, with a closing unit (1) according to one of Claims 1 until 15 . Method for monitoring a clamping unit of a molding machine, in which - a semi-finished product (8) is arranged in a molding tool (3), - the molding tool (3) is opened by a closing movement of clamping plates (2) on which parts of the molding tool (3) are mounted, is closed, - the clamping plates (2) are subjected to a clamping force and - at least one clamping force value prevailing between the clamping plates (2) and/or at least one position value of at least one of the clamping plates (2) is measured, characterized in that - at least one reference force introduction point of the clamping plates (2) is fixed, - the closing movement of the clamping plates (2) is interrupted, prevented or reversed and/or the application of clamping force is interrupted or prevented if at least one calculated force application point (L) and the at least one reference force application point do not essentially correspond . procedure after Claim 17 , characterized in that a position of the semi-finished product (8) is measured, a reference position for the semi-finished product (8) is defined and the closing movement of the clamping plates (2) is interrupted, prevented or reversed and/or the application of the closing force is interrupted or prevented, if the detected position and the reference position of the semi-finished product (8) do not essentially match. procedure after Claim 17 or 18 , characterized in that at least one reference closing force and/or at least one reference position of the clamping plates (2) is defined and the closing movement of the clamping plates (2) is interrupted, prevented or reversed and/or the application of clamping force is interrupted or prevented if the at least one clamping force value and the at least one reference clamping force and/or the at least one position value and the at least one reference position are not in the agree essentially. Procedure according to one of claims 17 until 19 , characterized in that at least one reference production cycle is carried out, in which at least one clamping force value prevailing between the clamping plates (2) and/or at least one position value of at least one of the clamping plates (2) and/or a layer of the semi-finished product (8) is measured, and the closing force value is specified as the reference closing force and/or the position value as the reference position and/or a calculated force application point as the reference force application point and/or the position of the semi-finished product (8) as the reference position. Procedure according to one of claims 17 until 20 , characterized in that a semi-finished product (8) containing fibers and/or textiles and/or plastics and/or metals and/or an organic sheet is used.

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