JP2018116056A - Apparatus for monitoring metering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for periodically and automatically inspecting a metering device capable of detecting both the size of a droplet and the position of the metered droplet.SOLUTION: An apparatus for monitoring a metering device includes, on its top surface, a droplet receiving element to which a droplet can be applied by the metering device. The apparatus additionally includes: an image taking and evaluating device for determining the droplet diameter of a droplet on the droplet receiving element; and a gauge for determining the weight of the droplet.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a device for monitoring a metering device for metering a liquid medium in the form of droplets.

  When manufacturing electronic components and electronic equipment, a number of manufacturing steps require an adhesion process. In order to prevent damage to the workpiece or parts on the workpiece, the application of the adhesive is carried out in a non-contact manner using so-called jet valves, i.e. by spraying. The requirements regarding process safety, accuracy and reproducibility for the metering system used in this process are clearly increasing as the dimensions of the adhesive surface are reduced.

  The object of the present invention is therefore to create a device for regularly and automatically checking the metering device, which detects both the size of the droplet and the position of the metered droplet. Is possible.

  The solution to this problem is achieved according to the features of claim 1, in particular when the device comprises a droplet receiving element, and on the upper surface of the droplet receiving element the metering device is in its metering position, Droplets can be applied by a metering device. The apparatus further includes an image capture and evaluation device for determining the droplet diameter of the droplet on the droplet receiving element and a meter for determining the weight of the droplet.

  A process for controlling metering if the drop diameter and the drop weight and the drop volume are determined from them using the apparatus according to the invention, thus deviating from the reference value. Parameter correction may be performed. Unlike conventional systems where metering volume determination is typically performed through, for example, calculating the weighted average of 100 or 1000 droplets metered into a container on a meter. According to the invention, the volume and size of each drop can be calculated very accurately.

  Advantageous embodiments of the invention are described in the description, the drawings and the dependent claims.

  According to a first advantageous embodiment, the droplet receiving element is movable in the device. Thereby, a large number of droplets are analyzed in one and the same device, and by the movement of the droplet receiving element, each droplet to be measured is vacant in the droplet receiving element, in particular at each step. It is applied to a partial area.

  According to a further advantageous embodiment, the droplet receiving element can be transparent or translucent, so that an optical analysis of the droplet applied to the droplet receiving element can be performed from the bottom surface of the droplet receiving element. is there. This again has the advantage that the image detector of the image capture and evaluation device, such as a camera, can be placed directly under the droplet, thereby increasing the accuracy of the measurement. .

  According to a further advantageous embodiment, the droplet receiving element is formed in a tape shape and may in particular comprise a foil tape or a film tape. Such a foil tape or film tape can be manufactured as a disposable member at low cost, and at the same time, an inexpensive disposal process considering the environment has been established.

  In addition, it may be advantageous if the droplet receiving element is arranged on a feeding and winding mechanism. This is because, in this case, the part of the droplet receiving element that has already been coated with droplets can be rolled up after optical analysis and weight calculation. At the same time, the droplet receiving element is paid out from stock.

  According to a further advantageous embodiment, the image capture and evaluation device may have a single image detector, for example a single camera. By using only one image detector, manufacturing costs are kept low. At the same time, there is no need to combine or analyze or evaluate images from more than one camera together.

  According to a further advantageous embodiment, the image capture and evaluation device can comprise an image detector, the optical axis of which is at an angle with the normal to the droplet receiving element, the angle being , In particular between about 15 ° and about 25 °, in particular about 10 °. In this way, the image detector is placed diagonally and its optical axis is not oriented perpendicular to the applied droplet, so that the image detector can be used not only for the droplet but also for the outside of the droplet This area is also detected optically, so that when the metering device is present at the metering position, the metering device itself can be optically analyzed. In this way, using an image capture and evaluation device, whether the metering device nozzle is fouled, for example whether there is media, particles or hardened media adhering to the nozzle tube or nozzle. Can be confirmed. In this connection, it is advantageous if an image capture and evaluation device is used to simultaneously detect the image area of the droplet present on the droplet receiving element and the image area of the metering device at the metering position. obtain. Thereby, the analysis time is shortened, and the state of the metering device as well as the droplet size can be analyzed with a single image evaluation.

  If the image detector of the image capture and evaluation device is present in contact with the bottom surface of the droplet receiving element, the size of the droplet and the state of the metering device are detected easily and accurately.

  In order to improve the analysis of the metering device present at the metering position above the droplet receiving element, the image capture and evaluation device can have a mirror. This is because such a mirror can be used to optically detect an area hidden by a droplet by the image detector of the image capturing and evaluation apparatus.

  According to a further advantageous embodiment, the meter can have a piezoelectric element arranged below the droplet receiving element. In particular, if the droplet receiving element is movable in the device, the droplets applied on the droplet receiving element are first analyzed using an image capture and evaluation device, and then by movement of the droplet receiving element, It is positioned above the piezoelectric element that is a component of the measuring instrument. At this position, the weight of the applied droplet can be measured, so that the volume of the droplet can subsequently be calculated.

  According to a further advantageous embodiment, the meter can determine the weight of the droplet through an analysis of the resonance curve of the piezoelectric element. Through the metering electronics integrated in the meter, the resonance curve or resonance frequency of the piezoelectric element is changed once when the droplet is present on the piezoelectric element and once when the droplet is not present on the piezoelectric element. The phase shift caused by being measured can be measured. The drop mass changes the impedance adaptation of the piezoelectric element, thereby shifting the resonant frequency and resonant amplitude. By comparing both resonance curves it is possible to calculate the mass of the droplet very accurately and subsequently through the known mass per unit volume (spezifische Masse) for each medium The volume of can also be determined.

  According to a further advantageous embodiment, the position of the drop on the drop receiving element can also be determined using an image capture and evaluation device, so that the position of the drop is in a metering position. It can additionally be recognized whether it is precisely centered with respect to the nozzle outlet of the device or whether the droplets are jetted somewhat obliquely and thus offset with respect to the axis of the nozzle outlet. In order to determine the angle at which the droplet was ejected, the determination of the droplet position can be performed multiple times, at least twice, with varying spacing between the nozzle outlet and the droplet receiving element. The metering angle is calculated from the relationship between the displacement of the droplet position and the change in interval. This also has an advantage in a metering device with a nozzle tube that is inclined with respect to the droplet receiving element, for example, for metering into a recess in the side of the housing.

  Basically, the determination of droplet size and droplet position can be done automatically by an image capture and evaluation device with suitable image processing software or image recognition software. In this connection, the image capture and evaluation device has an interface for controlling the metering device, and the image capture and evaluation device determines the metering position and / or metering amount of the metering device. It may be advantageous to be able to change. In this way, if deviations from the desired parameters occur during operation, not only the droplet size but also the droplet position can be automated and changed completely automatically, Or it can be adapted.

  According to a further advantageous embodiment of the invention, the device according to the invention comprises a purification module for a metering device, the purification module comprising a purification tape guided on the upper side of the feeding element. The feeding element has a spherical feeding surface. With such a purification module, the metering device is a metering needle and abuts the spherical feeding surface, so that the cleaning tape subsequently moves between the feeding surface and the metering needle, thereby The metering needle is purified. The feeding surface having a spherical configuration ensures that the metering needle or nozzle outlet of the metering device contacts the cleaning tape as widely as possible and is cleaned. This effect can be maximized by configuring the payout surface as a spherical surface.

  According to a further advantageous embodiment, the device comprises a purification module for a metering device, the purification module comprising a vacuum chamber, the vacuum chamber being provided with a sealing element It has an inflow opening. Such a purification module is suitable for a metering device having a flat nozzle. This is because in this case the metering device can be placed on the sealing element of the purification module until the sealing with the flat nozzle opening is complete. The medium can then be sucked out of the nozzle tube by creating a low pressure in the chamber. This is because the sealing element seals the vacuum chamber against the surroundings. In this connection, it can be advantageous for the sealing element to have an annular bead for a particularly good seal.

  In the context of this application, a liquid medium is understood to be a fluid medium that is not gaseous, in particular an adhesive or chemical component that must be accurately metered in very small quantities.

  An image detector is understood to be, for example, a camera, but also a camera chip, a CCD module, or a combination of these components and optical components such as lenses.

  The metering position of the metering device is understood to be the position where the metering device is present when ejecting (spraying) a droplet onto the droplet receiving element.

  The purification module described in the context of the monitoring device according to the invention is advantageously used in combination with a monitoring device, but can also be used without a monitoring device.

  In the following, the invention will be described purely by way of example using advantageous embodiments and with reference to the accompanying drawings. Shown in the drawings is the following:

It is a perspective view of the module for monitoring a metering device. It is a figure which shows the module which concerns on FIG. 1 which removed the side part. FIG. 2 is a side view, partly in section, of the module according to FIG. 1 attached to a substrate. FIG. 3 is a partially enlarged view of FIG. 2. It is a perspective view of the purification module for a flat type nozzle. FIG. 2 is a side view, partly in section, of a purification module for a metering needle.

  The apparatus for monitoring a metering device for metering a liquid medium in the form of droplets as shown in FIG. 1 has a module 10 with a cuboid body, in which the droplet reception is carried out. The element 12 is movable in the form of a transparent or translucent foil tape, which is fed out from the supply roll 14 and wound up on the receiving roll 16. Collars 17 are provided on both sides of the receiving roll 16 so that the medium applied to the droplet receiving element 12 in the direction of the arrow D is crushed when wound up and contaminates the surroundings. Disappear. Furthermore, the collar 17 may improve the guidance of the wound foil tape.

  The foil tape or droplet receiving element 12 is driven through an electric motor 18 that drives a roll core 20 (see FIG. 3), in particular a stepping motor. Both the supply roll 14 and the accommodation roll 16 are exchangeable, and are connected to the roll core by a spring-based slip clutch. The roll core is rubbed with the attached bearing shaft 22 (FIG. 3) by a spring and a piston in the feeding roll 14, and the contact pressure for the rubbed connection is selected to be small. The roll 14 is only slightly braked and the foil tape remains pulled as it is unwound. The winding roll 16 is connected to the roll core by the same slip clutch, and the roll core 20 of the winding roll 16 is strongly pressed against the drive shaft 23 of the motor 18 by a screw.

  The motor 18 is actuated by the control of the image capture and evaluation device 25 not shown in detail so that the droplet receiving element 12 is stepped out of the supply roll 14 and taken up by the receiving roll 16 in stages. Can be made. In doing so, the droplets metered (from above) on the droplet receiving element 12 move from left to right.

  In the direction of arrow D (FIG. 1) by the metering device 30 (FIG. 4), the droplet applied to the droplet receiving element 12 is configured by the image capture and evaluation device 25, ie as the only camera 26. And is analyzed using an image detector that is positioned below the droplet receiving element 12 and thereby captures an image of the bottom surface of the droplet receiving element 12.

  As shown in FIG. 4, the optical axis OA of the camera 26 is oriented such that the optical axis forms an angle α of about 10 ° with the normal L to the droplet receiving element 12. In other words, since the optical axis OA of the camera 26 is oriented obliquely rather than perpendicular to the droplet receiving element 12, an image of a droplet (not shown) present on the droplet receiving element 12. The region and the image region of the metering device 30 existing at the metering position can be detected simultaneously. The metering needle 32 (FIG. 4) of the metering device 30 that can be hidden by the metered droplet can also be detected optically, so that the device shown in FIG. In addition, the mirror 34 (see also FIG. 2) attached obliquely can be used to detect an image limited by the peripheral rays S1 and S2.

  1, 2, and 4, the apparatus according to the present invention is further provided with a measuring device, the measuring device having a piezoelectric element 40, and the piezoelectric element 40 is a droplet receiving element 12. The droplet receiving element 12 is placed on the piezoelectric element in a plane. The foil tape of the droplet receiving element 12 is guided so that the foil tape is placed on the surface of the piezoelectric element 40 by a constant tension above the end face of the piezoelectric element 40 which is basically a rectangular parallelepiped. At that time, the housing of the module 10 in the region of the piezoelectric element 40 and the piezoelectric element 40 itself are also slightly curved, thereby ensuring that the foil tape is in good contact with the piezoelectric element. The piezoelectric element 40 is connected to an electronic device incorporated in the module 10 (not shown). Through the measurement of the phase shift of the piezoelectric element 40 using the electronic device that is a component of the measuring instrument, the liquid crystal is applied once without applying the liquid droplet, and once with the resonance curve or resonance frequency of the oscillator. Can be measured. Through the resulting resonance frequency and resonance amplitude shift, the mass of the droplet can be derived very accurately, and its volume is determined through the weight per unit volume of the droplet.

  Control above the metering device, which also incorporates the control of the robot with which the metering device is in contact with the above-mentioned device that automatically evaluates droplet size, droplet position and droplet weight By incorporating it into the metering system, it is possible to automatically adapt and control the metering process. In that case, if the droplet is too small or too large and the position of the valve when the robot moves is correspondingly adaptable, and the droplet is nozzled by the image capture and evaluation device If perceived to be off-axis, the system can correct the amount of metering by adapting the valve opening time or opening stroke.

  As shown in FIG. 3, the module 10 can be placed on the robot substrate 11 or in the work area of the robot, where the fixing is two magnets 28 and 30 fixed to the module 10. Is done by. Two pins connected to the substrate 11 are further provided for accurate positioning. That is, the short pin 29 existing between the two magnets 28 and 30 and the long pin 31 engaged with the recess 27 in the module 10 whose side surface is opened. Locking of the purification module (FIGS. 5 and 6) described later is performed in the same manner. Electrical contact for power supply and communication of the module 10 is made through a connector 42 (FIG. 4) that plugs into an appropriate counterpart of the substrate 11 when the module is installed and locked.

  A purification module 10 'for the metering device 30 is shown in FIG. As in the case of the module 10, two rolls 14 ′ and 16 ′ are provided inside the main body configured in the same manner as the main body of the module 10, and the fleece tape 50 is provided from the roll 16 ′. It is unwound and taken up by a take-up roll 14 'that is also driven by a motor 18'. At that time, a fleece tape 50 used as a cleaning tape is guided between the two rolls 14 ′ and 16 ′ via the feeding element 52, and the feeding element 52 has a spherical feeding surface, The shaft 54 is rotatably attached. The feeding element 52 is formed as a rubber roll, and forms a spherical surface as a feeding surface in the area of the fleece tape 50 that comes into contact. That is, the fleece tape 50 is curved in the region both in the transport direction and in the direction transverse to the transport direction. This ensures that the needle 32 (FIG. 4) or nozzle outlet of the metering device 30 is cleaned by contact with the fleece. For cleaning, the metering device 30 is moved by the robot above the cleaning module 10 ′ and lowered to the fleece 50. Subsequently, the fleece tape 50 is moved by the motor 18 'so that the fleece tape 50 rubs along the nozzle outlet and cleans the nozzle outlet. The purification module 10 'is basically suitable for all kinds of nozzles, but may be particularly advantageous when used in flat nozzles.

  For the operation of the motor 18 ', an approach sensor for detecting the approach of the metering device can be incorporated in the module 10'. It is also possible to mount a sensor with the aim of the fleece tape 50 next to the fleece tape 50 to be paid out, which sensor can be used if the roll is almost empty or if there is only a small residue on the roll. If it exists, it can be recognized.

  FIG. 6 shows a further purification module 10 ″, which has a vacuum chamber 60 in which a low pressure can be formed. This low pressure can be formed using a venturi nozzle and a pressure control valve (proportional valve) incorporated in the module 10 ". Alternatively, such a low pressure is also formed by a corresponding connection from the outside. The low pressure chamber 60 of the module 10 ″ has an inflow opening 62 arranged on its upper surface, which is provided with a sealing element 64 made of a suitable rubber material. The sealing element 64 has an annular bead 66 on its upper surface, and the annular bead 66 is configured to be located in the center of the passage 68 in the sealing element 64. In this way, the metering device 30 with the nozzle needle 32 can be moved over the module 10 ″ by the robot and the seal 64 with the nozzle is completed, whereby the seal 64 is It is possible to connect the nozzle outlet to the vacuum chamber 60 and lower it until it seals against the surroundings. Subsequently, a low pressure is formed in the chamber 60, thereby existing in the nozzle 32 and the nozzle tube. Media can be aspirated. Any pressure sensor incorporated in module 10 "monitors whether a sufficiently low pressure has been created and whether the valve is mounted to seal on module 10". In order to avoid hardening of the medium in the nozzle tube while the valve is stopped, cleaning of the nozzle needle 32 is possible. , Purification of the nozzle tube and is important.

  The purification module 10 ″ is basically suitable for all kinds of nozzles, but may be particularly advantageous when used with a nozzle needle because the nozzle needle enters the low pressure chamber 60 and is purified in the low pressure chamber 60. Because it can be done.

10 module 10 ', 10 "purification module 11 substrate 12 droplet receiving element 14, 14' supply roll, feed roll, feed mechanism 16, 16 'receiving roll, take-up roll, take-up mechanism 17 color 18, 18' motor 20 Roll core 22 Bearing shaft 23 Drive shaft 25, 26 Image capture and evaluation device 26 Image detector, camera 27 Recess 28, 30 Magnet 29, 31 Pin 30, 32 Metering device 32 Needle 34 Mirror 40 Piezoelectric element, meter 42 Connector 50 Fleece tape, purification tape 52 Feeding element 54 Shaft 60 Vacuum chamber, low pressure chamber 62 Inflow opening 64 Seal element 66 Annular bead 68 Passage D Arrow L Vertical OA Optical axis S1, S2 Peripheral ray α Angle

Claims (19)

A device for monitoring a metering device (30) for metering a liquid medium in the form of droplets,
On its top surface a droplet receiving element (12) onto which droplets can be applied by the metering device (30) in a metering position;
An image capture and evaluation device (25, 26) for determining a droplet diameter of a droplet on the droplet receiving element (12);
A meter (40) for determining the weight of the droplet;
Including the device.   Device according to claim 1, characterized in that the droplet receiving element (12) is movable in the device.   Device according to claim 1 or 2, characterized in that the droplet receiving element (12) is transparent or translucent.   Device according to any one of the preceding claims, characterized in that the droplet receiving element (12) is configured in the form of a tape, in particular comprising foil tape or film tape.   Device according to any one of the preceding claims, characterized in that the droplet receiving element (12) is arranged on a feeding and winding mechanism (14, 16).   Device according to any one of the preceding claims, characterized in that the image capture and evaluation device (25) has a unique image detector (26).   The image capture and evaluation device (25) has an image detector (26), and the optical axis (OA) of the image detector is perpendicular (L) to the droplet receiving element (12). The device according to claim 1, wherein the angle (α) is between about 15 ° and about 25 °, in particular.   Using the image capture and evaluation device (25, 26), an image of a droplet present on the droplet receiving element (12) and an image of the metering device (30) at a metering position, 8. Device according to any one of the preceding claims, characterized in that it can be detected simultaneously.   The image capture and evaluation device (25) comprises an image detector (26), the image detector detecting an image of the bottom surface of the droplet receiving element (12). A device according to any one of claims 1 to 8.   The image capture and evaluation device (25, 26) has a mirror (34), whereby a metering device (in its metering position above the droplet receiving element (12)) ( 30. The device according to claim 1, wherein 30, 32) images are detected.   11. The meter according to any one of the preceding claims, characterized in that the meter comprises a piezoelectric element (40), the piezoelectric element being arranged below the droplet receiving element (12). The device according to item.   12. Device according to claim 11, characterized in that the droplet receiving element (12) rests on the piezoelectric element (40) in a plane.   Device according to claim 11 or 12, characterized in that the meter calculates the weight of the droplets through an analysis of the resonance curve of the piezoelectric element (40).   14. The position of a droplet on the droplet receiving element (12) can be determined using the image capture and evaluation device (25, 26). The device according to item.   The image capturing and evaluating device (25, 26) has an interface for controlling the metering device (30), and the metering and evaluation device (25, 26) uses the metering. 15. Device according to any one of the preceding claims, characterized in that the metering position and / or the metering amount of the device (30) can be changed.   For the metering device (30), it has a purification module (10 ′) with a purification tape (50) guided on the upper side of the feeding element (52), the feeding element (52) Device according to any one of the preceding claims, characterized in that it has a spherical payout surface.   The apparatus according to claim 16, wherein the feeding surface is partially spherical.   For the metering device (30), it has a purification module (10 ″) with a vacuum chamber (60), which has an inlet opening (62) provided with a sealing element (64). A device according to any one of the preceding claims, characterized in that   19. Device according to claim 18, characterized in that the sealing element (64) has an annular bead (66).