DE102019120932B4 - Method for picking up components from a component belt connected by means of a splice connection, automatic placement machine - Google Patents

Abstract

A method for picking up components (192) by a placement head (130) of an automatic placement machine (100), the components (192) being located in a second component belt (282) which follows a splice connection (285) which is preceded by a first component belt ( 281) connects to the subsequent second component belt (282), comprising the method of conveying, by means of a component feed device (140), a plurality of first components (192) located in the first component belt (281) and a plurality of first components (192) located in the second component belt ( 282) located second components (192) to a component pick-up point (116) of the component feeder (140); detection of the splice connection (285) which moves in the direction of the component pick-up point (116) or the component pick-up point ( 116); detection, caused by the detection of the splice connection (285), of an actual recess position from a recess (385) in the second component part rt (282) when the recess (385) is at least approximately at the component pick-up point (116); determining a positional deviation (ds) of the actual recess position compared to a predetermined target recess position of the recess (385) in the second component belt ( 282); and picking up the second components (192) by the placement head (130), wherein the placement head (130) is positioned above the component pick-up point (116) as a function of the determined positional deviation (ds) in such a way that displacements of provision positions of second components (192) which shifts are caused by the position deviation (ds) are at least approximately compensated; characterized in thatA) the splice connection (285) is detected by a sensor device (288) which detects a connecting element (286) between the first component belt (281) and the subsequent second component belt (282), the connecting element (286) having a metallic material and the sensor device (288) has an inductive sensor, a capacitive sensor, a sensor for measuring a magnetic field, a sensor for measuring an electric field and / or a sensor for measuring an electric resistance .; or B) the detection of the splice connection (285) is based on a monitoring of a tensile stress in the first component belt (281) and / or in the second component belt (282), it being concluded from a change in the tensile stress that the splice connection (285) is disengaging moved in the direction of the component collection point (116) or has passed the component collection point (116).

Description

Technical area

The present invention relates generally to the technical field of manufacturing electronic assemblies, component carriers being equipped with electronic components. The present invention relates in particular to a method for picking up components by a placement head of an automatic placement machine, the components being located in a second component belt which follows a splice connection which connects a preceding first component belt to the following second component belt. The present invention further relates to an automatic placement machine which is configured to carry out the method for fetching components and to fit a component carrier with the fetched components.

Background of the invention

The assembly of component carriers with electronic components, in particular surface mount devices (SMD) components, is usually carried out with automatic assembly machines according to the so-called “PICK-AND-PLACE” or “COLLECT-AND-PLACE” principle Components picked up by a placement head of the placement machine, transported to a placement area in which there is a component carrier to be assembled, for example a printed circuit board, and then placed at predetermined component installation locations on the component carrier.

To ensure a high placement rate, i.e. a high number of components that are processed within a given period of time, the components are preferably packaged in component tapes and fed sequentially to the assembly process by means of a suitable component feed device for such tapes. In the case of a prefabricated belt, one component is located in one of a plurality of recesses which are formed in a fixed one-dimensional grid in the belt in question. The recesses are clearly referred to as belt pockets or simply as pockets. With a ready-made component belt, an automatic placement machine can be supplied with components over a comparatively long period of time and operated without a standstill.

However, it is obvious that the supply of the components comes to a standstill when the last components have been removed from the end of a belt. In order to be able to continue a placement process as uninterrupted as possible, the beginning of a subsequent second belt is connected in a known manner to the end of a preceding first and at least partially used belt. Such a connection between two straps, which is typically carried out using a suitable connection element, for example a clip element and / or an adhesive strip, is also referred to as “splicing”.

Since a splice connection between two successive component belts is never perfect, in practice there is a shift of the one-dimensional grid of the (second) recesses in the subsequent second belt with respect to the one-dimensional grid of the (first) recesses in the preceding first belt. This shift can occur along and / or perpendicular to the longitudinal extension of the one-dimensional grid. In many cases, this in turn leads to an undesired shift in the pick-up positions of the components which are located in the subsequent second belt and are provided by the component feed device in question. This can lead to errors when the components are picked up by the placement head.

US 2007 130 756 A1 discloses a placement apparatus having a component feeder. The component supply device can convey components which are contained in a component belt assembled by means of a splice connection. A splice connection between two component belts is detected with a splice point detector on the input side with regard to belt transport. The pick-up position for the sequentially conveyed components is located directly above a pin wheel which is driven by a motor and which engages with its radially protruding pins in transport holes in the relevant component belt. A so-called belt channel, in which the respective component belt is guided, extends between the splice point detector and the pin wheel. If the splice point detector detects a splice connection element, then the spliced component tape is conveyed forwards for a few more steps until the beginning of the second spliced component tape has just passed the pick-up position. The conveying of the spliced component belt is then briefly interrupted and the position of the center point of a second recess in the second component belt is measured. A possible splice-related position deviation of the second recess in question from a first grid of first recesses in the first component belt is measured.

US 2007 011 869 discloses that an accumulation of errors when collecting components can be used as an opportunity to once again determine a positional deviation of the recesses at the pick-up position, the positional deviation occurring when the relevant component feed device is "newly docked" to a chassis of the placement machine. A splice point detection by means of a splice point detector is also disclosed.

US 2008 020 1940 A1 discloses that splice-related position deviations in the grid of recesses in a spliced component belt can be recognized by the fact that the components are no longer picked up centrally by the suction gripper in question.

Summary of the invention

The invention is based on the object of increasing the process reliability when picking up components by a placement head when the components are removed from a second component belt which follows a splice connection that connects a preceding first component belt to the following second component belt.

This object is achieved by the subjects of the independent claims. Advantageous embodiments of the present invention are described in the dependent claims.

According to a first aspect of the invention, a method for picking up components by a placement head of an automatic placement machine is described, wherein the components are located in a second component belt that follows a splice connection which (along a transport direction of the second component belt) a preceding first component belt with the subsequent second component belt connects. The method according to the invention has the features of claim 1. These features include (a) conveying by means of a component feed device, a plurality of first components located in the first component belt and a plurality of second components located in the second component belt to a component pick-up point of the component feed device; (b) a detection of the splice connection which is moving in the direction of the component collection point or has passed the component collection point; (c) a detection, caused by the detection of the splice connection, of an actual recess position of a recess in the second component belt when the recess is at least approximately at the component pick-up point; (d) determining a positional deviation of the actual recess position from a predetermined target recess position of the recess in the second component belt; and (e) a pick-up of the second components by the pick-and-place head, the pick-and-place head being positioned above the component pick-up point as a function of the determined positional deviation in such a way that displacements of provision positions of second components, which displacements are caused by the positional deviation, are at least approximately completely compensated are. In this context, “at least approximately compensated” means either complete compensation or almost complete compensation.

The method described is based on the knowledge that the process reliability when picking up components by a placement head can be increased in an efficient manner that precisely when undesired shifts of actual supply positions of components compared to predetermined target supply positions in connection with a splice connection occur are expected or occur with an increased probability, a compensation procedure is initiated. In this procedure, shifts in the provision positions of second components to be picked up in the future are at least approximately compensated for by suitable control or positioning of the placement head. This means that the second components to be picked up in the future can be picked up at least approximately in the middle by a component holding device, in particular by a suction gripper, of the placement head despite the shifts in their readiness positions. In this context, picking up in the middle can mean in particular that a longitudinal axis of the component holding device coincides with an axis of the second component in question, which axis is a (central) axis of symmetry of the component in question, which is perpendicular to an upper side of the component or a normal this top represents.

The displacements are typically unwanted displacements, which arise in particular due to an offset of a one-dimensional grid of the (second) recesses in the second component belt with respect to the (first) recesses in the first component belt, which offset is caused by an imperfect splice connection. The term “one-dimensional grid” relates to the pitch of the recesses in the respective component belt along the longitudinal extension of the belt. In clear terms, the (undesired) displacements result from an offset between (i) a first grid of first recesses in the first component belt and (ii) a second grid of recesses in the second component belt. As already mentioned above, this offset occur along and / or perpendicular to the longitudinal extent of the one-dimensional grid.

The term “component pick-up point” in this document relates in particular to a location which is stationary in relation to the component feed device. The component pick-up point is the place at which, with optimal operation, all components are made available to the placement head for pick-up without any positional deviations or tolerances. This means that in optimal operation the staging positions of all components coincide with the component pick-up point.

According to an exemplary embodiment of the invention, the actual recess position is detected optically by means of a camera. This has the advantage that the actual recess position can be recorded in a simple and reliable manner by means of known methods for image processing. A camera which is specially provided for this detection can be used as the camera. Such a special camera can preferably be retrofitted to an already known placement machine.

According to a further exemplary embodiment of the invention, the camera is a circuit board camera of the placement machine. This has the advantage that no additional hardware and in particular no additional camera need be used to carry out the described method in relation to a known placement machine. The method described can thus essentially be implemented by using suitable software by means of a data processing device of the placement machine.

In this document, the term “circuit board camera” means in particular a camera which is provided in an automatic placement machine to measure the exact position of a component carrier to be placed which has been introduced into a placement area of the placement machine. Precise knowledge of the position of a component carrier to be assembled in the coordinate system of the automatic placement machine is absolutely necessary so that the assembly head can be positioned during assembly in such a way that the components are placed exactly at the specified component installation locations on the component carrier.

The circuit board camera can be a camera which is attached to a surface positioning system together with the placement head and, in particular, can be moved together with the placement head. It is thus advantageously not necessary to provide a separate portal system for the camera, which, triggered by detection of the splice connection, detects the recesses in the area of the collection point or in the area around the collection point.

According to a further exemplary embodiment of the invention, the method further comprises (i) detecting, caused by the detection of the splice connection, at least one further actual recess position of at least one further recess in the second component belt when the at least one further recess is at least approximately located at the component collection point; and (ii) determining at least one further positional deviation of the at least one further actual recess position from at least one predetermined further desired recess position of the at least one further recess in the second component belt. When the second components are picked up, the placement head is also positioned as a function of the at least one specific further positional deviation.

In clear terms, in this exemplary embodiment, after the detection of a splice connection, not only one recess but several recesses (one after the other at or in the vicinity of the component pick-up point) are detected and their position deviation is determined in each case. Due to the increased number of specific position deviations, a mean position deviation can be determined, for example by simple averaging or other statistical calculations, which corresponds with greater accuracy to the actual position deviation of recesses for second components to be picked up in the future. This has the advantage that a (statistical) error, which can never be completely avoided, is not so significant when recording a position deviation. In other words, it is obvious that errors in the detection of individual position deviations are less significant the greater the number of recesses in the second component belt which are detected and for which a position deviation is determined in each case.

According to a further exemplary embodiment of the invention, the splice connection is recognized by a sensor device or by means of a sensor device which detects a connecting element between the first component belt and the subsequent second component belt. In this way, the transition from picking up (i) first components from the first component tape to (ii) second components from the second component tape can be recognized with high reliability and, in particular, with great spatial accuracy. In other words, the sensor will show exactly when when conveying the Components the transition from the first components to the second components takes place.

When using a suitable sensor to detect the connecting element, the splice connection can advantageously be detected before the second components are fed to the component pick-up point or before the second components are picked up from the component pick-up point. This has the advantage that the procedure for detecting the recess (s) and for determining the position deviation (s) can be started immediately at the latest when the first of the second components are picked up or picked up by the assembly head at the component pick-up point . A detection of the recess (s) is preferably already started before the splice connection has reached the collection point. This means that at the beginning of the procedure recesses are recorded in which the first components are located. The detection of the recess (s) is preferably completed when a predetermined number of recesses in which there are second components have been detected.

According to the invention, in a first variant of claim 1, the connecting element has a metallic material. Furthermore, the sensor device has an inductive sensor, a capacitive sensor, a sensor for measuring a magnetic field, a sensor for measuring an electrical field and / or a sensor for measuring an electrical resistance.

The connecting element made of or with a metallic material can be implemented in a known manner by means of a clamp element or by means of several clamp elements. Since a metallic material can be detected particularly reliably by at least one of the named sensor types, in this exemplary embodiment the splice connection is detected with particularly high reliability.

According to a further exemplary embodiment of the invention, the connecting element has an adhesive material. Furthermore, the sensor device has an optical sensor, in particular a light barrier and / or a sensor for measuring reflected or scattered light.

In this exemplary embodiment, the connecting element can for example be implemented by means of an adhesive strip or have an adhesive strip. The optical sensor can detect the presence of the adhesive connecting element in that the connecting element blocks an optical path between a light transmitter, for example a light-emitting diode, and a light receiver, for example a photodiode. This optical path can run through predetermined through openings in the two component belts, the adhesive connecting element covering one or more of these through holes in the region of the splice connection.

Alternatively or in combination, light reflected or scattered on the adhesive connecting element can also be detected, which differs in intensity and / or in spectral distribution from the light which is reflected or scattered on the material of the relevant component tape. Here, too, the corresponding sensor can use a light-emitting diode as a light transmitter and a photodiode as a light receiver.

According to a further exemplary embodiment of the invention, the splice connection is recognized by an evaluation device which monitors the occurrence of errors when the components are picked up by the placement head and which, if such errors accumulate, concludes that the splice connection has passed the component pick-up point.

Component pick-up errors can be recognized, for example, by the fact that a component was not picked up at all or fell off after being picked up (poorly) by the corresponding component holding device designed as a suction gripper or suction pipette. Both can be done in a known manner by an optical inspection of at least the tip of the suction gripper or the suction pipette by means of a suitable component sensor.

The evaluation device can be part of a data processing device for the coordinated control of the operation of other components of the placement machine. The evaluation device can be implemented by means of software or hybrid by means of a combination of software and hardware.

According to a further embodiment of the invention, the splice connection is recognized by means of a further camera and an image processing device connected downstream of the further camera, the relative spatial position between a (second) component removed from a component holding device and (a tip) of the component holding device being determined becomes.

This type of detection of the splice connection is based on the knowledge that the positional deviation of the recesses in the second component belt caused by the splice connection or the displacements of the Provision positions of the second components no longer leads to a central reception of the corresponding components by the component holding device. Of course, such a relative position determination can also be carried out for a plurality of recorded components and the accuracy and reliability of this procedure for recognizing the splice connection can be improved as a result.

According to a further exemplary embodiment of the invention, the further camera is a component camera of the placement machine. The use of a so-called component camera to detect the fact that the splice connection has passed the component pick-up point and at least some of the second components are no longer picked up in the middle has the advantage that with conventional placement machines an optical position inspection of the picked up components is performed Reference to the receiving component holding device is carried out anyway by means of a component camera. Precise knowledge of the relative spatial position between the received component and the corresponding component holding device is in fact absolutely necessary in order to ensure a high level of placement accuracy. Deviations in position are compensated in a known manner by appropriate positioning of the placement head when the component in question is placed on the component carrier to be fitted.

According to the invention, according to a second variant of claim 1, the detection of the splice connection is based on a monitoring of a tensile stress in the first component belt and / or in the second component belt, with a change in the tensile stress indicating that the splice connection is moving in the direction of the component pick-up point moved or passed the component collection point.

This principle of the detection of the splice connection can be based on the fact described above that the (imperfect) splice connection results in an offset between (i) a first grid of first recesses in the first component belt and (ii) a second grid of recesses in the second component belt comes. Associated with this is an equally large offset between a second grid of second lateral holes in the second component belt and a first grid of first lateral holes in the first component belt, with a pin wheel of the component feeder in succession when the totality of both component belts is transported engages the side holes. It is therefore evident that the offset with respect to the rasters of the side holes leads to a change in the tensile stress in the second component belt.

The detection of the splice connection can also be based on the fact that the connection element leads to increased frictional resistance, for example in the belt transport path. Then the drive of the component feed device has to overcome a correspondingly higher mechanical resistance.

A special mechanical sensor is not absolutely necessary for recognizing the change in tensile stress. In preferred exemplary embodiments, the tensile stress is namely monitored by continuously measuring the demand for electrical energy or power for a drive motor of the pin wheel of the component feed device. In this context it is obvious that with a higher tensile stress the energy or power requirement of the drive motor is greater than with a lower tensile stress. The energy or power requirement can be measured in a simple manner by means of the current required to operate the component supply device.

According to a further aspect of the invention, an automatic placement machine for placing electronic components on component carriers is described. The automatic placement machine described has (a) a placement head for picking up components which are located in a second component belt which follows a splice connection which (along a transport direction of the second component belt) connects a preceding first component belt to the following second component belt; (b) a component supply device for conveying a plurality of first components located in the first component belt and a plurality of second components located in the second component belt to a component collection point; (c) a device for detecting the splice connection which is moving in the direction of the component collection point or has passed the component collection point; (d) a device for detecting, caused by the detection of the splice connection, an actual recess position of a recess in the second component belt when the recess is at least approximately at the component pick-up point; (e) a device for determining a positional deviation of the actual recess position from a predetermined target recess position of the recess in the second component belt; and (f) a control device for positioning the placement head before picking up the second components, the placement head being positioned above the component pick-up point as a function of the determined positional deviation such that displacements of provision positions of second components, which displacements are caused by the positional deviation, are at least approximately compensated.

The described automatic placement machine is also based on the knowledge that an (undesired) shift in the provision position of the second component in question, which shift is caused by an imperfect splice connection, is at least approximately compensated for by suitable positioning of the placement head immediately before a second component is picked up can. As a result, the process reliability can be increased during collection and also during further handling of the collected components.

The device for detecting the splice connection can be the sensor device described above in all of its variants. Alternatively or in combination, the device for detecting the splice connection can be implemented by means of software, which the splice connection based on the evaluation or monitoring described above (i) the occurrence of errors during component pick-up and / or (ii) a change in the relative spatial Position between at least one recorded second component and the component holding device receiving the respective component. The tensile stress in the second component belt can also be monitored, as also described above, in order to detect a splice connection.

The device for detecting the actual recess position can be the camera described above in all its forms.

The device for determining the positional deviation can be any data processing device which can also be provided for other tasks in the operation of the placement machine. These tasks include, for example, a coordinated control of the movements or the operation of the component feeder, the placement head and / or other common components of the placement machine such as a transport device for moving component carriers to be assembled into an assembly area and for moving out at least partially assembled component carriers from the placement area.

It should be noted that embodiments of the invention have been described with reference to different subjects of the invention. In particular, some embodiments of the invention are described with method claims and other embodiments of the invention with a device claim. However, when reading this application, it will immediately become clear to the person skilled in the art that, unless explicitly stated otherwise, in addition to a combination of features belonging to one type of subject matter of the invention, any combination of features relating to different types of Subjects of the invention belong.

It should also be noted that the term “have” does not exclude other elements and that the “a” does not exclude a plurality. Elements that are described in connection with different exemplary embodiments can also be combined.

Further advantages and features of the present invention emerge from the following exemplary description of currently preferred embodiments.

Figure list

• 1 shows a schematic representation of an automatic placement machine according to an exemplary embodiment of the invention.
• 2 shows in an enlarged illustration a component feed device of the placement machine according to FIG 1 .
• 3 illustrates an offset in the positions of recesses in a component belt caused by a splice connection.
• 4th shows in a block diagram the control computer of the placement machine according to FIG 1 .

Detailed description

It is pointed out that in the following detailed description features or components of different embodiments that are identical or at least functionally identical to the corresponding features or components of another embodiment are provided with the same reference symbols or with reference symbols which are shown in FIG the last two digits are identical to the reference symbols of corresponding identical or at least functionally identical features or components. In order to avoid unnecessary repetition, features or components that have already been explained using a previously described embodiment are no longer explained in detail at a later point.

1 shows a schematic representation of an automatic placement machine 100 for equipping component carriers or printed circuit boards with electrical components 192 . The placement machine 100 has a chassis as the stationary support structure 102 on. On the chassis 102 is a stationary support rail 104 attached or formed, which extends along a y-direction. On the stationary support rail 104 is a support arm 106 attached, which extends along an x-direction and which by means of a not shown drive motor can be moved along the y-direction. The corresponding direction of travel is marked with a double arrow "Y". On the carrier arm 106 is a mounting element 108 attached, which can be moved by means of a further drive motor, also not shown, along the x direction. The corresponding direction of travel is marked with a double arrow "X". The components support rail 104 , Carrier arm 106 and mounting element 108 together with the two drive motors, not shown, represent a so-called surface positioning system or portal system with which a placement head 130 can be positioned within an xy plane.

The assembly of the component carrier 190 takes place in an assembly area 110 . The component carrier to be fitted is 190 by means of a transport device 112 , for example a conveyor belt, into the assembly area 110 transported. After at least partial assembly with components 192 becomes the component carrier 190 by means of the transport device 112 transported away. The corresponding transport directions are in 1 each marked with an arrow T.

How out 1 you can see the placement head 130 on the mounting element 108 attached. The placement head can 130 between component collection points 116 a component supply system and the mounting area 110 be proceeded. According to the exemplary embodiment illustrated here, the component supply system comprises a plurality of component supply devices 140 , which are the electronic components 192 at one of the component collection points 116 provide.

A control device 118 , which among other things with the placement head 130 via the data line shown in dashed lines 118a and is communicatively coupled to the drive motors, not shown, ensures, in a known manner, that the assembly runs smoothly. According to the embodiment shown here, the control device 118 , which are mainly used to control the operation of the portal system (stationary support rail 104 , movable carrier arm 106 , movable assembly element 108 ) and the placement head 130 is responsible from a higher-level control computer 170 of the placement machine 100 coordinated. The tax calculator 170 controls or coordinates the operation of all components of the placement machine 100 .

In the assembly mode, the assembly head 130 to the component collection points 116 moves where components 192 be included. Then the placement head 130 together with the recorded components 192 in the assembly area 110 driven where the components 192 on the component carrier provided 190 be put on. Then the placement head 130 "Empty" driven back to the component feed system, where components were again 192 be included.

How out 1 can be seen, the placement machine 100 two cameras on. A first stationary camera 120 is used to measure the components picked up by the placement head 192 . The placement head is used for this 130 above the camera 120 positioned so that the picked up components 192 into the detection range of the camera 120 reach. In this component measurement, for example, the exact angular position of a recorded component 192 be measured. When the component in question is put on 192 a deviation in the angular position can be compensated for in a suitable manner by a suitable rotation of a corresponding component holding device, so that the component in question 192 in a correct angular position on the component carrier 190 is put on.

According to the embodiment shown here, the camera 120 , which is also referred to in this document as a component camera 120 is referred to, also used for a non-central mechanical recording of the respective component 192 to be recognized by the component holding device in question. As already described in detail above, such an off-center receptacle can be caused by an unintentional displacement of the exact ready position of the relevant component 190 while picking up the component 190 at the component collection point 116 caused. This unwanted displacement can be caused by a splice connection with which two component belts are connected to one another.

A camera 122 is used for the precise measurement of markings on the top of the component carrier to be fitted 190 are appropriate. This allows the exact spatial position of the component carrier 190 within the assembly area 110 recognized and when positioning the placement head 130 to the effect that the components 192 also actually exactly at a specific target position on the component carrier 190 be put on. According to the embodiment shown here, the camera is 122 on the placement head 130 attached and is used to measure the markings on the component carrier 190 together with the placement head 130 proceed.

According to the embodiment shown here, the camera 122 along with a downstream image evaluation after the detection of a splice connection is used to detect a positional deviation caused by the (imperfect) splice connection of at least one recess in a component belt following the splice connection. To do this, the assembly operation is briefly interrupted and the camera 122 is over the area of the relevant component collection point 116 driven to optically capture the recess in question. Appropriate image evaluation from the camera 122 The recorded image then provides the exact actual recess position of the relevant recess as well as the positional deviation of the actual recess position from a predetermined target recess position.

2 shows a schematic overview of a component feed device in operation 140 of the placement machine 100 . The component feeder 140 has a chassis 242 on, in which a belt transport route 243 is formed, along which a component belt along a belt transport direction Day is transported. How out 2 As can be seen, the transported or conveyed component belt is a spliced belt with a preceding first component belt 281 by means of a splice connection 285 with a subsequent second component belt 282 connected is. A connecting element is used for this 286 used, which is an adhesive strip according to the embodiment shown here.

The transport of the two interconnected component belts 281 and 282 is powered by a belt drive 244 caused which a motor 244a as well as a transport device 244b having that of the engine 244a is driven. How out 2 can be seen, according to the embodiment shown here, the transport device 244b designed as a gear or a so-called sprocket, which on its outer circumference in 2 Has engagement elements, not shown, which in transport holes, also not shown, of the component belts 281 , 292 intervene.

The second component belt 292 is connected on the input side by a belt reel 295 provided by which he is operating the component feeder 140 is unwound (before splicing the two component straps 281 , 282 was also the first component belt 281 wound on such a belt reel). The component belts emptied of components are on the output side 281 , 292 sent to waste disposal. This is done in a waste container 296 , in which there is a cutting device 297 which is the component belts 281 , 282 cuts into small pieces. The small pieces represent a belt waste 298 represent.

The component feeder 140 also has in or on top of the chassis 242 a cover sheet processor 246 on which cover foils of the component belts 281 , 282 processed or processed in such a way that the components located in recesses or belt pockets are freely accessible from above. The processing of the cover films takes place in a known manner by means of a special tool, not shown, which is in a fixed position directly or indirectly on the chassis 242 is attached and which ensures that when transporting the relevant component belt 281 , 282 the respective cover film is peeled off. The removed cover sheets are also sent to waste disposal.

Immediately after their exposure, the components reach 192 the component collection point 116 in which they are held in a known manner by a component holding device 231 of a placement head 130 can be removed. According to the exemplary embodiment shown here, the component holding device is a so-called suction pipette 231 educated. In 2 a component that has just been removed is shown and denoted by the reference number 192 Mistake.

The component feeder 140 also has a stationary on the chassis 242 attached sensor device 288 on which produces a signal when the connector 286 the detection range of the sensor device 288 happens. Depending on the type of connecting element 286 can the sensor device 288 , as already described above, for example have an inductive sensor, a capacitive sensor or an optical sensor.

3 illustrates an offset caused by a (imperfect) splice connection ds the positions of recesses 385 in a component belt. To make this clear and precise, in 3 above a one-piece section of a component belt 380 shown without a splice connection. The component belt 380 has a plurality of recesses 385 on, in each of which there is an electronic component 192 is located. The positions of the recesses 385 and thus also the positions of the components 192 represent an equidistant grid. The distance between two adjacent recesses 385 is in 3 marked with "s".

In 3 a section of a component belt is shown below which has a splice connection which connects the ends of two component belts 281 and 282 connects with each other. The Splice connection is substantively by means of a connecting element designed as an adhesive strip 286 realized.

In practice it is usually not possible to remove the ends of the component straps 281 and 282 to be connected in such a way that the equidistant grid extends over both component belts without an offset 281 and 282 extends away. In most applications it will be the case that the distance between (i) the last recess 285 of the first component belt 281 and (ii) the first recess 285 of the second component belt 282 is larger than the grid dimension or the pitch "s". This increase in distance at the connection point is in 3 shown clearly larger than is the case in practice only for the sake of clarity. As illustrated in the figure, the increase in the distance leads to an offset of the grid of the second component belt 282 compared to the grid of the first component belt 281 along the longitudinal direction of the component belts 281 and 282 . This offset is in 3 marked with "ds".

It should be noted that in practice an offset between the two belt grids does not usually only occur along the longitudinal direction of the belt. Rather, an offset usually also occurs along a direction perpendicular to the longitudinal direction. An offset in relation to the direction of the grids, ie an "angular offset" between the two directions of the two grids, is also possible. For the sake of clarity, the 3 but only an offset along the longitudinal direction of the belt is shown. However, the direction of the offset does not play a role in the compensation procedure described in this document.

It is obvious that due to this offset “ds” the components in the second component tape 282 are provided at a slightly different location for the placement head than the components of the first component belt 281 .

According to the embodiment shown here, this offset ds The positional deviation of the actual recess positions caused by the corresponding target recess positions is then used by means of the in 1 shown camera 122 and a downstream image evaluation determines when a splice connection has been recognized. If the actual recess positions in the first component belt 281 are identical to the nominal recess positions, then the offset ds identical to the stated position deviation.

To ensure a reliable inclusion of the components 192 of the second component belt 282 to ensure the determined positional deviation of the control device 118 (see. 1 ) communicated. This then ensures that the placement head 130 to pick up the components 192 is moved to a slightly different position, so that the position deviation due to the changed positioning of the placement head 130 is compensated.

Because the optical detection of the recesses 385 through the camera 122 not only requires time but also requires at least a brief interruption of the assembly operation, this detection is only carried out when a splice connection has been recognized. As already explained in detail above, the detection of a splice connection can most easily be done by means of the sensor device 288 be performed.

Alternatively (or in combination), however, the detection can also take place without this additional sensor device (compared to a conventional placement machine) in various ways, which have also already been described above. For this purpose, special data processing is required, for example in the control computer 170 of the in 1 illustrated placement machines 100 can be carried out.

4th shows the control computer in a block diagram 170 . According to the embodiment shown here, the control computer 170 different function blocks or units implemented by means of software and / or by means of hardware, so that, depending on the specific application, one or more evaluations can be carried out, each of which provides information when a splice connection is in the direction of the component pick-up point 116 moved or the component collection point 116 happened.

How out 4th can be seen, the control computer 170 a collection error evaluation unit 462 , a position offset evaluation unit implemented by means of an image processing device 464 as well as a tensile stress evaluation unit 466 on. However, it is pointed out (again) that it is not necessary that the control computer 170 has all of these units.

By means of the collection error evaluation unit 462 is monitored and evaluated whether the frequency of collection errors increases. A pickup error can, for example, as explained above, be detected by a suitable component sensor. An increase in the frequency of pick-up errors is an indication that a splice connection is the component pick-up point 116 happened.

By means of the position offset evaluation unit 464 can be monitored whether the components 192 (still) in the middle of the relevant component holding devices 231 be included. Since after passing a splice connection the components 192 are usually no longer recorded in the middle, this can also be an indication of the passage of a splice connection 285 be.

Using the tensile stress evaluation unit 466 can be a tensile stress in the second component belt 282 be monitored. As also already described above, a (imperfect) splice connection 285 and / or a mechanical frictional resistance of the connecting element 286 lead to a change in tensile stress.

List of reference symbols

100

Placement machine

102

Chassis (from placement machine)

104

stationary support rail

106

movable carrier arm

108

movable assembly element

110

Placement area

112

Transport device

116

Component collection point

118

Control device

118a

Data line

120

stationary camera / component camera

122

moving camera / circuit board camera

130

Placement head

140

Component feeders

170

Tax calculator

190

Component carrier / circuit board

192

Electronic Components

231

Component holding device / suction pipette

242

chassis

243

Belt transport route

244

Belt drive

244a

engine

244b

Transport device / gear / sprocket

246

Cover film processing device

281

first component belt

282

second component belt

285

Splice connection

286

Connecting element

288

Sensor device

295

Belt reel

296

Waste bin

297

Cutting device

298

Belt waste

Day

Direction of transport belt

380

Component belt

385

Recesses

s

Grid dimension / pitch

ds

Offset / position deviation

462

Collection error evaluation unit

464

Position offset evaluation unit / image processing device

466

Tensile stress evaluation unit

Claims (6)

Method for picking up components (192) by a placement head (130) of an automatic placement machine (100), the components (192) being located in a second component belt (282) which follows a splice connection (285) which is preceded by a first component belt ( 281) connects to the following second component belt (282), the method comprising conveying, by means of a component feed device (140), a plurality of first components (192) located in the first component belt (281) and a plurality of first components (192) in the second component belt (282) located second components (192) to a component pick-up point (116) of the component supply device (140); Detecting the splice connection (285) which is moving in the direction of the component pick-up point (116) or has passed the component pick-up point (116); Detecting, caused by the detection of the splice connection (285), of an actual recess position of a recess (385) in the second component belt (282) when the recess (385) is at least approximately at the component pick-up point (116); Determining a positional deviation (ds) of the actual recess position in relation to a predetermined target recess position of the recess (385) in the second component belt (282); and picking up the second components (192) by the mounting head (130), the mounting head (130) being positioned above the component pick-up point (116) as a function of the determined positional deviation (ds) in such a way that displacements of provision positions of second components (192 ), which displacements are caused by the position deviation (ds), are at least approximately compensated; characterized in that A) the splice connection (285) is recognized by a sensor device (288) which detects a connecting element (286) between the first component belt (281) and the subsequent second component belt (282), the connecting element (286) comprising a metallic material and the sensor device (288) has an inductive sensor, a capacitive sensor, a sensor for measuring a magnetic field, a sensor for measuring an electric field and / or a sensor for measuring an electric resistance. or B) the detection of the splice connection (285) is based on a monitoring of a tensile stress in the first component belt (281) and / or in the second component belt (282), it being concluded from a change in the tensile stress that the splice connection (285) has moved in the direction of the component collection point (116) or has passed the component collection point (116). Method according to the preceding claim, wherein the actual recess position is detected optically by means of a camera (122). Method according to the preceding claim, wherein the camera is a circuit board camera (122) of the placement machine (100). The method according to one of the preceding claims, further comprising detecting, caused by the detection of the splice connection (285), at least one further actual recess position of at least one further recess in the second component belt when the at least one further recess is at least approximately at the component Pick-up point (116) is located; Determining at least one further positional deviation of the at least one further actual recess position compared to at least one predetermined further desired recess position of the at least one further recess in the second component belt (282); wherein when the second components (192) are picked up, the placement head (130) is further positioned as a function of the at least one further determined position deviation. Method according to one of the preceding claims, wherein the connecting element (286) has an adhesive material and the sensor device (288) has an optical sensor, in particular a light barrier and / or a sensor for measuring reflected or scattered light. Placement machine (100) for placing electronic components (192) on component carriers (190), the placement machine (100) having a placement head (130) for picking up components (192) that are located in a second component belt (282), the one Splice connection (285) follows, which connects a preceding first component belt (281) to the subsequent second component belt (282); a component feed device (140) for conveying a plurality of first components (192) located in the first component belt (281) and a plurality of second components (192) located in the second component belt (282) to a component collection point (116) ); a device (288, 462, 464, 466) for detecting the splice connection (285) which is moving in the direction of the component collection point (116) or has passed the component collection point (116); a device (122) for detecting, caused by the detection of the splice connection (285), an actual recess position of a recess (385) in the second component belt (282) when the recess (385) is at least approximately at the component pick-up point (116) is located; a device (170) for determining a positional deviation (ds) of the actual recess position in relation to a predetermined target recess position of the recess (385) in the second component belt (282); and a control device (118) for positioning the placement head (130) before picking up the second components (192), the placement head (130) being positioned above the component pick-up point (116) as a function of the determined positional deviation (ds) in such a way that Displacements of provision positions of second components (192), which displacements are caused by the positional deviation (ds), are at least approximately compensated; characterized in that the automatic placement machine (100) further comprises A) a sensor device (288) for detecting the splice connection (285), the sensor device (288) being configured, a connecting element (286) between the first component belt (281) and the subsequent one to detect second component belt (282), wherein the connecting element (286) comprises a metallic material and the sensor device (288) comprises an inductive sensor, a capacitive sensor, a sensor for measuring a magnetic field, a sensor for measuring an electric field and / or a sensor for measuring an electrical resistance .; or B) a device for detecting the splice connection (285) based on a monitoring of a tensile stress in the first component belt (281) and / or in the second component belt (282), it being concluded from a change in the tensile stress that the splice connection ( 285) has moved in the direction of the component collection point (116) or has passed the component collection point (116).

Images