CN112312757A

CN112312757A - Compensating for positional deviations of a pocket of a second component tape caused by a splice between a first component tape and a subsequent second component tape

Info

Publication number: CN112312757A
Application number: CN202010741876.7A
Authority: CN
Inventors: 弗洛裡安·安托奇; 亚历山大·沃兹舍克; 马库斯·马什
Original assignee: ASM Assembly Systems GmbH and Co KG
Current assignee: ASMPT GmbH and Co KG
Priority date: 2019-08-02
Filing date: 2020-07-29
Publication date: 2021-02-02
Anticipated expiration: 2040-07-29
Also published as: DE102019120932A1; DE102019120932B4; CN112312757B

Abstract

The present invention describes a method for picking up a component by a mounting head of an automatic mounter, which includes: (a) feeding a plurality of first components in the first component tape and a plurality of second components in the second component tape to a component pick-up point of the component feeding device by means of the component feeding device; (b) identifying splices that have moved in the direction of or passed the component pick point; (c) recording the actual notch location of the notch in the second component tape when the notch is at least approximately at the component pick-up point as a result of identifying the splice; (d) determining a positional deviation of the actual notch position relative to a predetermined target notch position of the notch in the second component tape; and (e) picking up a second component by the placement head, wherein the placement head is positioned above the component pick-up point according to the determined positional deviation. The invention also describes an automatic placement machine configured to perform a method for picking up components and to place the picked components onto a component carrier.

Description

Compensating for positional deviations of a pocket of a second component tape caused by a splice between a first component tape and a subsequent second component tape

Technical Field

The present invention relates generally to the field of electronic component manufacturing, wherein electronic components are mounted to component carriers. The invention relates in particular to a method for picking up components by means of a mounting head of an automatic mounting machine, wherein the components are located in a second component tape following a splice connecting a preceding first component tape with a subsequent second component tape. The present invention also relates to an automatic mounter configured to execute a method for picking up a component and mounting the picked component to a component carrier.

Background

The mounting of electronic components, in particular Surface Mounted Device (SMD) components, to component carriers is usually done using an automatic placement machine according to the so-called PICK-AND-PLACE (PICK-AND-PLACE) or PICK-AND-PLACE (cool-AND-PLACE) principle. The component supplied by the component feeding device is picked up by a mounting head of the automatic mounter, is sent to a mounting area where a component carrier (e.g., a printed circuit board) to be mounted is located, and is then placed on the component carrier at a predetermined component mounting position.

In order to ensure high mounting performance, i.e. to handle a large number of components within a preset period of time, it is preferred to assemble the components into a component tape and to feed the components sequentially to the mounting process by means of a component feeding device adapted for such a component tape. In the assembled component tape, there is one component in each of one of the plurality of recesses configured as a fixed one-dimensional grid in the associated component tape. These recesses may also be visually referred to as element band pockets or simply pockets. With the component tape assembled, it is possible to supply the component to the automatic mounter over a long period of time, and to perform the operation without stopping the machine.

It is clear that the feeding of the components is stopped when the last component is removed from the end of the component tape. In order to be able to continue the mounting process as uninterrupted as possible, the start of the subsequent second component tape is connected in a known manner to the end of the preceding at least partially consumed first component tape. This connection of the two component tapes is usually done using suitable connectors, such as clamping elements and/or adhesive tapes, also known as "splicing".

The splice between two successive component tapes can never be perfect, so in practice the one-dimensional grid of (second) notches in a subsequent second component tape is displaced with respect to the one-dimensional grid of (first) notches in a preceding first component tape. Such a shift may occur along and/or perpendicular to the elongation of the one-dimensional grid. In many cases this in turn leads to an unintentional displacement of the picking position of a component located in a subsequent second component tape and provided by the associated component feeding device. This may cause an error in picking up the component by the mounting head.

Disclosure of Invention

The object of the present invention is to improve the operational stability when picking up a component by a mounting head when a second component tape follows a splice portion connecting a preceding first component tape and a succeeding second component tape, when removing the component from the second component tape.

The solution of the invention to achieve the above object is the subject of the independent claims. Advantageous embodiments of the invention are described in the dependent claims.

According to a first aspect of the invention, a method is described for picking up components by a mounting head of an automatic mounter, wherein the components are located in a second component tape which follows (in a transport direction of the second component tape) a splice connecting a preceding first component tape with a subsequent second component tape. The method comprises the following steps: (a) feeding a plurality of first components in the first component tape and a plurality of second components in the second component tape to a component pick-up point of the component feeding device by means of the component feeding device; (b) identifying splices that have moved in the direction of or passed the component pick point; (c) recording the actual notch position of the notch when the notch in the second component tape is at least approximately at the component pick-up point as a result of identifying the splice; (d) determining a positional deviation of the actual notch position relative to a predetermined target notch position of the notch in the second component tape; and (e) picking up the second component by the placement head, wherein the placement head is positioned above the component pick-up point in accordance with the determined positional deviation in order to at least substantially completely compensate for a displacement of the feeding position of the second component due to the positional deviation. In this context, "at least substantially compensated" means completely compensated or almost completely compensated.

The method is based on the following recognition: if an undesired shift of the actual feeding position of the components with respect to the predetermined target feeding position due to the splice is expected or the probability thereof is increased, the compensation procedure is started in due time, so that the operational stability when picking up the components by the mounting head can be improved in an effective manner. In this procedure, the feed position shift of the component to be picked up in the future is at least substantially compensated for by appropriately controlling or positioning the mounting head. This means that the component holding device of the placement head, in particular the suction gripper thereof, can pick up the second component at least approximately centrally despite a shift of the feed position of the second component to be picked up in the future. In this context, centrally picking up means in particular that the longitudinal axis of the component holding device coincides with the axis of the associated second component, which axis is the (central) symmetry axis of the associated component, which is perpendicular to the upper side of the component or represents the normal of this upper side.

The displacement is often an undesired displacement, which is caused in particular by an offset of the one-dimensional grid of (second) notches in the second component tape with respect to the (first) notches in the first component tape, which offset is caused by a less than complete splice. In this context, the term "one-dimensional grid" relates to the pitch of the notches in each component tape along the longitudinal extent of the component tape. In short, the reason for the (non-ideal) shift is the offset between (i) the first grid of first notches in the first component tape and (ii) the second grid of second notches in the second component tape. As mentioned above, such a displacement may occur along and/or perpendicular to the elongation of the one-dimensional grid.

In this context, the term "component pick-up point" refers to a location which is fixed in position relative to the component feeder. The component pick-up point is a point where all components can be picked up by the mounting head without any positional deviation or tolerance during an optimum operation. This indicates that in optimum operation, the feed position of all components coincides with the component pick-up point.

According to an embodiment of the invention, the actual notch position is optically recorded by means of a camera. This has the advantage that the actual notch position can be recorded in a simple and reliable manner by means of the known image processing methods. For the camera, a camera dedicated to such recording may be used. Such a dedicated camera can preferably be retrofitted on known automatic placement machines.

According to another embodiment of the present invention, the camera is a circuit board camera of an automatic mounter. This has the advantage that the method can be performed in conjunction with known automatic placement machines without having to use additional hardware, in particular without having to use additional cameras. In this way, the method can be implemented basically by means of the data processing means of the automatic placement machine by using suitable software.

In this context, the term "board camera" refers to a camera provided in an automatic mounter for measuring the exact position of a component carrier to be mounted that has been loaded into a mounting area of the automatic mounter. That is, the position of the component carrier to be mounted in the coordinate system of the automatic mounter should necessarily be known with certainty so that the mounting head can be positioned during mounting so as to accurately place the component onto the component carrier at the predetermined component mounting position.

The circuit board camera may be a camera that is attached to the surface positioning system along with the mounting head and in particular moves along with the mounting head. It is therefore advantageous that the camera, which is triggered by the identification of the splice, records the notch in the area of the pick-up point or in the area around the pick-up point, without having to provide a separate gantry system for the camera.

According to another embodiment of the invention, the method further comprises: (i) recording at least one further actual notch position of the at least one further notch when the at least one further notch in the second component tape is at least substantially located at the component pick-up point as a result of the identification of the splice; and (ii) determining at least one further positional deviation of the at least one further actual notch position relative to at least one further predetermined target notch position of the at least one further notch in the second component tape. The placement head is further positioned when picking up the second component based on the determined at least one further positional deviation.

In short, in the present embodiment, after the splice is identified, not only one notch but a plurality of notches (successive notches at or near the component pickup point) are recorded, and their positional deviations are determined respectively. As the number of specific position deviations increases, a mean position deviation can be determined by a simple mean value calculation or other statistical calculation, which has a higher corresponding accuracy with respect to the actual position deviation of the recess of the second component to be picked up in the future. This has the advantage that (statistical) errors which are absolutely unavoidable when recording position deviations are no longer of great importance. In other words, it is clear that the greater the number of notches in the second component tape that register and respectively determine the position deviation, the less important the error in registering a single position deviation.

According to another embodiment of the invention, identifying the splice is done by or by means of a sensor device detecting a connection between a first component tape and a subsequent second component tape. In this way, a transition from (i) picking up a first component from a first component tape to (ii) picking up a second component from a second component tape can be identified with high reliability and in particular with high spatial accuracy. In other words, the sensor will accurately indicate when the component transfer transitions from the first component to the second component.

In case a suitable sensor is used for identifying the connection, the splice can be identified in an advantageous manner even before the second component is brought to the component pick-up point or before the second component is picked from the component pick-up point. This has the advantage that the procedure of recording the recesses and determining the position deviation starts at the latest when the first few components of the second component are picked up or received by the placement head at the component pick-up point. Preferably the notch recording is started already before the splice reaches the pick-up point. This means that at the start of the procedure the notch in which the first few elements are located will be recorded. When a predetermined number of notches in which the second element is located are recorded, the recording of the notches is preferably ended.

According to another embodiment of the invention, the connection member comprises a metallic material. The sensor device further 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 a resistance.

The connection made of or comprising a metallic material can be realized in a known manner by means of one clamping element or by means of a plurality of clamping elements. At least one of the sensor-type metal materials can be detected particularly reliably, so that in the present embodiment the splice can be detected with very high reliability.

According to another embodiment of the invention, the connecting element comprises an adhesive material. The sensor device further comprises an optical sensor, in particular a grating and/or a sensor for measuring reflected or scattered light.

In this embodiment, the connection may be realized by means of an adhesive tape or with an adhesive tape, for example. The optical sensor may detect the presence of the adhesive connector because the connector blocks the optical path between the light emitter (e.g., light emitting diode) and the light receiver (e.g., photodiode). The light path may pass through predetermined through holes in the two component tapes, the adhesive connection covering one or more of these through holes in the region of the splice.

Alternatively or in combination, it is also possible to detect reflected or scattered light at the adhesive bond, the intensity and/or spectral distribution of which differs from the reflected or scattered light at the material of the component tape concerned. Here, the corresponding sensor may also use a light-emitting diode as light emitter and a photodiode as light receiver.

According to another embodiment of the invention, the identification of the splice is done by an evaluation device which monitors for errors occurring when picking up the component by the mounting head and deduces that the splice has passed the component pick-up point when such errors accumulate.

For example, the following element pick-up errors can be identified: the component holding device, which is configured correspondingly as a suction gripper or suction tube, fails to pick up a component at all or drops after (improperly) picking up a component. Both cases can be accomplished in a known manner by optical inspection of at least the suction grip or the tip of the suction tube by means of suitable component sensors.

The evaluation device may be part of a data processing device for coordinating the operation of other components of the automatic placement machine. In this case, the evaluation means may be realized by software or by a combination of software and hardware.

According to a further embodiment of the invention, the recognition of the splice is carried out by means of a further camera and an image processing device connected downstream of the further camera, wherein the relative spatial position between the (second) component received by the component holder and the (tip of the) component holder is determined.

This way of identifying the splice is based on the following recognition: a positional deviation of the notch in the second component tape or a displacement of the feed position of the second component due to the splice results in the component holding device no longer receiving the respective component centrally. It goes without saying that such a relative position determination can also be performed for several picked components, thereby improving the accuracy and reliability of such a splice identification procedure.

According to another embodiment of the present invention, the additional camera is a component camera of an automatic mounter. The fact that the splice has passed the component pick-up point and no longer receives at least some of the second component centrally using a so-called component camera has the following advantages: in conventional automatic placement machines, optical position checking of the received component with respect to the receiving component holding device is always performed by means of a component camera. In order to ensure high precision mounting, the relative spatial position between the picked component and the respective component holding device must be known with certainty. The positional deviation is compensated in a known manner by appropriately positioning the placement head when placing the component concerned on the component carrier to be placed.

According to a further embodiment of the invention, the identification of the splice is based on monitoring a tensile stress in the first component tape and/or the second component tape, wherein from the change in tensile stress it is concluded that the splice has moved in the direction of or has passed the component pick-up point.

The principle of identifying a splice may be based on the fact that an (imperfect) splice results in an offset between (i) a first grid of first notches in a first component tape and (ii) a second grid of second notches of a second component tape. In connection therewith, the offset between the second grid of second side holes in the second component tape and the first grid of first side holes in the first component tape is also equal, the pinwheels of the component feeding device engaging successively in the side holes when transferring the whole two component tapes. It is therefore clear that the offset with respect to the grid of side holes results in a variation of the tensile stress in the second component strip.

The identification of the splice can also be based on the fact that the connector causes an increase in frictional resistance, for example in the component tape transport path. The drive of the component feeding device must then overcome a correspondingly higher mechanical resistance.

No special mechanical sensors are absolutely necessary to identify the tensile stress variations. In a preferred embodiment, the tensile stress is monitored by continuously measuring the electrical energy or power requirement of the drive motor of the pin wheel of the element feeding device. It is clear in this connection that the energy or power requirement of the drive motor is greater at higher tensile stresses than at lower tensile stresses. The energy or power requirement can be measured in a simple manner by the current required to operate the element feeding device.

According to another aspect of the present invention, an automated placement machine for placing electronic components onto component carriers is described. The automatic mounter includes: (a) a placement head for picking up components located in a second component tape following (in a transport direction of the second component tape) a splice connecting a preceding first component tape with a following second component tape; (b) a component feeding device for feeding a plurality of first components in a first component tape and a plurality of second components in a second component tape to a component pick-up point; (c) means for identifying a splice that has moved in the direction of or has passed the component pick point; (d) means for recording the actual notch position of the notch when the notch in the second component tape is at least approximately at the component pick-up point due to the identification of the splice; (e) means for determining a positional deviation of the actual notch position relative to a predetermined target notch position of the notch in the second component tape; and (f) control means for positioning the placement head before picking up the second component, wherein the placement head is positioned above the component pick-up point in accordance with the determined positional deviation in order to at least substantially compensate for a displacement of the feeding position of the second component due to the positional deviation.

The automatic placement machine is also based on the recognition that: the (non-ideal) shift of the feeding position of the relative second component due to the imperfect splice is at least substantially compensated by appropriately positioning the head immediately before picking up the second component. This improves the process reliability at pick-up and at other handling of the picked-up components.

The means for identifying the splice can be the sensor means of all the variants described above. Alternatively or in combination, the means for identifying the splice may be implemented by means of software which identifies the splice based on the above described evaluation or monitoring of (i) errors occurring in picking up the component and/or (ii) changes in the relative spatial position between the received at least one second component and the respective component holding means of the received component. Also as described above, the tensile stress in the second component tape may also be monitored to identify the splice.

The means for recording the actual notch position may be the camera of all embodiments described above.

The means for determining the positional deviation may be any data processing means which may also be provided for other tasks in the operation of the automatic placement machine. These tasks include, for example, coordinated control of the movement or operation of component feeding devices, mounting heads and/or other conventional components of the automatic mounter, such as a transfer device for moving component carriers to be mounted to a mounting area and moving at least partially mounted component carriers out of the mounting area.

It should be noted that embodiments of the invention have been described above in connection with different inventive subject matter. In particular, certain embodiments of the invention are described by means of the method claims, while other embodiments of the invention are described by means of the product claims. It will be clear to a person skilled in the art, after reading the present application, that in addition to a combination of features belonging to one type of inventive subject matter also any combination of features belonging to different types of inventive subject matter is possible, unless explicitly stated otherwise.

It should also be noted that the term "comprising" does not exclude other elements, and "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined.

Further advantages and features of the present invention will become apparent from the following description of preferred embodiments thereof, given by way of illustration.

Drawings

Fig. 1 shows a schematic diagram of an automatic mounter according to an embodiment of the present invention.

Fig. 2 shows an enlarged view of a component feeding device of the automatic mounter according to fig. 1.

Fig. 3 shows the positional offset of the notches in the component tape due to the splice.

Fig. 4 shows a block diagram of a control computer of the automatic placement machine according to fig. 1.

Description of reference numerals:

100 automatic mounter

102 (of automatic placement machines)

104 static support rail

106 movable support arm

108 moveable assembly

110 mounting area

112 transfer device

116 component pick-up point

118 control device

118a data line

120 still camera/element camera

122 movable camera/circuit board camera

130 mounting head

140 element feeding device

170 control computer

190 element carrier/printed circuit board

192 electronic component

231 element holding device/suction tube

242 frame

243 component tape transport route

244 element tape drive

244a motor

244b conveyor/gear/sprocket

246 film covering processing device

281 first component tape

282 second component band

285 splice

286 connecting pieces

288 sensor device

295 tape winder

296 waste container

297 cutting device

298 waste of component tape

Tg element belt transport direction

380 element belt

385 notch

s lattice spacing/pitch

ds offset/position offset

462 pick-up error evaluation unit

464 offset estimation unit/image processing device

466 tensile stress evaluation unit.

Detailed Description

It should be noted that in the following detailed description, features or components of different embodiments that are identical or at least functionally identical to corresponding features or components of another embodiment are labeled with the same reference numerals or the last two digits of the reference numerals thereof are the same as the reference numerals of the corresponding features or components that are identical or at least functionally identical. For the sake of brevity, features or components that have been described based on the foregoing embodiments will not be described in detail below.

Fig. 1 shows a schematic view of an automatic placement machine 100 for placing electronic components 192 onto component carriers or printed circuit boards. The automatic placement machine 100 has a frame 102 as a stationary load-bearing structure. The frame 102 has attached or configured thereto a stationary support rail 104 extending in the y-direction. Attached to the stationary support rail 104 is a support arm 106 which extends in the x-direction and can be moved in the y-direction by means of a drive motor (not shown). The corresponding direction of movement is marked with the double arrow "y". Attached to the support arm 106 is an assembly 108 which can be moved in the x-direction by means of a further drive motor (also not shown). The corresponding direction of movement is marked with a double arrow "x". The component support rails 104, support arms 106 and assembly 108 together with two drive motors (not shown) represent a so-called surface positioning system or gantry system with which the placement head 130 can be positioned in the xy-plane.

Mounting of the component carrier 190 is completed in the mounting area 110. Before mounting, the component carrier 190 to be mounted is conveyed into the mounting area 110 by a conveying device 112 (e.g., a conveyor belt). After the component 192 has been at least partially mounted, the component carrier 190 is transported away by means of the transport device 112. The respective conveying directions are marked in fig. 1 by arrows T.

As shown in fig. 1, the placement head 130 is secured to the assembly 108. The mounting head 130 can be moved between the component pickup point 116 and the mounting area 110 of the component feeding system by appropriately controlling a driving motor (not shown). According to the embodiment shown in the present figure, the component feeding system comprises several component feeding devices 140, which provide electronic components 192 at respective component pick-up points 116.

The data line 118a and the drive motor (not shown), which are represented by dashed lines, are in particular communicatively coupled to the control device 118 of the placement head 130 to ensure that the placement is carried out smoothly in a known manner. According to the embodiment shown in the present figure, the control device 118, which is mainly responsible for controlling the operation of the gantry system (the stationary support rail 104, the movable support arm 106, the movable assembly 108) and the placement head 130, is coordinated by a superior control computer 170 of the auto-placement machine 100. The control computer 170 controls or coordinates the operations of all the components of the automatic mounter 100.

In a mounting operation, the mounting head 130 moves to the component pick-up point 116 where the component 192 is picked up. Subsequently, the mounting head 130 moves together with the picked-up component 192 into the mounting area 110, where the component 192 is placed on the provided component carrier 190. Thereafter, the placement head 130 is "empty" to move back to the component feeding system, where the component 192 is again picked up.

As shown in fig. 1, the automatic mounter 100 also has two cameras. The first stationary camera 120 is used to measure the component 192 picked up by the placement head. For this reason, the mounting head 130 is positioned above the camera 120 so that the picked-up component 192 reaches the recording area of the camera 120. During such measurement of the component, for example, the precise angular position of the picked-up component 192 may be measured. By appropriately rotating the respective component holding device during the placing of the relevant component 192, an angular position deviation can be compensated in an appropriate manner in order to place the relevant component 192 onto the component carrier 190 in the correct angular position.

According to the embodiment shown in the figure, the camera 120 (also referred to as component camera 120 in the present embodiment) is also used to register that the associated component holding device is mechanically picking up the respective component 192 off-center. As detailed above, a possible reason for such non-centered pick-up is that the exact feeding position of the relevant component 190 is undesirably displaced when the component 190 is picked up by the component pick-up point 116. A possible cause of such an undesired displacement is the splice that connects the two component tapes to each other.

The camera 122 is used to accurately measure the mark attached to the top of the component carrier 190 to be mounted. In this way, the precise spatial position of the component carrier 190 within the mounting area 110 can be identified and taken into account when positioning the mounting head 130, i.e. the components 192 are actually placed on the component carrier 190 precisely at each particular target position. According to the embodiment shown in the present figure, the camera 122 is attached to the mounting head 130 and moves along with the mounting head 130 to measure the marks on the component carrier 190.

According to the embodiment shown in the present figure, after identifying the splice, the camera 122 together with a downstream image evaluation mechanism is used to record the (imperfect) splice-induced positional deviation of at least one notch in the component tape after the splice. To this end, the mounting operation is briefly interrupted and the camera 122 is moved over the area of the associated component pickup point 116 in order to optically record the associated notch. Appropriate image evaluation of the images taken by the camera 122 then provides the exact actual notch position of the relevant notch and the positional deviation of this actual notch position from the predetermined target notch position.

Fig. 2 is a schematic view showing an overview of the component feeding apparatus 140 in operation in the automatic mounter 100. The component feeding device 140 has a frame 242 in which a component tape conveyance path 243 is configured along which the component tape is conveyed in a component tape conveyance direction Tg. As shown in fig. 2, the component tape being conveyed or transported is a splice tape, wherein a preceding first component tape 281 is connected to a subsequent second component tape 282 by means of a splice 285. For this purpose, a connecting piece 286 is used, which according to the embodiment shown in the figure is an adhesive tape.

The transport of the two

component tapes

281 and 282 connected to one another is started by a component tape drive 244 having a motor 244a and a transport device 244b driven by the motor 244 a. As shown in fig. 2, the conveying device 244b is configured as a gear or a so-called sprocket wheel, according to the embodiment shown in this figure, having on its outer circumference engaging elements (not shown in fig. 2) which engage into conveying holes (also not shown) of the

component tapes

281, 282.

The second component tape 292 is supplied on the input side from a tape winder 295, from which the second component tape is unwound during operation of the component feeding device 140 (the first component tape 281 is also wound on this tape winder before the two

component tapes

281, 282 are spliced). The

component tapes

281, 282 of the emptying components are fed to waste removal on the output side. This is done in a waste container 296, wherein there is a cutting device 297 which cuts the

component tapes

281, 282 into small pieces. The small pieces represent component tape waste 298.

The component feeder device 140 also has a film treatment device 246 in or on the top of the machine frame 242, which film treatment device treats or handles the films of the

component tapes

281, 282 so that the components located in the pockets or pockets of the component tapes are freely accessible from above. The coating film is treated in a known manner by means of a special tool (not shown) which is attached directly or indirectly to the machine frame 242 in a fixed position and ensures that the respective coating film is peeled off when the

relevant component tape

281, 282 is transported. The peeled film is also sent to waste disposal.

The component 192 reaches the component pick-up point 116 immediately after its exposure, where it is removed by the component holding device 231 of the placement head 130 in a known manner. According to the embodiment shown in the figure, the component holding device is configured as a so-called suction tube 231. The just removed elements are shown in fig. 2 and are labeled with reference numeral 192.

The component feeding device 140 also has a sensor device 288 fixedly attached to the frame 242 that generates a signal when the link 286 passes through the sensing range of the sensor device 288. Depending on the type of connection 286, the sensor device 288 may, as mentioned above, for example have an inductive sensor, a capacitive sensor or an optical sensor.

Fig. 3 shows the positional deviation ds of the notch 385 in the component tape due to the (imperfect) splice. To clearly illustrate this, the upper diagram in fig. 3 shows a section of the component tape 380 without a splice over the entire length. The component tape 380 has a plurality of recesses 385, one electronic component 192 in each recess. The positions of the notches 385 and the positions of the elements 192 present an equidistant grid. The distance between two adjacent recesses 385 is marked with an "s" in fig. 3.

The lower drawing in fig. 3 shows a length of component tape with a splice connecting the ends of the two

component tapes

281 and 282 to each other. The splice is realized in particular by means of a connecting piece 286 constructed as an adhesive tape.

In practice, it is generally not possible to connect the ends of the

component tapes

281 and 282 in such a way that an equidistant grid extends over the two

component tapes

281 and 282 without an offset. In most applications this is: (i) the distance between the last indent 385 of the first component strip 281 and (ii) the first indent 385 of the second component strip 282 is greater than the pitch or pitch "s". For the sake of clarity, the increase in distance at such a connection is shown in fig. 3 to be much greater than in the actual case. As shown, the increase in distance causes the pixels of the second component tape 282 to be offset relative to the pixels of the first component tape 281 in the longitudinal direction of the

component tapes

281 and 282. This offset is labeled "ds" in fig. 3.

It should be noted that in practice, the offset between the two meshes generally occurs not only in the longitudinal direction of the component tape. Rather, it is also common for the offset to occur in a direction perpendicular to the longitudinal direction. There may also be an offset with respect to the grid direction, i.e. an "angular offset" between the two directions of the two grids. However, for the sake of clarity, only the offset in the longitudinal direction of the component tape is shown in fig. 3. But the direction of offset is not relevant to the compensation procedure described herein.

Obviously, because of this offset "ds", the placement of the components in the second component tape 282 provided to the placement head is slightly different than the placement of the components in the first component tape 281 provided to the placement head.

According to the embodiment shown in the present figure, when a splice is identified, the positional deviation of the actual notch position from the corresponding target notch position due to the offset ds is determined by means of the camera 122 shown in fig. 1 and the downstream image evaluation mechanism. If the actual notch position in the first component tape 281 is the same as the target notch position, the offset ds is the same as the positional deviation.

To ensure reliable pick up of the component 192 of the second component tape 282, the determined positional deviation is communicated to the control device 118 (see fig. 1). This ensures that the placement head 130 is moved to a slightly different position to pick up the component 192, thereby compensating for the positional deviation by changing the position of the placement head 130.

The optical recording of the recess 385 by means of the camera 122 is not only time-consuming, but also requires at least a brief interruption of the mounting operation, so that such recording is only performed when a splice has been identified. As detailed above, in the simplest case, the identification of the splice may be performed by the sensor arrangement 288.

However, alternatively (or in combination), the identification can also be carried out in a different manner without such additional sensor devices (in comparison with conventional automatic placement machines), see also above. For this purpose, special data processing is required, and this process may be executed in the control computer 170 of the automatic mounter 100 shown in fig. 1, for example.

Fig. 4 shows a block diagram of the control computer 170. According to the embodiment shown in this figure, the control computer 170 has various functional modules or units implemented by means of software and/or hardware so that one or more evaluations can be performed depending on the specific application, providing a report each time a splice has moved towards the component pick-up point 116 or has passed the component pick-up point 116.

As shown in fig. 4, the control computer 170 has a pickup error evaluation unit 462, a positional shift evaluation unit 464 implemented by an image processing device, and a tensile stress evaluation unit 466. It should again be pointed out that the control computer 170 may not necessarily have all these units.

The pickup error evaluation unit 462 monitors and evaluates whether the frequency of the pickup errors increases. As described above, the pick-up error can be recognized, for example, by a suitable component sensor. The increased frequency of the pickup error evidences that the splice has passed the component pickup point 116.

By means of the position deviation evaluation unit 464 it is possible to monitor whether the relevant component holder 231 (still) is centered on the receiving component 192. After the splice passes, the receiving element 192 is generally no longer centered, so this may also represent evidence of the splice 285 passing.

The tensile stress in the second component band 282 may be monitored by the tensile stress evaluation unit 466. Also as mentioned above, the mechanical frictional resistance of the (imperfect) splice 285 and/or the connector 286 may cause the tensile stress to vary.

Claims

1. A method for picking components (192) by a placement head (130) of an automated placement machine (100), wherein the components (192) are located in a second component tape (282) that follows a splice (285) that connects a preceding first component tape (281) with a subsequent second component tape (282), the method comprising:

-feeding a plurality of first components (192) located in the first component tape (281) and a plurality of second components (192) located in the second component tape (282) towards a component pick-up point (116) of the component feeding device (140) by means of a component feeding device (140);

identifying a splice (285) that has moved in the direction of the component pickup point (116) or has passed the component pickup point (116);

-recording an actual notch position of a notch (385) in the second component tape (282) when the notch (385) is at least substantially located at the component pickup point (116) as a result of identifying the splice (285);

determining a positional deviation (ds) of the actual notch position relative to a predetermined target notch position of a notch (385) in the second component band (282); and

-picking up a second component (192) by the placement head (130), wherein the placement head (130) is positioned above the component pick-up point (116) in dependence of the determined positional deviation (ds) in order to at least substantially compensate for a displacement of the feeding position of the second component (192) due to the positional deviation (ds).

2. The method of claim 1, wherein,

optical recording of the actual notch position is accomplished by means of a camera (122).

3. The method of claim 2, wherein,

the camera is a circuit board camera (122) of the automatic placement machine (100).

4. The method of claim 1, further comprising:

-upon identifying the splice (285), recording at least one further actual notch position of at least one further notch in the second component tape when the at least one further notch is at least substantially located at the component pick-up point (116);

determining at least one further positional deviation of the at least one further actual notch position relative to at least one further predetermined target notch position of at least one further notch in the second component tape (282);

wherein the placement head (130) is further positioned according to the determined at least one specific further positional deviation when picking up the second component (192).

5. The method of claim 1, wherein,

identifying the splice (285) is accomplished by a sensor device (288) that detects a connection (286) between the first component tape (281) and a subsequent second component tape (282).

6. The method of claim 5, wherein,

the connecting member (286) comprises a metal 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 a resistance.

7. The method of claim 5 or 6,

the connecting member (286) comprises an adhesive material, and

the sensor device (288) comprises an optical sensor, in particular a grating, and/or a sensor for measuring reflected or scattered light.

8. The method of any one of claims 1 to 4,

identifying the splice (285) is accomplished by an evaluation device (462) that monitors for errors in picking up the component (192) by the placement head (130) and infers that the splice (285) has passed the component pick point (116) when such errors accumulate.

9. The method of any one of claims 1 to 4,

identifying the splice (285) is carried out by means of a further camera (120) and an image processing device (464) connected downstream of the further camera (120), wherein a relative spatial position between (i) the component (192) received by the component holder (231) and (ii) the component holder (231) is determined.

10. The method of claim 9, wherein,

the additional camera is a component camera (120) of the automatic mounter (100).

11. The method of any one of claims 1 to 4,

identifying the splice (285) is based on monitoring a tensile stress in the first component tape (281) and/or the second component tape (282), wherein it is concluded from a change in the tensile stress that the splice (285) has moved in the direction of the component pick point (116) or has passed the component pick point (116).

12. An automated placement machine (100) for placing electronic components (192) onto component carriers (190), the machine (100) comprising:

a placement head (130) for picking up components (192) located in a second component tape (282) following a splice (285) connecting a preceding first component tape (281) with a subsequent second component tape (282);

a component feeding device (140) for feeding a plurality of first components (192) in the first component tape (281) and a plurality of second components (192) in the second component tape (282) towards a component pick-up point (116);

-means (288, 462, 464, 466) for identifying a splice (285) that has moved in the direction of the component pick point (116) or has passed the component pick point (116);

means (122) for recording an actual notch position of the notch (385) in the second component tape (282) when the notch (385) is at least substantially located at the component pick up point (116) as a result of identifying the splice (285);

means (170) for determining a positional deviation (ds) of the actual notch position relative to a predetermined target notch position of the notch (385) in the second element band (282); and

-control means (118) for positioning the placement head (130) before picking up the second component (192), wherein the placement head (130) is positioned above the component pick-up point (116) in dependence of the determined position deviation (ds) in order to at least substantially compensate for a displacement of the feeding position of the second component (192) due to the position deviation (ds).