Feeder replacement

Abstract

To provide an automatic replenishment system and method in which downtimes are minimized, and yet may still be administered by using an economically-reasonable number of automatic handling machines or exchange units.SOLUTION: Feeders at a placement machine are replaced, automatically, according to a new protocol in which a partially-depleted feeder is temporarily moved from its slot to an external storage, a full replacement feeder is put in its slot, and the partially-depleted feeder is returned to a spare slot of the placement machine, from where its remaining components are picked.SELECTED DRAWING: Figure 2C

Description

Technical Field

[0001] The present invention relates to a method for supplying SMT components in a feeder module to a placement machine during SMT placement operation, and a method for replacing a feeder module that has been used up in a placement machine during SMT placement operation.

Background Art

[0002] The present invention generally relates to the technical field of equipping component carriers such as printed circuit boards (PCBs), substrates, or workpieces with electronic components in a so-called surface mount technology (SMT) process.

[0003] The manufacture of electronic subassemblies is usually carried out with so-called placement machines, by which electronic components are automatically picked up from a component supply device and placed on a component carrier such as a printed circuit board. The movement of the components from the component supply device to their respective placement positions is performed by a component handling device, such as a so-called placement head. In most cases, such movement of components is generally performed by a single handling device called a placement head.

[0004] The most common package for small electronic components uses a carrier tape, sometimes called a "belt," in which small pockets are formed. Each pocket contains one component. Only one type of component is placed within each carrier tape. To save space and facilitate transportation, carrier tapes have conventionally been wound around spools to form reels. Typically, a tape reel is placed in a feeder module (usually simply called a "feeder") that includes drive means for driving the tape forward, such as a motor-driven pinwheel that engages holes provided along the length of the carrier tape, and a pickup area or window that provides access to the components. The feeder can be removably inserted into the placement machine. The placement machine has a number of parallel slots or tracks, each configured to releasably receive a feeder. In this way, multiple different feeders can be attached to the placement machine, and each feeder can supply a specific component to the placement machine.

[0005] Recently, a cartridge system has been proposed in which the reel is placed in a passive cartridge module or cassette, which can conveniently be a relatively inexpensive plastic container or envelope of defined shape that can be easily held by a robot, loaded at a central filling station, and then linked to a supply module that includes drive means for advancing the tape reel. Alternatively, if the placement machine itself has a tape drive mechanism, the cartridge module can be inserted directly into the placement machine along its slot. Examples of cartridge and feeder arrangements are described, for example, in Patent Document 1. In such a system, a feeder unit can be used to drive the carrier tape placed within the cartridge unit so that the component placed within the pocket of the carrier tape is moved to a picking area where the placement head of the placement machine can access the component. The picking area can be placed within the cartridge or within the feeder, depending on the specific design.

[0006] In the operation of the placement machine, it is necessary to be able to supply the placement machine with feeders (and / or cartridges depending on the setup) each containing a carrier tape.

[0007] Such retooling (i.e., the attachment of different feeders / cartridges) is currently a manual process that requires a high level of personnel input.

[0008] In the current standard manual replenishment method known as "splicing", the carrier tape from which the placement machine removes components is manually connected to a new tape. In this process, the old tape is rewound from the reel, connected (spliced) to the new carrier tape, and wound onto a new reel.

[0009] This process allows replenishment to be carried out before it is needed. Refilling does not need to be done at an exact time but needs to be done within a given period. This period is calculated and observed by software such as the Siplace Line Monitor. This ensures a certain decoupling of the process and creates a continuous order situation for the replenishment or filling process. In this way, the peak and trough of the load can be balanced to some extent.

[0010] Considerable efforts have been made in recent years to automate the replenishment and switching of materials.

[0011] As a specific background art, Patent Document 2 may be cited. As described in this document, an external exchange device may be provided for moving a feeder including both supply capacity and material storage between a storage location and an operating location, and the exchange device can be operated such that one or more placement machines move along the production line in a state parallel to the throughput direction of the workpiece. The exchange device can be operated to move along a rail attached along the production line and is supported by the rail (for this reason, the device may be called a "rail-guided vehicle"). Such an approach has various advantages. For example, by using rails attached to the machine, the exchange device is held in a fixed vertical position relative to the placement machine, thus avoiding any problems that may arise due to floor defects, and furthermore, a high level of positioning accuracy along the production line is possible. One advantage of such a system is that the rail-guided vehicle can obtain power directly and potentially continuously from the placement machine. However, there are also various drawbacks associated with such a system. For example, it is necessary to use dedicated exchange devices on each side of the production line, and there may be limitations on how closely adjacent lines can be placed. The described system lacks flexibility and, for example, cannot manage a cartridge-based supply system. The system is relatively slow and has been found to be expensive due to the need for dedicated equipment for each production line.

[0012] It has been recognized that a more flexible and potentially less expensive solution may be to equip an automated guided vehicle (AGV) with a feeder / cartridge exchange mechanism. As is well known in the art, an AGV is a small mobile robot device that can typically move across the floor by means of a wheeled chassis and has at least a certain degree of autonomy. AGVs are available from many manufacturers (therefore, they are relatively inexpensive and there is a possibility that the production line operator already owns a suitable AGV) and usually have an upper platform that can carry job-specific equipment.

[0013] Such an approach enables automated replenishment or automatic replenishment by feeder exchange, rather than the above manual splicing method. In such an automated process, the tape and reel are stored and transported within the feeder. The automatic handling system directly processes the feeder with the reel located within the feeder. In contrast to the manual splicing method that handles the reel and tape separately, the automated process can be processed using a certain defined feeder interface, simplifying the process. An important part of the automatic handling system is an exchange mechanism operable to move the feeder between the placement machine and another storage location.

[0014] To refill the material in the placement machine, the feeder is withdrawn from the track in the machine by the automatic handling system / exchange mechanism, and a new feeder replaces the old one in the same slot. To ensure that all components of the tape are used, it is necessary to refill the slot only when all components of the feeder are removed by the placement machine. This means that advanced refilling on the same track (possible in the manual splicing process) is no longer possible.

[0015] In such an automated process, there are two main causes of machine downtime where removal cannot be performed. i) First, while the feeder on the track is being exchanged, components cannot be removed from the feeder associated with the track. These downtimes can be minimized by replacing the feeder more quickly. ii) Additionally, if the automatic handling system does not change the feeder on the track when it is appropriate, i.e., it is too late and the components of the feeder run out before replacement, downtime may occur. This can happen, for example, when multiple feeders (production lines including placement machines or one or more placement machines) are used up simultaneously. In this case, assuming there is only one automatic handling system on the line, the feeders can only be replaced sequentially. Providing an additional automatic handling machine on the line may reduce this type of downtime, but this problem may still occur when three or more feeders are used up simultaneously. Additionally, providing an additional automatic handling machine significantly increases the cost for the operators of the production line.

[0016] Various efforts have been made to minimize the downtime occurring during the use of the automation process. For example, Patent Document 3 by the applicant, as well as Patent Documents 4 and 5, describe a method of placing a new or replacement feeder (second feeder) on a spare track within the same placement machine. After the components of the first feeder run out, the machine can take out the components from the second feeder. This type of method can significantly shorten the downtime and prevent the machine from stopping when properly implemented.

[0017] Such a method is schematically shown in FIGS. 1A to 1F.

[0018] FIG. 1A shows a placement machine 1 having a placement head 2 operable to remove components from a feeder module placed in any slot of the placement machine 2. Here, five slots are shown, but in reality, there are usually more slots than this. Of these five, three slots 3A, 3B, and 3C are "priority slots" appropriately arranged for efficient placement operation, and slots 4A, 4B are "reserve slots" that are not appropriately arranged. Therefore, when components are removed from a feeder module in such a reserve slot, it leads to inefficiency in the placement operation. For example, when a workpiece (not shown) undergoing the placement operation moves in the transport direction T through the placement machine 1, the placement positions of these workpieces in the placement machine 1 may be close to slots 3A to 3C. Therefore, to remove from the feeders of reserve slots 4A, 4B, additional movement of the placement head 2 between the feeder module and the workpiece and related additional movement time are required.

[0019] The position of the placement head 2 adjacent to slot 3C indicates that removal is currently being performed from the feeder module placed in that slot, i.e., the first feeder module "A". Here, the first feeder module A has sufficient components, that is, the components are not exhausted by the placement operation to the extent that replenishment is necessary or desirable.

[0020] Figure 1B shows the start of a replenishment operation that is triggered when the first feeder module A reaches a predefined shortage level indicated by a diagonal line across the first feeder module A. At this point, the mobile robot 5 is sent to the placement machine 2 and aligned in proximity to the slots 3A - C, 4A, B. The mobile robot 5 includes a storage 6 for temporarily holding at least two feeder modules. The storage 6 is movable along the axis X with respect to the base of the mobile robot 5, and the axis X is substantially parallel to the transport direction T when the mobile robot 5 is arranged to engage with the placement machine 1. This relative movement enables the storage 6, and thus the held feeder modules, to be aligned parallel to the transport direction T with respect to the slots 3A - C, 4A, 4B as required.

[0021] It should be noted that there are other possibilities for achieving such alignment between the held feeder modules and the slots 3A - C, 4A, 4B. For example, the mobile robot 5 itself can move precisely along the X - axis, in which case the relative movement of the storage 6 is not necessary. Alternatively, an exchange mechanism (see below) can be provided that can move the feeder module parallel to the X - axis during the movement between the storage 6 and the placement machine 1.

[0022] As shown in Figure 1B, the storage 6 includes a plurality of, here three, storage slots 7A - C, and each storage slot 7A - C is configured to releasably receive a feeder module in use. As shown, the second feeder module B is received within the storage slot 7B, and this second feeder module B includes components of the same type as the first feeder module A. The storage 6 is aligned with the placement machine 1 such that the storage slot 7B is aligned with the spare slot, in this case 4B. If necessary, the storage 6 is moved along the X - axis to achieve such alignment (not shown). During this stage, the picking by the placement head 2 continues from the first feeder module A.

[0023] As shown in FIG. 1C, next, the second feeder module B is moved by the switching mechanism 8 from the storage slot 7B to the spare slot 4B. Although not shown in detail in the figure, the switching mechanism 8 has a mechanical interface that can move the feeder module horizontally and in both directions orthogonal to the X-axis between the storage 6 and the placement machine 1 by engaging with the profiled section of the feeder module. For example, a simple type of switching mechanism 8 may include a paddle that can engage with a recess provided in the feeder module, and the paddle is attached to a drive belt that can be driven in either direction, so that the feeder module can be linearly pushed or pulled between the storage 6 and the placement machine 1. Exemplary switching mechanisms are described, for example, in Patent Documents 6, 7, and 8. The switching mechanism 8 can be arranged on the mobile robot 5, on the placement machine 1, or as a separate unit. During this stage, the extraction by the placement head 2 continues from the first feeder module A until the first feeder module A is completely used up.

[0024] As shown in FIG. 1D, when the first feeder module A is completely used up (as indicated by the two intersecting lines of the feeder module A), the placement head 2 starts to extract components from the second feeder module B in the spare slot 4B.

[0025] As shown in FIG. 1E, then the mobile robot 5 is sent to the placement machine 1. The storage 6 is moved along the X-axis so that an empty storage slot, here 7B, is aligned with the slot 3C. During this stage, the extraction by the placement head 2 continues from the second feeder module B.

[0026] As shown in FIG. 1F, next, the exchange mechanism 8 moves the empty first feeder module A from the slot 3C to the storage slot 7B. During this stage, the picking by the placement head 2 continues from the second feeder module B.

[0027] During the steps shown in FIGS. 1D to 1F, it can be seen that the placement head 2 picks from the second feeder module B while it is in the spare slot 4B. This is a drawback of such a method. Usually, the feeder modules arranged in each slot are carefully selected to optimize the placement speed. Thus, for example, components arranged in large numbers on the board can be arranged in slots slightly away from the nominal "home" position of the placement head, thereby minimizing the movement time of the placement head 2. Instead, if the feeder module is arranged in the spare slot, obviously its position may not be so optimized.

[0028] This lack of optimization can be corrected by moving the second feeder module B to the optimal slot, i.e., the original position of the first feeder module A (here the slot 3C) after the first feeder module A becomes empty. This is schematically shown in FIGS. 1G to 1J. As will be apparent from the following description, this movement requires downtime and components associated with the feeder module cannot be picked. There is at least some flexibility as to when the movement is carried out, so it may be possible to perform this at a relatively convenient time to reduce the impact on throughput, but still this downtime cannot be avoided.

[0029] As shown in FIG. 1G, the storage 6 moves left along the X-axis as shown until the empty storage slot, here 7C, is aligned with the spare slot 4B. During this stage, the picking by the placement head 2 continues from the second feeder module B.

[0030] As shown in FIG. 1H, the switching mechanism 8 then moves the second feeder module B to the slot 7C of the storage 6. During this stage, no extraction is performed.

[0031] As shown in FIG. 1I, the storage 6 moves to the right along the X-axis as shown until the storage slot 7C is aligned with the slot 3C. The switching mechanism 8 can then move the second feeder module B to the slot 3C. During this stage, no extraction is performed.

[0032] Finally, as shown in FIG. 1J, the placement head 2 can resume extraction from the second feeder module B in the slot 3C. The mobile robot 5 can move freely as needed and will eventually deliver the emptied first feeder module A to a collection station (not shown) for refilling.

Prior Art Documents

Patent Documents

[0033]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Summary of the Invention

Problems to be Solved by the Invention

[0034] An object of the present invention is to provide an automatic replenishment system and method that can still be managed by using an economically reasonable number of automatic handling machines or replacement units while minimizing downtime.

Means for Solving the Problems

[0035] According to the present invention, this object is achieved by a new procedure for replacing a used feeder module and thus supplying SMT components in the feeder module to a placement machine.

[0036] According to a first aspect of the present invention, there is provided a method for supplying SMT components in a feeder module to a placement machine during an SMT placement operation, the placement machine having a plurality of slots, each slot being configured to releasably receive a feeder module in use, and a first slot of the plurality of slots receiving a first feeder module containing a plurality of SMT components that are used up during the SMT placement operation, the method comprising: i) providing a replacement unit, the replacement unit comprising storage for temporarily holding at least two feeder modules, the storage comprising a second feeder module containing SMT components of the same type as the first feeder module; ii) moving the first feeder module from the first slot to the storage before the SMT components of the first feeder module are completely used up; iii) moving the second feeder module from the storage to the first slot; iv) moving the first feeder module from the storage to a second slot of the plurality of slots of the placement machine and the like.

[0037] According to a second aspect of the present invention, there is provided a method for replacing a feeder module that has been used up in a placement machine during SMT placement operation, the placement machine having a plurality of slots, each slot being configured to releasably receive a feeder module in use, and a first slot of the plurality of slots receiving a first feeder module containing a plurality of SMT components that are used up during SMT placement operation, the method comprising: i) providing an exchange unit, the exchange unit having storage for temporarily holding at least two feeder modules, the storage comprising a second feeder module containing SMT components of the same type as the first feeder module; ii) moving the first feeder module from the first slot to the storage before the SMT components of the first feeder module are completely used up; iii) moving the second feeder module from the storage to the first slot; iv) moving the first feeder module from the storage to a second slot of the plurality of slots of the placement machine and including.

[0038] Other specific aspects and features of the present invention are set forth in the appended claims.

[0039] For the purposes of the present invention, the term "feeder module" means any of the following. a) a feeder, i.e., a single module carrying a component tape reel and drive means for advancing the tape reel, or b) a cartridge module carrying a component tape reel for direct engagement with a placement machine including a separate supply module or tape drive means but not carrying the drive means.

[0040] As used herein, the term "mobile robot" includes automated guided vehicles (AGVs), rail-guided vehicles (RGVs) that are mobile robots that can be transported by placement machines or move along rails adjacent to placement machines, autonomous intelligent vehicles (AIVs), and the like.

[0041] Next, the present invention will be described with reference to the accompanying drawings (not to scale).

Brief Description of the Drawings

[0042]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 1E

Figure 1F

Figure 1G

Figure 1H

Figure 1I

Figure 1J

Figure 2A

Figure 2B

Figure 2C

Figure 2D

Figure 2E

Figure 2F

Figure 2G

Figure 2H

Figure 2I

Figure 2J

Embodiments for Carrying Out the Invention

[0043] Figures 2A to 2J schematically show the steps of a feeder module replacement method according to the present invention. Since these use the same devices as those shown and described above with reference to Figures 1A to 1J and can conveniently use them, the relevant reference numbers are retained for brevity.

[0044] FIG. 2A shows a placement machine 1 having a placement head 2 operable to remove components from a feeder module disposed in any of the slots of the placement machine 2. Here, five slots are shown, but in practice there are usually more slots than this. Of these five, three slots 3A, 3B, and 3C are "priority slots" appropriately arranged for efficient placement operation, and slots 4A, 4B are "spare slots" that are not appropriately arranged. Therefore, when components are removed from a feeder module in such a spare slot, it leads to inefficiency in the placement operation. For example, when a workpiece (not shown) undergoing the placement operation moves in the transport direction T through the placement machine 1, the placement positions of these workpieces in the placement machine 1 may be close to slots 3A to 3C. Therefore, to remove from the feeder modules of the spare slots 4A, 4B, additional movement of the placement head 2 between the feeder module and the workpiece and related additional movement time are required.

[0045] The position of the placement head 2 adjacent to slot 3C indicates that removal is currently being performed from the feeder module disposed in that slot, i.e., the first feeder module "A". Here, the first feeder module A has sufficient components, i.e., the components have not been exhausted by the placement operation to the extent that replenishment is necessary or desirable.

[0046] FIG. 2B shows the start of a replenishment operation triggered when the first feeder module A reaches a predetermined level of depletion indicated by a diagonal line across the first feeder module A. There are various ways in which the predefined depletion level of the feeder module A can be determined. For example, i) The run-out time of the first feeder module A can be determined, after which the SMT components of the first feeder module A are completely used up. Then, the predefined shortage level can be defined as the shortage level that occurs after a predefined sub-range of the determined run-out time. For example, if the predefined shortage level is set to occur after 70% of the run-out time, and it is determined that the run-out time of the feeder module is 10 minutes, the predefined shortage level occurs after 7 minutes. At this point, the replenishment operation is triggered. The run-out time of the feeder module A can be determined, for example, by knowing the initial number of SMT components held by the feeder module A, analyzing the use of those SMT components during the placement operation, counting the number of SMT components taken out, or analyzing the number of SMT components required to place each workpiece and counting the number of workpieces placed, or ii) The number of SMT components remaining in the first feeder module A can be determined, and when the number of remaining SMT components held by the feeder module A falls below the set number, the predefined shortage level is set. Also in this case, the number of SMT components remaining in the first feeder module A can be determined by knowing the initial number of SMT components held by the feeder module A, analyzing the use of those SMT components during the placement operation, counting the number of SMT components taken out, or analyzing the number of SMT components required to place each workpiece and counting the number of workpieces placed. The replenishment operation is started when the determined number of SMT components remaining in the first feeder module falls below the threshold.

[0047] At this point, the mobile robot 5, which is the replacement unit used in this embodiment, is sent to the placement machine 2 and aligned close to the slots 3A - C, 4A, B. The mobile robot 5 includes a storage 6 for temporarily holding at least two feeder modules. The storage 6 is movable along the axis X with respect to the base of the mobile robot 5, and the axis X is substantially parallel to the transport direction T when the mobile robot 5 is arranged to engage with the placement machine 1. Due to this relative movement, the storage 6, and thus the held feeder modules, can be aligned parallel to the transport direction T with respect to the slots 3A - C, 4A, 4B as required.

[0048] Note that there are other possibilities for achieving such alignment between the held feeder modules and the slots 3A - C, 4A, 4B. For example, if the mobile robot 5 itself can move precisely along the X - axis, the relative movement of the storage 6 is not necessary. Alternatively, an exchange mechanism (see below) can be provided that can move the feeder module parallel to the X - axis during the movement between the storage 6 and the placement machine 1.

[0049] As shown in FIG. 2B, the storage 6 includes a plurality of, here three, storage slots 7A - C, and each storage slot 7A - C is configured to releasably receive the feeder module in use. As shown, the second feeder module B is received within the storage slot 7B, and this second feeder module B includes components of the same type as the first feeder module A. The storage 6 is aligned with the placement machine 1, and an empty storage slot, here the storage slot 7C, is aligned with the slot 3C in which the first feeder module A is placed. If necessary, the storage 6 is moved along the X - axis to achieve such alignment (not shown). During this stage, the pick - up by the placement head 2 continues from the first feeder module A.

[0050] As shown in FIG. 2C, next, the first feeder module A is moved by the exchange mechanism 8 from the slot 3C to the storage slot 7C. Although not shown in detail in the figure, the exchange mechanism 8 has, for example, a mechanical interface that can engage with the profiled section of the feeder module to move the feeder module horizontally and in both directions orthogonal to the X-axis between the storage 6 and the placement machine 1. A simple type of exchange mechanism 8 may include, for example, a paddle that can engage with a recess provided in the feeder module, and the paddle is attached to a drive belt that can be driven in either direction, and thus can push or pull the feeder module linearly between the storage 6 and the placement machine 1. Exemplary exchange mechanisms are described, for example, in Patent Document 6, Patent Document 7, and Patent Document 8. The exchange mechanism 8 can be arranged on the mobile robot 5, on the placement machine 1, or as a separate unit. During this stage, the pick-up by the placement head 2 is not possible.

[0051] As shown in FIG. 2D, the storage 6 is moved along the X-axis, and the storage slot 7B that holds the full second feeder module B is aligned with the currently empty slot 3C. During this stage, the pick-up by the placement head 2 is not possible.

[0052] As shown in FIG. 2E, next, the exchange mechanism 8 moves the full second feeder module B from the storage slot 7B to the slot 3C. During this stage, the pick-up by the placement head 2 is not possible until the second feeder module B is fully moved to the slot 3C.

[0053] As shown in FIG. 2F, the storage 6 is moved along the X-axis, and the storage slot 7C that holds the partially used first feeder module A is aligned with the spare slot, in this case 4B, which provides a slightly more economical pick-up than the other spare slot 4A. During this stage, if necessary, the pick-up by the placement head 2 can be continued from the second feeder module B.

[0054] As shown in FIG. 2G, the switching mechanism 8 then moves the partially depleted first feeder module A from the storage slot 7C to the spare slot 4B. During this stage, the picking by the placement head 2 continues from the second feeder module B.

[0055] As shown in FIG. 2H, the placement head 2 can resume picking from the first feeder module A in the spare slot 4B. The mobile robot 5 can move freely as needed.

[0056] As shown in FIG. 2I, when the first feeder module A is completely depleted (as indicated by the two intersecting lines of the feeder module A), the placement head 2 can resume picking from the second feeder module B in the slot 3C.

[0057] Finally, as shown in FIG. 2J, the mobile robot 5 is sent to a position close to the placement machine 1, the storage 6 moves along the X-axis, and an empty storage slot, in this case 7C, is aligned with the spare slot 4B. The switching mechanism 8 then moves the empty first feeder module A from the spare slot 4B to the storage slot 7C. During this stage, the picking by the placement head 2 continues from the second feeder module B. The mobile robot 5 can move freely as needed and will eventually deliver the emptied first feeder module A to a collection station (not shown) for refilling. This step can be performed when convenient, and since the second feeder module B still has a good filling level, there is no urgency to collect the empty first feeder module A. This means that the mobile robot 5 can perform other, perhaps more urgent, operations in the meantime.

[0058] It can be seen that this method provides various advantages compared to the previous method shown in FIG. 1. ·The mobile robot can perform the refilling task before the components of the feeder module run out. As a result, the time-dependence can be reduced, and the performance requirements of the replenishment process are lowered. In the simulation, for the case of customers of smartphones with a line having 11 placement machines, it has been shown that 2 robots are required to execute all replenishment tasks within the time limit using the previous method before the feeder module is replaced on time. Using this method, the number of robots can be reduced to 1. ·By reducing the time-dependence, the replenishment process becomes more robust against automatic handling and production flow disruptions. As an example of such a machine disruption, two feeder module replacement events may occur in a short period, and it is necessary to determine which feeder module should be replaced first by prediction. However, due to disruptions such as pick errors, the prediction may become inaccurate. Therefore, the mobile robot may be sent to the wrong location, and the machine stoppage may be prolonged. The same applies to disruptions that affect the replenishment process, such as the presence of human operators in the passageway. ·Reducing the time-dependence decreases the prediction accuracy of the feeder module replacement event. ·Since the mobile robot is released from the line and more spare tracks are used on the line, the mobile robot obtains more blocks of "idle time" and can be used for tasks on other lines, switching, battery charging, etc. ·The period during which the track cannot be used is shorter compared to the previous method.

[0059] The above embodiments are merely illustrative, and other possibilities and alternatives will be apparent to those skilled in the art within the scope of the present invention. For example, some steps can be combined. For example, the mobile robot can move the partially depleted first feeder module to the spare slot and, at the same time, or immediately before or after that, take out any empty feeder module that may be present in another spare slot, such as one that became empty during the previous replenishment operation.

[0060] In the above embodiment, the exchange unit includes a mobile robot with storage. However, the present invention is not limited thereto, and other types of exchange units each including storage can be used. For example, an exchange unit that is at least temporarily held by the placement machine is known. Such an exchange unit is placed on the placement machine by the mobile robot, and the mobile robot can move while the exchange unit performs the necessary transfer of the feeder module, or can move along the side of the placement machine as needed (such as a so-called "rail-guided vehicle"), or is simply placed beside the placement machine as an option by a human operator (similar to a well-known changeover table). In all cases, the exchange mechanism can be provided as part of the exchange unit, or as part of the placement machine, or as a separate unit.

Explanation of Signs

[0061] 1 Placement machine 2 Placement head 3A - C Priority slots 4A, B Spare slots 5 Mobile robot 6 Storage 7A - C Storage slots 8 Exchange mechanism 9 Storage conveyor A First feeder module B Second feeder module T Transport direction X Horizontal axis

Claims

1. 1. A method for feeding SMT components in feeder modules to a placement machine during an SMT placement operation, the placement machine comprising a plurality of slots, each slot configured to releasably receive a feeder module in use, a first slot of the plurality of slots receiving a first feeder module including a plurality of SMT components to be consumed during the SMT placement operation, the method comprising: i) providing a replacement unit, said replacement unit comprising a storage for temporarily holding at least two feeder modules, said storage comprising a second feeder module containing the same type of SMT components as said first feeder module; ii) initiating a refill operation including moving the first feeder module from the first slot to the storage before the first feeder module is completely depleted of SMT components; iii) continuing the refill operation by moving the second feeder module from the storage to the first slot; iv) moving the first feeder module from the storage to a second slot of the plurality of slots of the placement machine; The method includes:

2. 2. The method of claim 1, wherein step i) includes providing an exchange mechanism operable to move a feeder module from one of the plurality of slots of the placement machine to the storage and to move a feeder module from the storage to one of the plurality of slots of the placement machine, and wherein in steps ii), iii), and iv), the first and second feeder modules are moved by the exchange mechanism.

3. 3. The method of claim 2, wherein the storage comprises a plurality of storage slots, each storage slot configured to releasably receive a feeder module in use, and the exchange mechanism is operable to move a feeder module from one of the plurality of slots of the placement machine to a storage slot and to move a feeder module from a storage slot to one of the plurality of slots of the placement machine.

4. The method of claim 2 , wherein the replacement unit comprises the replacement mechanism.

5. The method of claim 2 , wherein the placement machine comprises the exchange mechanism.

6. 2. The method of claim 1, wherein step iii) comprises using a placement head of the placement machine to remove an SMT component from the second feeder module in the first slot.

7. v) using a placement head of the placement machine to retrieve an SMT component from the first feeder module in the second slot.

2. The method of claim 1, comprising:

8. vi) using the placement head of the placement machine to remove SMT components from the second feeder module in the first slot when the first feeder module is completely depleted of SMT components.

8. The method of claim 7, comprising:

9. vii) moving the completely depleted first feeder module from the second slot to the storage.

9. The method of claim 8, comprising:

10. 2. The method of claim 1, wherein step ii) comprises determining a runout time of the first feeder module at which the SMT components of the first feeder module are completely depleted; and initiating the replenishment operation within a predetermined subrange of the determined runout time.

11. 2. The method of claim 1, wherein step ii) comprises: determining a number of SMT components remaining in the first feeder module; and initiating the replenishment operation when the determined number of SMT components remaining in the first feeder module falls below a threshold.

12. The method of claim 1 , wherein the replacement unit comprises a mobile robot.

13. The method of claim 12 , wherein the mobile robot comprises one of the group consisting of an automated guided vehicle, a rail guided vehicle, and an autonomous intelligent vehicle.

14. The method of claim 1 , wherein the feeder module comprises a feeder.

15. The method of claim 1 , wherein the feeder module comprises a cartridge module.

16. 1. A method for replacing a depleted feeder module in a placement machine during an SMT placement operation, the placement machine comprising a plurality of slots, each slot configured to releasably receive an in-use feeder module, a first slot of the plurality of slots receiving a first feeder module including a plurality of SMT components that are depleted during the SMT placement operation, the method comprising: i) providing a replacement unit, said replacement unit comprising: a storage for temporarily holding at least two feeder modules, said storage comprising a second feeder module containing the same type of SMT components as said first feeder module; providing said ii) moving the first feeder module from the first slot to the storage before the first feeder module is completely depleted of SMT components; iii) moving the second feeder module from the storage to the first slot; iv) moving the first feeder module from the storage to a second slot of the plurality of slots of the placement machine; The method includes:

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