Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K13/00—Apparatus or processes specially adapted for manufacturing or adjusting assemblages of electric components
  • H05K13/04—Mounting of components, e.g. of leadless components
  • H05K13/046—Surface mounting
  • H05K13/0469—Surface mounting by applying a glue or viscous material

Definitions

• the present invention relates to the field of manufacturing electronic component assemblies.
• the present invention relates to an apparatus for applying a viscous medium such as a soldering paste onto predefined surface portions of an electronic substrate before electronic components are mounted onto the substrate by means of an electronic component placement machine.
• the present invention further relates to an electronic component placement machine for mounting electronic components onto electronic substrates and to a manufacturing line for producing electronic circuit arrangements.
• the present invention relates to a method for applying a viscous medium onto predefined surface portions of an electronic substrate, in particular for applying soldering paste and/or a conductive glue onto predefined conductor junction areas formed on a printed circuit board.
• High performance manufacturing lines for producing electronic circuit arrangements typically comprise a plurality of electronic component placement machines.
• Figure 2 shows such a high performance manufacturing line 200, which comprises four electronic component placement machines 210.
• the placement machines 210 are arranged in a row along two transport roadways, a first transport roadway 201 and a second transport roadway 202.
• the two transport roadways 201 and 202 are aligned in parallel with respect to each other. They are used for transporting electronic substrates respectively printed circuit boards 260, onto which electronic components are mounted by means of the various placement machines 210.
• Each placement machine 210 comprises a frame 211 and four feeder tables 212.
• Each feeder table 212 comprises a plurality of feeder units for feeding various types of electronic components to the electronic component placement machines 210.
• Each placement machine 210 further comprises four mounting heads and four placement regions, which placement regions are located in a central region of the placement machine 210. Thereby, each of the two transport roadways 201 and 202 intersects two of the four placement regions, whereas each placement region is located adjacent a corresponding feeder table 212.
• the mounting procedure performed with the placement machines 210 starts with placing a printed circuit board 260 within a placement region. Thereafter, the corresponding mounting head collects one or more electronic components from the feeder units 212. Subsequently, the mounting head transports these electronic components towards the corresponding placement region and places these components onto predefined positions on the printed circuit board 260.
• the produced printed board assemblies 260 are forwarded to a reflow oven 206.
• the printed circuit boards 260 which have been equipped with electronic components, are heated such that soldering paste being located in between terminals of the electronic components and the corresponding lands on the printed circuit boards 260 is melted.
• soldering paste being located in between terminals of the electronic components and the corresponding lands on the printed circuit boards 260 is melted.
• the produced electronic circuit arrangements are removed from the manufacturing line 200 by means of an unloader unit, which is denoted with reference numeral 208.
• manufacturing lines for producing electronic circuit arrangements also comprise machines for applying soldering paste onto predefined surface portions of an electronic substrate. Such machines are also called solder paste printers.
• US 2004/0238595 Al discloses a solder paste printer comprising a substrate holder for holding a circuit board. Onto the circuit board a viscous material for bonding electronic components is printed by means of a squeegee through a screen mask.
• the high performance manufacturing line 200 shown in Figure 2 comprise two solder paste printers 207a and 207b.
• the two printers 207a and 207b are operated in parallel in order to be able to provide enough substrates to the electronic component placement machines 210, which are arranged downstream with respect to the printers 207a and 207b.
• the printers 207a and 207b are connected to the row of placement machines 210 by means of a shuttle 214.
• the shuttle 214 is used for transporting the printed circuit boards 260 being partially coated with solder paste to the transport roadway 207a and 207b.
• a printed circuit board loader 205 is used for feeding the bare printed circuit boards to the printer 207a respectively to the printer 207b.
• an apparatus for applying a viscous medium onto predefined surface portions of an electronic substrate in particular for applying soldering paste and/or a conductive glue onto predefined conductor junction areas formed on a printed circuit board.
• the provided viscous medium application apparatus comprises (a) an application device for applying the viscous medium onto predefined surface portions of the electronic substrate, and (b) an interface being adapted for attaching the apparatus to an electronic component placement machine .
• This first aspect of the present invention is based on the idea that by attaching the provided viscous medium applica- tion apparatus to an electronic component placement machine respectively an electronic component placement machine, a high performance manufacturing line for electronic circuit arrangements may be build up within a compact setup. At least compared to known high performance manufacturing lines, which typically comprise at least two separate viscous medium application apparatuses, significant less production floor space is needed.. Therefore, the efficiency for the production of electronic circuit arrangements can be increased because significant less production floor space is needed.
• the described apparatus enables the realization of manufacturing lines for producing electronic circuit arrangements, which manufacturing lines are significantly narrower or shorter than known lines comprising separate solder paste printing machines. Thereby, one or several of the described apparatuses can be used. Accordingly, the production rate for electronic circuit arrangements respectively electronic componentries can be increased.
• the viscous medium may be for instance soldering paste and/or an electric conductive glue in order to reliably contact electronic components, which are later placed onto predefined conductor junction areas respective lands being formed on the printed circuit board.
• soldering paste and/or electric conductive glues may rather be any material, which is used for manufacturing electronic circuit assemblies.
• Such a material may be for instance an electronic underfill material for mechanically fixing laminar components onto printed circuit boards. By using an underfill material mechanical stress, which is caused for instance because of temperature variations, may be absorbed.
• the term interface has to be understood in a wide manner.
• the interface comprises at least mechanical coupling elements, which allow for an attachment of the described apparatus to the electronic component placement machine.
• the outer dimensions of the described apparatus have to be adapted to a corresponding contour and/or shape of the placement machine.
• the interface may also comprise electrical and/or optical connectors, which allow for a power supply and/or a communication between the placement machine and the described medium application apparatus. Since the operation of the described apparatus is related to the placement machine, there is no need for providing an individual power supply and/or a processing unit. However, of course it is not excluded that the medium application apparatus comprises its own power supply and/or an individual data processor e.g. for controlling the operation of the application apparatus.
• the interface is designed in such a manner, that the apparatus can be integrated at least partially within an electronic component placement machine.
• This may provide the advantage the required space for the combination of the described medium application apparatus and the electronic component placement machine can be further reduced.
• outer housings of the medium application apparatus and the electronic component placement machine can interleave with each other.
• the interface is designed in such a manner, that the apparatus can be attached to an electronic component placement machine at a position where usually loading equipment for feeding electronic components to the electronic component placement machine is provided.
• loading equipment may be for instance a plurality of feeder modules, which are placed sideways with respect to a conveyor of the electronic component placement machine.
• the feeder modules are combined by means of a so-called feeder support table, which can be easily coupled to or decoupled from the placement machine. Therefore, by using the described interface the medium application apparatus can be easily interchanged with a feeder support table. This may provide the advantage the a placement machine can be easily reconfigured between a first operating mode wherein only electronic components are placed onto the substrate and a second operating mode wherein the viscous medium is applied to the substrates.
• the apparatus further comprises a first transport system for automatically transporting the electronic substrate.
• the first transport system may be for instance a conveying system, where the electronic substrates to be conveyed are simply placed on conveyor belt.
• the first transport system may comprise different portions, which are spatially convoluted with each other.
• the corresponding transport roadway may comprise one or more zigzags.
• the transport roadway may be formed in different levels such that required space for the first transport system may be significantly reduced.
• the apparatus further comprises a second transport system for automatically transporting a mask being used for partially covering the electronic substrate such that the viscous medium is selectively applicable to the predefined surface portions of the electronic substrate.
• the second transport system may be adapted for handling a plurality of masks such that the described apparatus can operate in an efficient way. This means that within a predefined time unit a high number of substrates can be provided with the viscous medium.
• the second transport system contributes to a closed loop transport system, such that after using a mask during the application procedure the mask can be used again for further electronic substrates.
• the closed loop may comprise different transport sections, whereby one transport section of the second transport system corresponds to at least one section of the first transport system.
• the first transport system and the second transport system comprise a common transport section, wherein the electronic substrates and the corresponding masks are conveyed together.
• clamping elements may be used in order to temporarily fixate a substrate and a corresponding mask to one another.
• the second transport system may be realized for instance by means of a conveying system.
• the application device comprises (a) a reservoir for storing the viscous medium and (b) a scraper element for transferring the viscous medium from the reservoir to the electronic substrate.
• the application device is arranged above the first transport system such that an electronic substrate together with a corresponding mask may be moved straight underneath the scraper element. Thereby, the viscous medium can be transferred through openings of the mask onto the electronic substrate.
• the arrangement of the application device respectively the scraper element directly above the scraper element may provide the advantage that the medium transfer is supported by the gravitational force.
• the described scraper element which preferably is located in a substantially fixed position within the medium transfer apparatus, enables a quasi-continuous material transfer to a plurality of different substrates in a sequential manner. Therefore, if there is a sufficient number of masks provided, the described medium transfer apparatus allows for a quasi - continuous printing of electronic substrates respectively printed circuit boards before these substrates are mounted with electronic components.
• the apparatus further comprises a flipping unit, which is adapted to flip the orientation of an electronic substrate such that the bottom side of the electronic substrate is turned upside down.
• the described flipping unit may provide the advantage that if initially the electronic substrate has been placed on top of a mask the fixed system comprising the electronic substrate and the mask may be rotated together such that after a flipping procedure the mask is located on top of the electronic substrate. This has the effect that the medium can be transferred top down through openings of the mask onto the electronic substrate.
• the apparatus further comprises a cleaning unit for removing residues of the viscous medium from a mask.
• the removal of the residues may be carried out shortly after the mask has been used for protecting certain surface portions of the electronic substrate. This may provide the advantage that these residues can be removed comparatively easy without having a big mechanical and/or chemical cleaning effort.
• the cleaning unit may be arranged within the first and/or preferably within the second transport system. This may provide the advantage that the cleaning procedure can be accomplished in an automated manner.
• an electronic component placement machine for mounting electronic components onto an electronic substrate.
• the provided electronic component placement machine comprises (a) a frame, (b) a handling head, which is moveable within the frame by means of a positioning system, and (c) an apparatus for applying a viscous medium onto predefined surface portions of an electronic substrate.
• Embodiments of the viscous medium application apparatus have been described above.
• the apparatus is detachably attached to the frame.
• This aspect of the present invention is based on the idea that by providing a standard electronic component placement machine with the viscous medium application apparatus described above, a high performance electronic circuit arrangement manufacturing line comprising a solder paste printer, a component placement machine and an oven can be build up within a more compact setup as compared to a line where solder paste printer and placement machine are separate machines .
• the handling head may also be denoted as a mounting head, as an equipping head and/or as a transfer head.
• the handling head is used for collecting electronic components and for placing the collected components onto predetermined positions onto the surface of an electronic substrate respec- tively a printed surface board.
• the predetermined positions are defined by appropriate conductor junction areas respectively lands, which are provided with a viscous medium such as solder paste and/or an electric conductive glue.
• the electronic component placement machine further comprises a first camera for detecting the position of electronic substrates, which have been fed to the apparatus for applying a viscous medium.
• the first camera is preferably a stationary camera, which, during usual operation of the electronic component placement machine, is used for measuring the position of an electronic component, which has been picked by a holding device of the handling head.
• the first camera might be positioned below a placement plane in which the electronic substrates are located during the mounting procedure respectively the placement procedure. This means that the substrates are viewed from the bottom to the top.
• the position detection of the electronic substrate can rely on the detection and the recognition of fiducials, which may be provided at the electronic substrates.
• the camera can be coupled to an evaluating processor unit, which takes care of an appropriate image processing.
• the evaluating processor unit can be integrated within a central processor unit controlling the operation of the whole electronic component placement machine.
• the handling head is capable of handling an electronic substrate being inserted into the apparatus for applying a viscous medium. This can be realized for instance if the handling head is movable by means of a positioning device, which allows for a wide positioning range extending more or less deep into the viscous medium application apparatus.
• a handling of an electronic substrate being located within the medium application apparatus can also be realized if the apparatus extends into the electronic component placement machine .
• Handling the electronic substrate by means of the handling head may provide the advantage that the spatial accuracy of the handling head can be exploited in order to place the electronic substrate with a high spatial accuracy at the mask. This means that no additional handling robot is necessary for the viscous medium application apparatus in order to position respectively place the electronic substrate onto the mask or vice versa. Therefore, the application apparatus can be realized with comparatively simple and cheap mechanical components .
• the electronic component placement machine further comprises a second camera for detecting the position of electronic masks being used for partially covering the electronic substrate such that the viscous medium is selectively applicable to the predefined surface portions of the electronic substrate.
• the second camera may be a movable camera, which, during usual operation of the electronic component placement machine, is used for measuring the position of electronic substrates, which have been inserted into a placement region of the electronic component placement machine.
• the second camera may be provided with an individual positioning system such that the second camera can be independently positioned.
• the second camera may be attached to the handling head such that when the handling head is moved also the second camera is automatically positioned.
• the second camera might be positioned above a placement plane in which the electronic substrates are located during the mounting procedure. Under the assumption, that also the masks are handled preferably within the placement plane, this means that the masks are viewed from the top. Therefore, if fidu- cials are used in order to make the mask recognition and/or the mask position detection more reliable, these fiducials have to be provided at the top surface of the masks .
• the second camera might also be used for inspecting at least portions of the viscous medium, which has before been applied to the substrate by means of the above described viscous medium application apparatus.
• the manufacturing line comprises an electronic component placement machine according any one of the embodiments described above.
• This aspect of the present invention is based on the idea that, compared to known manufacturing lines comprising at least one printing machine for transferring soldering paste onto lands of electronic substrates, the described manufacturing can be set up in a much more compact way. This is possible because an electronic component placement machine is employed, which is provided with the above-described viscous medium application apparatus. Therefore, no or not much space is required for carrying out a substrate respectively printed circuit board printing. Compared to known manufacturing lines the described manufacturing line can be realized with narrower and shorter dimensions. Therefore, the described manufacturing line may allow for realizing a high production rate per floor space.
• one, two or even more electronic component placement machines can be provided with one above-described viscous medium application apparatus .
• a usual electronic component placement machine can be reconfigured in a comparatively simple and effective way into the above described electronic component placement machine being provided with a viscous medium application device.
• a preferably way for reconfiguring the electronic component placement machine is to replace a feeder table by the medium application device.
• the manufacturing line might comprise a plurality of electronic component placement machines, which are typically arranged in series. However, also some of the placement machines might be arranged in parallel.
• the described manufacturing line might comprise other machines such as a reflow oven for permanently contacting the electronic components, which have been placed on electronic substrates respectively on printed circuit boards. Further, the manufacturing line might comprise an optical inspection machine for inspecting whether the electronic components have been placed on the correct position. Such an optical inspection machine might be arranged upstream and/or downstream with respect to the ov&n.
• a method for applying a viscous medium onto predefined surface portions of an electronic substrate in particular for applying soldering paste and/or a conductive glue onto predefined conductor junction areas formed on a printed circuit board.
• the provided method comprises (a) feeding an electronic substrate to an electronic component placement machine as has been described above, wherein the electronic substrate is supplied to the apparatus for applying a viscous medium, (b) handling the electronic substrate by means of the handling head, and (c) applying the viscous medium onto predefined surface portions of the electronic substrate.
• This aspect of the invention is based on the idea that for applying a viscous medium such as a soldering paste and/or an electric conductive glue it is not necessary to use an individual printing machine.
• the medium application can also be accomplished by using a medium application apparatus, which can be combined with a usual electronic component placement machine.
• the application apparatus can be integrated at least partially into the mounting apparatus such that a whole manufacturing line for electronic circuit arrangements can be set up within a significantly reduced floor space. By reducing the size of the required footprint area, the overall production costs for electronic equipment can also be reduced.
• feeding an electronic substrate might also comprise transporting the electronic substrate to a position, at which the electronic substrate can be received by the handling head.
• the first transport system described above in connection with the apparatus for applying a viscous medium may be utilized.
• the method further comprises inspecting the applied viscous medium.
• the amount of viscous medium and/or the distribution of the viscous medium within the predefined surface portions of the electronic substrate can be measured in order to prevent electronic substrates, which exhibit a deficient medium application, from being further processed. This may provide the advantage that it can be avoided that electronic components are mounted on deficient substrates.
• this substrate can be removed from the manufacturing process of electronic circuit arrangements.
• the method further comprises (a) forwarding the electronic substrate to a placement region of the electronic component placement machine and (b) placing electronic components onto the electronic substrate.
• a feeder table of the original electronic component placement machine may be replaced at least partially by the application apparatus.
• there may still exist remaining feeder modules for feeding electronic components to the placement region which can be employed.
• the number of different component types, which can be fed to the placement region may be limited.
• more than one placement machine is provided in series within a manufacturing line, such a limitation might be easily compensated by distributing various electronic components among different placement machines in an appropriate manner.
• the method further comprises measuring the position of the fed electronic substrate.
• the position measurement of the electronic substrate may be carried out by means of a camera corresponding to the first camera of the above-described electronic component placement machine.
• This first camera is preferably a stationary camera, which, during usual operation of the electronic component placement machine, is used for measuring the position of an electronic component, which has been picked by a holding device of the handling head.
• the first camera might be positioned below a placement plane within which the electronic substrates are located during the mounting procedure .
• the position detection of the electronic substrate is based on the detection and the recognition of fiducials, which may be provided at the electronic substrates. Depending on the optical properties of the electronic substrate these fiducials may have any appropriate color or colors and/or various shapes.
• the method further comprises feeding a mask to a predetermined position within the application device.
• This may provide the advantage that by combining the fed electronic substrate with the fed mask the viscous medium application can be easily restricted to the predefined surface portions.
• the medium application may by accomplished by means of a printing procedure, wherein the medium is transferred in a laminar way onto both the predefined surface portions and onto the mask.
• the method further comprises measuring the position of the fed mask.
• the position measurement of the mask may be carried out by means of a camera corresponding to the second camera of the above- described electronic component placement machine.
• This second camera may be a movable camera, which, during usual operation of the electronic component placement machine, is used for measuring the position of an electronic substrate.
• the second camera may be attached to the handling head such that when moving the handling head also the second camera is automatically positioned.
• the second camera is positioned above the placement plane in which the electronic substrates located during the mounting procedure. Under the assumption, that also the masks are handled preferably within the placement plane, this means that the masks are viewed from the top. Therefore, if fiducials are used for enhancing the reliability of the mask position detection, these fiducials have to be provided at the top surface of the masks .
• the step of handling the electronic substrate comprises placing the electronic substrate and the mask on top of each other. This means that the handling head places either the mask on the electronic substrate or the electronic substrate on the mask. Thereby, the results of the above described position detection of the electronic substrate and/or the mask may be taken into account .
• the handling head respectively the mounting head of the electronic component placement machine comprises -a very high precision. This means that after the positions of both the fed substrate and the fed mask have been measured precisely, no further position measurement is necessary.
• optical inspections systems which are usually assigned to the electronic component placement machine
• the relative position between the fed substrate and the fed mask can be evaluated very precisely.
• no additional camera systems are necessary.
• the mask and the electronic substrate have to be separated from each other before the electronic substrate is forwarded to a placement region of the electronic component placement machine.
• the step of handling the electronic substrate further comprises clamping the electronic substrate and the mask such they are fixed with respect to each other.
• clamping elements may be used in order to temporarily fixate the substrate and the mask to one another. Thereby, the clamped status has to be maintained at least until the viscous medium has been completely applied to the electronic substrate.
• the method further comprises (a) separating the mask from the electronic substrate and (b) cleaning the mask.
• the step of separating and the step of cleaning is preferably carried out after the viscous medium has been applied to the electronic substrate .
• the step of cleaning the mask may provide the advantage after using the mask for a medium application procedure for a first electronic substrate the same mask can be used again for a second substrate and for further substrates. Thereby, several masks can be used in a circulating manner such that a closed loop cycle for masks may be established.
• the cleaning causes residues of the viscous medium to be removed from the mask. Therefore, the cleaning is carried out preferably shortly after the mask has been used for protecting certain surface portions of the electronic substrate. This may provide the advantage that these residues can be removed comparatively easy without having a big mechanical and/or chemical cleaning effort .
• the cleaning procedure may be carried out by inserting the contaminated mask into a liquid cleaning agent.
• a corresponding container for the cleaning agent can be used, which is located above or preferably below a plane, within which the medium application is accomplished.
• the mask is conveyed within the medium application apparatus within different transport planes.
• This may provide the advantage that the medium application apparatus described above in detail can be realized in a compact design.
• the transport path of the electronic substrate respectively the printed circuit board can be arranged within different levels.
• the method further comprises flipping the orientation of an electronic substrate such that the bottom side of the electronic substrate is turned upside down.
• both elements may be rotated together such in the end the mask is located on top of the electronic substrate. This may provide the advantage that the medium can be transferred onto the electronic substrate downwards through openings of the mask.
• the step of applying the viscous medium comprises transferring the viscous medium from a reservoir to the electronic substrate by means of a scraper element.
• the scraper element may also be denominated a squeegee .
• the scraper element may be located in a substantially fixed position within the viscous medium transfer apparatus . This enables a quasi-continuous material transfer to a plurality of different substrates in a sequential manner. Therefore, if there are sufficient masks available, the transfer may be accomplished in a quasi-continuous manner by conveying the electronic substrates and the corresponding masks through a transfer region being assigned to the scraper element.
• the electronic substrate is a singularized electronic substrate. This may provide the advantage that it is no longer necessary to singularize cluster boards after the boards have been equipped with electronic components. If the employed electronic component placement machine comprises a mounting area which is large compared to the size of the singularized substrates, an appropriate carrier element might be used in order to exploit the large mounting area.
• the usage of singularized electronic substrates may further provide the advantage, that the corresponding single layouts for the singularized electronic substrates can be arranged closer together on a large original printed circuit board panel as it is provided by a manufacturer of the printed circuit board.
• Figure Ia shows a high performance manufacturing line according to an embodiment of the invention, which manufacturing line comprises one electronic component placement machine being provided with two viscous medium application apparatuses .
• Figure Ib shows an enlarged view of the electronic component placement machine depicted in Figure Ia, which placement machine is provided with two viscous medium application apparatuses .
• Figure Ic shows a further enlarged view of the electronic component placement machine depicted in Figure Ia, which placement machine is provided with two viscous medium application apparatuses .
• Figure 2 shows a standard high performance manufacturing line, which comprises two printed circuit board printers, four electronic component placement machines and an oven.
• Figure Ia shows a high performance manufacturing line 100 according to an embodiment of the invention.
• the manufactur- ing line 100 comprises a carrier loader 104, which feds carrier elements 103 to two transport roadways, a first transport roadway 101 and a second transport roadway 102.
• the manufacturing line 100 further comprises a plurality of electronic component placement machines 120, 110 being arranged in a row along the two transport roadways 101 and 102.
• the transport roadways 101 and 102 which are aligned in parallel with respect to each other, are used for transporting the carrier elements 103.
• the carrier elements 103 are adapted to carry singularized electronic substrates respectively printed circuit boards, which have a significant smaller area than the placement planes provided in each placement machine 120, 110.
• a first electronic component placement machine 120 is equipped with two viscous medium application apparatuses 150, which are attached to a frame of the placement machine 120.
• the viscous medium application apparatuses 150 are also referred to as printer modules.
• the printer modules 150 have been attached to the placement machine 120 by removing respectively a feeder table from an original placement machine and replacing these removed feeder tables with the printer modules .
• the printer modules 150 transfer soldering paste onto predefined surface portions of the electronic substrates. These predefined surface portions are conductor junctions respectively lands being formed on the surface of the substrates .
• Each placement machine 110 comprises a frame 111 and four feeder tables 112.
• Each feeder table 112 comprises a plurality of feeder units for feeding various types of electronic components.
• Each placement machine 110 further comprises four mounting heads (not depicted) and four placement regions, which placement regions are located in a central region of the placement machine 110. Thereby, each of the two transport roadways 101 and 102 intersects with two of the four placement regions and each placement region is located adjacent a corresponding feeder table 112. One of the four mounting heads is assigned to each placement region.
• the produced printed board assemblies are forwarded to a reflow oven 106.
• the printed board assemblies are heated such that soldering paste being located in between terminals of the electronic components and the corresponding lands on the printed circuit boards is melted. After cooling down, a permanent electric conductive connection is established between the electronic components and the corresponding conductor paths on the printed circuit board.
• the produced printed board assemblies are removed from the manufacturing line 100 by means of an unloader unit, which is denoted with reference numeral 108. Therein, the printed board assemblies are separated from the carrier elements 103.
• the carrier elements 103 are returned to the carrier loader 103.
• the carrier element return is indicated with reference numeral 109.
• the carrier return 109 can be accomplished manually for instance by using appropriate magazines being adapted to temporally accommodate a plurality of carrier elements 103. Alternatively, the carrier return 109 can be accomplished in an automated manner .
• Figure Ib shows an enlarged view of the electronic component placement machine 120.
• the placement machine 120 comprises a frame 121 and four placement regions 113.
• Carrier elements 103 which are adapted for carrying a plurality of singular- ized substrates 103, can be positioned within the placement regions 113.
• Electronic components can be mounted onto the carried substrates by means of mounting heads 125a, 125b, which are movable by means of positioning systems (not depicted in Figure Ib) .
• One mounting head 125a, 125b is assigned to each placement region 113.
• the mounting heads 125a being provided in the left part of the placement machine 120 are not used for mounting electronic components, because in the left part of the placement machine 120 feeder elements have been replaced by printer modules 150.
• the printer modules 150 are used for applying soldering paste onto junction areas of the electronic substrates .
• the printer modules 150 are connected respectively coupled to the main body of the placement machine 120 by means of an interface 130.
• the interface comprises mechanical coupling elements, which allow for a removable attachment of the printer modules 150 to the electronic component placement machine 120.
• the outer dimensions of the printer modules 150 are adapted to a corresponding contour of the placement machine 120.
• the interface 130 also comprises electrical connectors, which allow for a power supply and/or for a communication between the placement machine 120 and the printers 150.
• the printer modules 150 are partially integrated within the placement machine 120. Therefore, the corresponding mounting respectively handling heads 125a can handle electronic substrates, which are currently processed by a printer module 150.
• the mounting heads 125a are used for placing a bare electronic substrate onto an appropriate mask. More details regarding the printing procedure will be given later with reference to Figure Ic.
• the right part of the placement machine 120 corresponds to a known high performance placement machine.
• Feeder tables 122 are provided in order to provide electronic components to the mounting heads 125b being arranged on the right side of the placement machine 120. By means of the mounting heads 125b the electronic components are placed on printed circuit boards .
• Figure Ic shows a further enlarged view of the electronic component placement machine 120.
• the lower printer module 150 is depicted in more detail.
• the setup of the printer module 150 and the components of the printer module 150 are illustrated in connection with the explanation of a procedure for applying a viscous medium onto predefined surface portions of electronic substrates 160.
• the viscous medium is a soldering paste.
• the soldering paste application procedure starts with a step Sl, wherein singularized bare electronic substrates 160 are fed to a first transport system 155 for transporting the substrates 160.
• step S2 the electronic substrates 160 are transported along a direction indicated by an arrow.
• the substrates 160 are transported pairwise onto a conveyor 155.
• the movement of the substrates 160 is stopped.
• step S3 the mounting head 125a, which is movable by means of a positioning system 126, receives the electronic substrate 160 from the conveyor 155.
• the mounting head 125a may be equipped with special holding devices.
• the mounting head 125a may be equipped with a suction nozzle, which comprises a comparatively large suction opening in order to reliably pick up electronic substrates 160.
• step S4 the mounting head 125a is moved in order to position the electronic substrate 160 in a field of view of a fixed first camera 123, which field of view is directed upwards.
• the electronic substrate 160 is temporarily positioned within the field of view of the first camera 123, fiducials being provided at the substrate 160 are measured. By evaluating the position of the measured fiducials the position of the electronic substrate 160 within the coordinate system of the placement machine 120 is determined.
• the first camera 123 is a stationary camera, which is usually used for measuring the position of an electronic component, which has been picked by an appropriate suction nozzle of the handling head.
• the first camera 123 is positioned below the placement plane 113. This means that the substrates 160 are viewed from the bottom to the top .
• step S5 masks 170 are fed to a second section 155b of the first transport system 155.
• a second transport system 165 is employed, which is partially arranged below a third section 155c of the first transport system 155.
• the masks 170 are used for partially covering electronic substrates 160 such that, within a further step described below in more detail, the viscous medium can be selectively be applied to the predefined surface portions of the electronic substrate 160.
• step S6a fiducials provided at the mask are measured by- means of a movable second camera 127.
• the second camera 127 is a so called substrate camera 127, which is usually employed for measuring the position of a printed circuit board, which has been introduced in the placement plane and which is prepared for being mounted with electronic components.
• the second camera 127 is positioned above the placement plane 113 in which electronic substrates are located during a usual mounting procedure. Since also the masks 170 are handled within the placement plane 113, this means that the masks 170 are viewed from the top. Therefore, the fiducials being used in order to make the mask recognition more reliable are provided at the top surface of the masks 170.
• the position of the mask 170 within the coordinate system of the placement machine 120 is determined. Further, since the position of the substrate is already known, the spatial relationship between the mask 170 and the substrate 160 is also established.
• step S6b the mounting head 125a places the substrate 160 onto the mask 170. Thereby, the usual spatial accuracy of the mounting head 125a is sufficient. Since further spatial offsets are not expected, no further optical measurement is necessary.
• two substrates 160 are sequentially placed on one mask 170. This means that each mask is designed for two substrates 160.
• step S6c the substrate 160 and the mask 170 are fixed to each other by means of appropriate clamping means. Thereby, the relative spatial position between the substrate 160 and the mask 170 will be maintained until the clamping means are released.
• step S7 the mask 170 and the electronic substrate 160 are commonly conveyed on the second section 155b of the first transport system 155. At the end of the second section 155b, the movements of the mask 170 and the substrates 160 is stopped.
• step S8 a flipping unit 175 flips the mask 170 and the substrates 160. Thereafter, the substrates 160 are located at the bottom and the mask 170 is located at the top. According to the embodiment described here, the flipping is carried out pairwise with respect to the masks 170. This means that two masks each being provided with two substrates 160 are commonly f1ipped.
• step S9 the flipped mask 170 and substrates 160 are further conveyed by means of a third section 155c of the transport system 155 to an application device 180.
• step SlO soldering paste is applied to predefined surface portions of the substrates 160 by means of a scraper element 181.
• the application device 180 is arranged above the first transport system 155 such that the electronic substrates 160 are moved straight underneath the scraper element 181. Thereby, the soldering paste can be transferred from a reservoir 182 through openings of the mask 170 onto the electronic substrates 160. Thereby, the soldering paste transfer is supported by the gravitational force.
• the application device 180 respectively the scraper element 181 is located at a fixed position within the printer module 150. This enables a quasi-continuous material transfer to a plurality of different substrates in a sequential manner. If there is a sufficient number of masks 170 provided, the described printer module 150 allows for a quasi -continuous printing of printed circuit boards 160 before these boards 160 are mounted with electronic components within other placement regions 113.
• step SIl which is carried out in a separation unit 185, the substrates 160 are separated from the mask 170.
• the separation unit is located below the plane of the first transport system 155. After separation the masks are transferred to a cleaning unit 190 and the substrates 160 are transferred to a fourth section 155d of the substrate transport system 155.
• step S12 which is carried out in the cleaning unit 190, residues of the soldering paste are removed from the mask 170.
• the removal of the residues is carried out shortly after the mask 170 has been used for protecting certain surface portions of the electronic substrate 160 during step SlO.
• step S13 the cleaned mask 170 is returned to the second section 155b of the first transport system 155 by means of the second transport system 165, which has already been described above. Thereby, a closed cycle for reusing masks is realized.
• step S14 the substrates 160 are conveyed by means of the fourth section 155d of the substrate transport system 155 towards a position, at which the substrates 160, which are now provided with soldering paste, can be optically inspected.
• step S15 the substrates 160 are optically inspected. Thereby, the amount of soldering paste and/or the distribution of the soldering paste within the predefined surface portions of the electronic substrate 160 is measured.
• Electronic substrates 160 which comprise a deficient paste application, can be removed from the production process. According to the embodiment described here, the optical inspection is accomplished by means of the camera 127, which is attached to the mounting head 125a.
• the electronic substrate 160 is transported to the carrier element 103, which in the meantime has been fed to the placement region 113.
• these substrates 160 can be commonly moved along the second transport roadway 102 towards further placement regions 113.
• electronic components are placed onto the substrates 160 in a known manner.
• a further placement region 113 may be for example the downstream placement region 113 of the placement machines 120.
• the further placement regions 113 may also be placement regions of the placement machines 110, which are located downstream with respect to the placement machine 120.
• feeder units / feeder table 214 shuttle

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Electric Connection Of Electric Components To Printed Circuits (AREA)
• Supply And Installment Of Electrical Components (AREA)

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• 2006
  • 2006-11-30 EP EP06838679A patent/EP2087783A1/en not_active Withdrawn
  • 2006-11-30 CN CN200680056891.6A patent/CN101647332B/zh not_active Expired - Fee Related
  • 2006-11-30 WO PCT/US2006/045837 patent/WO2008066531A1/en active Application Filing

Non-Patent Citations (1)

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