Abstract:
A component mounter has two or more feeder carriages and two or more mounting heads corresponding to the feeder carriages. The mounting heads pick up components from each feeder carriage. A transfer device is able to pass components requiring transfer between the mounting heads. The transfer of components enables the mounter to be used efficiently by transferring components to a different mounting head when the operation of one of the mounting heads stops.

Description:
FIELD OF THE INVENTION 
     The present invention relates to component mounters and mounting methods such as for mounting electronic components onto substrates. 
     BACKGROUND OF THE INVENTION 
     Component mounters for mounting electronic components such as semiconductors on substrates are equipped with a feeder carriage provided with multiple parts feeders for supplying components. A mounting head picks up components from the feeder carriage for mounting them on a substrate. If many types or numbers of components are to be mounted in the same mounting stage, two or more pairs of feeder carriages and mounting heads, without being limited to a single pair of the feeder carriage and mounting head, are disposed on the same mounting stage. These several pairs operate independently to mount components. 
     A recognizer captures an image of a component picked up by the mounting head while being held with a nozzle of the mounting head before mounting the component on the substrate to identify each component and detect positional deviation. In many cases, one recognizer is provided per mounting head when several mounting heads are disposed on the same mounting stage. Accordingly, if any problem occurs with one of these recognizers, the component held by the mounting head corresponding to this problematic recognizer is not recognized, and thus the mounting operation of the mounter stops. 
     In addition, some components require high precision recognition. Such components need to be set on a feeder carriage that will cause them to be examined by the high precision recognizer. Although several recognizers may be placed on the same mounting stage that on the same mounting stage are different types, only some of the recognizers may be high precision type. Accordingly, if the number of components requiring high precision recognition exceeds the capacity of the high precision recognizer, the components cannot be placed in regular feeder carriages even though the regular feeder carriages have space. They cannot be placed in regular feeder carriages due to the need for precision recognition. 
     As described above, the use of this type of conventional mounter may result in stopping the mounting operation being implemented by a combination of a feeder carriage and mounting head using a recognizer which has been stopped, even if there are several alternative feeder carriages and mounting heads. Alternatively, the capacity of the feeder carriage may not be effectively utilized due to mismatching between types of components and recognizers, causing undesired discrepancies. Consequently, the conventional mounter may not be efficiently utilized. 
     SUMMARY OF THE INVENTION 
     The present invention aims to offer a mounter and a mounting method for improving the efficiency of use of component mounters. 
     The component mounter of the present invention comprises the following: 
     (a) more than one feeder carriage; 
     (b) more than one mounting head provided corresponding to the feeder carriages for picking up components from each feeder carriage; and 
     (c) transfer means for passing a component requiring transfer between the mounting heads. 
     The above configuration enables the improvement of the efficiency of use of the mounter by passing the component to another mounting head even when the operation of one of the mounting heads has been stopped. 
     The mounting method of the present invention comprises the following steps of: 
     (a) picking up a component from a first mounting head; 
     (b) passing the component from the first mounting head to a second mounting head; and 
     (c) placing the component on the substrate using the second mounting head. 
     The above method enables the more efficient use of the mounter as a result of passing the component to another mounting head when the operation of one of the mounting heads has been stopped. 
     Another mounting method of the present invention comprises the following steps of: 
     (a) picking up a component from a first feeder carriage using a first mounting head; 
     (b) passing the component from the first mounting head to a second mounting head; 
     (c) recognizing the component using a recognizer installed on a second feeder carriage for supplying components to the second mounting head; and 
     d) placing the component on the substrate using the second mounting head after recognition. 
     The above method enables the use of the second recognizer to recognize the component even if the operation of the first mounting head stops or a discrepancy occurs between the type of component and the first recognizer installed on the first feeder carriage for supplying components to the first mounting head. Accordingly, the efficiency of use of the mounter may be improved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective of a component mounter in accordance with a first exemplary embodiment of the present invention. 
     FIG. 2 is a plan view in accordance with the first exemplary embodiment of the present invention. 
     FIG. 3 is a side view in accordance with the first exemplary embodiment of the present invention. 
     FIG. 4 is a plan view of a component mounter in accordance with a second exemplary embodiment. 
     FIGS. 5 and 6 are side views in accordance with the second exemplary embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Exemplary embodiments of the present invention are described below with reference to drawings. 
     First Exemplary Embodiment 
     FIG. 1 is a perspective, FIG. 2 is a plan view, and FIG. 3 is a side view of a component mounter in the first exemplary embodiment of the present invention. 
     First, the configuration of the mounter in the first exemplary embodiment is described with reference to FIGS. 1 and 2. A transfer rail  2  is disposed in the x-axis direction at the center of a base  1 . The transfer rail  2  transports and positions a substrate  3  onto which components are to be mounted. More than one feeder carriage (a first feeder carriage  41  and second feeder carriage  42 ) is disposed at both sides of the transfer rail  2 . Multiple tape feeders  5  are set on each of the feeder carriages  41  and  42 . Each tape feeder  5  stores parts such as electronic components carried on a tape. The feeder carriages  41  and  42  supply each component by feeding the tape at a predetermined pitch. 
     Y-axis tables  61  and  62  are disposed on both ends of the base  1 . X-axis tables  71  and  72  are then placed on the Y-axis tables  61  and  62 . The x-axis table  71  moves horizontally in the Y direction by driving the Y-axis table  61 . The x-axis table  72  moves horizontally in the Y direction by driving the Y-axis table  62 . A mounting head  81  is attached to the x-axis table  71 , and a mounting head  82  is attached to the x-axis table  72 . 
     The head  81  moves horizontally by driving the Y-axis table  61  and x-axis table  71  in combination. Then, a nozzle  810  (see FIG. 3) picks up a component from the feeder carriage  41 , and mounts it on the substrate  3 . In the same way, the head  82  moves by driving the Y-axis table  62  and x-axis table  72  in combination for picking up another component from the feeder carriage  42  with a nozzle  820  (see FIG.  3 ), and mounts it on the substrate  3 . A first recognizer  91  is disposed on the way from the feeder carriage  41  to the transfer rail  2 , and a second recognizer  92  is disposed on the way from the feeder carriage  42  to the transfer rail  2 . The recognizer  91  recognizes the component held by the head  81  from underneath, and in the same way, the recognizer  92  recognizes the component held by the head  82  from underneath. Each component is thus identified and any positional deviation of a component is detected. A transport conveyor  10  is disposed in the Y direction over the transfer rail  2  crossing the transfer rail  2 . The conveyor  10  is disposed in a movement area of the heads  81  and  82 . As shown in FIG. 3, a component P picked up by the head  81  from the feeder carriage  41  is placed on the conveyor  10  (shown by an arrow  100 ). The conveyor  10  is then driven to transport the component P to the other end (shown by an arrow  200 ). This enables the head  82  originally for the feeder carriage  42  to pick up the component P stored in the feeder carriage  41 . In other words, the component P is passed from the head  81  to the head  82  by means of the conveyor  10 . The above describes the case of passing a component from the head  81  to the head  82 . Naturally, components may be passed the other way. 
     The operation of the mounter in the first exemplary embodiment as configured above is described next. 
     As shown in FIG. 2, the substrate  3  on the transfer rail  2  is positioned at a predetermined location. Mounting of components then starts. During mounting, the head  81  picks up components from the feeder carriage  41 , and the head  82  picks up components from the feeder carriage  42 . The recognizer  91  recognizes components held by the head  81 , and the recognizer  92  recognizes components held by the head  82 . These components are then mounted on the substrate  3 . 
     If any abnormality in mounting operations occurs with one of the recognizers  91  and  92 , the use of the faulty recognizer is stopped, and a different recognizer is used for recognition. For example, if the operation of the recognizer  91  stops, the component P picked up from the feeder carriage  41  at the side of the recognizer  91  which has been stopped is transported to the other side of the conveyor  10 . Then, the head  82  on the other side picks up this component P for recognition using the recognizer  92  on the other side, and mounts it on the substrate  3 . Here, the component P is a transferred component. 
     In some cases, the recognizer  91  and recognizer  92  may not have the same function. For example, the recognizer  91  may be used for high precision recognition, and the recognizer  92  for regular precision recognition. If the number of components requiring high precision recognition exceeds the capacity of the feeder carriage  41  at the side of the recognizer  91 , some of these components requiring high precision recognition are also set on the feeder carriage  42 . These components requiring high precision recognition are picked up by the head  82  from the feeder carriage  42  and then passed from the head  82  to the head  81  via the conveyor  10  for recognition by the recognizer  91 . 
     As described above, the present invention makes it possible to maintain efficient and uninterrupted use of a mounter with two or more pairs of mounting heads and feeder carriages without closing down the feeder carriage and mounting head even if breakdown of the recognizer occurs or if a discrepancy appears between the component to be recognized and the recognizer by providing transfer means for passing components between two or more mounting heads. 
     Second Exemplary Embodiment 
     FIG. 4 is a plan view, and FIGS. 5 and 6 are side views of a component mounter in the second exemplary embodiment of the present invention. The second exemplary embodiment of the present invention describes another transfer means for passing components without using the transfer conveyor described in the first exemplary embodiment. 
     FIG. 4 illustrates a placement table  11  instead of the conveyor  10  on the mounter shown in FIG.  2 . The table  11  is disposed within the movement area of the mounting heads  81  and  82  so that the component P picked up by the head  81  from the feeder carriage at one side, such as the first feeder carriage  41 , may be placed on the table  11 . This component P is then picked up by the head  82  for passing the component P from the head  81  to the head  82 . Accordingly, the table  11  acts as transfer means for passing the component in the second exemplary embodiment. 
     FIG. 6 also shows another transfer means other than the use of a transfer conveyor. In FIG. 6, the head  81  has a rotation mechanism  121 . The head  82  also has a rotation mechanism  122 . As shown in FIG. 6, the heads  81  and  82  are rotatable through  90  degrees on a horizontal axis. The head  81  holding the component P may be rotated to maintain a nozzle  810  of the head  81  horizontally to face a nozzle  820  of the head  82 , also rotated horizontally, so that both nozzles  810  and  820  come into proximity. Then, the head  81  stops the vacuum suction holding the component P to release the component P, and the head  82  then holds the component P by suction. This completes the passing of the component P from head  81  to head  82 . In this example, heads  81  and  82  having the rotation mechanisms  121  and  122  themselves are transfer means. The use of such transfer means makes it possible to achieve the same result as described in the first exemplary embodiment. 
     As described above, the present invention is equipped with transfer means for passing components between two or more mounting heads. This makes it possible to increase the efficiency of use of the mounter, even if the operation of one recognizer is halted or one recognizer is not suitable for some of the components, by using another appropriate recognizer for recognizing the components.