Abstract:
Resin sealed lead frames are processed by modular processing work stations related in number to a plurality of steps used in processing the lead or leads of the resin sealed lead frame. The work stations are separate modules which are detachably interconnected, whereby the number of modules can be exactly correlated to the number of steps actually required for processing the lead or leads of the resin sealed lead frame. As required, modules can be added or omitted. The resin sealed lead frame is sequentially advanced through the modules in steps corresponding to at least two pitches, whereby one pitch is defined as the on-center spacing between two neighboring products on the lead frame. Such feed advance permits performing at least two processing steps simultaneously. Thus, the method for processing the resin sealed lead frame and the apparatus therefore are adaptable to a change in the type of processing and to the production volume.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to methods of processing lead frames in which an electronic part such as an IC (Integrated Circuit) is sealed with resin, hereinafter simply referred to as a resin sealed lead frame, and apparatuses therefor. More specifically, the present invention relates to a method of processing resin sealed lead frames for cutting a prescribed portion of the resin sealed lead frame or separating each electronic section forming a product, on the resin sealed lead frame and an improvement of the apparatus for performing the method. 
     2. Description of the Background Art 
     A first type of prior art related to the present invention will now be described with reference to FIGS. 11 and 12A to  12 C. FIG. 11 generally shows a processing apparatus for a resin sealed lead frame according to the first type of prior art. FIGS. 12A to  12 C schematically show an arrangement of a so-called QFP (Quad Flat Package) type resin sealed lead frame A in which outer leads  3  protrude from four sides of a resin sealed molding or mold package  2  in which an electronic part  1  is sealed. 
     In a resin sealed lead frame A shown in FIGS. 12A to  12 C, a lead frame body  4  and a die pad  6  for mounting an electronic part  1  are connected by a pinch lead  5 . A dam bar  7  is provided for preventing melted resin material from flowing out of a mold cavity at the time of sealing the electronic part  1  with resin. A cavity  8  serves as a resin pool. Four electronic parts  1  are mounted to the lead frame body  4  and each part  1  is electrically connected to a prescribed outer lead. 
     For separating each electronic section or product from the resin sealed lead frame A, for example, various cutting steps, such as cutting of the cavity  8 , cutting of the resin at the dam bar  7 , cutting of the dam bar  7  itself, cutting of a tip connecting portion of the outer lead  3  and cutting of the pinch lead  5 , must be performed. 
     A plurality of such cutting steps, for example, the above mentioned resin cutting step and the dam bar cutting step can be performed almost simultaneously, depending on the thickness, shape or the like of the lead frame body  4 . At the same time, any unnecessary step should be eliminated. The above mentioned separation of each electronic section is performed by a lead processing apparatus having an upper mold or tool  9  and a lower mold or tool  10 , for example as shown in FIG.  11 . 
     The lead processing apparatus illustrated in FIG. 11 is structured to perform only the above mentioned cavity cutting step, the dam bar cutting step and the pinch lead cutting step. More specifically, the lead processing apparatus shown in FIG. 11 is provided with a structure of a so-called sequentially feeding mold and includes: an upper mold base  11 ; a punch holder  12  fixed to the upper mold base  11 ; a punch blade  13  fixed to the punch holder  12 ; a stripper blade  14  suspended from the punch blade  13 , a cavity cutting punch  15  for cutting the cavity  8 ; a dam bar cutting punch  16  for cutting the resin at the dam bar  7 ; and a pinch lead cutting punch  17  for cutting the pinch lead  5 . 
     Base portions of punches  15 ,  16  and  17  are fixed to the same punch holder  12  through the punch blade  13 , and their tip blades are fitted onto a punch guide  18 . Dies  19 ,  20  and  21  are arranged on the lower mold  10 , respectively corresponding to punches  15 ,  16  and  17 . 
     As shown in FIG. 11, the resin sealed lead frame A is fed to a prescribed position between the upper and lower molds  9  and  10 , and the cutting steps are sequentially performed by the punches  15 ,  16 ,  17 , and the dies  19 ,  20 ,  21  while sequentially feeding each electronic section on the resin sealed lead frame A. Thus, each electronic section is sequentially separated. 
     As described above, in the conventional lead processing apparatus, each punch used for cutting and separating the electronic sections or product from the resin sealed lead frame A, is integrally fixed to one mold base, and the die corresponding to the punch is integrally fixed to the other mold base. 
     When the leads of a different type of resin sealed lead frame are to be processed, the above described conventional lead processing apparatus cannot be directly used. Then, a different lead processing apparatus for the resin sealed lead frame must be provided, or any unnecessary punches and dies fixed to the mold base  11  must be removed so that different punches and different dies required for the lead processing can be integrally fixed to the mold base. 
     Providing a dedicated separate lead processing apparatus for every kind of resin sealed lead frame is very uneconomical, and changing of the punches and dies for every kind of resin sealed lead frame requires not only a laborious operation but also skill for the fine adjusting after the tool and die change. 
     A second type of prior art related to the present invention will now be described with reference to FIGS. 13A and 13B. It is noted that elements corresponding to those of the above described first type of prior art shown in FIGS. 12A to  12 C are denoted by the same reference numerals. FIGS. 13A and 13B schematically show an exemplary arrangement of a resin sealed lead frame in which outer leads  3  protrude from two sides of a resin sealed molding  2  including an electronic part  1 . 
     In the resin sealed lead frame according to the second type of prior art shown in FIGS. 13A and 13B, a cradle  4  and a die pad  6  for mounting the electronic part  1  are connected by a pinch lead  5 . A dam bar  7  is further provided to prevent melted resin from flowing out of a mold cavity at the time of sealing the electronic part  1  with resin. A prescribed number of electronic parts  1  are mounted on a cradle  4  and each part is electrically connected to a prescribed inner lead  28 . 
     For the step of separating each electronic section or product from the resin sealed lead frame, a lead processing apparatus having a so-called sequentially feeding mold is used. The sequentially feeding mold includes a punch and die for cutting and thereby performs each cutting step while sequentially feeding the resin sealed lead frame to a prescribed position between the punch and die. For example, the mold sequentially performs cutting of resin and removal of resin at the dam bar  7 , cutting of the dam bar  7 , cutting of a tip connecting portion of an outer lead  3 , and cutting of the pinch lead  5  or the like. 
     It is noted that if a mold for bending the outer lead  3  is provided along with the above described mold for cutting, a step of bending the outer lead can be simultaneously or separately performed. However, as the bending of the lead is performed in a manner substantially similar to that of the above mentioned cutting steps, a further description thereof is not necessary. 
     In the conventional method of processing the lead or leads described with reference to FIGS. 13A and 13B, the products are pressed by cutting molds which are spaced by one pitch along the feeding path while sequentially feeding the products on the lead frame by a distance equal to one pitch. One pitch is defined as the on-center spacing between two neighboring products along the feeding path. In the final processing step, each product is sequentially cut and separated from the resin sealed lead frame to produce separate products. For increasing the production volume per period of time, the number of lead processing apparatuses having similar functions and structures must be increased. For example, to double the production volume in the same period of time, two lead processing apparatuses having similar structures must be provided, whereby the equipment costs, and the required space for the equipment is doubled. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a method for processing a resin sealed lead frame capable of accommodating a change in the processing operation and a change in the production volume for processing the resin sealed lead frames and an apparatus for performing such a change accommodating method. 
     The method of processing resin sealed lead frames according to the invention has achieved the above described objects by the combination of the following steps: 
     (a) preparing said resin sealed lead frames with products ( 2 ) on said resin sealed lead frames ( 4 ) having a spacing corresponding to a first pitch (P) defined as an on-center distance between neighboring products ( 2 ) on said resin sealed lead frames ( 4 ), 
     (b) assembling a second number n of processing tool modules ( 100 ,  101 , . . . ) for each of said first number N of processing operations, in series along a processing feed advance path, so that a total number M of processing tool modules corresponds to M=N·n for performing said operations on said resin sealed lead frames, and 
     (c) sequentially feeding said resin sealed lead frames with said products on said resin sealed lead frames ( 4 ) along said processing feed advance path in steps having a step length corresponding to a second pitch (P′) that is equal in length to said second number n times said first pitch (P), thus P′=n·P, and wherein said second number n is at least equal to two for simultaneously processing at least two of said products on said resin sealed lead frames. 
     A processing apparatus according to the present invention for performing the above described first embodiment of the present method is characterized in that the processing means corresponding to the plurality of processing steps are separate modules which are detachably connected to a base. 
     According to the present invention, the processing apparatus is easily modified by combining separate, detachable modules selected with regard to which processing steps are to be performed. Thus, the present apparatus can be simply and promptly restructured by suitably connecting or disconnecting the modules as necessary. 
     Therefore, a dedicated lead processing apparatus does not need to be prepared for every kind of the resin sealed lead frame, and the operation of changing punches and dies, fine adjusting operation after the change or the like have been eliminated. As a result, the apparatus can simply cope with a change in the processing operation for processing the lead of the resin sealed lead frame, whereby the productivity for making various products considerably increases. 
     According to the present invention, since the dedicated lead processing apparatus does not need to be prepared for every kind of the resin sealed lead frame, an economic advantage is achieved. The number of modules can be increased or decreased depending on the actual lead processing operation, other operation conditions or the like. In addition, the processing means for the unnecessary steps can be eliminated from the lead processing apparatus, so that an overall reduction in the equipment cost can effectively be achieved. 
     According to another aspect, a method of processing a resin sealed lead frame according to the present invention relates to a processing method using a processing apparatus for the resin sealed lead frame including: a feeding portion for the resin sealed lead frame before the lead processing, provided along a feeding path of the resin sealed lead frame; a lead processing portion for the resin sealed lead frame connected to the feeding portion; and a removing portion for the resin sealed lead frame after the lead processing wherein the removing portion is detachably connected to the lead processing portion. In the processing method, the resin sealed lead frame is sequentially fed by a plurality of pitches or at least two pitches, whereby one pitch is the on-center spacing between two neighboring products on the resin sealed lead frame and the apparatus comprises a plurality of lead processing basic units having the same lead processing function detachably connected in series in the lead processing portion. A prescribed lead processing is performed for the products by the plurality of lead processing basic units in the lead processing portion at prescribed positions spaced by a plurality of pitches of the resin sealed lead frame. Subsequently, the resin sealed lead frame is removed from the removing portion. 
     In the method for processing the resin sealed lead frame, a step of cutting and separating the products on the resin sealed lead frame is further provided before removal of the resin sealed lead frame from the removing portion of the apparatus. 
     The processing apparatus for performing the above described processing method according to the second aspect includes: a feeding portion ( 30 ) for the resin sealed lead frame before lead processing which is provided along a feeding path of the resin sealed lead frame; a lead processing portion for the resin sealed lead frame detachably connected to the feeding portion; and a removing portion for the resin sealed lead frames after the lead processing, whereby the removing portion is detachable connected to the lead processing portion. The lead processing portion includes a plurality of lead processing basic units which have the same lead processing function and are detachably connected in series. 
     Thus, the present invention effectively provides a processing method and apparatus for resin sealed lead frames capable of simply and promptly accommodating a change in the production volume. 
     A lead processing apparatus provided with one lead processing basic unit as the lead processing portion or a plurality of (two or more) lead processing basic units can be selected and employed as required. When the structure including at least two lead processing units as the lead processing portions is selected and employed, the production volume can be increased multiple times, corresponding to the number of the lead processing basic units. 
     Further, when at least two lead processing basic units are provided as the lead processing portions, the feeding portion for the resin sealed lead frame upstream of the lead processing and for the removing portion for the resin sealed lead frame downstream of the lead processing, may be the same. Therefore, as compared with the case where at least two lead processing apparatuses having full functions and structures are separately provided, an overall reduction in the overall equipment cost and space for the lead processing apparatus has been achieved. 
     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic front view generally showing a processing apparatus for a resin sealed lead frame according to a first embodiment of the present invention. 
     FIGS. 2A to  2 D are schematic front views showing modules of the processing apparatus for the resin sealed lead frame shown in FIG. 1, respectively corresponding to a cavity cutter, a resin cutter, a dam bar cutter and a pinch lead cutter module. 
     FIG. 3 is a schematic front view generally showing a structure of a cavity cut module according to a second embodiment of the present invention. 
     FIG. 4 is a schematic front view generally showing a processing apparatus for the resin sealed lead frame according to the second embodiment of the present invention, where the cavity cutter module corresponding to FIG. 3 is connected to the other modules. 
     FIGS. 5A and 5B are schematic diagrams generally showing a processing apparatus for a resin sealed lead frame according to a third embodiment of the present invention, where FIG. 5A shows a basic structure thereof and FIG. 5B shows another lead processing portion having the same function added to the basic structure shown in FIG.  5 A. 
     FIG. 6A is a front view schematically showing an enlargement of a main portion of a lead processing section of the lead processing apparatus shown in FIGS. 5A and 5B, and FIG. 6B is a plan view schematically showing an enlargement of a main portion of the resin sealed lead frame of the apparatus. 
     FIGS. 7A and 7B are diagrams showing steps for performing the function of the basic structure of the lead processing apparatus corresponding to FIG.  5 A. 
     FIGS. 8A and 8B are diagrams showing steps for performing the function of the structure of the lead processing apparatus of FIG. 5B to which another lead processing portion is added. 
     FIG. 9A is a schematic diagram generally showing a lead processing apparatus according to a fourth embodiment of the present invention, and 
     FIG. 9B is a diagram showing the steps and respective function thereof. 
     FIG. 10A is a schematic diagram generally showing a lead processing apparatus according to a fifth embodiment of the present invention, and 
     FIG. 10B is a diagram showing the steps and respective function thereof. 
     FIG. 11 is a front view generally showing an overall structure of a processing apparatus for a resin sealed lead frame according to the first type of prior art. 
     FIG. 12A is a plan view schematically showing the resin sealed lead frame according to the first type of prior art, 
     FIG. 12B is a front view, and 
     FIG. 12C is a plan view schematically showing an enlarged view of a part of the conventional resin sealed lead frame. 
     FIG. 13A is a front view schematically showing a resin sealed lead frame according to the second type of prior art, and 
     FIG. 13B is a plan view schematically showing the conventional lead frame. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     Now, a first embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2A to  2 D. 
     Referring to FIG. 1, the processing means for performing a plurality of processing steps required for finishing the leads of resin sealed lead frames are separately provided as modules in the present apparatus. The separate modules are detachable and can suitably be connected to or disconnected from the apparatus as necessary. Thus, a structure of the processing apparatus provided with a desired lead processing portion can be employed. 
     More specifically, the above described processing apparatus includes: a feeding portion including a feeding module  100  for the resin sealed lead frame A, a cavity cutter module  101  connected to the feeding portion  100 ; a resin cutter module  102  connected to cavity cutter module  101 ; a dam bar cutter module  103  connected to the resin cutter module  102 ; a pinch lead cutter module  104  connected to dam bar cutter module  103 ; and a receiving portion also formed as a module for receiving a product  105  connected to the pinch lead cutter module  104 . All modules are integrally connected in series with each other. 
     The feeding portion  100 , the modules  101  to  104  and the receiving portion  105  are detachable from the apparatus. 
     Pitches P between any two of feeding portion  100 , modules  101  to  104  and receiving portion  105  which are integrally connected in series are all equal to one another. Thus, modules  101  to  104  form the processing apparatus which includes only processing means which are necessary for performing the desired steps by selecting only necessary modules and suitably connecting or disconnecting the same depending on a thickness, shape or the like of a lead frame body  4 . 
     As modules  101  to  104  can be suitably combined depending on the actual requirements of the operation for processing the lead of the resin sealed lead frame, the apparatus is advantageously adjustable to any specific operation. In addition, any processing means for unnecessary steps can be removed from the apparatus, so that a reduction in the overall equipment cost can be achieved. 
     It is noted that the cutting process for the resin sealed lead frame A is very difficult when pitches P for the products on the resin sealed lead frame A and hence pitches P for modules  101  to  104  are narrow. Then, as indicated by a reference character  2 P in FIG. 1, the above described pitch P may be, for example, doubled to have two pitches. In this case, the resin sealed lead frame A may be sequentially fed or stepped by two pitches and the cutting process for the resin sealed lead frame A may be performed by each module corresponding to the sequentially advanced position. 
     Provided in the above described feeding portion  100  for resin sealed lead frame A is a portion of a magazine holding a plurality of resin sealed lead frames A. The magazine holding the resin sealed lead frames A is transported to a prescribed position in the cavity cutter module  101  connected to the feeding portion  100  by a suitable transporting mechanism such as an engageable chuck not shown. 
     Referring to FIG. 2A, cavity cutter module  101  includes: an upper mold base  102 ; a punch holder  107  fixed to the upper mold base  106 ; a punch blade  108  fixed to the punch holder  107 ; a stripper blade  109  suspended from the punch blade  108 ; a cavity cutter punch  110  for cutting at least one cavity  8  of the resin sealed lead frame; a punch guide  111  for mounting a tip blade of the punch  110 ; and a die  112  positioned on the side of the lower mold corresponding to punch  110 . A cavity  8  permits the flow of resin where needed. 
     Cavity cutter punches  110  are arranged corresponding to the number and positions of cavities  8  in each product on the resin sealed lead frame A. For example, two cavities  8  are formed in one product on the resin sealed lead frame A shown in FIGS. 12A to  12 C, so that a total of two cavity punches  110  are provided. 
     Thus, cavities  8  for the resin sealed lead frame A which have been transported to a prescribed position in the cavity cutter module  101  by the above described transporting mechanism, are simultaneously cut or punched by the cutter punch  110  and the die  112  at the time of clamping the upper and lower molds together. 
     The resin sealed lead frame A which has been subjected to the cavity cutting step is transported to a prescribed position in a resin cutter module  102  connected to the cavity cutter module  101  by the above mentioned transporting mechanism. 
     Referring to FIG. 2B, the resin cutter module  102  is provided with substantially the same structure as that of cavity cutter module  101  except for the resin cutter punch  113  and the die  114  for cutting the resin at the dam bar  7  of the resin sealed lead frame A. Therefore, the elements which are substantially the same as those of the cavity cutter module  101  are denoted by the same reference numerals in FIG.  2 B. 
     The resin at the dams in the resin sealed lead frame A which has been transported to a prescribed position in the resin cutter module  102  by the above mentioned transporting mechanism is simultaneously cut by the resin cutter punch  113  and the die  114  at the time of clamping of the upper and lower molds together. 
     After the resin cutting step the resin sealed lead frame A is transported to a prescribed position in dam bar cutter module  103  connected to the resin cutter module  102  by the transporting mechanism. 
     Referring to FIG. 2C, the dam bar cutting module  103  has a structure which is substantially the same as that of each of the above described modules except for a dam bar cutter punch  115  and a die  116  for cutting the dam bar  7 . Therefore, the elements which are substantially the same as those of the above described modules are denoted in FIG. 2C by the same reference numerals. 
     The dam bars  7  of the resin sealed lead frame A which has been transported to a prescribed position in dam bar cutter module  103  by the transporting mechanism, are simultaneously cut by dam bar cutter punch  115  and the die  116  at the time of clamping of the upper and lower molds together. 
     After the dam bar cutting step the resin sealed lead frame A is transported to a prescribed position in the pinch lead cutter module  104  connected to the dam bar cutter module  103  by the above mentioned transporting mechanism. 
     Referring to FIG. 2D, the pinch lead cutter module  104  has a structure which is substantially the same as that of each of the above described modules except for a pinch lead cutter punch  117  and a die  118  for cutting the pinch lead  5  in the resin sealed lead frame A. Therefore, the elements which are substantially the same as those of the above described modules are denoted in FIG. 2D by the same reference numerals. 
     The pinch leads  5  of the resin sealed lead frame A which has been transported to a prescribed position in the pinch lead cutter module  104  by the above mentioned transporting mechanism, are simultaneously cut by the pinch lead cutter punch  117  and the die  118  at the time of clamping of the upper and lower molds together. 
     Each product which has been cut and separated from the resin sealed lead frame A by the above described pinch lead cutting step is transported to a receiving portion also referred to as receiving module for each product  105  connected to pinch lead cutting module  104 . 
     In operation the resin sealed lead frame A is sequentially fed or stepped by the transporting mechanism to a prescribed position between the upper and lower molds in each of the modules  101  to  104  from the feeding portion  100  for sequentially performing the cutting steps by the punches  110 ,  113 ,  115 ,  117  and the dies  112 ,  114 ,  116 ,  118 . As described above, the separated product is transported toward the receiving portion  105  by the transporting mechanism. 
     It is noted that as the pitches P for the feeding portion  100 , for the modules  101  to  104  and for the receiving portion  105  which are integrally connected in series are all equal to one another, a process similar to that described above can be performed for a resin sealed lead frame having such an equal pitch P. 
     When any of the steps performed by the modules  101  to  104  is not necessary depending on the state of the actual operation for processing the leads of the resin sealed lead frame, and depending on the other operation conditions or the like, the module related to the unnecessary step may be removed. Conversely, if any additional processing step is required, a module related to the additional step may be added to the apparatus. 
     Now, a second embodiment of the present invention will be described with reference to FIGS. 3 and 4. 
     In the above described first embodiment, one product on the resin sealed lead frame A is sequentially processed by each of the modules  101  to  104 . In the second embodiment, a plurality of products on the resin sealed lead frame are simultaneously processed by each of the modules. For example, in FIG. 3, the resin sealed lead frame A carries four products. FIG. 3 also shows an exemplary structure of a cavity cutter module  201  for simultaneously cutting cavities for four products. 
     More specifically, the structure of the cavity cutter module  201  is substantially the same as that of the cavity cutter module  101  according to the first embodiment, except that the cavity cutter punch  210  and the die  212  are provided for cutting the flow cavities of four products. In the present embodiment, an upper mold base  206 , a punch holder  207 , a punch blade  208 , a stripper blade  209  and a punch guide  211  are also provided. 
     As in the cavity cutter module  201 , a punch and a die for processing the above described four products is provided in each of the other modules. 
     The pitch P between the cavity cutter punch  210  and the die  212  arranged in cavity cutter module  201  and the pitch P for the products on the resin sealed lead frame A are all equal. In the second embodiment shown in FIGS. 3 and 4, as in the case of the first embodiment shown in FIGS. 1 and 2, the modules are detachable and can be suitably connected or disconnected as necessary as shown in FIG. 4, so that a processing apparatus provided with processing means related to desired steps, is obtained. 
     As in the above described first embodiment, the second embodiment shown in FIGS. 3 and 4 also includes a feeding portion  200  for the resin sealed lead frames A, the cavity cutter module  201 , the resin cutter module  202 , the dam bar cutter module  203 , the pinch lead cutter module  204  and the receiving portion  205  for each product. 
     In operation of the second embodiment, the resin sealed lead frames A are transported from the feeding portion  101  to the cavity cutter module  201  by a suitable transporting mechanism, for simultaneously cutting flow cavities for four products. 
     As in the cavity cutting step, the resin sealed lead frames A are sequentially transported to a prescribed position between the upper and lower molds in each of the modules  202  to  204  connected to the cavity cutter module  201  for simultaneously performing the respective cutting step by the punch and die for the above mentioned four products. 
     As described above, each of the separated products needs only to be transported to the receiving portion  205  by the transporting mechanism. 
     It is noted that the pitch P between the punch and the die in each of modules  201  to  204  and the pitch P of the products on the resin sealed lead frame A are equal to each other, whereby the step of transporting the resin sealed lead frame A to each of the modules  201  to  204  can be accurately and surely performed by the transporting mechanism. 
     In the above described embodiments, only the step of cutting and separating each product from the resin sealed lead frame is described as the step required for processing the leads. However, a so-called forming step for bending and forming an outer lead of each product in a prescribed shape may be included as a step required for processing each lead. 
     Thus, as in the case of each of the modules  101  to  104  and  201  to  204 , the processing means related to the step required for lead forming is provided as a separate module and which is detachably connected to the pinch lead cutter module  104 ,  204  or the like. The separate module performs the final step. The product which has been cut and separated is transported to a forming module by a suitable transporting mechanism. In this case, not only the step of cutting and separating each product from the resin sealed lead frame is performed, but also lead forming of each product can be automatically performed sequentially after the last cutting step, so that a practical advantage is obtained. 
     A third embodiment of the present invention will now be described in detail with reference to FIGS. 5A to  8 B. 
     Referring to FIG. 5A and 6A, a processing apparatus according to the present embodiment includes as a basic structure thereof: a feeding portion  30  for a resin sealed lead frame before lead processing; one lead processing basic unit  31  connected to the feeding portion  30  as a lead processing portion for the resin sealed lead frame; and a removing portion  32  for removing the resin sealed lead frame connected to the lead processing basic unit  31  after completion of the lead processing. 
     It is noted that the feeding portion  30  in the above described basic structure sequentially feeds resin sealed lead frame  33  along a feeding path by one pitch by a suitably provided feeding mechanism, not shown. 
     The lead processing basic unit  31  is provided with a mold including a required punch and a die for cutting spaced by a distance of one pitch equal to an on-center pitch between the neighboring products on the resin sealed lead frame  33 . 
     In the illustrated exemplary structure, provided along the feeding path of the lead frame are: a punch and die for a resin cutter A 1  for cutting the resin at the dam bar  131  of the resin sealed lead frame  33  as shown in FIG. 6B; a punch and die for a dam bar cutter B 1  for cutting the dam bar  131 ; and a punch and die for a lead cutter C 1  for cutting a connecting tip portion of an outer lead  132 . 
     Referring to FIG. 6B, the resin sealed lead frame according to the present invention includes: a cradle  133 ; a pinch lead  134  connecting the cradle  133  and a die pad for mounting an electronic part; and a resin sealed molding  135  of the electronic part. The resin sealed lead frame has substantially the same shape and structure as those of the resin sealed lead frame shown in FIGS. 13A and 13B. 
     Further, resin sealed lead frame  33  which has been subjected to the resin cutting, dam bar cutting and the lead cutting processes at the lead processing basic unit  31  can be removed by one pitch by a suitable removing mechanism, not shown. 
     It is noted that the product on the removed resin sealed lead frame  33  is generally cut and separated by the next step and, subsequently, a lead bending process for the outer lead  132  is performed. As will later be described, the cutting and separating step for each product may be performed by a product cutting and separating portion on the resin sealed lead frame at the removing portion  32  or between lead processing basic unit  31  and the removing portion  32 . 
     Further, a structure for automatically aligning the separated works and transporting them to the next step may be employed. 
     Now, referring to FIG. 5B, another lead processing basic unit  310  has been added to the basic unit  31 . Both units function in the same way. The respective processing apparatus shown in FIG. 5A will now be described. 
     The combined structure of the lead processing portion with the lead processing basic unit  310  added includes: a feeding portion  30  for the resin sealed lead frame positioned upstream of the lead processing which is the same as the above for the basic structure; a lead processing basic unit  31  for the resin sealed lead frame; and a removing portion  32  for the resin sealed lead frame downstream of the unit  310 . The additional lead processing basic unit  310  functions in the same way as that of lead processing basic unit  31 . The unit  310  is detachably added between the lead processing basic unit  31  and the removing portion  32 . Detaching means are not shown. 
     Similarly, the additional lead processing basic unit  310  comprises: a punch and die A 2  for resin cutting which is of the same type as that for the lead processing basic unit  31 ; a punch and die for the dam bar cutter  32 ; and a punch and die for the lead cutter C 2 . 
     It is noted that in the above described structure, at least the lead processing basic unit  31 , the additional lead processing basic unit  310  to be added and the product removing portion  32  need to be detachably connected by suitable simple detaching means. However, each portion, namely the feeding portion  30 , the lead processing basic units  31 ,  310  and the removing portion  32 , is formed as a module, so that a structure with detachably connected modules is obtained. 
     The steps and functions in the above described basic structure of the processing apparatus will now be described with reference to FIGS. 7A and 7B. 
     The basic structure is constructed similarly to that of the conventional lead processing apparatus, so that the resin sealed lead frame may be sequentially fed by one pitch along the feeding path and pressed by molds for cutting which are spaced by one pitch. More specifically, as shown in FIG.  7 B( a ), the resin sealed lead frame  33  is fed to a lead processing basic unit  31  by one pitch, whereby a first product portion  33   a  is advanced by a feeding mechanism for a resin cutting step A 1  at the dam bar  131  by a punch and die that performs the resin cutting step A 1 . 
     Then, as shown in FIG.  7 B( b ), the resin sealed lead frame  33  is further stepped by one pitch of portion  33   a  for performing a dam bar cutting step B 1  by a respective punch and die. At the time when the first portion  33   a  is subjected to the resin cutting step A 1  and to the dam bar cutting step B 1 , the following second pitch portion  33   b  is subjected to a similar resin cutting step A 1  as seen in FIG.  7 B( b ). 
     As shown in FIG.  7 B( c ), the resin sealed lead frame  33 , after the resin cutting step A 1  and the dam bar cutting step B 1  are completed, is further stepped by one pitch for performing a lead cutting step C 1  for cutting a tip connecting portion of the outer lead  132  by a punch and die for the lead cutting C 1 . At the time when the first portion  33   a  is subjected to the resin cutting step A 1 , the dam bar cutting step B 1  and the lead cutting step C 1 , the following second portion  33   b  is subjected to a resin cutting step A 1  and to a dam bar cutting step B 1  while the following third portion  33   c  is subjected to a resin cutting step A 1 . 
     Then, as shown in FIG.  7 B( d ), the resin sealed lead frame  33 , after completion of the resin cutting step A 1 , the dam bar cutting step B 1  and the lead cutting step C 1 , is further stepped by one pitch, so that it is removed from the removing portion  32 . At that time, the second pitch portion  33   b  is subjected to the resin cutting step A 1 , the dam bar cutting step B 1  and lead cutting step C 1  as described above. The following third portion  33   c  is subjected to the resin cutting step A 1  and to the dam bar cutting step B 1  while the following fourth portion  33   d  is subjected to the resin cutting step A 1 . 
     It is noted that the cutting and separating step D 1  for each product can be successively performed by providing a work cutting and separating portion D 1  on the above described resin sealed lead frame at the removing portion  32 , or between the lead processing basic unit  31  and the removing portion  32  as indicated by a dotted line in FIG.  7 A. In this case, only the cradle  133  which has been subjected to the above described steps needs to be removed. 
     Further, the products, see the first portion  33   a  shown in FIG.  7 B( d ) after completion of product cutting and separating step D 1  may be automatically aligned and transported to the next step. 
     Now, the steps and functions for the structure to which another lead processing portion having a function substantially the same as that of the lead processing portion is added will be described with reference to FIGS. 8A and 8B. 
     It is noted that the steps and functions of the combined structure are different compared to those steps of the above described basic structure in that the lead processing basic unit  31  and the removing portion  32  are detachably connected and another lead processing added unit  310  is provided with a function which is the same as that of the lead processing basic unit  31 . The added unit  310  is detachably positioned between the lead processing basic unit  31  and the removing portion  32 . Therefore, a lead processing apparatus having only one or at least two lead processing units can be selected and employed as required. 
     If the lead processing apparatus having two lead processing units  31  and  310  is selected and employed, the resin sealed lead frame  33  is sequentially fed by two pitches to double the production volume. 
     When such a structure is employed, as compared with the case where two lead processing apparatuses of the same kind having full functions are provided, an overall reduction in equipment costs and space requirements for the lead processing apparatus are achieved. 
     As shown in FIG.  8 B( a ), the resin sealed lead frame  33  is first fed by two pitch portions  33   d  and  33   b  by the feeding mechanism of the feeding portion  30  of the lead processing basic unit  31 . The first pitch portion  33   a  is subjected to a dam bar cutting step B 1  for cutting the dam bar  131  and the second pitch portion  33   b  is subjected to a resin cutting step A 1  for the dam bar  131  by a punch and die for the resin cutting A 1  and a punch and die for the dam bar cutting B 1  of the lead processing basic unit  31 . 
     As shown in FIG.  8 B( b ), first and second product portions  33   a  and  33   b  after the above described steps are further fed by two pitches. The first product portion  13   a  is subjected to a resin cutting step A 2  by a punch and die for the resin cutting step A 2  of another lead processing basic unit  310 , and the second product portion  33   b  is subjected to the lead cutting step C 1  by a punch and die for the lead cutting C 1  in lead processing basic unit  31 . At that time, the first portion  33   a  is subjected to a dam bar cutting step B 1  and a resin cutting step A 2 , and the second portion  33   b  is subjected to a resin cutting step A 1  and a lead cutting step C 1 . Further, the following third product portion  33   c  is subjected to dam bar cutting step B 1 , and still following fourth portion  13   d  is subjected to a resin cutting step A 1 . 
     Then, as shown in FIG.  8 B( c ), the first and second product portions  33   a  and  33   b , following the above described steps, are further stepped by two pitches. The first portion  13   a  is subjected to a lead cuttings step C 2  by a punch and die for the lead cutting C 2  in the lead processing basic unit  310 , and the second portion  38   b  is subjected to a dam bar cutting step B 2  by a punch and die for the dam bar cutting B 2  of the lead processing basic unit  310 . 
     At that time, the first portion  33   a  is subjected to a dam bar cutting step B 1 , a resin cutting step A 2  and the lead cutting step C 2 , while the second portion  33   b  is subjected to a resin cutting step A 1 , a lead cutting step C 1  and a dam bar cutting step B 2 . The following third portion  33   c  is subjected to a dam bar cutting step B 1  and a resin cutting step A 2 , while a fourth portion  33   d  is subjected to a resin cutting step A 1  and to a lead cutting step C 1 . The still following fifth portion  33   e  is subjected to a dam bar cutting step B 1  and a sixth portion  33   f  is subjected to a resin cutting step A 1 . 
     As shown in FIG.  8 B( c ), the first portion  33   a , after the dam bar cutting step B 1 , the resin cutting step A 2  and the lead cutting step C 2 , and the second portion  33   b , after the resin cutting step A 1 , the lead cutting step C 1  and the dam bar cutting step B 2 , are further fed by two pitches and then removed from the removing portion  32 . Therefore, at that time, the third portion  33   c  is subjected to the dam bar cutting step B 1 , the resin cutting step A 2  and the lead cutting step C 2  as shown in FIG.  8 B( d ). The fourth portion  33   d  is subjected to the resin cutting step A 1 , the lead cutting step C 1  and the dam bar cutting step B 2 . The fifth portion  33   e  is subjected to the dam bar cutting step B 1  and to the resin cutting step A 2 . A sixth portion  33   f  is subjected to the resin cutting step A 1  and the lead cutting step C 1 . Further, the following seventh portion  33   g  is subjected to the dam bar cutting step B 1 . The eighth portion  33   h  is subjected to the resin cutting step A 1 . 
     It is noted that two work cutting and separating machine sections D 1 , D 2  corresponding to two pitches of transportation, are provided at the removing portion  32 , or between the lead processing basic unit  310  and the removing portion  32  as indicated by a dotted line in FIG. 8A, so that the cutting and separating steps D 1 , D 2  can be performed sequentially after the above described steps have been completed. In this case, only the cradle  133  which has been subjected to the above described steps, needs to be removed. 
     The products, see first and second portions  13   a  and  13   b  shown in FIG.  8 B( d ) after the lead cutting and the separating steps D 1 , D 2  may be automatically aligned and transported to the next step. 
     As described above, in the structure in which the additional lead processing basic unit  310  performing the same function as the lead processing basic unit  31  is added to the basic structure of the aforementioned processing apparatus, the added unit is inserted between the lead processing basic unit  31  and the removing portion  32 . All units or at least the basic unit is detachably connected. Therefore, the lead processing apparatus may be structured to have only one lead processing basic unit as shown in FIG. 5A, or two lead processing basic units  31 ,  110  as shown in FIG.  5 B. 
     In addition, at least the lead processing basic unit  31  and additional lead processing basic unit  310  or removing portion  32  is detachably connected in a module, whereby the number of the lead processing portions can suitably be changed as necessary. 
     When the lead processing apparatus provided with two lead processing basic units  31  and  310  is used, the production volume is doubled. Moreover, in the enlarged structure, the feeding portion  30  and the removing portion  32  may be the same as in the apparatus with only one basic unit. Therefore, as compared with the case where two lead processing apparatuses of the same kind having full functions are provided, overall reduction in equipment cost and space for the lead processing apparatus can be advantageously achieved. 
     The present invention is not limited to the above described embodiments, and various modifications can be made without departing from the scope of the invention. 
     For example, lead processing may be performed for resin sealed lead frames having different pitches as shown in FIG. 9A, because of the shape, width W or the like of the above mentioned lead processing portion. 
     In this case, however, the following adjustment of the pitches enables the above described lead processing. 
     More specifically, a required space S (corresponding to two pitches) is provided between the two lead processing basic units  31  and  310  as well as between the lead processing basic unit  310  and the removing portion  32 . 
     In the space S, a lead processing step is not performed. Thus, to perform processing by another lead processing basic unit  310  after processing by the lead processing basic unit  31 , the resin sealed lead frame may be fed by four pitches, see the first portion  33   a  shown in FIGS.  9 B( b ) and ( d ). Further, for feeding from the additional lead processing basic unit  310  to the removing portion  32  or from the additional lead processing basic unit  310  to the work cutting and separating portions (D 1 , D 2 ), the resin sealed lead frame may be similarly advanced by four pitches. 
     Despite the above mentioned functional difference, the structure shown in FIG. 9A is similar to the structures of the first and second embodiments in the feeding step for sequentially feeding the resin sealed frame by two pitches, in the lead processing step for performing a prescribed lead processing for the portions spaced by two pitches, and in the removing step. Therefore, the structure shown in FIG. 9A, can provide substantially the same effect as that of the above described embodiments. 
     In the embodiment shown in FIG. 9A, the feeding step for sequentially feeding the resin sealed lead frame by two pitches, the lead processing step for performing a prescribed lead processing for portions spaced by two pitches and the removing step are performed. The number of pitches by which the resin sealed lead frame is fed is at least two. 
     Now, referring to FIGS. 10A and 10B, the resin sealed lead frame will be described as being sequentially fed by three pitches. 
     FIG. 10A shows a structure in which three lead processing basic units  31 ,  310  and  311  are positioned along a feeding path of the resin sealed lead frame, a space S corresponding to a required pitch is provided between the lead processing basic unit  311  and the removing portion  321 . The removing portion  321  includes three work cutting and separating stations D 1 , D 2 , D 3 . 
     As shown in FIGS.  10 B( a ) to ( f ), despite the functional difference in the feeding step for sequentially feeding the resin sealed lead frame by three pitches, the lead processing step for performing a prescribed lead processing for portions spaced by three pitches, the work cutting and separating step and the removing step for removing the resin sealed lead frame, substantially the same function and effect can be obtained by sequentially feeding the resin sealed lead frame by a plurality of pitches for performing a prescribed lead processing for the portions spaced by the plurality of pitches. 
     In each of the embodiments shown in FIGS. 9A and 10A, a mechanism for inspecting the state of lead processing or the like can suitably be arranged at the portions spaced by at least two pitches, while making use of the space S. 
     Although the present invention has been described and illustrated in detail, it is to be understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.