the disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements . it should be noted that references to “ an ” or “ one ” embodiment in this disclosure are not necessarily to the same embodiment , and such references mean “ at least one .” fig1 through 3 show an assembler mechanism 100 , which is applied for fetching a first workpiece ( not shown ) and a second workpiece ( not shown ) and bonding the first workpiece to the second workpiece . the assembler mechanism 100 includes a support seat 10 , a plurality of first picking members 30 , two driving members 40 , four second picking members 50 , two positioning assemblies 80 , and a limiting assembly 90 . the first picking members 30 are mounted on the support seat 10 , for picking the first workpieces . the two driving members 40 are mounted on opposite end portions of the support seat 10 . each of the two second picking members 50 is connected to and driven by one driving member 40 , and passes through the support seat 10 , for picking the second workpiece . the two positioning assemblies 80 are located on sides of the support seat 10 . the limiting assembly 90 is located on a middle portion of the support seat 10 . the positioning assemblies 80 are configured to position the second workpiece along a first direction . the limiting assembly 90 is configured to position the second workpiece along a second direction . the support seat 10 includes a support base 11 , a connection member 13 , and a plurality of guiding rails 15 . the support base 11 is a substantially rectangular plate , and includes a first support surface 113 and a second support surface 115 opposite to the first support surface 113 . the connection member 13 is securely mounted on the first support surface 113 . the second support surface 115 defines two first mounting slots 1151 adjacent to one side thereof ( shown in fig3 ). the two first mounting slots 1151 are substantially parallel to and spaced from each other . the second support surface 115 further defines a second mounting slot 1153 substantially perpendicular to the first mounting slots 1151 and a third mounting slot 1155 crosses with the second mounting slot 1153 in a middle portion thereof . one guiding rail 15 is mounted in each of the first mounting slots 1151 , in the second mounting slot 1153 , and in the third mounting slot 1155 . the first picking members 30 are mounted on the support base 11 spaced from each other and protruding from the second support surface 115 . the two driving members 40 are securely mounted on opposite end portions of the first support surface 113 . each driving member 40 includes a main body 41 and a driving portion 43 connected to the main body 41 . the main body 41 is securely mounted on the first support surface 113 . a middle portion of the driving portion 43 is connected to and driven by the main body 41 . the driving portion 43 includes two mounting end portions 431 opposite to each other . each second picking member 50 is mounted on one mounting end portion 431 of the two driving members 40 , and passes through the support seat 10 and protrudes out from the second support surface 115 . each second picking member 50 includes a connection portion 51 and a suction portion 53 connected to the connection portion 51 . the connection portion 51 passes through the support base 11 and is movable therein . one end portion of the connection portion 51 is connected to the mounting end portion 431 , and the other end portion of the connection portion 51 is connected to the suction portion 53 , such that the connection portion 51 and the suction portion 53 are movable relative to the support base 11 when driven by the corresponding driving member 40 . when the first picking member 30 is in an original state , a distance from a free end of the first picking member 30 to the support base 11 is greater than a distance from a free end of the suction portion 53 to the support base 11 , such that when the first picking members 30 fetches the first workpiece , the second picking members 50 may not intervene . in an illustrated embodiment , the connection portion 51 is hollow and substantially cylindrical , and connected to a vacuum generator ( not shown ), such that the second workpiece can be picked up and released by the suction portion 53 . in other embodiments , the second picking members 50 can be in other structures according to the second workpiece . the two positioning assemblies 80 are located on the second supporting surface 115 side by side . each of the positioning assemblies 80 includes a positioning member 70 , a movable member 81 , and a driving member 83 . the positioning members 70 are mounted on the second support surface 115 , each corresponding to the two first mounting slots 1151 . the movable member 81 is connected to the guiding rail 15 in the first mounting slot 1151 . the driving member 83 is mounted on the second support surface 115 , for driving a movable member 81 to slide along the guiding rail 15 in the first mounting slot 1151 toward or away from the positioning member 70 . the limiting assembly 90 includes two limiting members 91 , a pushing member 93 , a driving member 95 , and a plurality of locking members 97 . the two limiting members 91 are mounted on two guiding rails 15 in the second mounting slot 1153 , and aligned in one straight line . each limiting member 91 includes a main body 913 , a limiting end 915 , and a pushing end 917 . the main body 913 is securely mounted on the second support surface 115 , and defines a sliding through slot 9131 . the limiting end 915 bends through substantially ninety degrees from one end portion of the main body 913 . the pushing end 917 is formed on the other end portion of the main body 913 opposite to the limiting end 915 . the pushing end 917 defines a first sliding portion 9171 . the pushing member 93 is slidably mounted on one guiding rail 15 in the third mounting slot 1155 . the pushing member 93 defines a sliding through slot 931 . the pushing member 93 includes two second sliding portion 933 engaged with the first sliding portions 9171 of the two limiting members 91 . in the illustrated embodiment , the first sliding portion 9171 is an oblique sliding groove in the pushing end 917 and the second sliding portion 933 is a protrusion engaged with the oblique sliding groove . in other embodiments , the first sliding portion 9171 can also be arc - shaped groove . the driving member 95 is fixedly mounted on the second support surface 115 away from the positioning member 70 , and is connected to the pushing member 93 . when the driving member 95 drives the pushing member 93 , the two limiting members 91 move toward or away from each other . each locking member 97 passes through one of the sliding slots 9131 and the sliding through slots 931 , and is securely connected to the support base 11 . the assembler mechanism 100 further includes four blocking members 20 . each blocking member 20 is mounted on the second support surface 115 adjacent to one of the four second picking members 50 . in assembly , the first picking members 30 are mounted on the support base 11 according to the positions required for the welding of the second workpiece . the two driving members 40 are mounted on opposite end portions of the first support surface 113 . each two second picking members 50 are mounted on opposite mounting end portions 431 of one driving member 40 . the two positioning members 70 are mounted on the second support surface 115 . each movable member 81 is slidably mounted on the guiding rail 15 in the first mounting slot 1151 , and each driving member 83 is mounted on the second support surface 115 and connected to a movable member 81 . two limiting members 91 are slidably mounted on the guiding rail 15 in the second mounting slot 1153 , and the pushing ends 917 of the two limiting members 91 are adjacent to each other . the pushing member 93 is slidably mounted on the guiding rail 15 in the third mounting slot 1153 and crossed with the two limiting members 91 , such that the two second sliding portion 933 are engaged with the first sliding portions 9171 of the two limiting members 91 . one end portion of the connection member 13 away from the support base 11 is fixed to a robot arm ( not shown ). in use , first , the first picking member 30 picks up a first workpiece . the second picking members 50 are moved to and pick up a second workpiece , and then are stopped by the blocking member 20 . the two positioning members 70 resist against opposite sides of the second workpiece , the first workpiece contacts a surface of the second workpiece . the movable members 81 are moved toward the positioning members 70 , and the two limiting members 91 are moved toward each other , such that the second workpiece is positioned along two directions . then , the assembler mechanism 100 is moved to a laser station , for example , for the robot arm to weld the first workpiece to the second workpiece . the positioning assemblies 80 and the limiting assembly 90 can cooperatively position the first workpiece and the second workpiece , such that during motion of the assembler mechanism 100 , the first workpiece will not deviate from the second workpiece . thus , a welding quality and yield is improved . in other embodiments , the first mounting slots 1151 , the second mounting slot 1153 , and the third mounting slot 1155 can be omitted , and the guiding rails 15 can be directly mounted on the support base 11 . a number of the driving members 40 and the second picking members 50 can be changed as needed , and the position of the driving members 40 can be changed as needed . the positioning assemblies 80 can be omitted , and the second workpiece can be positioned by the limiting assembly 90 . the limiting assembly 90 can be omitted , and the second workpiece can be positioned by the positioning assemblies 80 . while the present disclosure has been described with reference to particular embodiments , the description is illustrative of the disclosure and is not to be construed as limiting the disclosure . therefore , various modifications can be made to the embodiments by those of ordinary skill in the art without departing from the true spirit and scope of the disclosure , as defined by the appended claims .