| 摘要 |
PURPOSE:To prevent the yield of thin burr, by forming at least two protruded parts in parallel, in an apparatus, in which the protruded parts are provided on the parting surface of a mold in parallel with the longitudinal direction of a tie bar part. CONSTITUTION:When the amount of plastic deformation of a lead frame h2 is small with respect to a protruded part 4a (preset value is h1), which is provided on the parting surface of a mold, thick burr 8 is yielded on the lead frame on the side of the mold inner than the protruded part 4a. The thick burr 8 is connected to a mold part 7. Therefore, the thick burr remains to the final process, and defects are caused in the products. In order to eliminate the thin burr, a protruded part 9 is further provided on the side of the mold inner than the protruded part 4. Thus, the thick burr 8 is cut from the mold part 7 and removed until the final process. The width of the protruded part 4 for removing the thin burr is made to be m1 (m1 is about 1/2 the width of a tie bar 3) with respect to a line l1 on the inner side of the tie bar 3 of the lead frame 1. The protruded part 9 for removing the thick burr 8 is provided on the side of the mold inner than the protruded part 4. The width of the protruded part 9 is made to be m1, too. |
