Abstract: A press forming die is fabricated by initially fabricating a die forming panel, by press forming, which provides a die surface for the press forming die. During fabricating the die forming panel, a shaped panel is obtained by initially press forming a first blank material with a die forming prototype and a punch forming prototype. Next, the shaped panel is mounted onto the punch forming prototype again and, thereafter, a die forming panel is obtained by press forming a second blank material. The die forming panel is then mounted on a frame body and a backup material is formed between a space between the frame body and the die forming panel, thereby fabricating the press forming die. Since the die surface of the press forming die can be shaped by press forming, the press forming die can be simply fabricated.

Abstract: An economical method of producing a press-forming die is disclosed wherein a master die and a master punch are relatively reciprocated with a full stroke and a shorter stroke to produce a press-formed panel and a half-pressed panel. After an elastic material is applied to one surface of the half-pressed panel, the press-formed panel is fitted over the master punch, and the half-pressed panel is forced against the press-formed panel with the elastic material facing away from the press-formed panel, whereby the half-pressed panel is shaped into a die panel complementary in contour to the shape of the press-formed panel. A back-up material such as high-strength cement is then applied to the rear surface of the die panel whereby a press-forming die is produced.

Abstract: An economical method of producing a press-forming die is disclosed wherein a master die and a master punch are relatively reciprocated to produce a press-formed panel. A working surface of the master die is cut down by a predetermined cutting depth, and the press-formed panel is fitted over the master punch. While a second blank sheet having a thickness equal to the cutting depth of the master die working surface is placed between the master die and the press-formed panel fitted over the master punch, the master die and punch are relatively reciprocated whereby the second blank sheet is press-formed into a die panel. A back-up material such as high-strength cement is then applied to the rear surface of the die panel whereby a press-forming die is produced. A method of producing a press-forming punch is also disclosed.

Abstract: An economical method of producing a press-forming die is disclosed wherein a master die and a master punch are relatively reciprocated with a full stroke and a shorter stroke to produce a press-formed panel and a half-pressed panel. After an elastic material is applied to one surface of the half-pressed panel, the press-formed panel is fitted over the master punch, and the half-pressed panel is forced against the press-formed panel with the elastic material facing away from the press-formed panel, whereby the half-pressed panel is shaped into a die panel complementary in contour to the shape of the press-formed panel. A back-up material such as high-strength cement is then applied to the rear surface of the die panel whereby a press-forming die is produced.

Abstract: An economical method of producing a press-forming die is disclosed wherein a master die and a master punch are relatively reciprocated to produce a press-formed panel. A working surface of the master die is cut down by a predetermined cutting depth, and the press-formed panel is fitted over the master punch. While a second blank sheet having a thickness equal to the cutting depth of the master die working surface is placed between the master die and the press-formed panel fitted over the master punch, the master die and punch are relatively reciprocated whereby the second blank sheet is press-formed into a die panel. A back-up material such as high-strength cement is then applied to the rear surface of the die panel whereby a press-forming die is produced. A method of producing a press-forming punch is also disclosed.

Abstract: A press forming die is fabricated by initially fabricating a die forming panel, by press forming, which provides a die surface for the press forming die. During fabricating the die forming panel, a shaped panel is obtained by initially press forming a first blank material with a die forming prototype and a punch forming prototype. Next, the shaped panel is mounted onto the punch forming prototype again and, thereafter, a die forming panel is obtained by press forming a second blank material. The die forming panel is then mounted on a frame body and a backup material is formed between a space between the frame body and the die forming panel, thereby fabricating the press forming die. Since the die surface of the press forming die can be shaped by press forming, the press forming die can be simply fabricated.

Abstract: A fuel tank has a superior outer appearance. A body and a bottom are aligned to each other in a vertical direction to form a sealed closed space for storing fuel between both members. The body is formed as a container having an opening in a downward direction. A connected end part is bent inward in a continuous manner from a lower end of its outer surface. The opening is covered from below with the bottom and its circumferential edge is overlapped on the connected end while its position is set and connected at its entire circumference by brazing.

Abstract: A fuel tank has a superior outer appearance. A body and a bottom are aligned to each other in a vertical direction to form a sealed closed space for storing fuel between both members. The body is formed as a container having an opening in a downward direction. A connected end part is bent inward in a continuous manner from a lower end of its outer surface. The opening is covered from below with the bottom and its circumferential edge is overlapped on the connected end while its position is set and connected at its entire circumference by brazing.