| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a funnel part capable of inexpensively mass-producing funnel parts by using a material mainly made of paper.SOLUTION: A funnel part is formed via a step of forming a blank by stamping a sheet material by a die, a step of rolling the blank, partially overlapping and welding it, and forming a first intermediate of a tapered form, a step of folding back and welding a narrow side opening of the first intermediate throughout a whole circumference to form a second intermediate, a step of folding back a wide side opening of the second intermediate toward an outer side throughout a whole circumference to form a third intermediate having a sidewall part, and a step of carrying out drawing by pressing the third intermediate by a die, and forming a cylindrical discharge part composing the narrow side opening, a first tapered part of a tapered form connected to the discharge part, and a second tapered part of tapered form connected to the first taper part and having a taper angle smaller than the first tapered part. |
