A flame port structure for burning a gas includes a first continuous spiral strip, a second continuous spiral strip and a first outflow passage. The first continuous spiral strip has a first side edge, a second side edge and a first plurality of annular segments, and the second continuous spiral strip has a third side edge, a fourth side edge and a second plurality of annular segments, wherein each of the first plurality of annular segments and each of the second plurality of annular segments respectively have two first longitudinal opposite surfaces and two second longitudinal opposite surfaces. The first outflow passage has a first defining wall formed on each of the first respective longitudinal surfaces from the first side edge to the second side edge. The first outflow passage is structured so that the gas produces a specific combustion.

A method of manufacturing a separator includes subjecting a metal thin sheet material to be transported to stepwise forming working at an identical location by a plurality of press machines having different working shapes and arranged sequentially from an upstream side to a downstream side in a transport direction of the metal thin sheet material to form a flow passage groove. The thin sheet material is subjected to annealing treatment in at least one space of spaces between the press machines arranged adjacent to each other in the transport direction of the thin sheet material.

A method of manufacturing a separator includes subjecting a metal thin sheet material to be transported to stepwise forming working at an identical location by a plurality of press machines having different working shapes and arranged sequentially from an upstream side to a downstream side in a transport direction of the metal thin sheet material to form a flow passage groove. The thin sheet material is subjected to annealing treatment in at least one space of spaces between the press machines arranged adjacent to each other in the transport direction of the thin sheet material.

The present disclosure provides a method for manufacturing a middle frame for mobile terminal and a mobile terminal with a middle frame. The method may include: providing a metal plate; forming a number of elongated protrusions arranged in parallel on the plate, the elongated protrusions each extending along a length direction of the metal plate; forming a tubular blank by bending the metal plate such that each of the elongated protrusions extends around the tubular blank; and cutting the tubular blank into a number of annular pieces, wherein each of the annular pieces includes one of the elongated protrusions.

The present disclosure provides a method for manufacturing a middle frame for mobile terminal and a mobile terminal with a middle frame. The method may include: providing a metal plate; forming a number of elongated protrusions arranged in parallel on the plate, the elongated protrusions each extending along a length direction of the metal plate; forming a tubular blank by bending the metal plate such that each of the elongated protrusions extends around the tubular blank; and cutting the tubular blank into a number of annular pieces, wherein each of the annular pieces includes one of the elongated protrusions.

A method for forming a metal sheet includes forming a metal sheet to have curved portions that are alternately continuous in a corrugated pattern and angled sidewall portions between top parts of adjoining curved portions by use of a pair of forming dies that are moved close to or away from each other. The forming includes bending the metal sheet by pressing a position corresponding to a boundary part between the top part and the sidewall portion of the metal sheet by a convex curved surface of the forming die by moving the pair of forming dies close to each other and thereafter forming the sidewall portions by compression.

A method for forming a metal sheet includes forming a metal sheet to have curved portions that are alternately continuous in a corrugated pattern and angled sidewall portions between top parts of adjoining curved portions by use of a pair of forming dies that are moved close to or away from each other. The forming includes bending the metal sheet by pressing a position corresponding to a boundary part between the top part and the sidewall portion of the metal sheet by a convex curved surface of the forming die by moving the pair of forming dies close to each other and thereafter forming the sidewall portions by compression.

A manufacturing method of a body frame includes a pre-strain step of press molding a wavy shape portion in the body frame to apply pre-strain after any press molding to mold the body frame.

A manufacturing method of a body frame includes a pre-strain step of press molding a wavy shape portion in the body frame to apply pre-strain after any press molding to mold the body frame.

A method for manufacturing a press molded product includes forming a plurality of corner portions in a pressed portion of a pressed member, providing the pressed member between a first die and a second die, and press molding the pressed portion to decrease a height of the pressed portion. The press molding includes forming a pair of first bent portions in the pressed portion by means of the corner portions, the pair of first bent portions being bent to protrude toward the second die, forming a second bent portion in the pressed portion by means of the corner portions while holding the pair of first bent portions by a pair of holding portions, the second bent portion being bent to protrude toward the first die from a position between the pair of first bent portions, and pressing and deforming the second bent portion.