Fan and manufacturing method thereof

A fan, comprising:

• a motor base having a bearing stand in a center portion thereof;
• a bearing accommodated within said bearing stand;
• an impeller comprising:
• a metallic case having a top surface and a sidewall extended axially from an outer periphery of said top surface;
• plural blades disposed around an outer periphery of said metallic case;
• and
• a rotating shaft protruded from a center portion of said top surface and penetrated through said bearing stand, wherein no raised ring structure is formed in said top surface of said metallic case, and said rotating shaft and said metallic case are jointed together by a laser welding process;
• a stator disposed around an outer periphery of said bearing stand;
• and
• a magnetic element disposed on an inner wall of said metallic case and aligned with said stator.

A method for manufacturing a fan, said method comprising steps of:

• providing a metallic case having a top surface and a sidewall extended downwardly from an outer periphery of said top surface;
• combining a rotating shaft with said metallic case by a laser welding process, so that said rotating shaft is protruded from a center portion of said top surface of said metallic case;
• placing a combination of said rotating shaft and said metallic case within a mold, and producing a hub and plural blades by a plastic injection molding process, wherein said hub is sheathed around said metallic case, and said blades are disposed around an outer periphery of said hub;
• providing a motor base having a bearing stand in a center portion thereof, and accommodating a bearing within said bearing stand, and disposing a stator around an outer periphery of said bearing stand;
• and
• disposing a magnetic element on an inner wall of said metallic case, and penetrating said rotating shaft through said bearing such that said magnetic element is aligned with said stator.