Balance trainer, mold assembly for making the same, and manufacturing process thereof

A mold assembly for manufacturing a balance trainer comprising:

• a dome mold forming:
• a domed cavity therein;
• a girdle sleeved and fixed on the dome mold and encompassing the domed cavity;
• a surface of the domed cavity and an inner surface of the girdle forming a continuous curved surface together;
• and
• a cover fixed on the girdle and enclosing the continuous curved surface;
• the girdle located between the dome mold and the cover.

A manufacturing process of a balance trainer, which comprises a dome and a base, including the following steps in sequence:

• preparing ingredients for making a dome and ingredients for making a base respectively;
• feeding the ingredients for making the dome into a dome cavity of a dome mold of a mold assembly;
• fixing a membrane on the dome mold and thereby the ingredients of making the dome enclosed by the membrane and the dome mold;
• and then mounting the girdle on the membrane, a diameter of the membrane being larger than an outer diameter of a girdle of the mold assembly;
• feeding the ingredients for making a base on the membrane and in the girdle;
• covering and sealing the girdle and dome mold via a cover of the mold assembly, and thereby the ingredients for making a base enclosed by the membrane, the girdle, and the cover;
• rotational molding, which includes the following acts in sequence:
• putting the mold assembly into a rotary furnace;
• and
• rolling and heating the mold assembly;
• and
• finishing, which including the following acts in sequence:
• taking out the mold assembly from the rotary furnace;
• cooling the mold assembly;
• and
• taking out the dome and the base from the mold assembly.