Method of making a window panel with a synthetic resin frame

A method of making a window panel having a synthetic resin frame, comprising:

• forming a synthetic resin frame for said window panel by extruding synthetic resin through a die, which is a component of an apparatus, into a specific shape along the peripheral portion of a plate-like material for a window on at least one surface of the plate-like material, said die being moved under control by information previously input into said apparatus in order to trace a locus along the periphery of the plate-like material, with the locus and the angular position of the die being corrected by absorbing the error in the distance between a guide attached to said die and in contact with the periphery of said plate-like material, both said guide and said die being components of said apparatus, and the plate-like material by the swinging or the expansion/contraction movement of a cushion means which is a component of the means of said apparatus which holds the plate-like material;
• and
• curing the synthetic resin frame which is formed so that the synthetic resin frame is formed integrally with the peripheral portion of the plate-like material.