Method of and apparatus for producing a product with a coating layer

A compression molding apparatus for producing a product with a coating layer applied over a surface of the product in a mold, said apparatus comprising:

• compression molding means, comprising two mold dies, for forming a mold cavity therebetween, said two mold dies being displaceable relative to each other so as to change a mold cavity pressure;
• injection means for injecting a fluidized thermosetting plastic material of the curing layer in said mold cavity,
• pressure sensing means embedded in either of the two mold dies for detecting a peak of a drop in pressure in the product and providing a signal representative of said peak of said drop;
• displacement sensing means disposed between said two mold dies for detecting a peak of a relative displacement between said two mold dies caused by injecting said fluidized thermosetting plastic material in said mold cavity and providing a signal representative of said peak of said relative displacement;
• and
• control means for changing said mold cavity pressure, lower than said molding pressure, once a predetermined time period has lapsed, said predetermined time period being determined so as to expire a certain time after said signal representative of said peak of said drop in pressure has lapsed, said fluidized thermosetting plastic material being injected, at said coating pressure, by said injection means so as to form the coating layer, said control means then changing said mold cavity pressure to a curing pressure, no higher than said molding pressure, at which the coating layer is cured after receiving said signal representative of said peak of said relative displacement, and from said curing pressure to a finishing pressure, between said coating pressure and said curing pressure, at which the coating layer is thermoset.