Molding tool construction and molding method

A molding tool construction, comprising:

• a steel substrate;
• a first insulating layer comprising zirconia and having an electrical resistivity of at least about 1012 ohm-centimeters and thermal conductivity of about 0.2 to about 2 watts/(meter-kelvin) wherein the first insulating layer is applied as a thermal-sprayed coating;
• a heating element applied as a thermal-sprayed coating;
• a second insulating layer comprising alumina and having an electrical resistivity of at least about 1012 ohm-centimeters and a thermal conductivity of at least about 20 watts/(meter-kelvin);
• wherein the second insulating layer is applied as a thermal-sprayed coating;
• first molding layer comprising tungsten and having a specific heat capacity of about 100 to about 2,500 joule/kelvin;
• and
• a second molding layer comprising nickel and having a Rockwell hardness of at least about 40;
• wherein the first insulating layer is interposed between the substrate and the heating element, the second insulating layer is interposed between the heating element and the first molding layer, and the first molding layer is interposed between the second insulating layer and the second molding layer.

A molding tool construction, comprising:

• a steel substrate;
• a first insulating layer comprising zirconia, having a thickness of about 0.2 to about 0.5 millimeters, having an electrical resistivity of at least about 1014 ohm-centimeters, and having a thermal conductivity of about 0.2 to about 1 watts/(meter-kelvin);
• wherein the first insulating layer is applied as a thermal-sprayed coating;
• a heating element comprising titanium, titania, titanium nitride, or a combination thereof;
• wherein the heating element is applied as a thermal-sprayed coating;
• a second insulating layer comprising alumina, having an electrical resistivity of at least about 1014 ohm-centimeters, and having a thermal conductivity of at least about 40 watts/(kelvin-meter);
• wherein the second insulating layer is applied as a thermal-sprayed coating;
• a first molding layer comprising tungsten and having a specific heat capacity of about 100 to about 2,500 joule/kelvin;
• wherein the first molding layer is applied as a thermal-sprayed coating;
• and
• a second molding layer comprising nickel and having a Rockwell hardness of at least about 50;
• wherein the second molding layer is applied by electroplating;
• wherein the first insulating layer is interposed between the substrate and the heating element, the second insulating layer is interposed between the heating element and the first molding layer, and the first molding layer is interposed between the second insulating layer and the second molding layer.