Preparation method of PTC heating film

The invention relates to the technical field of heating film materials, in particular to a preparation method of a PTC (Positive Temperature Coefficient) heating film, which comprises the following steps of: printing conductive silver paste on a PI (Polyimide) film, measuring the thickness of the conductive silver paste, and putting the PI film printed with the conductive silver paste into a baking area to be baked to form a silver paste layer; printing a layer of carbon paste on the silver paste layer, measuring the thickness of the carbon paste, and baking the PI film printed with the carbon paste in a baking area to form a carbon paste layer; putting the processed PI film into a film laminating machine, and cutting the heating film coated with the cover film into single heating films through a cutting table; removing a cover film at a bonding wire position of the cut single heating film by using laser, punching a rivet at the bonding wire position, hammering the rivet, and welding a lead after hammering th