Patent ID: 9698573
Date: 2017-07-04
CPC Classifications: H01T

Claim:
1. A method of making an extruded insulator for a spark plug, comprising the steps in the order of: mixing together ceramic particles, a liquid medium, and a binder to form a ceramic paste; inserting the ceramic paste into an extrusion die; inserting an arbor into the ceramic paste in the extrusion die; extruding the ceramic paste around the arbor so as to form an extruded section; severing the extruded section from the rest of the ceramic paste in the extrusion die so as to form a severed extruded section, wherein the severed extruded section includes the arbor; and removing the arbor from the severed extruded section so as to form an extruded insulator blank having a stepped internal bore to form the extruded insulator for the spark plug.