When you purchase induction equipment, the perishable tooling (i.e., induction coils) will become a point of reoccurring cost over the life of the program. The loss of production that occurs when an induction coil fails and the equipment is idled, is more costly. It is important to note that some coils have a short usable life while others will last for months or years. Some of the notable factors include the coil type, equipment process parameters, the quality of the coil design, and specific coil features employed. All these influence coil life, some profoundly. Due to the number of factors that influence coil life, no induction equipment supplier can closely approximate the expected coil life. A proper understanding of these factors will enable the program manager to execute proper planning for the annual cost of induction coil tooling, number of coils on hand, coil changeover schedule, and possible downtime of induction equipment. It is important that your induction coil supplier has the expertise to provide you with good coil designs and is committed to continuous improvement by resolving early failure modes to maximize coil life.

This presentation reviews selected innovations related to induction hardening of various automotive powertrain transmission and engine components, including but not limited to induction surface hardening of complex geometry shafts. Thanks to several innovative designs (patented and patent pending), important goals were achieved. Process flexibility in shaft scan hardening has been substantially enhanced thanks to a novel inverter design that allows controlling independently frequency and power during scanning. This innovation allows improving quality of induction hardened components maximizing production rate and process flexibility. When applying single-shot hardening for heat treatment of output shafts, flanged shafts, yoke shafts, sun shafts, intermediate shafts, drive shafts and others, coil life is often limited due to a necessity to “squeeze” coil current in a certain area, maximizing power density. This seemingly unavoidable feature of the great majority of single-shot inductors represents a “weak link”, limiting coil life expectancy. Thanks to innovative design (patent-pending) of a single-shot inductor, its life was increased approximately nine times. Process sensitivity has been dramatically reduced. Other benefits include measurable improvement in process robustness, coil reliability and maintainability.