May 2023 Volume 5

ENERGY

How To Win Efficiency and Influence Your Forging Costs: A Case Study of Induction Heater Performance, Part One By Josh Carney

The method of heating forging stock via electromagnetic induction is both practical and efficient. A single induction heater consumes more energy than the combined total electrical load of all other machinery employed in the forging process. Modern utility billing practices obscure the energy cost of individual production machine units, and a quantified view is wanting. This article describes the method of measuring and calculating the actual energy cost of an individual production machine. The machine studied is an inline billet induction heating system. This article also investigates the electrical efficiency of a modern induction heating installation and the practices which support efficient operation. The plant electrical utility bill presents a significant variable cost to a forging company’s operating expenses. Induction heating (IH) equipment makes up a substantial portion of the plant's electrical load. In forging, we know some things in detail about manufacturing costs, and some things are unclear. For example, the price of material stock is clear, as are tooling fees and labor costs, but the actual price of the energy to produce a forging is often unknown. It would be to our advantage to have this information. Why? Production energy costs influence the final cost of a forged part, and having energy cost information helps determine final pricing. It also gives insight into which products are most profitable to produce and aids in decision-making when seeking to improve efficiency. The challenge in measuring the per-unit cost of production arises from utility billing practices.

Since the electric utility/provider (EP) places their meter at the service entrance and not the point of use, e.g., the forge press or induction heater, the EP bill cannot provide any insight into the individual power consumption of the forging line equipment. It is merely an aggregate measurement of all the equipment in use. An example of this is in Figure 1, with a central point termed the ‘service entrance’ and equipment supplied by branch circuits. The solution to this problem is using an energy survey to determine the price-per unit value of the energy costs of a machine. This article will examine the methods and outcome of an energy surveymeasuring the amount of electricity an induction billet heater uses during a production shift. First is the example calculation of billet heating cost per unit using actual energy consumption data. Second is the measurement of energy efficiency. Part two of this article explores the winning production activities that positively affect energy efficiency. Part two also examines several facets of operational efficiency and its influence on the final cost of a forging. Survey Test Procedures The IH unit surveyed was a three-coil inline billet induction heater. Electrical energy consumption data was collected using a Dranetz™ brand power monitoring device. It was installed at the incoming power connection of the induction heater to record the power used during a production run.

Figure 1: An example of the service entrance and branch circuits

Dranetz™ power monitor installed at the induction heater

FIA MAGAZINE | MAY 2023 11