induction heating - Page 3 of 3 - induction heating machine manufacturer

how does induction heating work?

A source of high frequency electricity is used to drive a large alternating current through a induction coil. This induction heating coil is known as the work coil. See the picture opposite.
The passage of current through this induction heating coil generates a very intense and rapidly changing magnetic field in the space within the work coil. The workpiece to be heated is placed within this intense alternating magnetic field.
Depending on the nature of the workpiece material, a number of things happen…
The alternating magnetic field induces a current flow in the conductive workpiece. The arrangement of the work coil and the workpiece can be thought of as an electrical transformer. The work coil is like the primary where electrical energy is fed in, and the workpiece is like a single turn secondary that is short-circuited. This causes tremendous currents to flow through the workpiece. These are known as eddy currents.
In addition to this, the high frequency used in Induction Heating applications gives rise to a phenomenon called skin effect. This skin effect forces the alternating current to flow in a thin layer towards the surface of the workpiece. The skin effect increases the effective resistance of the metal to the passage of the large current. Therefore it greatly increases the induction heating effect of the induction heater caused by the current induced in the workpiece.

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Heating Shrink Fitting Camshaft Gear

Induction Heating Shrink Fitting Camshaft Gear with IGBT Induction Heater

Objective: Heating a camshaft gear with a bore size of 1.630″ to shrink fit over a steel shaft that has a diameter of 1.632″. A temperature of 5000F is required for the gear to expand 0.002″ in order to slip over the shaft. Production is presently done at a rate of 15-20 gears per 24 hour shift by heating the gear
on a hot plate. The hot plate heating cycle lasts for approximately 45 minutes.
The customer would like to explore the options available in terms of heating times and machine size.
Material: Steel Camshaft Gear measuring 7″ in diameter, 1″ thick, with a bore size of 1.630″.
Temperature: 5000F
Application: A unique three (3) turn helical coil along with the various DAWEI solid state induction power supplies were used to achieve the following results:
– 5000F was reached in three (3) minutes while using the DW-HF 5, 5 kW output solid state induction power supply.
– 5000F was reached in five (5), eight (8), and ten (10) minutes using the DW-HF-3, 5 kW output solid state induction power supply.
– Even heating was observed as a result of the unique three (3) turn helical induction coil.
Equipment: DW-HF-35 and DW-HF-55 kW output solid state induction power supplies respectively, including remote heat stations and a unique three turn helical coil made from 3/16″ copper tubing and having a 4.4″ inside diameter.
Frequency: 62 kHz

What Is Induction Heating?

What Is Induction Heating?

Induction heating is the process of heating an electrically conducting object (usually a metal) by electromagnetic induction, where eddy currents (also called Foucault currents) are generated within the metal and resistance leads to Joule heating of the metal.Induction heating is a form of non-contact heating,when alternating current flows in the induced coil, varying electromagnetic field is set up around the coil, circulating current(induced, current, eddy current) is generated in the workpiece(conductive material), heat is produced as the eddy current flows against the resitivity of the material.The basic principles of induction heating have been understood and applied to manufacturing since the 1920s. During World War II, the technology developed rapidly to meet urgent wartime requirements for a fast, reliable process to harden metal engine parts. More recently, the focus on lean manufacturing techniques and emphasis on improved quality control have led to a rediscovery of induction technology, along with the development of precisely controlled, all solid state induction power supplies.

How Induction Heating Work?

An induction heater (for any process) consists of an induction coil (or electromagnet), through which a high-frequency alternating current (AC) is passed. Heat may also be generated by magnetic hysteresis losses in materials that have significant relative permeability. The frequency of AC used depends on the object size, material type, coupling (between the work coil and the object to be heated) and the penetration depth.High Frequency Induction heating is a process which is used to bond, harden or soften metals or other conductive materials. For many modern manufacturing processes, induction heating offers an attractive combination of speed, consistency and control.

What’s Induction Heating Applications

Induction heating is a rapid ,clean, non-polluting heating form which can be used to heat metals or change the conductive material’s properties. The coil itself does not get hot and the heating effect is under controlled. The solid state transistor technology has made induction heating much easier,cost-effective heating for applications including soldering andinduction brazing ,induction heat treating, induction melting,induction forging etc.