Induction Heating is used to cure organic coating such as paint on metallic substrates by generating heat with in the subtract .By this mean curing occurs from within minimizing the tendency for formation of coating defects . A typical is application is drying of paint on sheet metal. Induction heating of metal parts to adhesive induction curing temperatures is utilized in a many automotive processes, such as the use of thermosetting adhesives to produce clutch plates, brake shoes and auto bumper components. Shafts are typically bonded to the squirrel cage rotors in the manufacture of small motors. In copying machines, plastic components are adhesively bonded to aluminum rotors; a thermoplastic glue is used to hold foam rollers on metal shafts. Once the rollers wear out, the shaft is heated and the foam replaced. Modern induction heating can solve many of these problems. Heating with induction provides reliable, repeatable, non-contact and energy-efficient heat in a minimal amount of time, so that the curing process can be completed with minimal energy and time. Improved temperature ramping cycles can be achieved with computer control of the solid state power supply. To eliminate extra steps for loading and unloading ovens, induction heat stations can be incorporated into a production line. Finally, induction heating can be performed in extremely clean environments, vacuum conditions or special atmospheres, allowing for unique curing solutions.
Although induction heating is normally used with metals or other conductive materials, plastics and other non-conductive materials can often be heated very effectively by using a conductive metal susceptor to transfer the heat. Typical RF power supplies forĀ induction curing applications range fromĀ 4 to 60kW, depending on the parts and application requirements.
In order to want to improve safety and productivity, and reduce energy costs, by using induction instead of resistive heating. To maximize productivity, they want to be able to heat 3 brass rods at a time to 780Ā° C within 25 seconds. For this application test, we are only heating one rod, so our goal is to heat the single rod to 780Ā° C within 25 seconds with less than 45 kW of power. This will ensure that when heating 3 rods, that the 110 kW system will meet the production requirements.
Equipment DW-HF-70kWĀ Induction Heating Power Supply, operating between 10-50 kHz
Materials ā¢ Brass rod ā¢ Custom coil, 10 turns, D=50mm, designed and manufactured by DaWei Induction Power Technologies for this specific application ā capable to heat 3 rods at a heat cycle.
Key Parameters Temperature: 780Ā° C Power: 70 kW Voltage: 380 ā 480 V Time: 24 sec Frequency: 32 kHz
Process:
The DW-HF series Power Supply was connected to the DW-HF-70kw Heat Station.
The custom Coil was attached to the Heat Station.
The Brass rods were placed inside the Coil.
The Power Supply was turned on.
The DW-HF series operating at 20 kW was able to successfully heat the single brass rod within 24 seconds, which was less than the 25 second time requirement established for the test. Three brass rods are expected then to heat within 25 seconds with approximately 60 kW of power (3 rods will be 3x the load and 3x the power). The 90 kW Induction system will therefore meet the customerās requirements.
A source of high frequency electricity is used to drive a large alternating current through a induction coil. ThisĀ induction heating coilĀ is known as the work coil. See the picture opposite. The passage of current through thisĀ induction heating coilĀ 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 inĀ Induction HeatingĀ 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 theĀ induction heaterĀ caused by the current induced in the workpiece.
MagneticĀ Induction HeaterĀ Ā is a process equipment which is used to melt,braze,forge,bond,heat treating,harden or soften metals or other conductive materials. For many modern manufacturing processes,Ā Magnetic induction heating equipmentĀ offers an attractive combination of speed, consistency and control.The basic principles of magneticĀ induction heatingĀ 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.
MagneticĀ Induction HeaterĀ relies on the unique characteristics ofĀ induction heatingĀ radio frequency (RF) energyĀ – that portion of the electromagnetic spectrum below infrared and microwave energy. Since heat is transferred to the product via electromagnetic waves, the part never comes into direct contact with any flame, the inductor itself does not get hot, and there is no product contamination. When properly set up, the process becomes very repeatable and controllable.
Main Characteristicsļ¼
ćĀ 1.IGBT module and soft switiching inverting technologies are as in the production of theĀ generator,higherĀ reliability can be do.ć
ćĀ Ā 2. Small and portable ,compared with SCR controlled machine only 1/10 working space is needed. 3.Ā High efficiency to save energy,high efficiency and power far can be maintained
ćĀ 4.Ā The generator is adatable in a large frequency range from 1KHZ to 1100KHZ,installation can be done very easilyĀ according to our manual.ćć
Ā Ā Ā Ā Ā 5.Ā 100%duty cycle ,continuous working ability at maximum power.ćć
Ā Ā Ā Ā Ā 6.Ā Constant power or constant voltage control mode.
Ā Ā Ā 1.Ā Ā IGBT module and inverting technologies of the first generation been used.
Ā Ā Ā 2.Ā Ā Simple structure and light weight and easy for maintenance.
Ā Ā Ā 3.Ā Ā Simple to operat ,afew minutes is enough to learn it.
Ā Ā Ā 4.Ā Ā Simple to install,installation can be done by unprofessional person very easily.
Ā Ā Ā 5.Ā Ā advantages of the model with timer,the power and the operatingtime of the heating period and the rain period Ā can be preset repectively,to realize a simple heating curve,this model is suggested to use for batch productionĀ to improve the repeatability.
Ā Ā 6.Ā Ā Ā The separated models are designed to fit the dirty surrounding of some cases.
ļ»æInduction Preheating Hot Rod Heading With IGBT Heating Units
Objective Heat a waspaloy rod to 1500ĀŗF (815.5ĀŗC) for hot headingĀ application Material Waspaloy rod 0.5ā (12.7mm)OD, 1.5ā (38.1mm) length,Ā ceramic liner Temperature 1500 ĀŗF (815.5ĀŗC) Frequency 75 kHz Equipment ā¢ DW-HF-Ā 20 kW induction heating system, equipped with aĀ remote workhead containing two 1.32Ī¼F capacitors for aĀ total of .66Ī¼F ā¢ An induction heating coil designed and developedĀ specifically for this application. Process A seven turn helical coil is used to heat the rod. The rod isĀ placed inside the coil and power is applied for two seconds providing enough heat to penetrate the inner core. An opticalĀ pyrometer is used for close loop temperature control and a ceramic liner is used so the rod does not touch the coil. Results/Benefits Induction heating provides: ā¢ Low pressure and minimal residual stress ā¢ Better grain flow and microstructure ā¢ Even distribution of heating ā¢ Improved production rates with minimal defects
Induction Brazing Carbide To Stainless Steel Shaft With IGBT Heating Units
Objective Brazing a cone shaped carbide to a stainless steel shaft for a digger Material Cone shaped carbide 1.12ā (28.4mm) dia, 1.5ā(38.1mm) tall,Ā stainless steel shaft 1.12ā (28.4mm) dia and various length, blackĀ brazing flux and braze shims Temperature 1500 ĀŗF (815 ĀŗC) Frequency 277 kHz Equipment ā¢ DW-UHF-10Ā kW induction heating system, equipped with a remoteĀ workhead containing two 1.0Ī¼F capacitors for a total of 0.5Ī¼F ā¢ An induction heating coil designed and developed specifically forĀ this application. Process A three turn helical coil is used to braze the carbide to the shaft. TheĀ steel shaft is fluxed and the braze shim placed on top. The carbideĀ tip is fluxed and placed on top of the shim, lining up the countersunkĀ hole in the carbide. The hole is not fluxed because the flux outgasesĀ and causes the carbide to build up pressure and attempt to repelĀ from the shaft. Power is applied for 85 seconds for the braze shim toĀ flow and make a good joint. DAWEIās customer has a customerĀ who is unhappy with the braze quality of their digger so ourĀ customer is looking for a better quality brazing process.Ā DAWEIāsĀ customer is very happy with the sample brazedĀ diggers and the help he received from the Ameritherm lab inĀ developing his brazing process. Results/Benefits Induction heating provides: ā¢ Rapid localized heating only where needed ā¢ Creates clean, controllable joints ā¢ Hands-free heating that involves no operator skill forĀ manufacturing ā¢ Even distribution of heating
Ā induction brazing machine
Induction_heating_catalogue.pdf
