Induction Preheating Hot Rod Heading With IGBT Heating Units
Objective Heat a waspaloy rod to 1500ºF (815.5ºC) for hot heading application Material Waspaloy rod 0.5” (12.7mm)OD, 1.5” (38.1mm) length, ceramic liner Temperature 1500 ºF (815.5ºC) Frequency 75 kHz Equipment • DW-HF- 20 kW induction heating system, equipped with a remote workhead containing two 1.32μF capacitors for a total of .66μF • An induction heating coil designed and developed specifically for this application. Process A seven turn helical coil is used to heat the rod. The rod is placed inside the coil and power is applied for two seconds providing enough heat to penetrate the inner core. An optical 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: • Low pressure and minimal residual stress • Better grain flow and microstructure • Even distribution of heating • 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 1.12” (28.4mm) dia, 1.5”(38.1mm) tall, stainless steel shaft 1.12” (28.4mm) dia and various length, black brazing flux and braze shims Temperature 1500 ºF (815 ºC) Frequency 277 kHz Equipment • DW-UHF-10 kW induction heating system, equipped with a remote workhead containing two 1.0μF capacitors for a total of 0.5μF • An induction heating coil designed and developed specifically for this application. Process A three turn helical coil is used to braze the carbide to the shaft. The steel shaft is fluxed and the braze shim placed on top. The carbide tip is fluxed and placed on top of the shim, lining up the countersunk hole in the carbide. The hole is not fluxed because the flux outgases and causes the carbide to build up pressure and attempt to repel from the shaft. Power is applied for 85 seconds for the braze shim to flow and make a good joint. DAWEI’s customer has a customer who is unhappy with the braze quality of their digger so our customer is looking for a better quality brazing process. DAWEI’s customer is very happy with the sample brazed diggers and the help he received from the Ameritherm lab in developing his brazing process. Results/Benefits Induction heating provides: • Rapid localized heating only where needed • Creates clean, controllable joints • Hands-free heating that involves no operator skill for manufacturing • Even distribution of heating
High Frequency Induction Cap Sealing With IGBT heating units
Objective To heat an aluminum foil inside a plastic shampoo cap for sealing Material 2.0” diameter, plastic flip top cap, with a 0.9” diameter aluminum foil seal Temperature 250 – 300 ºF (120 – 150 °C) Frequency 225 kHz Equipment DW-UHF-7.5 kW, induction heating system, equipped with a remote heat station containing two 1.5 μF capacitors (total capacitance 0.75 μF). An induction heating coil designed and developed specifically for this application. Process A three-turn two-position helical coil is used to heat the aluminum foil in a tunnel style assembly. Product (containers) passes easily under the induction coil. The assembly is located such that the entire perimeter of the aluminum foil is heated uniformly. The container and cap is placed under the coil and RF power delivered for 0.12 seconds. The aluminum foil heats and seals to the plastic of the cap. Results/Benefits This induction heating configuration fulfills the process requirements and: • uses a simple, economical coil design • increases throughput with a dual-position coil • delivers quality, consistent seals • offers a repeatable process, well-suited for automation
Induction Heating Aluminum Foil For Cap Sealing with IGBT inductive heater
Objective An induction heater is used to heat a polymer laminated aluminum foil in 0.5 to 2.0 seconds. The heat produced in the aluminum foil melts the polymer that bonds to the neck of a plastic container. Material Aluminum foil, polyethylene, polypropylene, polyvinylchloride, polystyrene, polyethylene terephthalate, styrene acrylonitrile Temperature 300 – 400 (ºF), 149 – 204 (ºC) Frequency 50 to 200 kHz Equipment DAWEI solid-state induction power supplies operating between 1 & 10 kW at frequencies of 50- 200 kHz. These units operate with remote sealing heads which allows the main power cabinet of the equipment to be located away from the immediate production area. Distances of up to 100 meters are possible. The microprocessor is used to control and protect the system and ensures that the optimal operating frequency is maintained at all times and that each container receives the same amount of heat energy from cycle to cycle. Process Two different types of aluminum foil laminates are available for this application. The first assembly includes backing board/reseal, a wax layer, aluminum foil, and a heatseal film for supported systems (Figure 1). The second assembly includes a high temperature film, aluminum foil, and a heatseal film for unsupported systems (Figure 2). The procedure is to fit the foil membrane into the cap and to fit the cap to the container after the product is filled. Results For the aluminum foil assembly as shown in Figure 1, heat induced in the metallic foil by the induction coil almost instantaneously melts the polymer coating and the neck of the container forming a hermetic seal between the heat seal film and the rim of the container. The heat also melts the wax between the aluminum foil and the back board. The wax is absorbed into the back board. This results in an air tight bond between the aluminum foil/membrane and the rim of the container, the back board is released and remains in the cap.
Process (cont’d) In the case of unsupported membranes in Figure 2, one side of the aluminum foil is coated with a heat sealable polymer film and this face that will be in contact with and sealed to the container. The other side of the foil that will be in contact with the cap has a higher melting-point film that prevents adhesion of the aluminum to the cap allowing the end user to unscrew the cap. Unsupported membranes are typically used where the end user pierces the tamper evident membrane prior to dispensing the product. The aluminum foil acts as a vapor barrier preserving the freshness of the product and prevents it from drying.
Shrink Fit Steel Gear onto Shaft With High Frequency Induction Heating Units
Objective Heat the bore of a hardened spur steel gear to shrink fit onto a gear motor shaft. This is part of a chair for the disabled. Material Steel gear 2.5” (63.5mm) OD, .75” (19mm) ID x .625” (16mm) thick, temperature indicating paint Temperature 400 ºF (204 ºC) Frequency 300 kHz Equipment • DW-UHF-3.2 kW induction heating system, equipped with a remote workhead containing two 0.66 μF capacitors for a total of 1.32 μF • An induction heating coil designed and developed specifically for this application. Process A four turn helical internal coil is used to heat the gear bore. The coil is inserted into the gear bore and power is applied for 90 seconds to reach the required 400 ºF (204 ºC) and expand the gear bore. The gear is then placed on the shaft and allowed to cool, creating the shrink fit between the gear and the shaft. Results/Benefits Induction heating provides: • No pre-heat cycle, heat is available on demand • Energy efficient, heats only the part, not the atmosphere around it • Controlled, even distribution of heating • Faster production times
Induction Shrink Fitting Carbide Ring With IGBT Induction Heating Units
Objective Shrink fitting a carbide ring into a steel valve seat Material Steel valve seat 6” (152.4mm) OD with 3” (76.2mm) ID hole & .75” (19mm) thick, carbide ring Temperature 500 ºF ( 260 ºC) Frequency 85 kHz Equipment •DW-HF-15kW induction heating system, equipped with a remote workhead containing two 0.50 μF capacitors for a total of 0.25 μF • An induction heating coil designed and developed specifically for this application. Process A three turn helical coil is used to heat the steel valve seat. The steel valve seat is placed in the coil and heated for 50 seconds to enlarge the center hole & drop the carbide ring in for the shrink fitting process. Results/Benefits Induction heating provides: • Accurate and repeatable results • Ease of integration into existing production lines • Energy efficient, only heats the part, not the atmosphere around it • Hands-free heating that involves no operator skill for manufacturing • Even distribution of heating
Induction Shrink Fit Aluminum Shaft with IGBT induction heating systems
Objective Heat aluminum impeller blades to 200 ºF (93 ºC) and shrink fit onto a shaft. Material Aluminum impeller blades with a .28” (7.109mm) bore, aluminum shaft Temperature 200 ºF (93 ºC) Frequency 255 kHz Equipment • DW-UHF-6W induction heating system, equipped with a remote workhead containing one 1.0μF capacitor. • An induction heating coil designed and developed specifically for this application. Process A split two turn helical coil is used to evenly heat the opening on the impeller blade. The impeller blade is heated for 20 seconds to reach the 200 ºF (93 ºC). The impeller blades are then removed from the coil & slipped over the shaft to complete the shrink fitting application. Results/Benefits Induction heating provides: • Repeatable results • Reduced cycle time, lower consumables cost • Even distribution of heating
Inductioin Shrink Fitting Aluminum Pulley With IGBT Heating Units
Objective Heat aluminum pulley for insertion of an inner bearing for the automotive industry Material Aluminum pulley 2.3” (60mm) OD x 1.6” (40mm) ID x 1” (27mm) high and inner bearing 0.7” (17.8mm) high x 1.6” (40mm) dia Temperature 464 ºF (240 ºC) Frequency 283 kHz Equipment • DW-UHF-4.5kW induction heating system, equipped with a remote workhead containing two 0.33μF capacitors for a total of 0.66μF • An induction heating coil designed and developed specifically for this application. Process A three turn helical coil is used to heat the aluminum pulley. The pulley is heated to 464 ºF (240 ºC) in 20 seconds to expand the inner diameter and then the inner bearing is inserted to form the completed part. Results/Benefits Induction heating provides: • Defined and controlled heat pattern • Process easily integrated into automated system • Even distribution of heating
Induction Shrink Fitting Assemble Connecting Rods With IGBT Heating Units
Objective Assemble connecting rods with a more accurate control of the heat Material Rod has an OD of .9125” (23.18mm), knuckle has an ID of .9125” (23.18mm) with an interference of .0001” (.0025mm). Knuckle assembly is forged steel Temperature 400 ºF (204 ºC) Frequency 210 kHz Equipment • DW-UHF- 3.5 kW induction heating system, equipped with a remote workhead containing two 1.0μF capacitors for a total of 0.5 μF • An induction heating coil, designed and developed specifically for this application. Process A six turn helical coil is used to heat the connecting rod for 13 seconds. The coil is perpendicular to the axis of the bore to promote even heating around the circumference. The connecting rod is then assembled with the piston for shrink fitting. Results/Benefits Induction heating provides: • More accurate control of heat vs a flame burner. Only heats knuckle, not the whole part. • Lower temperature used to prevent discoloring. • Increased productivity due to repeatability & ease of operation. A foot pedal & timer is used. • No product contamination.
Objective To use induction to prepare cast iron assemblies for shrink fit assembly Material Customer supplied cast iron rocker arms of varying sizes Temperature 450 ºF (232 °C) Process Time 20 seconds Frequency 148 kHz Equipment DW-UHF-5.0 kW, 150-400 kHz solid state induction heating system, equipped with a remote heat station containing one 1.0μF capacitor An induction heating coil designed and developed specifically for this application. Process A four-turn helical coil heats the ring at one end of the assembly. The coil is designed to concentrate the field towards the center of the assembly where the thermal mass is greatest. Across the heated ring, the coil presents a lighter field. After heating, a pin is place within the ring and the assembly is water quenched. The heat time varies from part to part but is less than 20 seconds. Results/Benefits Induction heating satisfies the needs of this process for: • rapid part heating • flexibility for parts of differing geometries • individual, series part heating, suitable for automation • a clean source of heat • even heat distribution
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
Induction Shrink Fitting For Inserts with IGBT Shrink fitting Heater
Objective: To heat an aluminum fuel pump housing measuring 8″ x 4 1/2″ x 3 1/2″ to 3750F, allowing steel parts to be inserted. Presently the housings are heated for over one hour in a convection oven. The areas that are to have steel parts inserted measure 1.5″ and 0.6875″ in diameter. In addition, the insertion process lasts for a little over one minute, so 3750F should be maintained for a period of time to complete the process. Material: Aluminum Pump Housing measuring 8″ x 4 1/2″ x 3 1/2″ Steel insertion parts. Temperature: 3750F Application: By using the DW-HF- 25, 25 kW output solid state induction power supply the following results were achieved. – 3750F was reached in one (1) minute to allow for insertion. – 20 housings were successfully heated using a five (5) turn right angle pancake coil. Equipment: Ameritherm SP 25, 25 kW output solid state induction power supply including one (1) remote heat station containing four (4) capacitors totalling 1.0 μF, and a five (5) turn right angle pancake coil made from 3/16″ copper tube. Frequency: 80 kHz