Technologies

Brazing Aluminum to Copper Tubes with Induction

Brazing Aluminum to Copper Tubes with Induction

Objective: To heat an aluminum manifold to 1050 ĀŗF (566 ĀŗC) for a brazing application:

Material :

  • Cu tubes (3/4″/19mm)
  • Cu tubes (5/8″/15.8mm)
  • AI tubes (3/8″/9.5mm)
  • AI manifold (5/8″/15.8mm)
  • AI manifold (3/4″/19mm)
  • Lucas-Milhaupt Handy One alloy 30-832
  • Braze wire

Temperature 1050 ĀŗF (566 ĀŗC)

Frequency 260 kHz

Equipment DW-UHF-10KW 150-500 kHz induction heating system equipped with a remote heat station containing two 1.5 Ī¼F capacitors.

  • A two-turn oval helical induction heating coil designed and developed specifically for the aluminum assembly
  • A five-turn helical induction heating coil designed and developed specifically for brazing the Cu tubes to AI joint assembly

Process Braze : pre-forms were designed to fit the aluminum tubes. Then the four aluminum tubes were placed into the manifold and the assembly was inserted into the coil. The assembly was heated for approximately 70 seconds, at which point it reached the targeted temperature and braze flowed. For the Cu tubes, a braze pre-form was also designed for them, wound around the tubes, and the assembly was placed inside the coil. The heating cycle time was approximately 100 seconds. Some joints required stick feeding of braze to fill the entire joint area due to the braze wire size. If the cycle time was lengthened, the need for stick feeding would be eliminated.

Results/Benefits: Precise, repeatable heating:

  • The client wanted more precise and repeatable heating than a torch could deliver, which induction was able to achieveĀ .
  • Temperature control: Induction allows for superior temperature control when compared to other methods, including a torch, which the client desired

 

Induction Brazing Aluminum Pipes

Induction Brazing Aluminum Pipes

Objective: Brazing two aluminum pipes simultaneously to an aluminum evaporator core

Material 2 aluminum pipes 0.72″ (18.3mm) diameter, evaporator core 9.88″ x 10.48″ x 1.5″ thick (251mm x 266.3mm x 38mm), braze rings

Temperature 610 ĀŗF (321 ĀŗC)

Frequency 250 kHz

Equipment ā€¢ DW-UHF-20KW induction heating system, equipped with a remote workhead containing two 1.5Ī¼F capacitors for a total of 0.75Ī¼F ā€¢ An induction heating coil designed and developed specifically for this application.

Process A four turn helical pancake coil is used to heat the 2 pipes simultaneously. Three braze rings are placed on each joint and power is applied for 90-100 seconds to create a leak proof joint on both pipes. Narrative ā€¢ Customer is requiring a 40 seconds heat time for both brazes. In order to meet this requirement 3 units will be utilized to braze 2 joints each for a total of 6 joints in 90-100 seconds. The customer is currently using a flame process which can burn away the thin flange at the joint area and create scrap parts. By switching to induction for this application the customer is decreasing their scrap parts and also increasing their quality and production rate.
Results/Benefits Induction heating provides:
ā€¢ Repeatable leak free joints
ā€¢ Increased part quality, less scrap
ā€¢ Hands-free heating that involves no operator skill for manufacturing
ā€¢ Even distribution of heating

Brazing Cutting Tool with Induction

Brazing Cutting Tools with Induction

Objective: To braze cone and shaft for a cutting tool

Material Customer supplied parts

Temperature indicating paint Braze preforms

Temperature 1300 – 1400 ĀŗF (704 ā€“ 760 Ā°C)

Frequency 400 kHz

Equipment: DW-UHF-6kw-I, 250-600 kHz induction heating system, including remote heat station using two 0.66 Ī¼F capacitors (total 1.32 Ī¼F) A two-position, two-turn induction heating coil designed and developed specifically for this application.

Process: Two sets of parts are placed in the individual coils. Braze preforms are placed on the cone at the joint. The assembled part is placed inside the induction heating coil and heated until the braze melts.

Results/Benefits: efficient coil design enables simultaneous heating of two parts on the single 2kW system. dual braze is accomplished within required process time, increasing process throughput

Brazing carbide shaft with induction

Brazing carbide shaft with induction

Objective: Braze a carbide shaft to a steel tube

Material: Carbide shaft 1/8″ to 1″ diameter (varying sizes) Steel tube 3/8″ to 1 Ā¼” OD Silver solder braze

Temperature: indicating paint

Temperature: 1400 Ā°F for 60 seconds Frequency300 kHz

Equipment: DW-UHF-6KW-III, 150-400 kHz solid state induction heating system equipped with a remote heat station containing two 0.66 Ī¼F capacitors (total 1.32 Ī¼F) A multi-turn helical coil

Process: Silver solder is applied to where the carbide shaft and steel tube meet. The clearance between the two parts is approximately .0005″. A small piece of solder braze is placed on the part and then the part is heated. It takes about 60 seconds to flow the braze with the best heat migration and solder flow. Even though the part can be heated faster, optimal results are obtained at 60 seconds.

Results/Benefits: Induction heating provides even, precise heat. Precise directed heat is required for the solder braze to flow evenly around the part to assure a good joint.

Brazing Brass Fittings With Induction

Brazing Brass Fittings With Induction Objective :To heat brass tubing assemblies to 750Ā°C for a brazing application. The tubing diameter varies from 3 to 8 inches (76.2 to 203.2 mm) Material: Brass tubing Brass flange Braze rings Braze flux Temperature :1382Ā°F (750Ā°C) Frequency 200 kHz Equipment DW-UHF-20KW, 150-500 kHz induction heating power supply, equipped with … Read more

Brazing Thin Copper Tube With Induction

Brazing Thin Copper Tube With InductionĀ 

Objective: To braze a thin copper oval tube to a brass fitting at 1400 Āŗ F and to cap the other end of the copper tube with a brass plate.

Material: Brass fitting – 0.875 in2 and 2.5 in long (22mm2 x 64mm) Copper tube 0.01 in (0.254mm) wall Brass plate 0.10 in (2.54mm) thick and 0.5 in X 0.25 inch Braze alloy shim and white flux

Temperature: 1400 ĀŗF (760 Ā°C)

Frequency: 300 kHz

Equipment: DW-UHF-10KW induction power supply equipped with a remote heat station using two 1.32Ī¼F capacitors (total 0.66 Ī¼F) Two custom-designed induction heating coils. Process A split, f our-turn induction coil is used to deliver the heat energy into the brass fitting (Fig. 1). To prevent over heating of the edges of the brass fitting and the thin copper tube, a smaller coil diameter (Fig. 2) was added to deliver heat into the brass fitting. A braze shim preform is placed at the joint area, and is then covered with white flux. The height of the coil is adjusted to deliver proportional heat to the assembly. This setting raises the temperature of the thicker brass piece and the thin copper tube at the same rate enabling a uniform flow of the braze shim preform. The other end of the copper tube is brazed successfully using a 2-turn helical coil (Fig.3.)

Results/Benefits ā€¢ Preservation of the copper’s mechanical properties ā€¢ Minimized heat migration along both ends of the tube ā€¢ Reduced heat-up time (under 60 sec.)

Brazing Copper Assemblies With Induction

Brazing Copper Assemblies With Induction Objective:To heat copper ā€˜Tā€™ assemblies to 1400(760) ĀŗF(ĀŗC) for brazing Material: Copper ā€˜Tā€™ assemblies,Silver-copper eutectic braze,White flux Temperature: 1400(760) ĀŗF(ĀŗC) Frequency: 250 kHz Equipment: DW-UHF-20KW, 450 kHz solid state induction powerĀ supply with a remote heat station containing two 1.32 mFĀ capacitors (total capacitance 0.66 mF). A custom-designedĀ induction heating coil. Process A … Read more

Brazing Copper Tube to Brass Fitting With Induction

Brazing Copper Tube to Brass Fitting With InductionĀ 

Objective: To use induction heating to braze a copper tube to a brass fitting using a preform braze wire. Processing is to occur under an atmosphere of Nitrogen and 4% Hydrogen gas. The braze preforms melt at 1190Ā°F, but the parts need to be kept below 1300Ā°F. The parts need to be processed at a rate of 175 to 200 per hour which translates into 18 seconds of heating time per part.

Material Copper Tubing Measuring 0.5″ OD and 2″ Long, Brass fitting, Braze Preform, No Flux.

Temperature Above 1190Ā°F but not to exceed 1300Ā°F

Frequency :300 kHz

Equipment: DW-UHF-10KW output solid state induction heating power supply with three (3) busses, eight (8) capacitors totaling 0.66 Ī¼F, and a unique four turn helical coil. Process The DW-UHF-10KW output solid state power supply along with a unique four turn helical coil were used to achieve the following results.

Results ā€¢ The requested atmosphere was provided under a bell jar by supplying 95% Nitrogen/5%Hydrogen at a rate of 25-30 cfh. ā€¢ A heating cycle of only 10 seconds was necessary to attain sufficient braze flow which surpasses the required limit of 18 seconds.

Brazing Eyeglass Frames With Induction

Brazing Eyeglass Frames With Induction

Objective: Produce repeatable braze joints for the assembly of eyeglass frames. Induction heating is to be used to achieve quality braze joints on the nose bridge, brow bridge and nose piece. Brazing is to be done at 1300Ā°F with approximately 3-5 seconds allowed for heating. Surface quality is of utmost importance since limited post-brazing cleanup is preferred.

Material: Monel Bridge With 18% Silver Braze

Temperature: 1300Ā°F

Frequency: 600 kHz

Equipment:DW-UHF-4.5KW output solid state induction power supply.

Process The DW-UHF-4.5KW output solid state induction power supply was utilized to achieve the following results: ā€¢ A temperature of 13000F was reached in 3 seconds through the use of a three turn, 0.2″ ID, transverse helical coil. This coil design allows for the pinpoint application of heat to a specific area. ā€¢ Surface flaws were kept to a minimum due to the use of a gas flood which was comprised of Hydrogen and an inert agent. The Hydrogen acts as a “fluxing” agent which eliminates the need for flux. The inert gas eliminates oxidation of the metal components when at brazing temperature. These two features produce a finished product without the need for post-brazing cleanup. ā€¢ Present fixturing can be kept due to the use of transverse heating which allows for easy removal of the finished product. Results Overall, induction heating fulfilled all of the objectives established by the customer to produce quality braze joints for the manufacture of eyeglass frames.

Brazing Copper Tube with Induction

Brazing Copper Tube with Induction

Objective: To braze a copper tube ( 3/8″ OD by 2-4″ long) into a 3/8″ fitting in less than 10 seconds. Heating must take place in a channel type coil to allow for easy loading of parts.

Material Copper Tubing and Fitting with Braze and Stay Silv White Flux

Temperature 1300Ā°F

Frequency 215 kHz

Equipment DW-UHF-10kw output solid state induction power supply equipped with a standard heat station containing eight 0.33 Ī¼F capacitors for a total of 0.66Ī¼F, a step down transformer, and a specifically designed induction heating coil.

Process DW-UHF-10kw solid state induction power supply was setup to achieve the following results: Ā· 2.0 kW of power was directly loaded into the copper tube resulting in a heating time of 7.2 seconds to reach the necessary 13000F for brazing.

Results& Processing ease was achieved through the design of a unique channel type coil comprised of three turns of 1/8″ copper.

=