Induction Brazing Copper Assembly With High Frequency Heating Equipment

Objective Brazing a copper pivot assembly
Material Two copper uprights 2” (5cm) wide x 4” (10.2cm) high, copper base 3” (7.6cm) x 2” (5cm) and .5” (1.3mm) thick with 2 channels for the uprights to the slide into, braze shims and black flux
Temperature 1350 ºF (732 ºC)
Frequency 200 kHz
Equipment •DW-UHF-20kW 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 heat the base of the assembly. The copper uprights and two braze shims are placed in the grooves in the base and black flux is applied. The assembly is placed in the coil and power is applied for 4 minutes to braze both the uprights in place.
Results/Benefits Induction heating provides:
• Rapid localized heat which can minimize oxidation and reduce cleaning after joining
• Consistent and repeatable joints
• Hands-free heating that involves no operator skill for manufacturing
• Even distribution of heating

Brazing Brass To Copper With Induction

Objective: To braze brass end-connectors to copper tubes used in aircraft assembly air lines Material brass end connectors, copper tubes of different diameters

Temperature 1400 ºF 750°C

Frequency 350 kHz

Equipment DW-UHF-4.5KW induction heating system, including a three turn helical induction coil using two 0.33μF capacitors (total 0.66μF)

Process For smaller diameter parts, flux is applied to the entire part and the copper tube to brass joint is assembled using brazing preforms (allowing for the same amount of braze in each joint). The assembly is placed in the coil and heated for 20-30 seconds reaching a temperature of 1400°F. For larger copper tube assemblies, the same process is used, but the braze alloy is stick-fed to the joint to prevent the alloy from flowing out of the joint. A foot switch control is recommended to enable better control of the process.

Results/Benefits

Economy: Power is consumed during the heating only

Consistency: the results of braze joints are repeatable and uniform