Brazing and Soldering Processes
Torch brazing is by far the most common method of mechanized brazing in use. It is best used in small production volumes or in specialized operations, and in some countries, it accounts for a majority of the brazing taking place. There are three main categories of torch brazing in use: manual, machine, and automatic torch brazing.
Manual torch brazing is the process of applying heat using a gas flame placed on or near the brazed joint. The torch can be held or fixed in a fixed position depending on whether the operation is completely manual or with a degree of automation. Manual brazing is most commonly used in small batch production or in applications where part size or configuration makes other brazing methods impossible. The main disadvantages are the high labor costs associated with this method and the operational skills required to obtain a high quality brazed joint. Flux or self-fluxing materials are needed to prevent oxidation. If the torch is brazed with oxygen and hydrogen instead of oxygen and other flammable gases, copper torch brazing can be performed without the use of flux.
Machine torch brazing is often used where repeated brazing operations are performed. The method is a mixture of automatic and manual operation, where the operator often places brazing materials, flux and jig components while the machine mechanism performs the actual brazing. The advantage of this method is that it reduces the high labor and technical requirements of manual brazing. Since there is no protective atmosphere, this method also requires the use of flux and is most suitable for small to medium batch production.
Automatic torch brazing is a method that requires little manual labor in the brazing operation, except for loading and unloading machines. The main advantages of this method are: high productivity, uniform brazing quality and reduced operating costs. The equipment used is basically the same as that used for machine torch soldering, the main difference being that the machine replaces the operator in the part preparation.