When do you think brazing?

Brazing as a means to make a part.

So far, we've been talking about brazing as a way of joining two or more metals into a permanent assembly. And we've limited our discussion to the situations where you have a metal assembly in mind from the outset, from initial product concept through finished piece. Now let's discuss brazing from a very different point of view. Think about the parts your company fabricates, and consider where any of those parts now made as monolithic units, might not be made more efficiently as brazed assemblies. Consider this real-life story...

A company was fabricating thousands of small, closed-end metal cylinders. The part looked like this:

For years the cylinders were machined out of solid bar stock, with considerable labor required to drill and bore the blind holes. Finally, someone suggested that the cylinder was actually two parts--bar stock cut-offs brazed into lengths of stock tubing:

The assembly is a lot less expensive to make than the machined part and it works just as well.

Think Brazing at the beginning.

The time to consider brazing is at the beginning, when you're first planning or designing and metal component. Ask yourself if the part should be made as a single unit, or if it can better be made as an assembly of simple components. The "assembly" approach may help you eliminate expensive casting, forging and machining operations. It may save materials. It may enable you to use low-cost stock forms--sheet, tube, rod, stampings or extrusions. It will almost invariably be lighter in weight than the monolithic part, and will probably work better as the metals in the assembly can be selected to match their functions. Let's look at some typical metal "parts." First we'll see how they're made be conventional casting, forging and machining methods. And then we'll see how the could be made better and more economically as brazed assemblies.

From casting to sheet metal.

You're designing a housing, with threaded holes in the flange. You could make it as a casting. But consider instead making it as a brazed assembly, joining bar stock sections to a sheet metal deep draw:

The brazed assembly works just as well as the casting. And it's a lot cheaper to make, because you're putting the thickness only where you really need it--in the flange and not the shell. You save weight, materials and labor.