FAQ: How to Use a Metal Bellows In An Application

One of the most frequently asked questions about metal bellows at a tradeshow, Lunch-N-Learn, or bellows design class  is “What can I use these for?”  Sure bellows are neat to look at and fun to handle but how can I use one in my application? This curiosity stems from the fact that a bellows is “spring” like. Basically bellows are flexible seals. However, when made from metal the bellows will also exhibit a predictable spring rate due to the elastic property of the material of construction unlike leather, cloth, or plastic/rubber bellows. Hence, metal bellows are essentially “sealed springs.” Specifically, precision engineered metal bellows convert pressure, mechanical, vacuum, and temperature changes into linear or rotational motion.

Typically, engineering classes don’t offer a bellows 101 course. If they did then you would know there are several methods in which metal bellows can be manufactured. Electrodeposited or electroformed bellows are produced by plating metal onto a precision-machined bellows shaped form or aluminum mandrel. The metal is most often nickel but can be a combination of nickel, copper, gold, and silver. The edges are trimmed and the mandrel is chemically dissolved. The electrodeposition process allows for precise controls of the bellows wall thickness. They can be as thin as 0.0002 inches with the smallest possible diameters up to 0.020 inches (5 mm). Electrodeposited bellows are compressible up to 45% of their free length, with a high cycle life of 100,000, highly flexible, and are leak resistant.

Edge-welded bellows can be made from several different materials. These materials include stainless steel, Inconel, titanium, and many others. They are produced by welding metal diaphragms that have been stamped from strip material, stacked together, and welded (inner diameter to inner diameter, then outer diameter to outer diameter) using plasma, laser, arc, or electron-beam welding.

The following FAQ, “How to Use Metal Bellows for Different Applications” addresses that all important question, “what can I use these for?”

Read the entire FAQ here.