Q: What’s a Bellows?

A: A metal bellows has the physical form of a flexible, lightweight, spring-like accordion (with the appearance of ribbed or corrugated tubing). But don’t let appearances deceive you. These are precision engineered components that are typically custom designed to perform a variety of engineering functions in a broad array of machine components and assemblies.

Q: What does it do?

A: Specifically, precision-engineered metal bellows convert pressure, mechanical, vacuum and temperature changes into linear or rotational motion. They can also be used in flexible electronic contact applications. Bellows provide a specifically defined dynamic response as part of a larger machine component or assembly often providing a more precise, more reliable or less costly alternative to an existing engineering solution.

Q: How is it made?

A: Simply stated the process of electrodeposition or electroforming involves building thin layers of metal onto a precision-machined mandrel and chemically removing the mandrel. See the entire electroforming manufacturing process here (provide link)

Q: What materials are available to have the bellows made in?

A: Nickel, Copper, Silver and Gold. Usually the materials are the types of metals that can be formed by electroplating.

Q: How long do they last?

A: Can be designed to have infinite cycle life. Our design engineers will design a bellows to meet your application specification and/or provide options to optimize the performance.

Q: What is the maximum pressure the bellows can take?

A: Up to 3000 PSI. The specific application requirements will help us calculate the actual maximum pressure. The bellows outside diameter and axial stroke distance will have the greatest impact when determining the maximum pressure.
A: Besides soldering, our bellows can be welded and various adhesives including epoxies onto mating components.

Q: What type of ends are needed for welding a bellows to a hub?

A: The preferred method of welding Servometer® bellows is with an electron beam welder. Since this method does not use filler material, it is important that there is no gap between the bellows and hub at the weld joint. Ends such as Type A, D, or I will result in bad, incomplete, porous welds since it is difficult to eliminate gaps between the bellows and hub and there is limited material available for fusion. An end such as Type E will provide a good weld joint because the flange can be pressed against the hub, eliminating any gap, and the beam can be focused perpendicular to the axis of the bellows ensuring that there is plenty of material from the bellows and hub that can be fused together. (provide link or show illustration of A,D and E ends)

Q: What can be done to protect a nickel bellows or electroform from corrosion, or make it biocompatible?

A: Depending on the application and media the bellows or electroform will be exposed to, it can be plated with a thin layer of gold or coated with parylene. Gold adds protection against corrosion in all types of climates and environments, and is also an excellent conductor of electricity. Parylene is a polymer coating that provides moisture, chemical, and dielectric barrier properties, as well as dry-film lubricity. Both gold and parylene are biocompatible.

Q: What is reverse bending?

A: From the free length, the bellows may be operated in compression and anywhere therein to max compression and up back to the free length, OR, from the free length, the bellows may be operated in extension and anywhere therein up to max extension and back to the free length. Reverse bending is when the bellows is operated in compression and is moved through the free length into the extension and vice versa. Reverse bending will reduce the cycle life of the bellows.

Q: What is “mutually exclusive” as it applies to our bellows drawing table?

A:The bellows should not be made to max out all capable movements at the same time. Offset and Bending movements reduces available stroke capability. Contact engineering for specific design requirements.

Q: Can they be Laser welded?

A: Servometer® does not offer laser welding but several of our customers have reported successful leak tight result with laser welding.

Q: How long does it take to Quote a custom bellows?

A: Most custom bellows will be quoted within 3 weeks. When we need to request additional performance specifications or review design options with our customers the process could be delayed.

Q: What is the lead time for a custom Bellows?

A: On the first order the bellows lead time could be 6 weeks and assemblies 8 weeks. For repeat orders it would be one weeks less.

Q: Where are my free samples?

A: Generally, standard sample requests are fulfilled within 48 hours upon their receipt. When the sample is mailed you will receive a confirmation via email that your sample is on its way. If you don’t receive an email confirmation that your request has been fulfilled please contact our Customer Service department. Contact Customer Service or phone # 973-785-4630