Engineering

A Welded Metal Bellows is a segmented flexure device that is shaped like of a corrugated tube. It is made by welding multiple thin metal foil diaphragms together on the ID & OD. The elastic characteristic of this configuration allows the bellows to achieve considerable flexibility, mostly in the axial direction while maintaining a leak-tight hermetic seal.

A typical cross section would have this shape.

The unique shape of the mating diaphragm pairs permit them to nest in a very compact space while providing movement in response to mechanical and pressure inputs.

KSM uses Proprietary software and 3D Modeling to design the best bellows for your application.

Basic Application Data for Design

Finite Element Analysis

FEA (Finite Element Analysis) is a method that can predict device performance level in actual operating conditions and reflect this into the design. The FEA model can illustrate the predicted stresses on the bellows with a visual representation in 3D or animation.

By using FEA tool, KSM is able to use the predicted data on lifespan, spring constant, MED (mean effective diameter) and other characteristics to optimize the bellows design.

Lifespan of bellows is acquired by fatigue analysis and fatigue strength calculated from applying stress-lifespan (S-N) graph derived from FEA analysis. By using fatigue analysis we can not only predict the lifespan of bellows, we can also acquire critical points and safety-ratio required for specific products which can lead to more stable and robust design.

From this analysis the proper bellows diaphragm geometry is derived. It is this geometry that is the basis for the bellows diaphragm form tooling and weld fixtures that are used to manufacture the bellows.

KSM Bellows Engineering Program

The KSM Bellows Engineering Program is a design tool produced from our accumulated technologies and experience. By utilizing this program, optimized designing is possible with minimal time. This optimization provides KSM the capability to produce bellows that achieve:

  • Highest Life
  • Lowest Cost
  • Compact Space


3D Bellows Design, using the FEA Method