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TRU-FLEX flexible metal exhaust products: Exhaust bellows

The Flexible Exhaust Products business unit of TRU-FLEX is engaged in the research, development, design and application of a range of technologies centered around exhaust bellows which are sometimes referred to as corrugated flexible pipe or some other similar terms. We spoke with Mr. Jaroslav Szytow, Plant Manager TRU-FLEX (Europe) in Zimna Wódka, Polska.

Hans Dieter Jung
Sales Director

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+49 7631 1809 410

The basic production steps

A continuous production concept

Production requirements:

  • Thin walled tubes for single or multiple wall application
  • Materials: steel, Inconel, stainless steel, Titanium

    Equipment specification I for tube diameters 50 – 150mm

    • Tube diameter: 50 – 150 mm
    • Tube length: 250 – 2000 mm
    • Material thickness: 0,2 – 0,5 mm
    • Materials: steel, stainless steel, inconel, titanium
    • Weld source: Laser
    • Cycle time: approx 40 seconds for 1000 mm tube (4 m weld speed)


    Equipment specification II for tube diameters 60 – 250mm

    • Tube diameter: 60 – 250 mm
    • Tube length: 250 – 1250 mm
    • Material thickness: 0,3 – 0,8 mm
    • Materials: steel, stainless steel, inconel, titanium
    • Weld source: Laser
    • Cycle time: approx 22 seconds for 1000 mm tube (4 m weld speed)

    Concept of tube forming and laser welding system Flexistar

    • The clamping tool consists of a tool cage with multiple segments.
    • A servo motor controls the clamping and adjustments.
    • This unique concept provides for sequential production of different tube diameters, without any tool-change.
    • The individual radial clamping elements are centrally adjusted at the time of diameter change.
    • The rolled tube is automatically pushed through the welding station and deposited on the accumulation table.


    • Scratch free handling
    • Sequential production
    • No change-parts, no change-over time
    • Compact production cell, reduced floor space
    • No change tools required for roll former nor welder
    • Maximum flexibility without extra costs (tooling, change over time, scrap)
    • Automatic diameter adjustment
    • Most economical production for ranges of medium and large lot sizes, job lists
    • High productivity and availability with minimum man power
    • Highest weld seam quality due to innovative and economical laser welding source
    • Selection of laser source (CO2, Diode, Disk, YAG, Fibre)
    • Ideal material flow from blank to the finished product
    • Simple operation due to parameter- and program control – Easy to use