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Grotnes is focused on developing more efficient and adaptive products and systems for the manufacture of exhaust after-treatment components.  Grotnes (Hess) was a technology pioneer for spinformed catalytic converters in North America and has since expanded its technology to complete canning systems with full part tractability, including the patented "Adaptive Gap Control" (AGC) and "Rotary Sizing".   The system is modular so the equipment can be configured specific to customer needs, as we support all sizes of converter and filter assemblies.

Mat & Substrate Measurement Station

  • Weigh and Measure with Poka Yoke system: Provides non-contact measurement of the substrate diameter and length as well as the support mat weight to determine the target shell diameter for a specific Gap Buld Density (GBD).

Weight and non-contact measurements
Adaptive Gap Control (patented)
Wrap and Insert Stations

Wrapping Station

There are manual and automated options for wrapping the substrates

Insertions Station

This station inserts single or multiple substrate/ mat assemblies with hard or soft stuffing options.  Position, Pressure and Velocity can be monitored during insertion.

Sizing Station

This station forms the shell circumference to the target diameter.   There are three options:

  • Barrel Sizer - Using segmented tooling to radically reduce the shell to the predetermined target diameter.

  • Rotary Sizer (patented) - The Rotary Sizer uses rotary tooling to allow radial reduction over multiple substrates as it moves axially across the tooling.

  • Pre-Expand - A segmented expander is used to expand the shell diameter to a target determined by the measurement process.  The substrate/ mat assembly is then hard stuffed through a funnel.

Barrel Sizer
Rotary Sizer (patented)


Automatic or Manual  assembly process to wrap a catalytic converter substrate in a mat and insert the assembly into a shell. Both hard and soft stuffing utilizing advance techniques including weigh & measure, AGC, barrel/rotary sizing.

  • Adaptive Gap Control (patented):  A pressure based system that measures the substrate and support mat together as an assembly (simulating the conditions in the shell), and determines the shell diameter for an accurately targeted holding pressure.

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