Case Studies

G.E Silos 2020

Case Study

With a desire to reduce the task times and effort in the processes of roll forming and drilling during silo manufacture, GE Silos contacted Custom Automation to develop new solutions to achieve these objectives with consistency, reliability and improved operator conditions.

Roll Forming

The Roll Forming machine needed to be capable of accepting both 1.0mm and 1.6mm thick x 1200mm wide stock coil and without change of settings, produce a near matching formed profile on both thicknesses. Additionally, there were requirements to be able to accept sheet from the two separate sheet coil spinners, cleanly guillotine the sheet and finally to curve the formed sheet to the required diameter.

The sheet also needed to be easily removed from the rolling machine and the alternative sheet loaded. This was achieved within a comparatively small footprint considering it included:

  • Pinch rollers that straighten/feed the stock sheet;
  • Guillotine to provide a clean finished cut edge;
  • 3 station roll profile forming;
  • Final station curving to create the silo “hoop”. This is manually adjusted/set against a graduated scale.

The Roll Forming machine measures the sheet length and then guillotines the sheet and completes the forming. The Pinch Rollers hold the cut stock sheet ready to either feed it into the Roll Forming machine or for manual changeover to the alternative stock coil thickness.



The objective was to automate the laborious task of drilling of the silo overlapping joints prior to riveting, thus reducing manpower required and the potential of repetitive strain injury due to large number of holes required.

Requirements were:

  • Ease of setup;
  • Selectable hole spacing;
  • Selectable silo diameter (therefore number of holes to drill);
  • Drill size capacity of 4.8mm up to 6.8mm through 7mm of steel;
  • Capable of working heights of 1m up to ~4m, to allow drilling of hoops and base frame connections;
  • Local controls (Start, Stop, E/Stop etc.) on the Drilling Rig;
  • Compact Drill Rig but still provide good access for drill change;
  • Minimal foot print;
  • Good visibility of the drilling process;
  • Fully guarded, with interlocked access door.

It was decided to develop a suspended Drilling Rig that utilised a tensioned cable wrapped around the silo to both hold the Rig against the silo (to oppose the drilling forces) but also provide a means by which the Drilling Rig can drive/index itself around the silo. The Drilling Rig is suspended from a spring balance to give zero gravity effect with tracking achieved utilising the formed profile of the silo wall.

Currently, 2 different drill heights can be pre-set via adjustable index pins (+- 20mm from nominal).


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