Understack vs. Overstack Shingles: A Practical Guide

Dieser Artikel ist auf Englisch verfügbar. Learn why understack shingles are required for some 4-corner cartons and how the right packing system maintains productivity and ergonomics.

Understack vs. Overstack Shingles: A Practical Guide Image

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Understanding Shingles & Packing Systems 



A Practical Guide for Folder-Gluer Operations 

 

Overstacked or Understacked Shingle?

 
A shingle is the overlapping stream of folded cartons exiting a folder-gluer's delivery belt.  

All standard packing systems are designed for overstack shingles. Most packers use gravity to drop boxes into a case, which does not work with an understack shingle. 

21-073 An overstack shingle exiting the folder-gluer’s delivery belt

Overstacked shingle exiting the folder-gluer. 

 

21-073 Overstack and Understack shingles against each other

 

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Overstack Shingle:

  • Each new box is stacked on top of the previous one. 

  • Standard for 99% of production runs. 

  • Compatible with all packing systems. 


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Understack Shingle 

  • Each new box is stacked under the previous one. 

  • Required for certain 4-corner box styles. 

  • Boxes cannot fall by gravity — limits packing options. 

Why Are Understack Shingles Used?  

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With certain 4-corner boxes, the front flap can spring open as it exits the folder-gluer, creating a hook point that catches the next incoming box — causing a jam or crash. When this happens, the operator must switch to understack mode to keep production running smoothly.  

 

Factors that increase the likelihood of this include the rigidity of the carton, the size of the flaps, and the resulting spring effect. 

 

IMPACK’s ERGOSA Semi-Automatic Packer: The Only Packer Built for Understack 



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The ERGOSA is the only packing system capable of handling understack shingles with no extra customisation and no added cost. It features a specialized mode for optimized packing of each box type. 
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The ERGOSA’s Vertical Mode is specifically designed for 4-corner boxes and allows you to pack from an understack shingle without needing to turn or invert your boxes. 

 

ERGOSA: One packer, both shingle types — no compromises.

Wrist movement

Key benefit: the ERGOSA offers optimized packing of other box types exiting the folder-gluer in the overstacked method including the option to turn the box to re-orient the glued edge. Automatic box turning eliminates wrist movements.