Report: Typical box defects that disrupt smooth operations

The journey of corrugated boxes began in India since 2008. That was when there was "de-servation" on the size and capacity of box plants.

Today, the corrugated box industry in India converts about 4.8 million MT of paper into about 7 to 7.5 billion square meters of corrugated boxes every year.

After the de-reservation the capacity output for a corrugation box plant, more than 375 automatic corrugation lines have been set up in India. And there are more than 12000-14000 semi automatic lines (litho lam type). In terms of output this translates into: the automatic lines contribute to 40% of capacity with a conversion ratio of 2.0 million MT; while the semi automatic lines contribute to 60% with a converting ratio of 2.7 million MT

60-65%  of demand from FMCG companies for corrugated boxes. This is growing at 8-10% per year. The trend is: Most FMCG products has shifted from five-ply construction to a three-ply. In most cases, Patel said, the boxes have case sealing using hot-melt gluing systems which tend to increase the overall rigidity of three ply (single wall) boxes and contributes to better in-transit performance.

So? What does a good corrugated box do?

It protects the content against damage and against pilferage. It promotes the brand and allows productive packing.

Today, the definition of a good box is changing. A good box must enable productive packaging. This means, it should permit the following: case dispensing, case forming, auto case filling, case closure, batch identification (inkjet or dot matrix printing).

The other thing a good box must do, is reduce the typical box defects that disrupt smooth operations on an automatic packing line.

Defects and their effect

Typical defect one is: flap and panel warp

Effect on automatic line: This causes, case extraction failure; forming failure; filling failure; closing failure – hotmelt joints

Typical defect two is: ghost crease lines

Effect on automatic line: extraction failure and formation failure

Typical defect three is: excessively stiff/out-of-line creases.

Effect on automatic line: formation failure and jamming closure failure (spring back)

Typical defect four is: inadequate slot gap at manufacturer’s joint

Effect on automatic line: fouling of flaps at closure

Typical defect five is: fish tailing at manufacturer’s joint

Effect on automatic line: poor formation and jamming; failure at case closing

Typical defect six is: wash boarding

Effect on automatic line: extraction failure, formation failure and closure-hotmelt joint failure

Typical defect seven is: misregistered slots

Effect on automatic line: formation failure and jamming

The corrugated box has to not only protect its content but also has to ensure non-stop, snag-free running of the packing line.

In India, each and every corrugated box is a potential failure point and the tolerance for defects is very low.

Fundamental process and associated defect

During the production of corrugated board and in-process handling the associated defects are: board warp (flap and panel warps, wash-boarding and flap crease defects and ghost creases

During the conversion of corrugated board into corrugated boxes the associated defects are: misregistered slots, fishtailing, inadequate slot gap at manufacturer’s joint and ghost creases.

The root causes for box defects

The Defect: board warp

The Cause: operator’s inefficiency in adjusting machine according to running conditions, vast difference of moisture between top and bottom liner; paper moisture variation across the profile or MD

The Defect: ghost crease lines.

The Cause: improper design and adjustment of stacker, manual handling of boards

The Defect: wash boarding.

The Cause: inappropriate ratio of glue application to paper gsm, lack of tension on liner papers

The Defect: excessively stiff and out-of-line creases.

The Cause: inadequate creasing pressure

The Defect: inadequate slot gap at manufacturer’s joint.

The Cause: improper creasing pressure at printer-slotter, improper setting and alignment of folder beams at flexo folder gluer (FFG)

The Defect: fish tailing at manufacturer’s joint.

The Cause: improper creasing pressure at printer slotter, improper setting of squaring device at FFG

The Defect: misregistered slots.

The Cause: due to board warp, improper feeder setting and alignment

Conclusion:  My takeaway

The corrugated box vendor has to upgrade his board and box making capabilities to meet the emerging requirements. Simultaneously, the packing line machinery manufacturers need to design and manufacture machines that are cost effective plus highly reliable given the likely increase in demand for automated packing lines.