Archive for the ‘Corrugating’ Category

Just how many corrugators are there?

August 2, 2017

Ron asks,

I’m doing some basic research on the corrugation market. My questions are:

  • How do I find out how many corrugators (machines) there are Worldwide by region?
  • And is there a way to know the width of each of the devices, such as over 2 meters, under, etc?
  • I’m also trying to answer the same question for Asitrades and Laminators.

That is a very tough question, especially from a global perspective! We know that the 432 +/- corrugators in the US are mostly 98″-110″.  Specs would be about the same in Europe and Canada.  Mexico is modernizing and we’re seeing 2.5 – 2.8 meter machines going in.  China is spending the capital.  Australia and New Zealand are modern. The rest of the word is, well, the rest of the world.  I would start by getting in touch with the corrugator manufacturers like BHS, Fosber, Agnati, etc. perhaps they can provide a worldwide overview of corrugator footprints. For Asitrades try touching base with Bobst. Most recently they are in the 65” range, but one of the newest located on the US East Coast is an 87” machine.

Industry publications often offer buyers guides, or directories of equipment suppliers. You may want to research some of those for lists of equipment suppliers. AICC’s member directory found on also provides a means to search equipment suppliers (Associate Members:) that may be able to provide information.

— Ralph

Cracking Litho-lam, Does ‘Sides’ Matter

May 8, 2017

Clint asks,

I have a question that I hope you can answer.  When using the same liner board on both the inside and outside of a singelwall sheet, why do you see more of the “flute lines” on one side versus the other?  What causes that and does it have more effect on fracturing the liners when you are creasing one side versus the other?

This came up when one of my customers was laminating a litho label on SInglewall.  They normally laminate it to the good side (less visible fluted lines).  Because some of the sheets were slightly warped, they laminated some on the bad side (more lines).  After converting there was some fracturing of the litho (not liners).   We saw less fracturing of the litho on the labels that were laminated to the bad side.  From a logical standpoint, if you put the label on the bad side and it is a weaker paper, I think the label may stretch easier versus being glued to a heavier liner.  Also, the inside of the box would look better (less visible flute lines) so I would assume this should be the norm unless you are just spot labeling something.  Keep in mind, the liners on the inner and outer were supposedly the same paper.

What are your thoughts on this?


Thank you for an excellent question. Yes, I can add some insight.

Tensile strength and stretch of the liners are impacted differently in the singleface and doubleback operations. Also temperatures and starch application are different in the two operations. Fracturing can occur in one liner and not the other. Learning flutes can have an impact. Microphotographs of the cross section of the combined sheet can begin to reveal some issues.

Of course starch application and amount can signal issues as you described. World class consumption would be about 1.4 # per msf.

– Ralph

Checking Starch Viscosity

May 4, 2017

Ralph asks,

Lately we have been having a debate about the perfect temperature for the starch viscosity testing. We use the stein-hall cup for our tests. Is there any specific temperature where it is best to test at?

Temperature certainly plays a major role in the viscosity of starch. Starch viscosity changes about 10% for every 2 degrees Fahrenheit. We discussed your question briefly with Herb Kohler of Kohler Coatings. Herb says that most corrugating plants that he is familiar with try to maintain temperature of starch in their storage tanks between 100 and 105°Fahrenheit (37.8-40.6°C). This helps maintain a steady viscosity and optimizes the running speed of the corrugator. Above 105°F (40.6°C) and you’ll start to experience viscosity growth. Maintaining a set point of 102°F (38.9°C) is commonly recommended by industry experts. His experience has been that is far better and more accurate to check the starch viscosity at approximately the same temperature each time than to rely on temperature/viscosity correction charts.

Additional information about regarding corrugator starch viscosity can be found in this Ask Ralph article from Roman Skuratowicz Ideal Starch Viscosity for Corrugated.

— Ralph

Does 200# board require Mullen instead of ECT?

November 7, 2016

John asks,

If I order 200# C flute board with a 40# medium can I properly perform an ECT test on the board or do I have to stick with the Mullen test? We are trying to achieve 44 ECT by ordering a 42 – 40 – 42 liner combination. It is my understanding that if you order 200 flute board with any kind of medium it still requires a Mullen Test. Is that correct? Do you have to order an ECT liner combination such as 57 – 26 – 57 to properly test for an ECT value? Sometimes we do get the 44# ECT value but not always. Any suggestions would be helpful.

If I am being too complicated here, let me know. When you are considering that Mullen combination your incoming ECT levels will range from 45 to 60. That assumes that the corrugator has perfectly combined the liners to the fluted medium. This is not the real world. A good sheet supplier will know the strength characteristics of their containerboards and know what ECT levels they can achieve.

Have you ever considered EB double wall with even lighter and less fibre expensive that can still meet your needs?