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Box Compression

MEMBER'S QUESTION;

I noticed your question & answer section on the AICC website and I was hoping you couldhelp me.  I’m trying to learn as much as I can about box strength for shipping purposes. I work for a global snowboard company and I’m trying to figure out shipping specifications that we can send to our shipping partners around the world.

We’re using large coffin boxes to ship the snowboards. The boxes have a top and a bottom that measure below:

Tele Top- 66-1/2 x 40 x 12 ECT 86 Kraft
Tele Bottom- 66-1/2 x 40 x 12 ECT 86 Kraft

I’m trying to figure out how much weight is ok in each box, as well as how much weight can be stacked on top. I’ve seen the charts for ECT and Burst Testing, but I’m not sure if I’m reading them correctly. I was hoping you could help.

I appreciate your time.

ASK!RALPH RESPONDS:

One of the critical elements in determining compression is flexural stiffness which
is best predicted by the caliper of the combined board.  Can you provide me with the board combinations, flutes and final caliper of the construction.  Thank you.  You can have your provider/member contact me directly.

MEMBER'S UPDATE MORE INFORMATION:

I appreciate your help. Here’s the additional information I was able to find
about the Board Coffin Box that we use to ship our Snowboards.

Pin Adhesion Targets/Expected Values

MEMBER'S QUESTION:

I am trying to get a grasp on pin adhesion.  My starch supplier gave me the following minimums and targets to shoot for:

Grade                          Min                Target
26 lin- 35 lin                40#                  45#
42 lin                            45#                  50#
56 lin – 73 lin              52#                  57#

In a previous emai lyou stated “I like to see pin adhesion values average at 55#/linear foot of glue line, while others are willing to settle for 50#, the minimum values should not drop below 45#.”

I have tested 29 ECT and the DB Bottom Pan result was 41#.  Is 41# too low for 29 ECT?  The next day I tested 275 BC and the DB Bottom Pan result was 68#.  There were no changes to the starch settings on the machine between the two days. 

My question is: Why is there so much variability in the Pin Adhesion results and is that normal?  I check B flute and C flute pin adhesion once a week and there is always a large variance from week to week. 

 

ASK!RALPH RESPONDS:

ECT Comparisons

MEMBER'S QUESTION:

We have the opportunity to secure a substantial piece of business.  The customer's specifications reference box dimensions, ECT, and basis weight combinations.  I will submitt selected box samples to a third party lab for evaluation so that you will be able to offer suggestions as to alternative containerboard combinations that will give us both an environmental and economic sustainability advantage.

ASKRalph! Responds:

Below is an assessment of the five different samples you submitted for testing verses what the ECT potentials that could have been developed given the basis weights of the board combinations discovered during the evaluation.

Basis Weight

Combinations

all C Flute

Converted ECTs

Actual Results by Testing

Potential

ECT Ranges

Degradation Study

MEMBER'S QUESTION:

What do you know about ECT 24 replacing ECT 32 ? How would that be possible and what liners? Maybe replacing 150 mullen? What liner weights are used? Were the liner weights 35#. Doesn't 35# liners gets us to 32# now ??

ASKRALPH! RESPONDS:

In the Degradation Study started during the summer of 2008, and has continued to remain open, we  found several converters that have actually shipped boxes with ECTs below the 32# . These were  post press samples that were sent  that may or may not have been above a 32# ECT as incoming sheets. Since these "boxes" did not fail in the field (that we know of) one could assume that  these combined boards in the low twenties have actually substituted for what was described as 32# ECT. It all goes back to knowing your customers' needs.

Using 35# liners does not quaratee combined board performance.  Basis weights are not a good indicator of box performance! If one doesn't bond the components properlyt on the corrugator, flute the medium properly and crush the combined sheet in the converting operation ECT and box performance suffer.  There is a big difference between the potential in the roll stock and the finished product. 

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