ASKRalph! RESPONDS:

 Following is and excellent article by Color Resoultions that appeared in the September/October issue of AICC's BoxScore brochure.

 

MEMBER'S QUESTION:

At our corrugator and converting operations we know there are many TAPPI Test Methods that can be used to describe the properties of the linerboards and mediums we purchase.  What do you believe are the most important?

ASKRALPH! Responds:

Here are my thoughts on the most critical physical properties for each of the three major classes of containerboard that you purchase.  I believe that it is critical that you ask for actual reel positional data from each supplier.  As you buy narrow trim rolls from mills, you are more likely to obtain containerboards that are slit from the operator or drive sides of the paper machine.  Out on the edges of the paper machine, the physical properties are more likely to have higher variation indexes.

 

 

 Do not accept reel average specifications or physical property tests.  Push back on our upstream partners.  I can assist you in this effort and even lead the conversations with your mill reps.  There is a methodology for obtaining this infomation so that you can compare various product offerings.  Also seek out the upper and lower reject points for each of the physical properties.

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:

MEMBER'S QUESTION:
Here is my new question. How do I test the paper to be sure that the board combo weights are correct ? If we order a board combination of 42-26-42 how can I verify that the correct paper weights were used ? What test equipment and TAPPI standard should I use.

Thanks again for all your help.

ASKRALPH! RESPONDS:

Thank you for an easy to answer and  another good question this time.

The TAPPI test method for a basis weight analysis is “Grammage of Paper and Paperboard T-410”.  You will need to gently soak the sample apart in some warm water until the three components have separated from each other.  Take a single edge razor blade and gently scrape off the starch from the liners and the medium.  Be careful not to remove fibre.

The samples will need to be dried to 7 percent moisture. You will then need to measure the dimensions of the sample and then convert the weight per sample size into pounds per thousand square feet for the three components.  You can use an inexpensive scale to measure the weight of the samples.

Or, I could recommend an outside lab.  Surprise visits to your sheet suppliers to view the roll stock inventory and check production records and purchasing logs is always a good idea.