Archive for the ‘Corrugating’ Category

Outside Air Temp effect on Green Bond

May 23, 2022

Ron asks:

We had an overhead garage door installed prior to our 2018 corrugator project – the OEM had us install it for ease of bringing new equipment into the building. Certain times of the year, say April to October, the corrugator crews have the overhead door open and just have the screen door down to allow fresh outside air in.  This door is maybe 18′ from the corrugator stacker. Should we have any concern about green bond shock on a cooler morning. The stock coming off the hot plate section is 275 degrees +/- and if the outside air temp was 50 would you be concerned about that?  I haven’t been able to find any studies related to this. Your opinion would be greatly appreciated.

I would focus more on the final pin adhesion strength.  You should target values above 45 and up to 60 pounds per foot.  If the pH, viscosity, and starch temperatures in the pan are within your process parameters, green bond should not be an issue.

Let’s toss it out to our readers. Have any of our other corrugator operations had any experience with this scenario?

— Ralph

Need Help Running Quality Board Consistently

May 17, 2022

Debbie asks:

We’re looking for some training help for the proper operation of small format corrugators. We are looking to improve the quality and consistency of board produced across our shifts. Especially our “off shifts”. We are looking to develop a set of specification sheets or SOPs that all shifts will follow. We believe the specifications should include,

  • Pre-heating roll temperatures
  • Amount of wrap on preheating rolls
  • Flow rate for our moisturizers
  • Proper glue application
  • And any other specifications that should be controlled/maintained for the production of quality paperboard.

We understand there are many factors that go into making quality paperboard, but we would like to develop a baseline that could be used by our operators as a starting point or troubleshooting as well as the SOPs mentioned above.

Can you suggest some resources?

A good place to start would be the search functions on aiccbox.org and aiccboxscore.org. On aiccbox.org under the Learn tab you will find the “Packaging School”, you’ll find many educational resources focusing on everything from machine training (including corrugators) to sales, safety, HR training, and more.

AICC’s “Corrugated Essentials” is an excellent program that may meet many of your needs. If it’s not already on the schedule, it should be coming up on the schedule later this year. There are also online courses that are free to all registered members, many of which focus on corrugators, corrugator operations and production.

You can also contact me directly to discuss further.

— Ralph

Any Suggestions for Removing Starch

May 17, 2022

Carl asks:

As part of my internship, I’ve been tasked with investigating ways to remove starch build-up from our corrugator sections. We tend to get heavy build around the glue machines (of course), but also on many other components of the corrugator. Our crews can spend hours scraping and chiseling to remove build up. We try to stay on top of it, but since we are a high output operation it can quickly get ahead of us. In your experience have you come across any safe alternatives to remove buildup and how fast they may be?

You’re not alone. It seems like no matter how careful a corrugator operation is, it ends up with starch someplace we don’t want it. With the high speeds corrugators are running today, spray, sling and other types of transfer can quickly create unwanted buildup and even stalactites of starch.

There are chemical solutions available that will dissolve starch. Some are based on biodegradable enzymes and claim to be safe to crews and the environment. It’s said that these solutions/systems quickly dissolve dried starch, but how fast to go from buildup to clean machine will, of course, depend on how severe the buildup is. However, I believe it is safe to say that it will be quicker, probably much quicker and safer for the machine and crew than hammer and chisels.

What are other readers doing to keep their corrugators clean? Let us know.

— Ralph

Roll Hardness Testing

June 12, 2020

Chris asks,

I was recently appointment QA manager at my company and have dove head first into the realm of Schmidt Hammer(roll hardness) testing.  A very significant issue we have is with warp.  I have noticed that most of the time when I see a difference of greater than 10 on the Schmidt Hammer test we suffer from unacceptable warp issues.   Since I’ve started hardness testing inbound rolls we have adopted a pass fail system where any roll that tests to greater than 10 is rejected.  To add to this problem our supplier has adhered to a system that says anything under 15 is acceptable by industry standards.

What is your take on this?  Do you feel that it is unreasonable to ask the mill to commit to less than a 10 difference?

Also, the mill is questioning my testing methods.  TAPPI T834 suggests to sample a roll every 6 inches across the roll (the mill uses this sample frequency).  I have always been taught that as for a scientific process that the larger sample size yields more accurate result.  With this being said, I chose to test my rolls at a frequency of every 3 inches which would increase my sample size.

Do you feel that my testing method is in some way negatively affecting the results?  As in, is my sample size causing the rolls to “fail” on a more frequent basis?

 

I love the three inch method. However, you would not be able to correlate to any of the 140 +\- containerboard machine out there. I would agree you are more likely to find a wet streak with your protocol, but mill specs usually call for moisture deviation to be six inches or less.

Do you have linerboard specification sheets from other companies?  You may want to investigate roll hardness from other manufactures. If your supplier is so entrenched in their thinking you might consider saving their rolls and having one of their Corrugator supervisors show you how to run the board without warp. It’s a bold move!

 

— Ralph