As you may know I am a bit of a geek when it comes to board combinations. By picking and choosing what machines and what mill run our paper, we are now pretty consistently getting 38 ECT and above from 31-23-31. I confess that the 23# comes in at 24 or above, but the point stands. I have been doing much ruminating about all this.
We have a very long-time customer that went from 200# test to 32ECT, started having too many box failures due to stacking problems, and went back to 200# Mullen. Folklore at our company for years has been that this is an example of a customer use that better suits itself to Mullen than to ECT. Maybe there’s some Mullen magic? However, now I am coming around to the opinion that since our 42-23-42 generally tests a bit north of 44ECT, what we really had was success moving from 32ECT to 40 ECT. The Mullen probably had nothing to do with it.
Would you agree that it is probably rare that Mullen makes or breaks the success of a box?
Agreed. I was just on a case with another member whose boxes made from 100% recycled fibre failed in trailer storage after about three weeks. They performed in the past. As best I could determine, the linerboard had a low level of size and was subject to more degradation through swings in relative humidity (RH) and the box seemed to overhang one corner of the pallet. It’s all about an engineered approach to each customer’s total packaging system. Yours maybe more than Mullen verses ECT, are the recycled contents the same of the two sheets? ECT 40 is always a good compromise, but I know you like to get to the bottom of opportunities. Thanks for sharing the challenge.
Anyone one like to share their knowledge and experiences?