MEMBER: What is the standard/normal board grade combination for 48 ECT single wall? The issue is that we have a new potential customer and his current vendor is telling that customer that they can provide them with a 48 ECT S/W with a board grade comb. of either a 55/33/52 or 52/36/52; I know that you can very well get ECT values of 48 but you are correct there is no 48# ECT that I was aware of either, I just wanted to see what your opinion was and maybe I was not aware of something.
RALPH YOUNG: There needs to be a minimum of 255 # of combined ring crush from the components to achieve a 48 single wall ECT. Going with the perfect balance of putting 50% of the vertical strength into the medium and given a 1.43 take-up factor for C flute, then strive to find a medium with a 87 CDRC. This would only be possible with a 45# domestic semi-chem or a 31# Power Flute. Can you convert this on your single facers?
Yes, the board combinations suggested by your competitor should work. Knowing that your the typical converting operation needs 15% more ECT coming in the front door to overcoming destructive converting process than we need to look at engineering for 293# of combined ring crush from all the components
Not knowing your ability to gently form a thick medium and get all of its potential fluted ring crush out of the sheet, let me offer you some other possibilities. There are dependent on your roll stock suppliers providing the maximum ring crush potential in the containerboards. It is theoretically possible to design the finished structure from 35HP-45SC-35HP, but I would not suggest this combination. Moving to the next alternative we could use a 40# semi-chem medium and very "strong" 42# liners. Next would be a 36# semi-chem medium and the same 42# "strong" liners.
Send me the ring crush levels of the products that you have available and I will we engineer a better sustainability solution for you and the client.