When I was young, every time I felt a bit under the weather, my mom gave me “Elixir d’Anvers”. It was the cure to all illnesses. If it was a flu or an indigestion or whatever… “Elexir d’Anvers” took away the pain. I even heard that farmers where giving it to their horses when they had some stomach problems. (image courtesy Wikipedia)
It was nothing more than a herbal short alcoholic drink that was invented by a medical doctor as a simple and effective cure in 80 percent of the cases (and the alcohol in it was an additional advantage).
In exactly the simular way that “Elixir d’Anvers” was a cure to all illnesses, a cure to all Illnesses in the corrugating process is ‘less heat and less starch’
Let us some up some corrugating diseases and there cure:
- Slinging (glue splashing)
- Brittle bond
- Steam bubbles opening layers (secret blowing)
- Post warp
- Bad slitting/ bad cut off
- (and others)
- Less starch, less heat
For my job I do a lot of troubleshooting and problem solving and it is amazing how simple my job sometimes is (please do not tell this to my boss).
The very first thing I suggest, when confronted with a problem, is to reduce heat and starch to the minimum required, and in 80 percent of the cases the problem disappears, just like using Elixir d’Anvers.
I make it sound very easy, but to convince someone that is already using 30 years too much heat and too much starch is quite a challenge.
Some time ago I was at a company making heavy combinations for the fruit and vegetable market: the typical BC semi-chemical coated kraftliner and heavy paraffined brown kraft. They were complaining about honeycomb, wash boarding and bad bonding of the coated kraftliner.
Observing the double backer, I noticed that every time a certain combination came up with coated kraftliner, the operator put a 100% wrap around a small preheater just before the hotplates. I asked him: “Why do you put so much heat in this coated kraftliner?”. The answer I got was: “Because someone told me to do so, and if I do not do it then we have a bad bond.”
I enquired if he understood the physics behind what he was doing, but even when explaining it to him; he didn’t want to change this behavior. It was just an automatism based on the trigger word “CKL” coated kraftliner. This resulted in a not so good looking board, I would even dear to call it plain waste.
I had to be in the same plant the next day. I was a bit devious and closed the valve at the drive side that fed the steam in to this small preheater. After a while it was around 40 degrees Celsius and was only brought to this temperature because of the preheating of the liner in the triple stack big preheaters. Nobody noticed me doing this.
The next day when the same “challenging” combination came up the same operator again put a 100 percent wrap around the small preheater. The board was looking better today then yesterday and the operator called me and explained to me that having that 100 percent wrap around is essential for having nice board. Proudly he showed me the 100 percent wrap around and the board that looked a lot better compared to yesterday.
I listened to his story and nodded from time to time. Then I took out my IR camera and showed him the fact that the small preheater was completely cold ( as I had closed the valve the day before). He panicked first a bit and then he suddenly made the link to the better board and the less heat combination. In the coming runs he even put the wrap around on 10 % since he realized that someone had given him the wrong explanation.
It was probably a lucky shot, thirty years ago, but the quality standards for making board have also changed drastically during that time.
I would like to challenge all of you that are running with a lot of starch and heat to try the following.
Let us say that you are running with the first hotplate on 6 bar (single wall, just to keep it simple).
Reduce it to 3 bar and see what happens. Most probably nothing… Reduce it to 1 bar. Remember that with thick hotplates it takes about 12 to 15 minutes before temperatures go down.
If it changes nothing to the final board, then the question is: “Why are you running with those high temperatures in the first section?”
Give your corrugator some “Elixir d Anvers”, less starch and heat, and you will be amazed how many problems it solves.