Suhas
17th June 2013, 03:25 PM
Hello All,
Cavity balance and its % acceptance has been a very controversial topic. I did write an article on it and some of you may have already seen it. Here is the link, just FYI: http://fimmtech.com/index.php?id=6&subid=53 (scroll down to the bottom).
Now is my 'new' thought: Why calculate the imbalance as (Max-Min)/Min times 100? Let us say in a two cavity mold, the total amount of plastic will always be = Max + Min. So if the Max reduces by 1 gram, the Min will increase by 1 gram. So I think we need to look at 'Deviation from the Average'.
Example:
Cav 1: 8 grams, Cav 2: 12 grams.
Gate adjusted and then, Cav 1: 9 grams and therefore Cav 2 has to be 11 grams (if you are transfering on position)
If the balance was good - The amount of plastic in each cavity wold have been 10 grams.
So now your thoughts: Would we not calculate the % imbalance being - deviation from the 10 grams or in other words - deviation from the required average? I would love to get your thoughts.
Suhas
Cavity balance and its % acceptance has been a very controversial topic. I did write an article on it and some of you may have already seen it. Here is the link, just FYI: http://fimmtech.com/index.php?id=6&subid=53 (scroll down to the bottom).
Now is my 'new' thought: Why calculate the imbalance as (Max-Min)/Min times 100? Let us say in a two cavity mold, the total amount of plastic will always be = Max + Min. So if the Max reduces by 1 gram, the Min will increase by 1 gram. So I think we need to look at 'Deviation from the Average'.
Example:
Cav 1: 8 grams, Cav 2: 12 grams.
Gate adjusted and then, Cav 1: 9 grams and therefore Cav 2 has to be 11 grams (if you are transfering on position)
If the balance was good - The amount of plastic in each cavity wold have been 10 grams.
So now your thoughts: Would we not calculate the % imbalance being - deviation from the 10 grams or in other words - deviation from the required average? I would love to get your thoughts.
Suhas