hello i started to work in plastic blown film industry. I found your page as a result of research. I wish you success on your RU-vid channel. I am waiting for your help to share your experiences and training on this subject.
Hello, I have a question. I understand that molecular orientation is also the cause of the shrinking phenomenon in shrink wrap. As you say, MD-orientation is inherent to blown film extrusion. So, what if I want film that does not shrink? Do you set the nip rolls at the top of the bubble as slow as possible, do you anneal the film , or is there another method?
Plastic molecules always wants to go back to the original form, before it has been processed. So, film shrinks always a little bit. But you can adjust the shrinking by setting width of the blown film and with cooling for example. So if you want that film doesn't shrink much, keep cooling level quite high and width of the bubble as narrow as you can compared to your machines die. More widht, more it shrinks. Nip rollers are just for the thickness adjustment, meaning, if your machines screw runs for example 50rpm, the more you put speed to nip rollers, more thinner film you get. It doesnt effect straight to the shrinking.
I've been coming up with a bunch of equations at work, one of them is to figure out pounds an hour on a roll. So it goes something like this...a = layflat, b = pocket 1, c = pocket 2, x = a+b+c, y = pounds per hour going through extruders. so solving for z we have z=x/(2a)(y). Anyone else playing the game might find this interesting. I came up with this equation when we were making some film we cut over onto two shafts and we had restrictions on how many pounds of film on a roll.
@@darshpatadia6826 when u have light guage,hard material and bubble is in pot ,I mean when is very low :) But if u have soft material and big gauge, sometimes is ok and u have nice round profile ;)
