blown film formulas

 

Custom Search

blown film extruderBlown Film Formulas -- Click here for PDF format to save/print

Although computers, software packages, and calculators do most of the work these days, it is still good to be able to figure out blown film calculations on your own. By understanding the formulas, you will better understand the overall blown film operation.

Blowup Ratio (BUR) layflat (in) x .637 / die diameter (in)
Draw Down Ratio die gap width (in) / gauge (mil) / BUR x 1000
Film Length on Roll (ft) [roll diameter (in) + core diameter (in) x .13083] x [roll diameter (in) – core diameter (in) / gauge (mil) x 250]
Film Length on Roll Sheeting (ft)  [roll diameter (in) + core diameter (in) x .13083] x [roll diameter (in) – core diameter (in) / gauge (mil) x 500]
Gauge (mil) output (lb/hr) / line speed (ft/min) / layflat (in) / resin density (g/cm3) / .052
Line Speed (ft/min) output (lb/hr) / layflat (in) / gauge (mil) / resin density (g/cm3) / .052
Output (lb/hr) line speed (ft/min) x layflat (in) x gauge (mil) x resin density (g/cm3) x .052
Roll Diameter Tubing (in) square root of [{film length (ft) x gauge (mil)} / 32.7075) + core diameter (in)²]
Roll Diameter Sheeting (in) square root of [{film length (ft) x gauge (mil) / 65.415} + core diameter (in)²]
Roll Weight (lb) roll diameter (in)² - core diameter (in)² x layflat (in) x resin density (g/cm3) x .02836
Weight/1000 bags (lb) bag width (in) x bag length (in) x gauge (mil) x resin density (g/cm3) x .07225
Weight/Length (lb/1000ft) layflat (in) x gauge (mil) x resin density (g/cm3) x .867
Lbs/Hr/In Lbs/hr / 3.14 / die(in)
Lbs/rpm lbs/hr / screw speed
Grams/m layflat x gauge x .04762
Gauge in microns gram weight / layflat / .04762
Screw speed lbs/hr / 3.4
Die circumference die size / 25.4 x 3.14

 

smallbfllogo Privacy Policy | Company | Contact | ©2008 blownfilmline.com