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Author: devitg
Time: 08/17/01 06:00 PST
This is a reply to message no. 7724 by tfrey
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Current Topic:
Want formula to calculate roll diameter based on thickness
TAPE ROLL DIAMETER.

You must consider that both the roll volumen and the tape volumen are equal, and knowing that
the width tape is the same , is possible to consider that the roll cronw area and the tape area
seen  from side are equal too.

RollVolumen-CoreVolumen=TapeVolumen

RollVolumen=(Rolldiameter*Rolldiameter*pi/4)*Tapewidth
CoreVolumen=(Corediameter*Corediameter*pi/4)*Tapewidth
Tapevolumen=Tapelenght*Tapewidth*Tapethick
or

Rollarea-Corearea=Tapearea
Rollarea=(Rolldiameter*Rolldiameter*pi/4)
Corearea =(Corediameter*Corediameter*pi/4)
Tapearea=Tapelenght*Tapethick
Then assuming that:
pi=3.14159 and pi/4=0.785
c= Corediameter
r=Rolldiametre
tl=tapelengt
tt=Tapethick
You migth have the following data, all sizes in  inches or mm, here are in inches


c=2;  core diameter = 2"
tl=6000; tape length= 6000"
tt=.01;  tape length=.01" or 10 mill
So if both areas ar equal

(r*r*pi/4)-(c*c*pi/4)=tl*tt

then
r=((tl*tt/.785)+c*c)^0.5
^0.5 mean square root

For those date the answer is

Solution:

Variables    Values

c          =     2.0000000

r          =     8.9684514

tl         =     6000.0000

tt         =    .010000000

Gabriel

devitg@ciudad.com.ar












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