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 Author: devitg Time: 08/17/01 06:00 PST This is a reply to message no. 7724 by tfrey Reply | Original Message | New Topic | List Topics | List Messages on This Topic
 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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