Twist Per Inch of a yarn (TPI)

Theory:
              
 Twist: Twist may also be defined as thread which is usually the result of relative rotation of the two end.
         
Twist Types: There are two types of twist. They are S-twist and  Z-twist.

Twist Principle: One end will be fixed and another end will be turned this is the twist principle.

Objectives:

To measure the TPI of a yarn.
To determine the strength of the yarn.

Instruments:

1.Twist tester.
2.Yarn.
3.Scale.

Figure:

                              

yarn twist tester

Working procedure:

 - First of all, 10 inch yarn was taken.
 - Then yarn set on the twist tester machine.
 - Then screw of the machine twisted to the opposite side of the yarn twist.
 - When untwisting completed then the machine indicated.
 - Twist number taken from the machine display.

 Data measurement table:

No of Obs	Yarn Length (inch)	Twist number	TPI
1.	10	131	13

Conclusion:

After this experiment we have a clear idea about how to measure twist per inch with yarn twist tester.