Calculation in Draw Frame Machine

Ranishka Yeashan
University of Moratuwa, Sri Lanka

Draw Frame:
Drawframe is a very critical machine in the spinning process. Drawing is the operation by which slivers are blended, doubled and leveled. In short staple spinning the term is only applied to the process at a draw frame.It's influence on quality, especially on evenness is very big. If drawframe is not set properly, it will also result in drop in yarn strength and yarn elongation at break.The faults in the sliver that come out of drawframe can not be corrected . It will pass into the yarn.
Draw Frame Machine
Draw Frame Machine
Gearing Diagram of Draw Frame Machine:
X gear is a one gear and for the drawing purpose it is separated as two gears.
Gearing Diagram of Draw Frame Machine
Gearing Diagram of Draw Frame Machine
Intermediate and Total Mechanical Drafts
Let motor rpm is N
Finding roller rpm according to gear system

Intermediate Drafts
Since the roller diameters are equal in main drafting zone, draft is proportionate to the rollers rpm

Front Roller and Second Roller

Second Roller and Third Roller

Third Roller and Back Roller
In this moment TDC is equal to 40T

So the Total Draft without Tension draft from the Calender rollers

Total Draft = 4.011*1.015*1.485 = 6.046

Calender Roller Draft

Production of Machine per shift of 8 hrs at 85% efficiency where the sliver hank to be 3700 tex

Draft Constant
When TDC is a changeable gear wheel, we get the total draft as

Production Constant:
Production Constant is calculated under motor rpm of Nm, 85% efficiency and C tex of output sliver per hour.


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