Drawing or Draw Frame | Objects of drawing | Importance or Necessity of Draw frame

Draw Frame

                 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. In drawing slivers are elongated when passing through a group of pair rollers, each pair is moving faster than previous one. This permits combing, drawing and elongating of several slivers to make them strong and uniform.In most modern worsted drawing sets there are 3 passages of pin drafting and roving process.

Fig: Rieter draw frame

Objects of drawing

• To straighten the crimped, curled and hooked fibers.
• To make the fiber parallel to their neighbors.
• To improve uniformity of fibers by drafting and doubling.
• To reduce weight per length unit of sliver.
• To remove dust from slivers.
• To blend raw material of same hank perfectly.

Importance or Necessity of draw frame in yarn production

• To parallelization of fiber and blending the carded sliver, draw frame is needed.
• In carded sliver, fibers are present in hook form i.e. trailing hooks and leading hooks. To parallel these hooks raw frame is used.
• Majority of the fiber hooks in a carded sliver are trailing hooks while leading hooks are comparatively less.
• Trailing hooks are also known as major hooks, while leading hooks are known as minor hooks.

What should do for better performance of drawframe:

• Always keep a watch on humidity and temperature as it affects the working.
• Keep a watch on stop motions and ensure that no singles or doubles are fed to drafting. Ensure machine stopping before a broken sliver entering drafting zone.
• Verify the trumpets size as per the hank, and ensure in good condition.
• Keep a watch on the surface of the top rollers and pressure on top rollers.