Sunday, February 9, 2020

PRECAUTIONS OF DRAW FRAME PROCESS



PRECAUTIONS IN DRAW FRAME PROCESS:


The precautions are better than cure. The precautions always help to maximize the productivity and quality of product in every process. The rejection percentage get reduced to minimum level if we take precautions during any process. Thei precautions in draw frame process are as follows:

• The better fibre parallelisation generally results in more uniform yarns and a lower end breakage rate in spinning. 
  
• The wider back roller setting affects the yarn strength, yarn evenness and results in the form of increased imperfections. 

The wider front roller setting  improves yarn strength.

• The  higher top roller (back) loading reduces yarn strength and end breakage rate.  


The higher draft helps to improve the fibre arrangement in the sliver and makes the fibre more parallel along the sliver length. But evenness of sliver decreases. 

The higher the weight of sliver fed to draw frame, lower the yarn strength, yarn evenness, and it leads to higher imperfections in the yarn and more end breakages in ring spinning.  

The  Irregularities arise owing to the instability of the acceleration point over time. The aprons and rollers are used in the drafting zone to keep the fibre at the back roller velocity until the leading end is firmly gripped by the front roller, but individual fibre control is not achieved.  

• The  drafting wave is caused primarily not by mechanical defects as such but by the uncontrolled fibre movement of a periodic type resulting from the defects. As the fibre-accelerating point moves.

The speed of the coiler is selected correctly. Sufficient precaution is taken to set the coiler speed correctly. 

• The timing of correction is the time of response of auto leveller to act to level the variation when it reaches the correction point.

Since wide sliver funnel size affects the unevenness percentage of Sliver, so that it is selected precisely. But small funnel size results in form of more sliver breaks at the front.

The fibre scum is removed with the help of a wet cloth from the top roller at least once in a shift of 8 hrs. while 100% polyester is being processed.

The relative humidity of the draw frame department plays very important role in analyses of linear density of sliver. The related correction are made during calculating weight per unit length of sliver to avoid unwanted change in the draw frame draft.
When the changes are made in back roller setting, guide rails setting, delivery speed, break draft, the timing of correction in the auto leveller is also need to change.


                                   The end

No comments:

Post a Comment

Featured Post

WARP WINDING PROCESS, TYPES OF WARP WINDING MACHINES, PATTERNING, AND PACKAGE FAULTS

  WARP WINDING PROCESS: Warp winding may be classified in following categories: • Drum winding • Precision or spindle winding DRUM WINDING...