Defects In Blow Room Causes For Defects

Blow room is the first steps in spinning. Opening, cleaning, blending or mixing is done here. As a result different defects occur in different operation. Major defects or faults in blow room are mentioned below:

Defects in Blow Room:

1. Uneven lap
2. Irregular lap
3. Soft lap
4. Conical lap
5. Barrel shaped lap
6. Licking lap
7. Defective selvedge
8. Split lap
9. Dirty lap

Causes for Defects in Blow Room:
Important causes for defects in blow room are given below: 

Causes for Nep formation in Blow room:

• Cotton with too high or low moisture.
• Extremely fine cottons with high trash content.
• Reprocessing of laps and mixing of soft waste.
• Rough or blunt blades and bent pins on beaters.
• Narrow settings between the feed roller or pedal and beater.
• Long curved and U-bends in conveyor pipe lines.  
• Inappropriate ratio of fan to beater speed.
• Wider setting between stripping rail and beater blade. 

Causes for Curly Cotton: 

• Grid bars setting too close to beater.
• Hooked or bent pins on kirschner beater.
• Too wide a setting of stripping rail.
• Long and bent conveyor ducts with low fan speed.  

Causes for lap Licking : 

• Use of too much soft waste in mixing
• Too high fan speed, excessive beating.
• Cotton is damp or departmental humidity is high.
• Sticky nature of material

Causes for Conical Lap:

• Improper functioning of pedals on one side due to pedals being choked with dirt.
• Air entering at one side from under the grid bar of beater.
• Defective beater blade at one side.
• Uneven suction at the cages leaving to deposition of more material on one side than another.
• Lap roller racks, calander roller not exerting even pressure across the lap width. *Cages may not be properly levelled.

Causes for Soft Lap:

• Calender pressure inadequate due to wear and tear of weighting mechanism. 

Preventive Action or Remedies of Faults in Blow Room:

Preventive Action for Neps Formation:

For avoiding neps formation it is necessary to select the cotton according to moisture content in the cotton. In both cases if moisture content is less or more, our process will become critical.

As quality of our end product depends upon raw material. If cotton having more trash content then it is necessary to increase beating point. And this beating will directly affect our neps formation and neps formation will be more.

Cotton mixing supervisor should take action that during mixing soft waste and process lap not to be mix with fresh mixing. This step is necessary to avoid neps formation. As neps formation affect the quality of our yarn.

Preventive Action for Curly Cotton:
For getting good quality product it is necessary to keep trained staff for maintenance point of view. There is a need of technical person who have full grip on their work. They should check the setting of machine and to keep machine update to avoid the problems. Machine setting must not be wide not so close to avoid curly cotton problem.

Preventive Action for Lap Licking:
In order to prevent from lap licking it is necessary not to mix soft waste during mixing process. Avoid sticky nature cotton as in case sticky nature cotton then as a preventive action inside temperature of department is to be controlled. In this case low relative humidity and high temperature is needed.