Air-Jet Picking Process and Components

Air-Jet Picking Definition

• Air-jet picking is the process of drawing filling yarn from a supply package and inserting the yarn through the warp shed using an air stream.

Air-Jet Picking Major Parts

• Supply Package:

  • Can be cone or cheese shaped.
  • Yarn is unwound.
  • Weight varies depending on yarn type and count (2.5-10 lbs).

• Cone Stand:

  • Holds cones to feed yarn to the pre-winder.
  • Cones are mounted on rubber pegs.
  • A disc tensioner provides yarn tension during unwinding.
  • Disc tensioner guides yarn.

• Pre-winder/Weft Accumulator/Weft Feeder:

  • Feeds yarn to the main nozzle.
  • A magnetic pin detects the number of windings on the pre-winder dial.
  • Yarn is wound onto the pre-winder dial.
  • 2-3 picks of yarn are typically stored on the dial.
  • Winding numbers/pick length influence dial adjustments.
  • A nut adjusts dial diameter.
  • Red light on magnetic pin assembly blinks during winding.

• ABS (Automatic Brake System):

  • Ensures continuous weft yarn supply to the main nozzle.
  • Vibrates to detect yarn supply.
  • Stops the loom if yarn breaks.
  • Smooths yarn supply.

• Main Nozzle/Fixed Nozzle:

  • Feeds yarn to movable nozzle.
  • Number of nozzles depends on pre-winders used.
  • Proper alignment is important to avoid breakage.

• Tandom Nozzle/Movable Nozzle:

  • Blows weft yarn during pick insertion.
  • Passes yarn to sub-nozzles.
  • Number of tandem nozzles matches pre-winders.
  • Fixed on the sley and moves with reed.
  • Distance from weft cutter must be sufficient to avoid striking.
  • Number of main and tandem nozzles always matches.

• Relay Nozzles (Sub-nozzles):

  • Fitted on the sley.
  • Arranged across the reed.
  • Assist the main nozzle in blowing pick through the guide channel.
  • Divided into groups of 5 sub-nozzles, working in intervals.
  • Solenoid valves supply air pressure to sub-nozzles.
  • Air pressure increases from left to right in sub-nozzles.
  • Distance between nozzles depends on weft yarn count.
  • Drop in pressure between nozzles is compensated by nozzle spacing.

• Solenoid Valve:

  • Connects to relay nozzle and air tank.
  • Regulates air by electromagnetic function.
  • One valve operates 2-5 sub-nozzles.
  • Main nozzle has its own solenoid valve.

• Cutters:

  • Two cutters: one on picking side (weft cutter) and one on receiving side (leno cutter/waste cutter).
  • Weft cutter cuts weft yarn near the selvage.
  • Leno cutter separates leno waste.
  • Cutting position and degree are important parameters.

• Catch Cords:

  • Synthetic yarns.
  • Grip weft waste on receiving side.
  • 8-12 catch cords are common.
  • Independent shedding.

• Weft Sensors (FD1, FD2):

  • Two sensors on receiving side, 120-130mm apart.
  • Sense arrival of weft yarn.
  • FD1 ensures presence; FD2 ensures absence.
  • Machine stops if yarn is absent.

• Stretch Nozzles:

  • Stretch filling yarn during shed closing.
  • Mounted on receiving side.

• Profile Reed:

  • Reed with grooves (profile).
  • Directs filling yarn path.
  • Avoids warp yarn interference.
  • Cleaned to prevent warp/weft breakage.

• Temples:

  • Hold and stretch fabric during formation.
  • Different types (ring, pin) for different fabric weights.
  • Used on both fabric sides.