Bobbin Holders FAQ's

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The core function of a Bobbin Holder is to control the roving draw-out tension and maintain uniform roving delivery. The inbuilt braking system of the Bobbin Holder ensures the above function.
Secondly, the mechanism for holding and release of roving from simplex bobbin, the simplified ratchet mechanism in Autotex Bobbin holders ensures a reliable operation for a longer period of use. The ratchet mechanism of Autotex Bobbin holder is successfully tested for 1,00,000 strokes which is more than 20 years of life in normal working condition.

An opposition force which is required to control the over rotation of a Bobbin Holder, for a uniform delivery of roving is called the brake force of the bobbin holder, and it is provided internally under the dust cap.

The brake force depends on the material processed, count spun, back hank fed, lift of the roving bobbin, weight of the roving bobbin and the spindle speed. Autotex has designed MBS bobbin holders with flexibility to select the optimum brake force to suit the process parameters.

A Bobbin Holder's life span is decided by taking in to account the various parameters like material processed, count spun, lift weight of the roving bobbin, and fly level condition in a spinning department. In general the life of the Bobbin Holders is for 6 years, after which they should be changed.

Non-Rotating spare bobbin holders are provided for creeling the extra/spare roving bobbins in the front row of the creel. While loading and unloading the roving bobbins, if the bobbin holders are of fixed type without rocking it will tend to bend and break. For providing the swinging / rocking during loading and unloading, Autotex has introduced the flexibility to swing.

Under normal working conditions Autotex bobbin holders does not require maintenance in the general sense. However, some micro dust that is generated by the OHTC has the chance of getting accumulated on the rotating elements of the Bobbin Holders.
This needs cleaning by blowing compressed air underneath the cap at a normal pressure at six months interval.
An Autotex bobbin holder needs nil lubrication as they are made of a special bearing grade material.

Reconditioning of bobbin holders is not at all advisable. If reconditioned the replacement is being done by usage of inferior materials (to reduce cost) which not guarantee the performance and the yarn quality.

The smooth surface finish of the roving guide eye lets, roving hooks, tension rods, position of the tension rods, smooth movements of the traverse bars are the factors which enhance the performance of the Bobbin.
The fluff protector enhances the performance of the bobbin holder by preventing micro dust entry it is made out of best grade material that imparts strength and glossy surface finish. It also prevents the roving bobbins from the deposition of flies.

The bore of the empty bobbins has a boss extended inside with a chamfer at the end, where in the holding levers of the bobbin holders are seated. If this would have been damaged the levers may not get seated properly and parallely. And also, in some make of bobbins the ribs provided for boss support will be projecting above the boss, and this will disturb the levers from parallel seating. If so, the bobbin should be immediately changed.
The international concept for the bobbin design if of no ribs projection above the boss. And this will have the levers seated parallely.

The rotation of a bobbin holder should be smooth and uniform. If it is too free it will over run and stop. This will cause stretch which leads to thin places in the yarn.

Studies show that for best result the bobbin holder should be changed after 5-6 years of usage. More usage of the bobbin holders after this period may cause long term unevenness in the yarn.

If any affect to the quality of the yarn arises, the exact reason cannot be pin pointed due to arbitrary change of bobbin holders. The best way is to change the bobbin holders for a complete ring frame.

Studies with a proven framed method have shown a comparable yarn result in Autotex bobbin holders, in terms of rotation and opening and closing mechanism in bobbin holder. It is only a fraction of cost to that of imported bobbin holder.

The future oriented Automatic Bobbin Transport System takes care of the transportation of roving bobbins from the speed frame to the ring spinning frame. Autotex has developed a special version of bobbin holder known as Auto Creel Bobbin Holder. These bobbin holders are specially designed with sturdy construction to meet the precise mechanical and electronically controlled automation requirements.

The advanced speed frame consists of a link conveyor system for carrying full roving bobbins and empty bobbins. For this conveyor system Autotex has developed a special bobbin holder called speed frame bobbin holder. It is capable of fixing into the link of the conveyor, which moves along the speed frame.

The main yarn fault contributed by bobbin holders is long thin fault caused by creel stretch.
Generally in classimat results, the readings of H1, and I1 faults denotes the long thin faults. Long thin fault as per classimat system is defined as faults which have 30 to 40% cross sectional area of normal cross sectional area and extends to 32 cms. There are various reasons for occurrence of the long thin faults, as listed below.

CONTRIBUTORY CAUSES FOR YARN IMPREFECTION
IN RING SPINNING PROCESS: (source- SITRA)
  • High fiber length variation and immature fibres.
  • Uneven roving.
  • Eccentric top and bottom rollers in ring spinning.
  • Insufficient pressure on top rollers.
  • Too high a draft in ring frame.
  • Worn out rings.
  • Traveler clearer set closer.
  • Improper setting of tension bar.
  • Excessive fly liberation in ring frame.
  • Damaged top/bottom roller clearers.
  • Jerky movement of ring rail.
  • Cracked and worn bobbins.
  • Incorrect bobbin diameter and fit of bobbins.
  • Loose and worn out aprons.
  • Incorrect shore hardness of top rollers.
  • Incorrect apron nip opening and settings.
  • Excessive twist in roving.
  • Lack of control in temperature and humidity.
  • Creel stretch in ring frames due to the obstruction in free rotation of bobbin holders.
CONTRIBUTORY CAUSES AT PREPARATORY PROCESS FOR YARN FAULTS:
  • Excessive incidence of web falling (partial or full) or lap licking at cards.
  • Higher drafts at creel and coiler zone in draw frame.
  • Excessive variations in top roller pressure in draw frames.
  • Faulty stop motion of draw frames.
  • Loose top roller and bushes in draw frames.
  • Disturbance in the free rotation of creel calender rollers in draw frames.
  • Sliver stretch of the creel in speed frames due to too high a creel draft.
  • Too high a break draft in speed frame.
  • Excessive roving stretch due to improper function of builder mechanism.
  • Use of bobbin at speed frame with wide variation in bare bobbin diameter.
  • Sliver splitting in speed frames while drafting.
  • Use of excessive tension weights in single end winding.

MBS Bobbin Holder

The new innovation MBS bobbin holder is provided with adjustable multi brake system in 4 stages. It is flexible and user friendly to select the required brake force for the various processing requirements in a single bobbin holder with out removing the bobbin holder from the creel. And each stage is coloured for easy identification.

Most of the spinning mills need to process various materials like cotton, synthetic, worsted and other blends of various hank and counts. The setting in ring spinning machine are needed to be adjusted to achieve desired yarn parameters, in the line of adjustments the rotation of bobbin holder is also needed to be adjusted according to the processing requirements

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