Wednesday, March 4, 2020

PRECAUTIONS OF RING FRAME PROCESS


PRECAUTIONS OF RING FRAME PROCESS:

Following precautions are taken during ring frame process:

The "low weight of the traveller" does not allow the distraction of the  heat generated in the  available short period. This drawback of ring frame process makes traveller speed limited .

The   "very high spindle speed" causes thermal damage of traveller. The  speed restriction occurs during spinning of high strength cotton yarn. The traveller temperature increases up to 400°C - 500°C and the danger of the traveller annealing and failing  increases highly.

The top roller loading system plays important role in the drafting system. The "pneumatic loading system" gives improved performance and setting accuracy. The pressure actuating on the all the top rollers is regulated easily with the help of pressure regulating valve. This loading system helps to prevent the deformation of rollers during idle machine position because the pressure is reduced to minimum level.

When the spindle speed is increased, the friction work between ring and traveller (the build-up) increases.

 The upper apron should be pressed with controlled force against the lower apron accurately.


 When the synthetic or coarse material is processed in the ring frame, the possibility of wear of front top roller is increased. The lapping problem also occurs in the synthetic material processing. Hard rubber cots should be used to avoid these problems.


The use of longer lower apron has  advantages over shorter aprons. It can  be replaced easily  in case of damage. It also has less chances of chocking with fluff.

 A controlled spacing (exit opening) between upper and lower aprons at delivery point should be selected accurately according  to the fibre volume. The setting of this spacing is done with the help of a special tool called “spacer or distance clips”.

The "centring of the spindles" relative to the rings should be done precisely.  The optimum  degree of accuracy in centring of the spindles relative to the rings is required.

Speed of ring frame machine plays a great role in the yarn quality to be produced. The "total imperfection" gets increased when the working speed of machine increases.

The centring of spindle and ring should be conducted after a certain interval of time regularly.

•  The "degree of yarn hairiness" gets also increased due to burnt traveller. The quality analyses should be conducted after every speed change in ring frame process.

The use of "anti-wedge ring" allows to use traveller having lower centre of gravity and precisely adapted bow (elliptical travellers). This combination of  ring and traveller helps to achieve higher spindle speed in the ring frame machine.

 The "low crown ring" creates space for the passage of the yarn. The decreased curvature of the traveller and lowered centre of gravity can be obtained.

The low crown ring gets  widely used ring frame now. The low crown ring poses advantage over anti-wedge ring because it provides larger space for the passage of yarn.  All the shapes of traveller can be used with this ring except elliptical traveller.

Surface smoothness of ring  should be good but not too high. The high smoothness doesn't allow to develop the lubricating film on ring surface.

 If the speed of traveller gets increased beyond normal levels, the thermal stress limit of the traveller is increased highly. A drastic change in the wear behaviour of the ring and traveller gets  occurred.

The spinning tension affects the yarn strength little bite. The residual  elongation in the yarn gets reduced.

The increasing tension in the ring frame process also affects  yarn regularities. The total imperfection gets increased.

The higher spinning tension results in the form of  smaller spinning triangle. The smaller spinning triangle always helps to reduce the degree of hairiness.

The traveller must be shaped to match exactly with the ring in the contact zone, so that a single contact surface, with the maximum surface area is created between ring and traveller.

If the yarn clearance opening is too small, rubbing of the yarn on the ring causes roughness in the yarn. The fibres loss as fly gets increased.

When the yarn runs through the traveller, some fibres get liberated. The most of these fibres get float away as dust into the atmosphere, but the traveller catches some fibres. These fibres has the chances to generate Tufts. Thus the traveller weight can get increased. The end breakage rate can get increased too.

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