Ring Frame

 

Ring Spinning:

Ring Spinning Technology is a simple and old technology, but the production and quality requirements at the present scenario put in a lot of pressure on the Technologist to select the optimum process parameters and machine parameters so that a good quality yarn can be produced at a lower manufacturing cost.

Figure : Ring Frame

Points to be Considered in a Ring Frame

• Draft distribution and settings
• Ring and travellers
• Spindle speed
• Twist
• Lift of the machine
• Creel type
• Feed material
• Length of the machine
• Type of drive

Raw material characteristic plays a major role in selecting the above said process parameters in Ring Frame. Technical information and guidelines are given below based on the learnings from personal experience and discussions with Technologists. This could be used as a guideline and can be implemented based on the trials taken at site. Some of this information can be disproved in some other applications, because many of the parameters are affected by so many variables. A same machine or raw material cannot perform in the same way in two different factories. This is because of the fact that no two factories can be identical.

Drafting The break draft should depend upon the following,

• Fibre type
• Fibre length
• Roving T.M
• Main draft
• Main Draft Zone

Mostly for cotton fibers, short cradles are used in the top arm. Front zone setting is around 42.5 mm to 44 mm depending upon the type of drafting system. The distance between the front top roller and top apron should be around 0.5to 0.7mm when correct size top roller is used. This is normally taken care of by the machinery manufcturer. If a technician changes this setting, this will surely result in more imperfections, especially with karded count the impact will be more. Therefore when processing cotton fibres, care should be taken that the front zone setting should be according to the machinery.

Ring & Traveller

Ring diameter, flange width and ring profile depends upon the fibre, twist per inch, lift of the machine, maximum spindle speed, winding capacity etc.

Operating speed of the traveller has a maximum limit, because the heat generated between ring and traveller should be dissipated by the low mass of the traveller within a short time available.

If the cotton combed yarn is for knitting, traveller speed will not be a limiting factor. Since yarn TPI is less, the yarn strand is not strong enough. Therefore the limiting factor will be yarn tension. Following points to be considered

1) For 12s to 24s , 42mm ring with 180 mm lift can be used

2) For 24s to 36s, 40 mm ring with 180 lift can be used

3) For 36s to 60s , 38 mm ring with 170 mm lift can be used

4) For 70s to 120s, 36 mmring with 160 mm lift can be used.

5) If winding is a problem, it is better to go for reduced production with bigger ring dia.

6) Anti-wedge ring profile is better, because of better heat dissipation

7) Elliptical traveller should be used, to avoid start-up breaks in hosiery counts

8) Special type of travller clearer can be used to avoid accumulation of fibre on the traveller as traveller with waste does not perform well during start-up.

For polyester/cotton blends and cotton weaving counts yarn strength is not a problem. The limiting factor will be a traveller speed. For a ring diameter of 40 mm, spindle speed upto 19500 should not be a problem. Rings like Titan(from Braecker), NCN(bergosesia) etc, will be able to meet the requirements.

For spindle speeds more than 20000 rpm, ORBIT rings or SU-RINGS should be used. As the area of contact is more with this rings, with higher speeds and pressure, the heat produced can be dissipated without any problem. Normal ring and traveller profile will not be able to run at speeds higher than 20000 to produce a good quality yarn.

ORBIT rings will be of great help, to work 100% polyester at higher spindle speeds. Because, of the tension, the heat produced between ring and traveller is extremely high. But one should understand, that ,the yarn strength of polyester is very high. Here the limiting factor is only the heat dissipation. Therefore ORBIT RINGS with high area of contact will be able to run well at higher spindle speeds when processing 100% polyester.

While running 100% cotton, the fibre dust in cotton, acts like a lubricant. All the cottons do not form same amount of lubricating film. If there is no fibre lubrication, traveller wears out very fast. Because of this worn out or burn out travellers, microwelding occurs on the ring surface,< which results in damaged ring surface, hence imperfections and hairiness increases in the yarn.

Lubrication is good with west african cottons. It may not be true with all the cottons from West africa. In general there is a feeling, cottons from Russia, or from very dry places, lubrication is very bad. If the fibre lubrication is very bad, it is better to use lighter travellers and change the travellers as early as possible.

Traveller life depends upon the type of raw material, humidity conditions, ringframe speeds, the yarn count, etc. If the climate is dry , fibre lubrication will be less while processing cotton.

Traveller life is very less when Viscose rayon is processed especially semi dull fibre, because of low lubrication. 

Traveller life is better for optical bright fibres.

Traveller life is better for Poly/cotton blends, because of better lubricatiion between ring and traveller.

Because of the centrifugal force excerted by the traveller on the yarn, the particles from the fibre fall on the ring where the traveller is in contact. These particles act like a lubricating film between ring and traveller.

Rubber Cots and Apron

For processing combed cotton, soft cots (60 to 65 degree shorehardness) will result in lower U%, thin and thick places

There are different types of cores (inner fixing part of a rubber cot)available from different manufacturers. Aluminium core, PVC core etc. It is always better to use softer cots with aluminium core.

When softer cots are used, buffing frequency should be reduced to 45 to 90 days depending upon the quality of the rubber cots, if the mill is aiming at very high consistent quality in cotton counts.

If the lapping tendency is very high when processing synthetic fibres for non critical end uses, It is better to use 90 degree shore harness cots, to avoid cots damages. This will improve the working and the yarn quality compared to working with 83 degree shore hardness.

If rubber cots damages are more due to lapping, frequent buffings as high as once in 30 days will be of great help to improve the working and quality. Of course one should try to work the ring frame without lapping.

The basic reasons for lapping in the case of processing synthetic fibre is

End breaks

Pneumafil suction

Rubber cots type

Fibre fineness

Oil content(electrostatic charges)

Department temprature and humidity

Almost all the lappings orginate after an end break. If a mill has an abnormally high lapping problem the first thing to do is to control the end breaks,

After doffing

During speed change

During the maximum speed by optimising the process paramters.

It is obvious that fine fibres will have a stronger tendency to follow the profile of the roller. Therefore lapping tendency will be more.

If the fibre is fine, the number of fibres in the cross section will be more, therefore lapping frequency will be more.

If the pressure applied on the roller is more, then lapping tendancy will be more. Hence fine and longer fibres will have more tendency for lapping because of high top roller pressure required to overcome the drafting resistance.

If the pneumafil suction is less, the lapping tendency will be more both on top and bottom roller. But the pneumafil suction depends on the fan diamater, fan type, fan speed, duct design, length of the machine, profile of the suction tube etc. If any one of the above can be modified and the suction can be improved, it is better to do that to reduce the lapping.

The closer the setting between the suction nozzle and the bottom roller, the higher the suction efficiency and lower the lapping propensity

Higher roving twist will reduce the lapping tendency to some extent. Therefore it is better to have a slightly higher roving twist, provided there is no problem in ringframe drafting, when the lapping tendency is more

With Softer rubber cots lapping tendency will be more due to more surface contact.

The most minute pores, pinholes in the rubber cots or impurities in the cots can cause lapping. 

Therefore the quality of buffing and the cots treatment after buffing is very important. Acid treatment is good for synthetic fibres and Berkolising is good for cotton.

Electrostatic charges are troublesome especially where relatively large amount of fibre are being processed in a loose state e.g drawframe, card etc.Lapping tendency on the top roll increases with increasing relative humidity. The frequently held opinion is that processing performace remains stable at a steady absolute relative humidity, i.e. at a constant moisture content per Kg of dry air.

Twist:

The strength of a thread twisted from staple fibres increases with increasing twist, upto certain level. Once it reaches the maximum strength, further increase in twist results in reduction in yarn strength

Coarser and shorter fibres require more Twist per unit length than finer and longer fibres

Twist multiplier is a unit which helps to decide the twist per unit length for different counts from the same raw material.This is nothing but the angle of inclination of the helical disposition of the fibre in the yarn. This is normally expressed as TWIST PER INCH = TWIST MULTIPLIER * SQRT(Ne)

If the two yarns are to have the same strength, then the inclination angles must be the same

For 40s combed knitting application, if the average micronaire of cotton is 3.8 and the 2.5% span length is around 29 mm, Twist multiplier of 3.4 to 3.5 is enough . If the average micronaire is around 4.3, it should be around 3.6 to have better working in Ring frame.

• Cotton combed knitting T.M. = 3.4 to 3.6
• Cotton combed weaving T.M. = 3.7 to 3.8
• Cotton carded knitting T.M. = 3.8 to 4.0
• Cotton carded weaving T.M. = 3.9 to 4.2

The above details are for cottons of 2.5% span length of 27 to 30 mm and the average Micronaire of 3.7 to 4.4. For finer and longer staple, the T.M. will be lower than the above.

In general for processing polyester/viscose , the T.M. is as follows

• 51 mm, 1.4 denier fibre : T.M. = 2.7 to 2.9 for knitting application
• 51 mm, 1.4 denier fibre : T.M. = 2.9 to 3.1 for weaving application
• 44 mm, 1.2 denier fibre : T.M. = 2.9 to 3.0 for knitting application
• 44 mm, 1.4 denier fibre : T.M. = 3.0 to 3.1 for knitting application
• 38 mm, 1.2 denier fibre : T.M. = 3.1 to 3.3 for knitting application

Others

The following ROVING parameters will affect the ring frame process parameters

• Roving T.M.
• Bobbin weight
• Bobbin height

Now we can explain:

Higher the roving T.M., wider the back bottom roller setting or higher the break draft in ring frame

For combed material the creel height should be as low as possible in ringframe

Very long creel heights in ringframe, lower roving T.M. and heavier roving package will result in many long thin places in the yarn.(especially in combed hosiery counts)

In general 16 x 6 " bobbins are used. This helps to increase the spare rovings per machine with higher creel running time. Therefore one should aim at increasing the bobbin weight as well as increasing the number of spare rovings in the ring frame.

Normally 6 row creels are used in modern ring frames. Six row creels will accomodate more spare rovings compared to 5 row creels.(around 150 rovings for 1000 spindle machine.) Creel height should be as low as possible for cotton combed counts. Spare rovings will improve the operators efficiency.

Shorter machines are always better compared to longer machines. But the cost per spindle will go up. 

For cotton , polyester/cotton blends, poly/viscose(upto 44mm length), number of spindles upto 1200, should not be a problem. But maintenance is more critical compared to shorter machines.

For synthetic fibres with very high drafting resistance, it is better to use shorter machines, because the load on break draft gears and on second bottom rollers will be extremely high. If long machines are used and the maintenance is not good for such application, the bearing damages, gear damages, bottom roller damages etc. will increase. This will result in coarse counts, higher count C.V., long thin and thick places.

Four spindle drive is always better compared to Tangential belt drive. Because small variation in machining accuracy of bolster , spindle beam etc will affect the spindle speeds, thereby the twist per inch. Waste accumulation between contact rollers, bent contact rollers, damaged contact rollers, oil spilling from any one spindle etc. will affect the spindle speeds and thereby TPI. The spindle speed variation between spindles in a 5 year old ring frame will be very high in case of tangential belt ? drive compared to 4 spindle drive.

Noise level and energy consumption will be low in 4 spindle drive compared to Tangential belt drive

Compared to Contact rollers, Jockey pully damages are nil. I have worked with 20 year old ring frames with Jocky pulleys, but the variations in spindle speed between spindles is very less compared to a 5 year old ring frame with Tangential belt drive. I have made this comment based on my personal experience.

When processing coarse counts at higher speeds, the air current below the machine is a big problem with 4 spindle drive . This is due to the more running parts like tin rollers and jockey pullyes. This will lead to more fluff in the yarn, if humidification system is not good enough to suck the floating ,fluff.

If spindle speeds is high for cotton counts, every end breaks will result in more fluff in the department due to the free end of the yarn getting cut by the traveller when the distance between traveller and the bobbin with the yarn is less. Higher the delay in attending the end break , higher the fly liberation. If the number of openings of return air system for a ring frame is less and the exhaust air volume is not sufficient enough, then fly liberation from an end break will increase the end breaks and thereby will lead to multiple breaks. End break due to a fly entering the traveller will get struck with the traveller and will result in heavier traveller weight and that particular spindle will continue to work bad.

Multiple breaks are very dangerous, as it will result in big variation in yarn hairiness and the ring frame working will be very badly affected due to heavier travellers because of the fluff in the traveller.

Dry atmosphere in ring frame department will result in more yarn hairiness, more fly liberation and more end breaks

It is a good practice to change spindle tapes once in 24 months. Worn out spindle tapes will result in TPI variations which is determinetal to yarn quality.

Carding Process

 

Carding Process

Introduction:

Carding is the most important process in spinning. It contributes a lot to the yarn quality. The following process parameters and specifications are to be selected properly to produce a good quality yarn with a lower manufacturing cost cylinder wire(wire angle, height, thickness and population) flat tops specification licker-in wire specification doffer wire specification feed weight draft between feed roller and doffer cylinder grinding doffer grinding flat tops grinding cylinder, flat tops, doffer wire life Licker-in wire life Cylinder speed flat speed Licker-in speed setting between cylinder and flat tops setting between licker-in and feed plate setting between lickerin and under casing elements like, mote knife, combing segment etc. setting between cylinder and doffer setting between cylinder and back stationary flats setting between cylinder and front stationary flats setting between cylinder and cylinder under casing.

Setting of Carding Machine

Setting of Carding Machine

Fig: Carding Machine (Side View)

Cylinder Wire and Cylinder Speed:

Cylinder wire selection is very important, it depends upon cylinder speed, the raw material to be processed and the production rate. The following characteristics of cylinder wire should be considered.

• Wire angle
• Tooth depth
• Wire population
• Rib thickness
• Tooth profile
• Tooth pitch
• Tooth point
• Overall wire height

Wire front angle depends on mainly cylinder speed and coefficient of friction of raw material. Higher the cylinder speed, lower the angle for a given fibre. The cylinder speed in turn depends upon the production rate. Higher production means more working space for the fibre is required. It is the wire that keeps the fibre under its influence during carding operation. Therefore the space within the wire should also be more for higher production. Higher cylinder speed also increases the space for the fibre. Therefore higher cylinder speed is required for higher production. In the case of high production carding machines, the cylinder surface is very much higher, therefore even with higher number of fibres fed to the cylinder, the cylinder is renewing the carding surface at a faster rate.

Higher the cylinder speed, higher the centrifugal force created by the cylinder, this tries to eject the fibre from the cylinder, along with the trash. It is the cylinder wire's front angle which overcomes the effect of this force. Low front angle with too low cylinder speed and with high frictional force will result in bad quality, because the fibre transfers from cylinder to doffer will be less. Hence recycling of fibres will take place, which result in more neps and entanglements. The new profile with less free blade avoids loading of the cylinder with fibre and/or trash. This helps in keeping the fibres at the tip of the tooth. The movement of the fibres towards the tip of the tooth coupled with centrifugal action demands an acute front angle to hold the fibre in place during carding. Lack of stiffness associated with fine and/or long fibres necessitates more control during the carding process. This control is obtained by selecting the tooth pitch, which gives the correct ratio of the number of teeth to the fibre length. Tooth pitch reduction is therefore required for exceptionally short fibres and those lack stiffness. Number of points across the carding machine is decided by the rib width. It is selected based on the production rate and fibre dimensions. Finer the fibre, finer the rib width. The trend is to finer rib width for higher production.

The population of a wire is the product of the rib thickness and tooth pitch. The general rule is higher populations for higher production rates, but it depends upon the application. Sharp tooth points penetrate the fibre more easily and help to intensify the carding action. Cut-to-point wires are sharp and they have no land at all. The effective working depth of a cylinder wire tooth for cotton is approximately 0.2mm and for synthetic materials approx.0.4mm. Manmade fibres require more space in their cylinder wire than doe's cotton. More tooth depth allows the fibre to recycled, resulting in damaged fibres and neps. If tooth depth is insufficient, there will be loss of fibre control. This will result in even greater nep generation. Looking into the above details, the following specifications can be used as a guideline.

DOFFER, LICKER-IN AND FLAT TOPS:

The basic function of doffer is to strip the fibres from Cylinder. Please remember that the action between cylinder and doffer is carding action (or combing action or point to point action).

The doffer wire's front angle plays a very important role in releasing the fibre from the cylinder. For most carding applications the optimum angle is 60 degrees.

Increased population over 400 ppsi does not give any advantage in the production of quality yarn. For smaller doffers, 5 mm doffer wire height helps in transferring the fibres from cylinder to doffer.

If the fibre holding capacity of the doffer wire is less due to fibre friction or due to very high doffer speed, it is better to use a doffer wire with striations. For high production carding itis always better to use doffer wire with striations.

Licker-in plays a major role in opening the fibre tufts. In general 85 degrees is used both for synthetic and medium and long cottons. For coarse and dirty cottons 80 degrees can be used.

Strength, hardness and sharpness are very important for Lickerin wire. Licker-in wires should never be ground. Thinner blades penetrate the fibres more efficiently and increase the wire life.

Higher number of rows per inch gives better results. Now up to 12 rows per inch is being used. This is always better compared to 8 rows per inch.

If the wire pitch is not sufficient, it can be compensated by increasing the licker-in speed. Higher licker-in speeds for fine and long cottons will rupture the fibres. Licker-in speed depends upon the fibre type and the production rate.

It is better to use a flat top with more than one population. The general combination is 280/450. This is suitable for both cotton and synthetics. Please remember that the rigidity of the fillets is different for cotton and synthetic. If cotton flat tops are used for synthetic processing, the load on the cylinder will be more, more heat will be produced and hence the probability of cylinder loading due to electrostatic charge will be high.

Instead of using Rigid type flat tops, it is better to use semirigid type flat tops while processing synthetic fibres.

SETTINGS:

The setting between cylinder and doffer is the closest setting in the card. This setting mainly depends upon the cylinder speed, hank of the delivered sliver and the type of wire. Cylinder speed up to 360, the setting should be 0.1mm. For cylinder speeds more than 450, the setting ranges from 0.125 to 0.15.

If the setting between cylinder and doffer is very close, the wires will get polished and this will affect the fibre transfer. If the setting is too wide, the fibres will not be transferred to doffer from the cylinder, hence cylinder will get loaded. While processing synthetic fibres cylinder loading will badly affect the yarn quality. Moreover, it is difficult to improve the wire condition if the loading is severe. \

The only solution would be to change the wire. Therefore enough care should be taken while processing synthetic fibres.

The most critical setting in a carding machine is between cylinder and flat tops. While processing cotton, it can be as close as 0.175 mm provided the mechanical accuracy of flat tops is good. Since most of the cards are with stationary flats at the licker-in side, the setting from the back to front for flats can be 0.25, 0.2.0.2, 0.2, 0.2mm.

Closer the setting between cylinder and flats, better the yarn quality. Neps are directly affected by this setting. Of course, very close setting increase the flat waste. For processing cotton the setting can be 0.25, 0.2, 0.2, 0.2, 0.2mm. For synthetic fibres it can be 0.3, 0.25, 0.25, 0.25, 0.25mm

Most of the cards are with 6 to 1 1 stationary flats at the licker-in side. This setting can start with 0.4 mm and end with 0.25mm.

The wire points can start with 140 ppsi and end with 320 ppsi. The work done by the first few stationary flats is very high; therefore the wear of these flats is also high. It would be better if the first 50% of the flats are changed after 100000 kgs of production and the rest after 150000 kgs of production.

These stationary flats open the material so that, the setting between cylinder and flats can be as close as possible.

The setting between feed plate and Licker-in depends upon the type of feed plate. Conventional feed plate setting is decided mainly by the feed weight and to some extent by the fibre length and type. 

With the latest feed plate and feed roller arrangements, the setting is decided mainly by the fibre length and to some extent by the feed weight.

Normally the setting between the feed plate and Lickr-in is around 0.45 to 0.7mm, depending upon the feed weight and fibre type.

The setting between Licker-in and the first mote knife is around 0.35 to 0.5 mm. This helps to remove the heavier trash particles and dust. Closer the setting, higher the wastage. The setting between 

Licker-in and combing segments is around 0.45 to 0.6. This helps to open the material.

Some cards have two mote knifes in the Licker-in under casing. The setting is around 0.4 to 0.5mm. 

This helps to remove the smaller trash and dust particles.

The setting between the cylinder and stationary flats at Doffer side helps to transfer the fibres to doffer by stripping the fibres to the top of the cylinder wire. This setting can be as close as 0.15mm. 

The number of wire points on stationary flats also plays a major role. It is normally around 300 to 400. For a high production application it can be as high as 600.

For cotton processing, the stationary flats are fixed with a knife attachment. The setting should be as close as possible, i.e. around 0.15mm. This helps to remove the trash particles of very small size.

The setting between cylinder and cylinder under casing should be as per the manufacturer's recommendation. The design of under casing is different for different manufacturers. This setting is very important, as wrong settings will affect the fibre transfer and can also create air turbulence.

SPEEDS:

Higher cylinder speed helps fibre transfer. Higher the production, higher should be the cylinder speed.

Higher cylinder speed improves carding action, thereby imperfections are reduced.

Higher Licker-in speed for coarse fibres and dirty cotton helps to remove the trash and improves, the yarn quality. For fine and long cottons, higher speed results in fibre rupture, therefore, flat waste and comber noil will be more.

Higher flat speed, improves yarn quality and at the same time increases the flat waste.

With the same flat speed, higher the carding production, lower the flat waste and vice-versa.

Very high tension drafts will affect carding U%. It is better to keep the draft between feed rollers to doffer around 75 to 95. The results are found better with these drafts.

WIRE MAINTENANCE:

For a modern cylinder wire of 2mm height, grinding with the normal grinding stone is not recommended. It is better to use TSG grinder to grind the wire every 2nd or 3rd month, so that the 

sharpness of the wire is always maintained.

TSG grinder does not grind the wire, therefore if the wire is worn out very badly the quality improvement using this grinding machine will be nil. Frequent grindings are recommended. If TSG grinder is not available, it is better not to grind 2mm wires.

The number of traverse should increase depending upon the life of the wire. The number of traverse for successive grindings should be like this 3, 5, 10, 17 etc. Anyway the best method is to confirm with the microscope. If the grinding is not sufficient, the number of traverse should be increased.

Doffer is still working with a concept of Land formation. A normal grinding machine will be good for doffer grinding. All the wire points should be touched by the grinding stone. A slow and gradual grinding with the grind-out concept will give the best results. Harsh grindings will result in burr formation on the land. This will increase the number of hooks in the fibre; thereby the effective length of the fibre from this card will be reduced.

Flat tops grinding is very important. Every time a flat top is ground, yarn quality is improved. It is better to use a grinding machine with the emery fillet. Frequent flat tops grinding will result in less neps and the yarn quality will be consistent.

Some mills increase the life of the flat tops compared to cylinder wire. But it is better to change flat tops and cylinder wire together for better and consistent yarn quality.

It is a good practice to check the individual card quality before changing the wire.

Licker-in wire should be changed for every 150000 kgs. Earlier changes will further improve the yarn quality.

Stationary flats should be changed for every 150000 kgs. But it is a good practice to change the first 3 or 6 stationary flats at Licker-in side for every 100000 kgs. This helps to maximize the carding effect between cylinder and doffer which is critical for better yarn quality.

Reference # http://textilelearner.blogspot.com/

Draw Frame

 

Draw Frame

Draw frame is a machine for combining and drawing slivers of a textile fiber (as of hemp for rope manufacture or cotton for spinning). Drawing is the operation by which slivers are blended, doubled and levelled. In short staple spinning the term is only applied to the process at a draw frame. In drawing slivers are elongated when passing through a group of pair rollers, each pair is moving faster than previous one.

Objects of drawing

·          To straighten the crimped, curled and hooked fibers.

·         To make the fiber parallel to their neighbors.

·         To improve uniformity of fibers by drafting and doubling.

·         To reduce weight per length unit of sliver.

·         To remove dust from slivers.

·         To blend raw material of same hank perfectly.

Importance or Necessity of Draw frame in Yarn Production

·         To parallelization of fiber and blending the carded sliver, draw frame is needed.

·         In carded sliver, fibers are present in hook form i.e. trailing hooks and leading hooks. To parallel these hooks raw frame is used.

·         Majority of the fiber hooks in a carded sliver are trailing hooks while leading hooks are comparatively less.

·         Trailing hooks are also known as major hooks, while leading hooks are known as minor hooks.

Actions Involved in Draw Frame

Drafting: It is the process of increasing length per unit weight of sliver. It is mainly due to peripheral speed of the rollers.

Doubling: The process of combing two or more carded sliver into a single form is called doubling. In draw frame m/c generally six slivers are fed to convert into one i.e. six doubling.

Drawing: In the cotton industry the term is applied exclusively to processing on the draw frame, where the operation is one of doubling and drafting. Drawing= Drafting + Doubling.

Tasks of Draw frame

·         Equalizing

·         Parallelizing

·         Blending

·         Dust removal

Equalizing: One of the main tasks of draw frame is improving evenness over short, medium and especially long terms. Carded slivers are fed to the draw frame have degree on unevenness that cannot be tolerated in practice and slivers from the comber contain the “infamous” piecing. It is obscured by draw frame.

Equalizing is always performed by a first process, namely doubling and can optionally also be performed by a second process, namely auto leveling. The draft and the doubling have the same value and lie in the range of 6 to 8.

Parallelizing: To obtain an optional value for strength in the yarn characteristics, the fibers must be arranged parallel in the fiber strand. The draw frame has the tasks of creating this parallel arrangement. It fulfills the task by way of the draft, since every drafting step leads to straightening the fibers.

Blending: In addition to the equalizing effect, doubling also provides a degree of compensation of raw material variation by blending. Their results are exploited in particular way in the production of blended yarns comprising cotton or synthetic blends. At the draw frame metering of the individual components can be carried out very simply be selection of the number of slivers entering the machines.

Dust Removal: Dust is steadily becoming a greater problem both in processing and for the personnel involved. It is therefore important to remove dust to the greatest practical extent at every possible point within the overall process.

Dust removal can only be carried out to a significant when there are high levels of fiber. Since a large function the smallest particles adhere relatively strong to the fibers. High performance draw frame is equipped with appropriate suction removal systems; more than 80% of the incoming dust is extracted.

Blow Room

 

Blow Room

Blow room is the initial stage in spinning process. The name blow room is given because of the "air flow" And all process is done in blow room because of air flow. Blow room is consisting of different machines to carry out the objectives of blow room. In blow room the tuft size of cotton becomes smaller and smaller. In a word we can say a section in which the supplied compressed bales are opened, cleaned & blending or mixing to form uniform lap of specific length is called Blow room section. During the opening, cleaning, blending or mixing different faults or defects occur in blow room. Now I will discuss about faults/defects, causes and way to remedies in blow room section.

Problems/Faults/Defects in Blow Room:

1.      Low cleaning efficiency

2.      High nep generation and fibre rupture

3.      High variability in the delivered hank

4.      Formation of cat's tail

5.      Conical lap

6.      Lap licking

7.      Patchy lap

8.      Holes in lap

9.      Soft laps

10. Ragged lap selvedge

Causes and Remedies are discussed below:

Low cleaning efficiency:

Lower extraction of wastes than required for that mixing considering the trash content is one of the main reasons for low cleaning efficiency. Increase the wastes if the lint in the wastes is normal or nil. If the beater speeds are lesser than required, we get lower cleaning. Check the beater settings and correct them if needed. Increase the space between the grid bars. Close slightly the air-inlets under the grid bars towards the cotton entry side, and open those on the delivery side. Reduce the fan speed following the beaters by 100 to 200 RPM. If the grip of the feed roller is less, we shall get low cleaning efficiency. Therefore check for the grip. Also check the sharpness of the beaters. Check the synchronization of the machine working. The blending bale openers should work for 80 to 85% of the time of working of the final machine. If there is a back draught because of not cleaning the wastes under the machines, the cleaning efficiency shall come down.

High NEP generation and fibre rupture:

The main reasons are blunt beaters, burrs in grid bars, bent pins on beaters, higher beater speed, lower fan speed and excessive feed. A higher beater speed shall give more neps, if the material is not moved out of the beating area effectively. If materials return back to beaters, neps shall generate, hence check the setting of leather flaps, stripper knife etc. Excessive of soft wastes fed, and cottons with more immature fibres are major reasons for neps in opened material. Therefore have a control on the issue of soft wastes to mixing and spread them uniformly throughout the mixing.

High variability in the delivered hank:

Improper levels in the hoppers, improper action of feed regulators viz, cone drums, pedals, photocells, direct driving gear motors, etc are the normal reasons for variability in delivered hanks.

Formation of cat's tail:

If material movement is less and cottons are over beaten, we get this defect. By sharpening beater edges, increasing fan speeds, increasing the air in-let below the grid bar area of cotton entry, closing the striping knife and beater setting shall avoid cat's tail. The very important step in avoiding cat's tail is to avoid chocking of materials in beaters. Excessive use of cotton-spray oil, water etc., also causes cat's tails.

Conical lap:

Conical laps are due to, either higher quantity of cottons coming on one side of the lap, or due to unequal calendar and rack pressures in scutchers. Ensure equal opening of air-inlets under grid bars, replace torn leather lining at the cage, clean the cage thoroughly with emery paper, make pressure on lap spindle uniform on both the sides, remove the pedals and clean thoroughly, and check the pedals where it rests on fulcrum and also pedal fulcrum bar.

Lap licking:

Lap licking can be due to excessive addition of soft wastes in mixing, higher rack pressures, lower compacting of laps and excessive dampness in cotton. In case of polyesters, this problem shall be mainly due to static charges and higher bulk of fibres. The problem of lap licking can be reduced by increasing the pressure on calendar rollers, reducing the pressure on racks, increasing the quantity of antistatic, use of roving ends or lap fingers behind the calendar roller nip, blocking of top cage and by reducing the lap length.

Patchy lap:

Patchy lap is a result of unopened tufts. Ensure that the mixing is opened thoroughly, and increase opening points if feasible. Check tuft size at the delivery of each beater, and adjust the setting between feed roller and beaters, reduce the gauge between evener roller and inclined lattice, clean the cages, and increase effective suction at cages.

Holes in lap:

Holes in the lap can be due to different reasons. Check the cages for damage, and reduce tension draft.

Soft lap:

Lower calendar pressure makes the laps soft. Increase the calendar roller pressure.

Ragged lap selvedge:

Ragged lap selvedges are mainly due to uneven spots at the edges. Check for the rough spots on the sides of the feed plates, leather linings for the cages, and keep the edges of the scutcher clean.

References:

1.      Training and development of technical staff in textile industry by B. Purushothama

2.      Scribd.com/doc/62931880/Spinning

Study on different types of drives used in textile machine.

 

Experiment Name: Study on different types of drives used in textile machine.

Objective:

I)                   Observe different types of drives.

II)                Make a short report about drives.

Theory of drives: The parts of machine used to transmit motion from one component to another component then it’s called drives.

List of different types of drives:

I)                   Pulley & Belt

II)                Gear

III)              Sprocket and chain

IV)             Tappet.

V)               Variable drives.

I)                   Pulley & Belt:

A belt is a loop of flexible material used to mechanically link two rotating shafts most often parallel. Belt may be used as a source of motion to transmit power efficiently. Belts are looped over pulleys. Inn a two pulley system the belt can either drive the pulleys normally in one direction, or the belt may be crossed, so that the direction of driven shaft is reversed.

Types of pulleys and belt:

a)     Flat pulley and belt.

b)    V- belt

c)     Timing belt.

d)    Round belt.

e)    Etc.

A)   Flat belts and pulleys:

The flat belt is a simple system of motion transmission. It can deliver high power at high speed. But this wide belt and large pulleys required lots of space and high tension for operation.

Fig: Pulley and Belt

B)    V belts:

V belts are mostly used for transmission motion. They provide the best combination of traction, high speed of movement and long service life. It solved the alignment problem but it still there is a problem called slippage.

Fig: V- Pulley and belt

C)    Timing belt:

When the slippage of belt is a big matter to production there we used timing belt.

Fig: Timing Belt

D)   Round belt:

Round belts are circular cross section belt designed to run a pulley with v-groove. Round groove are only suitable pulley that guide the belts.

FIG: Round Belt

II)                Gear:

A gear is rotating machine parts having cut teeth which mesh with another toothed part to transmit power or motion.

Fig: Gear

Different types of gear:

I)                   Straight cut gears.

II)                Hailed gears.

III)              Bevel gears.

IV)             Warm gears.

.

a)    Straight cut gears:

These are simplest types of gear. They consist of a cylinder or disks with projecting radially. The each tooth is straight and align parallel to the axis of rotation.

b)    Hailed gear: Hailed gear offer a refinement over straight cut gear. The leading edges of the teeth are not parallel to the axis of rotation, but are set of an angle.

c)     Bevel gear:  A bevel gear is shaped like right circular cone with most of its of. It stands and make 45⁰  angle to transmit motion.

d)    Tappet: A tappet is a projection that imparts a linear motion of some other component with is a mechanism.

e)    Variable drive: Its slow the drives motion in time constantly.

Conclusion: Drives are important for transmit motion. Noted and draw diagram carefully.

Conclusion:………………………

Study on middle and back roller of ring frame machine.

 

Experiment Name : Study on middle and back roller of ring frame machine.

Introduction: Middle and Back roller operated in drafting zone of a ring frame machine. Th objective of that two roller is to draft the roving to convert into yarn.

Objective:

1) To learn about gearing of back roller.

2) To learn about gearing of middle roller.

3) To calculate those roller speed.

Figure:

Calculation:

Speed of middle roller =

(131 X 20 X 23 X 40 X 33 X 63 X 81) / (80 X 77 X 81 X 63 X 81 X 26) [131 = front roller speed]

= 6.131

Speed of back roller

(131 X 20 X 23 X 40 X 22 X 60 X 69) / (80 X 77 X 81 X 60 X 69 X 23) [131 = front roller speed]

= 4.62

Result : 

Speed of Middle roller = 6.131

Speed of Back Roller = 4.62

Conclusion:>>>>>>>>>>>>>>>>

Study on calculation of draft constant of ring frame machine.

 

Experiment Name: Study on calculation of draft constant of ring frame machine.

Introduction:

Drafting is one of the major operation of ring frame machine. Ring frame contain three pairs of roller called front roller, middle roller, back roller. Draft = Draft Constant / D.C.P

Objective:

1) To learn about draft, draft constant, D.C.P

2) To write a report according this experiment.

Figure:

Calculation:

Draft Constant = (23 X 60 X 81 X 77 X 80 )  / (69 X 22 X 1 X 23 X 20)  =  986

Draft =  Draft Constant / DCP = 986 / 40 = 24.65

Conclusion: >>>>>>>>>>>>>>>>>>.

Study on gearing of front roller of ring frame.

 

Experiment Name: Study on gearing of front roller of ring frame.

Introduction: Front roller is located on the drafting zone of the ring frame. Production of ring frame is depend on the speed of ring frame.

Objective:

1) To learn about gearing of front roller of ring frame.

2) To learn about related machine parts transmit motion to front roller.

Figure:

Calculation:

Speed of front roller

= (1440  X 6 X 36 X 39 X 19 X 50)  / (7 X 69 X 130 X 28 X 50)  RPM

= 131

Conclusion:>>>>>>>>>>

Study on spindle and spindle speed calculation of ring frame.

 

Experiment No: 02

Experiment Name: Study on spindle and spindle speed calculation of ring frame.

Theory : The ring frame  is the most widely used form of spinning machines due to significant advantages in comparison with the new spinning process.  Ring frame machine used to spinning fibres, such as cotton, flax or wool, to make a yarn. In ring frame, the roving is the first attenuated by using drawing rollers, then spun and wound around a rotating spindle which in its turn is contained within an independently rotating ring flyer.

The spindle is the main part of a ring frame which helps in twisting, winding simultaneously. Sometimes, spindle referred as ‘heart of spinning’. It hold the bobbin, somewhat loosely but tight enough to prevent slippage.

Objectives:

1. To know about the different parts of the ring frame.

2. To know about the function of the different parts of the ring frame machine.

3. To know about the driving mechanism of the spindle

Different Parts of Spindle:

• 
  
• The parts of spindle are given below:-
•     Spindle blade.
•    Wharve.
•        Bolster.
•       Lock.
•       Bearing.
•      Bolster cage.

Calculation:

Motor R.P.M = 1440

Motor pulley dia = 6"

Machine pulley dia = 7"

tin cylinder dia = 8"

Tape thickness = 1mm  = 0.0393"

spindle whrave dia = 0.95

slippage = 5 %

R. P. M of spindle = {1440X6X(8+0.0393)X.95} / {7X (0.95 + 0.393)}

                                = 9528.60  = 9529

Result : Speed of spindle 9529 R.P.M

Conclusion: >>>>>>

Study on passage diagram of ring frame

 

Experiment:  Study on passage diagram of ring frame.

Theory: 

The ring spinning machine was first invented in 1828 by the American Thorp. In 1830, another American scientist, Jenk, contributed the traveller rotating on the ring. There have been many development has done in ring spinning machine for the last years but the basic concept remained unchanged.

Objectives:

1. To produce required count of yarn from the supplied roving by the drafting.

2. To insert sufficient amount of twist to the yarn.

3. To winding the yarn onto the bobbin.

4. To build the yarn package properly.

Main Parts Ring Frame:

1. Creel

2. Guide roller

3. Trumpet

4. Drafting rollers

5. Yarn guide

6. Lappet

7. Balloon controlling ring

8. Traveler

9. Ring

10. Spindle

Diagram :

Description:

The feed material come from speed frame i.e. roving bobbin is placed on the creel. The creel which is attached to the machine is umbrella type. Then feed material is passed under the guide rollers and through the trumpet in to the drafting zone. Here some draft is inserted in to the roving. The draft system is 3 over 3 drafting system with apron. The delivery material that is delivered from the front roller is reached to the traveler over pneumatic waste collector, lappet and through balloon controlling ring. Lappet is used to control the material path and balloon controlling ring is used to control the balloon formation and spinning tension. Here roving is twisted by the movement of the traveler around the ring. The yarn is then wound on the ring cop.

Conclusion: >>>>>>>>>>>>>>>>>>>>>>>>>