Reasons for Poor Quality in Ring Spinning

Poor quality in spinning may be defined as a combination of factors such as the technical parameters of yarn being out of the acceptable tolerance limits of the customers, presence of objectionable faults and labels, improper packing leading to damages while handling, shabby packing resulting in time consumption while opening and extra space for storage, delay in despatch causing loss to the customer and penalty to the company, increased cost of manufacturing pushing the organization to a loss, short supplies and over productions leading to accumulation of finished material as stock. However, in practice, the terminology of quality is used for product parameters by the technicians in shop floor, but for the top management, everything is important as the company’s profitability depends on the total quality and not only on the technical parameters. The technicians, therefore, are suggested considering everything together and not concentrating only on the technical parameters.

It is a normal belief that adapting latest machinery with good technology results in good quality of yarns compared to old machinery and technology. Therefore, the mills invest on latest technology. There are number of factors responsible for the poor quality. They are raw materials, work methods, the condition of the machinery and the management systems adapted.

Raw material
There is a direct relationship between certain quality characteristics of the fibre and those of the yarn. Seventy to eighty percent of basic yarn quality is decided by the raw material. The fibre properties like the staple length, uniformity in staple length, short fibre contents, fineness, strength, elongation, maturity, etc., play a role. If the micronaire is coarse, the number of fibres in the yarn cross section will be less. This always results in lower strength and lower elongation. But it is easy to process coarse micronaire fibres in blow room and cards. Nepping tendency is less for coarse micronaire fibres. On the contrary, spinnability (in both speed frame and ring frame) is not good with coarser micronaire fibres. U% is affected by micronaire. Coarser the micronaire, higher shall be the U%. Coarser the fibre, higher the end breakage rate in spinning. Uster thin place (30%) in the yarn vary depending upon the fibre micronaire. Lower the micronaire lower the thin places and vice versa.

Raw materials if not suitable for the product being produced cannot give the quality parameters as needed. We need to understand the quality objectives of the product and decide the raw materials. The factors like feel of the fabric, hairiness in the surface of fabric, strength of the yarn and the fabric and dye ability are governed by the raw material properties. Just by spending more money on superior fine cotton cannot give the quality required by the customer, but shall increase the cost of manufacture leading to a loss to the company.

Raw material should be suitable for the machine being worked. The machines are normally designed for a range of raw materials, and we need certain modifications while working. The type of opening machines differ from cotton to synthetics, and also with in the cottons itself from fine to superfine cottons. Coarser wire points are used for carding polyester, whereas for cottons we have different wire configuration. The nose plates are different for cotton and polyester. In ring frames, large diameter bottom rollers of 30 mm are used for long staple synthetic fibres compared to 27 or 25 mm diameter for cottons. The cradle sizes used in drafting are different for different staple lengths. Similarly there are number of changes in the machine configuration to suit different raw materials. If we are not clear about the same, inspite of having latest machinery and good raw materials, we might produce bad quality yarns.

Variations, mix-ups, contaminations and damages in raw materials are also responsible for poor quality yarns. The selection of raw materials for the product and the machines play a vital role in getting the required quality. Apart from the selection of raw materials, the ways in which they are handled and used also play an important role. 
Following are some examples.
  1. Improper selection of raw material
  2. Variations in raw material
  3. Handling and storage damages
  4. Damages due to improper ginning in case of Cotton
  5. Fused fibres in case of synthetic staple fibres
  6. Presence of uncut fibres in staple fibres
  7. Packing of cotton bales with polyester cotton cloths/HDPE/polypropylene cloths
  8. Inadequate number of lots in a mixing
Work methods
The work methods are very critical for getting the required quality of yarn. One can get a good result inspite of fairly poor raw material or old machine provided appropriate work methods are followed. We can group the work method related factors as follows:
  • Old systems/practices not modified as per the new requirements
  • Inadequate training and lack of knowledge
Let us discuss the normal bad work practices seen at different processes of a spinning mill.

  • Not verifying the lot numbers and bale numbers before taking the mixing
  • Taking more bales from a lot for mixing
  • Not clearly defining/understanding the quantity of materials to be taken from each mixing component
  • Uncontrolled mixing of soft wastes
  • Putting all soft wastes at one place in a stack
  • Not taking materials from each bale uniformly while making a stack mixing
  • Not keeping the bales in allocated place while mixing or feeding to bale pluckers
  • Not removing the Hessian/HDPE covering and bale hoops properly
  • Not opening the cottons thoroughly
  • Not removing the big visible contamination while opening the bales and doing mixing
  • Keeping chappals/slippers, etc., near the mixing bin
  • Not cleaning the floor thoroughly before laying a new mixing
  • Not updating the identification boards
  • Pouring more water/cotton spray oil at one place
  • Handling the mixing in wet condition
  • Sleeping on the mixing bin during leisure hours
Blow room
  • Improper selection of cleaning and opening points for the mixing in hand
  • Not cutting the mixing vertically while feeding to mixing bale opener
  • Using improperly conditioned mixing in case of stack mixing
  • Feeding big lumps of cotton to bale breaker
  • Widening the settings to have more production
  • Too close a setting resulting in over beating and fibre damages
  • Laps of longer lengths
  • Applying excessive weights on lap spindles to get a compact lap
  • Not removing the accumulated wastes in time resulting in back firing and waste contaminations
  • Not cleaning the magnets on time
  • Not properly closing the doors
  • Not properly following colour codification for laps
  • Not maintaining the work area clean
  • Not cleaning the sensors in photo electric controls
  • Using of bent lap rods
  • Using torn filter bags
  • Cleaning the machines with brooms while working
  • Using compressed air for cleaning while machines are working
  • Bringing the laps on head or by touching it to the body
  • Not properly feeding the laps resulting in doubles or singles in sliver
  • Not removing the doubles and singles
  • Not removing the wastes in time
  • Not keeping the carding area clean
  • Not cleaning the card sides with a clean broom stick regularly
  • Twisting too much while piecing the slivers
  • Not following the correct colour codification and channeling
  • Not stripping the cards in time
  • Not removing the accumulated flat strips in time
  • Not cleaning the Phillipson rollers in time
  • Making the stop motions inactive
  • Keeping the doffer cover up while running
  • Keeping the side covers and belt guards open
  • Over filling the cans
  • Not removing the wastes from can bottom before placing below coiler
  • Using damaged cans and spring plates
  • Not cleaning the castors regularly
  • Pressing the sliver in the can by hand
  • Not covering the sliver in cans that are in stock
  • Use of compressed air for cleaning while machine is working
Draw frames
  • Not creeling the cans as per the allocation given (Card number wise or drawing delivery wise)
  • Keeping the feeding cans much away from the creel
  • Overlapping the slivers while piecing in the creel
  • Cutting the sliver in cans at creel and reversing for adjusting the cans in creel
  • Not removing the sliver wastes from the spring bottom before putting cans in the machine
  • Not removing the slivers from the can whenever there is a lapping
  • Making the stop motions inactive
  • Not getting the cots buffed in time
  • Replacing the top rollers without verifying the diameter and surface condition
  • Not greasing the top roller bushes in time with proper grease
  • Using sharp knives to remove lapping resulting in damaged cots
  • Not removing the suction box wastes in-time
  • Keeping the suction box doors half open
  • Putting cotton pads to get pressure on drafting rollers
  • Using damaged cans and springs
  • Using nails and hammer to remove cotton from jammed trumpets
  • Using trumpets without verifying their size and condition
  • Not ensuring proper alignment of can
  • Not following the correct colour codification and channeling
  • Over filling the cans
  • Pressing the sliver in can by hand
  • Use of compressed for cleaning while machine is working
  • Un-staggered sliver piecing
  • Checking the wrapping periodically and correcting the hank by changing the pinion
  • Bigger laps
  • Applying excessive pressure to take compact laps
  • Use of worn-out bare spools in lap forming machine
  • Allowing overlapping of slivers being fed to lap former
  • Overlapping the lap sheet while piecing
  • Overlapping the slivers on table for piecing
  • Not cleaning the top combs in-time
  • Not removing the accumulated comber noils in-time
  • Keeping tools, etc., on the sliver table
  • Inactivating the stop motions
  • Piecing the slivers by over twisting
  • Not following the correct colour codification and channeling
  • Over filling the cans
  • Using damaged sliver trumpets
  • Pressing the sliver in the cans by hand
  • Use of compressed air for cleaning while machine is working
Speed frames
  • Cutting the slivers at cans in the creel and distributing to other cans
  • Overlapping the slivers while attending a sliver run out
  • Cross creeling of cans
  • Sliver falling out of guide roller
  • Twisting too hard while piecing
  • Applying cotton to the top arms to get pressure
  • Pressing the front top cot to correct a loose end
  • Not verifying the spacers and condensers while replacing
  • Not putting back the fallen floating condenser while attending a break
  • Not following the correct colour codification and channeling
  • Not removing the accumulated clearer wastes on time
Ring frames
  • Keeping roving bobbins on the top of creel for long time
  • Overlapping of roves while replacing
  • Putting cotton in top arms for getting more pressure
  • Using sharp knives/hooks for removing lapping
  • In active bottom clearers resulting in partial lapping
  • Not attending a break for a long time
  • Cross-creeling
  • Not removing the last layers in the roving bobbin and allowing it run out fully
  • Keeping roving bobbins in the path of roving or on the top arms
  • Keeping the bobbins in the path of air flow of overhead cleaners
  • Not removing the bobbins while a tape is cut
  • Not following the running-in schedule of rings properly
  • Keeping excess travellers in the cup and not removing them while changing counts
  • Not cleaning the rings with dry cloth/cotton before replacing a burnt traveller
  • Piecing from over the cot
  • Correct piecing.
  • Double piecing at cop bottom:
  • Bypassing the yarn clearers
  • Not keeping the clearer area clean
  • Keeping tighter setting to get good yarn
  • Keeping excess tension to get a compact cone
Machinery condition
The poor quality of yarn from machinery can be attributed to the following:
  1. Worn out parts
  2. Improper maintenance and settings
Technology and parameters adapted
Technology and the parameters adapted play a vital role in deciding the quality of the yarn spun. Poor quality can be a result of the following:
  1. Adapting a technology verifying its appropriateness for the product and the activity, but just because it is latest.
  2. Not updating the technology for the requirement of the product.
  3. Not understanding the available technology, and hence not optimizing the parameters as needed.
Blow room
The operations in blow room need to be controlled depending on the quality characteristics desired in yarn. Some of the important yarn quality characteristics influenced by blow room performance either directly or indirectly are as follows:
  1. Evenness – by level of short fibres generated (increase in fibre rupture)
  2. Imperfections – by level of short fibres generated, degree of cleaning and opening and neps generated in blow room
  3. Neps – by additional neps generated in blow room
  4. Hairiness – by level of short fibres generated
  5. Consistency in count – by delivery of uniform product either lap or the feed to cards
  6. Consistency in property – by degree of mixing achieved
  7. Cleanliness – by degree of cleaning achieved and possible rupture of large trash particles
Different parameters and technology are given below:
  • Improper selection of cleaning and beating points
  • Improper selection of speeds, settings and ratio of beater and fan speeds
  • Inadequate controls
  • Longer lengths of pipes/ducts and excessive bends in the material passage
  • Improper control of air currents
  • Wrong selection of feed and hank organization
  • Wrong selection of wire points for the material and hank
  • Wrong selection of speeds and settings of different parts
  • Wrong selection of feed plates for the fibre in use
  • Improper control points for the activity
  • Inadequate control of humidity and temperature
  • Improper setting of auto-levellers
Draw frames
  • Improper adjustment of break draft and final draft combination
  • Improper settings for the hank and material being worked
  • Improper settings of the autoleveller
  • Hooks formations because of the type of trumpets used
While designing lap preparation, total draft, fibre parallelization, number of doublings, lap weight, etc., should be decided properly. This can be
  • Improper selection of half lap
  • Improper selection of trumpets
  • Inadequate control of humidity and temperature
  • Improper selection of feed for the noil% extracted
Speed frames
  • The drafting system not suitable for the fibres and hank
  • Improper selection of break draft and main draft for the fibres and the hank
  • The flyer size/type not suitable for the hank and the material in use
  • The bobbin lift and diameters not suitable for the hank of material produced
  • Improper selection of condensers and spacers
  • The twist multiplier not compatible with fibre length, hank and the drafting system at ring frame
Ring frames
  • The drafting system not suitable for the fibre, count and the hank organization
  • Improper selection of break draft and main draft combination for the hank and count
  • Improper selection of empty bobbins
  • Improper settings
  • Improper selection of spacers
  • The hardness of the cots not suitable for the fibres, hank, the counts spun and the rings and traveller not suitable for the fibre, count and the speed
  • Improper synthetic rubber
  • The rings and traveller not suitable for the fibre, count and the speed
  • The lappet eye not suitable for the fibres and count spun:
  • The combination of winding and binding coils not suitable
  • Selection of cone angle to the speed of the machine
  • Improper selection of empty cones
Management systems adapted
The management systems adapted play a major role in getting the required quality of materials in time at the estimated cost. Following are some of the mistakes normally done:
  1. Following a system designed in the past that is not suitable today
  2. Following a system followed at other mill not suitable for us
  3. Poor house keeping
  4. Improper/Inadequate communication
  5. Not maintaining log books and records in a simple way
Following are some of the examples of the effect of management systems adapted on the yarn quality:
  • Not clear about the quality requirements of each process
  • Not clear about the capability of the systems
  • Poor interactions with the people working on shop-floor regarding the quality requirements of the customers/products
  • Poor house keeping
  • Congested layout of machinery and processes
  • Keeping excess materials in stock and process as stand by
  • Keeping excess spares in the work area for emergency operations
  • Improper maintenance of records
  • Not reviewing the quality aspects periodically
  • Not taking sincere action on the quality control reports
  • Not analyzing the reasons for poor quality and taking ad-hoc decisions
  • Not respecting the experience, knowledge and intentions of the juniors
Frequent shifting and re-erections: In mills where long-term planning is not there, we see frequent shifting and re-erection of machines. This results in wearing out of the parts, misbalancing of the running parts and disturbance in levels and finally leading to breakdowns. The technicians have to spend more time on the dismantling and erection activities and cannot concentrate on maintaining other machines and monitoring the quality.


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