Thursday, 23 October 2008
Warp Preparation for Rope Dyeing-II
Oz tensioner: It consists of round cylinderical housing and is located at each running package in the creel. At the top and bottom of the housing is a small ceramic eyelet. Inside of the housing are two steel balls.The yarn is threaded up through the bottom eyelet, around the steel balls out through the top of the housing.
Tension is applied to the yarn as it passes around the steel balls inside of the housing.
Advantages: Tension at the front and back of the creel is constant. 2. Adjustments are never required. 3. It is almost maintenance free.
1. there is a limit to how much tension can be applied
2. Threading of tensioner is difficult
3. It is relatively expensive.
1. Capastan Type
2. Rotating Disc Type
Capastan Type: There is a round capastan mounted on a precision shaft. This capastan is positioned onto the bearings which are located inside of a round DC coil. The yarn is wrapped around the outer surface of the capastan. The action of the yarn being pulled out of the creel by warper rotates capastan. If no voltage is applied to the DC coil, an EM field is created under the capastan. A hysterisis ring is attached to the inside of the capastan which reacts to this EM field and as such creates resistance to free rotation of the capastan. This resistance to rotation adds tension to the yarn on the capastan's outer surface. Varrying levels of DC voltages are applied to each tensioner in the creel and will provide equal tension to each in the rope.
Rotating Disc Type: Two disks are mounted in the vertical position onto a ceramic shaft. Behind the inside disk is a DC coil. When voltage is applied to the DC coil, an electromagnetic field is created. The outside disk is steel and is of course attached to the magnetic field which has been created. It pulls tightly against inner disk; again depending upon the strength of the EM field created by the DC coil, the yarn is threaded between the two disks. A 4 RPM AC motor mounted on each tensioiner, turn these disks to prevent thread cutting.
Advantage of Capstan types:
- No electric motor
- yarn is not distorted due to pinching action of disk
- less maintenance
As speed of ball warping is slow, mechanical tensioner are normally sufficient.
5. After that the yarn is then threaded through the eyebrows down the length of the creel. Here self threading type of ceramic eyelet is generally sufficient.
6. A stop motion device is required
a. The drop wire system
- It is located on each vertical row at the front of the creel bands.It is inexpensive with very short reaction and response time.However, it is exposed to dust, and if the end should break at or near the warper, there may be enough residual tension on the yarn, holding it up and preventing the drop wire from falling.
b. Photoelectric system
Instead of drop wire, this system uses a faller which is attached to a shutter inside of an airtight housing. Inside this housing is a photocell having a transmitter at one end of the housing and a receiver at the other end. A light beam is emitted to the receiver and an open electric circuit is maintained. When an end breaks, the faller drops and the attached shutter passes through the light beam, thus imitating the stop signer to the warper. it is reliable, comparatively inexpensive, easy to thread and maintenance free. However,it suffers from the same problem of residual tension.
c. Electric Motion Sensor
It is normally mounted on the balloon shield at the yarn package. This system actually measures the motion of the yarn as it exits the package. The yan balloons through a light beam housed in the balloon shield. As long as the light beam is constantly broken by the ballooning motion, the system remains open when the end breaks, the ballooning action stops and sensor signals the warper to stop. The circular motion of the yarn passing through the light sensor keeps the lenses clean. It is reliable, fast acting and self cleaning. However it is expensive.
7. The yarn exists the creel and is threaded through the lease stand. It houses a unique reed which allows each adjacent yarn end to be raised or lowered in order to create a shed through the yarn sheet. A lease string is inserted through this shed at given intervals ( 1000 m) in order to maintain control of the yarn during reopening at the long chain beamer. It can be manually or pneumetically operated.
Wednesday, 22 October 2008
Tuesday, 21 October 2008
Warp Preparation Requirements for Rope Dyeing
Ball Warping: Equipment required to form the rope of yarn. It involves creeling multiple ends of yarn ( Between 350-500 ends) and collecting them into an untwisted rope for dyeing. the rope is wound onto a long cylinder called a log on a machine called as a ball warper.
1. Packages of yarn are preconditioned before ball warping
2. Packages are loaded into the creel ( larger lots- magine transefer creeL0 and smaller lots- swing gate or truck creel
3. Packages are placed on adapters. An adapter support the package of yarn and ensure that the package remains aligned to the tensioning devices. Wooden plug type adapter are most effective as they require least amount of exertion to remove the empty package.
Next Step is threading the tensioner located at each yarn package
1. Post and Disk tensioner. It has two posts mounted onto a flat base. two round disk are placed onto each post. The yarn is threaded between the disk and wrapped around the post. One of the parts is movable so that the angle of wrap can be varied. More tension can be added to the yarn by adding round weights onto the top disk.
Advantages are 1. Inexpnsive 2. does Marginally adequate job of maintaining yarn tension 3. Simple to thread up 4. Low maintenance requirements.
Disadvantages are 1. Yarn has a tendency to jump out from between the disks at the rear of the creel. 2. It is labour intensive- when different tension levels are required. 3. There is more frequency of cleaning up 4. It doesnt control tension well at higher speed.
2. The driven disk tensioner
It also uses twin disk arrangement, however the disks are supported from below- there are no posts. Tension is applied from above- there are weights or spring loaded.
A gear under each pair of disks is matched to another gear mounted on a continuous shaft which runs the length of the vertical tension post. This shaft is connected to a 4 rpm motor which rotates the disk.
Advantage of disk rotation are 1. Thread cutting prevention 2. Dampens out variation due to ballooning action of yarn. There is mor uniform tension 4. Less effor required to change tension levels.
Disadvantages are 1. It is more difficult to thread up, there is more maintenance due to electric motor used and at high speed the tension control is not well.
Monday, 20 October 2008
Process Control in Loom shed
It consists of two parts:
1. Increasing machine productivity
2. Improving quality or reducing defects
Control of the productivity can be done with
1. controlling nominal loom speed close to currently set standards.
2. Ensuring that loss of speed through belt slippage is minimum
3. Control of loss of loom efficiency by minimising:
a. Loom stoppage rate through correct maintenance
b. Control of down time of loom through corrective action on the basis of data collected by snap reading.
3. Factors effecting Loom efficiency
Various factors that affect the loom shed efficency are
2. Human ( Related to weaver skill and work methods)
Relating the three factors
The technical and human (weaver related) factors have a very basic relationship with loom efficiency. The relationship is
P = NEX
= NE at
or E = P/ Nat
Where P= operative efficiency
N= number of machines per operative
E= Machine efficiency
X= Service factor, and it is equal to the average time taken to clear the stops in unit running time of a machine and equals at.
a= average no of stops per unit running time of a machine
t= average time to clear a stop including walking time
Thus if during an hour, the operator spends on an average 30 minutes in clearing stops, 15 min in ancillary durites like bringing raw materials etc and 15 min on rest and relaxation then
operative efficiency = (30 x 100)/60 = 50%
Work load = (30+15)x100/60 = 75%
Thus to maximise loom efficiency
- The stoppage rate should be low
- the weaver should be trained so that he takes the minimum possible time for clearing a stop.
- the operative efficiency should not fall below the optimum level
- loom allocation should be optimum
Sunday, 19 October 2008
Costing in Drawing-in
Drawers and reachers are paid their basic wages on piece rate system. The rates are related to the type of cloth to be woven. the basis of allocation of expenses to the different types of cloths are
1. Basic Wages of drawers and Reachers= Rate per 1000 ends x total production in 1000 ends.
2. DA to drawers and reachers and all other expenses = total production/production per shift
Cost of Drawing-in
Unit costs of this process as cost per 1000 ends. The cost of this process is calculated as shown below:
Cost of drawing-in per piece lengtrh = (cost per 1000 ends x total no of ends x tape length)/ weaver's beam length
Reeds are generally counted using STOCKPORT system, which is based on the number of ends in two inches.
Ex. A 72s stockport reed means 72 dents on 2 inches or 36 dents per inch.
Particulars of reed while ordering
100s ST, 18 G., 44"x 5" blue
- Stockport reed of
- 100 count
- using dents of 18s wire gauge
- Reed is 44" long
- 5" deep
- there will be blue paper on baulk of the reed.
Ex. What will be the number of ends/inch in a reed of 3/80s stockport
80s stockport= 80 dents per 2 inches
= 40 dents per inch
Therefore no of ends per inch = 3 x 40 = 120
When a set contains 4 shafts, it is called a plain set.
The number of heald eyes per inch across the healds in a set expresses the count of the heald.
Ex: 60s count for a plain set means 60 heald eyes on 4 shafts per inch i.e. 15 eyes per inch per shaft. For a 6 shaft set, it becomes 60 heald eyes on 6 shafts per inch i.e. 10 eyes per inch per shaft.
Ex. Find the count of healds that will be required for weaving a 6 shaft satin fabric using 72s stockport reed, drawn 3 ends per dent.
No. of ends per inch in the reed = (3x72)/2 = 108 ends
Therefore no of healds /inch = 108/6= 18 healds per inch.
Thus we require 72s count of reeds in a plain set.
Saturday, 18 October 2008
Process Control in Drawing-in
The term drawing-in and warp tying refers to the operations involved in preparing the weaver's beam for the purpose of weaving fabrics on the loom.
The drawing-in process primarily consists of drawing ends from the weaver's beam through heald eyes of different harnesses and then through the dents of a reed in the order that is determined by the design of the fabric.
If a beam is to be worked with warp stop motion on the loom, specially when using closed drop-pins, the ends have to be drawn through these pins before drawing them through the heald eyes and reed dents.
conventionally drawing-in is carried out manually by two persons-one, the reacher for selecting and presenting the ends from the beam, and the other, the drawer for pulling ends through the drop-pins, heald eys and reed dents.
The main requirements of carrying out this process properly and efficiently are:
1. The operator should be aware of the principles of drawing-in and be trained to do the job speedily because any mistakes or delays in carrying out the process would prove to be costly.
2. The healds and reeds should be in good condition and of suitable specifications for ensuring that these are not the cause of warp breaks on the loom and of defects in the fabric.
3. The drawing of the beam should be done properly to avoid cross ends on the beam.
4. Suitable precautions should be taken to reduce the incidence of extra-ends and to compensate for the missing ends during the weaving of the loom.
CARE OF HEALDS AND REED
1. The healds and reed from the exhausted beam of the loom must be cleaned throughly to free them from fluff, size, rust etc. before using them for a new weaver's beam.
2. When warp tying is practiced, it should be ensured that the same set of healds and reed do not work on the loom for a long time, even if no apparent defect is noticed in them. This is because through cleaning of healds cannot be done on the loom itself and dirty healds are prone to give high warp breaks.
COMMON DEFECTS IN DRAWING-IN
1. Cross ends- To minimise the incidence of cross ends on the beam during weaving, the ends presented for drawing in or warp tying should be made to be parallel and in their respective positions as in the beam. Proper dressing of ends is, therefore, of great importance.
2. Extra Ends- some ends are generally cast out during drawing-in/warp tying to compensate for long missing ends on the weaver's beam.Whether to leave these ends or not should be governed by the method of cutting lappers at sizing.
If the lappers are cut and mended only after completion of a weaver's beam, there is no need of leaving extra-ends at drawing-in or warp tying. If however, the lappers are cut no sooner these are detected, the same ends should not be withdrawn or not taken for tying.
Friday, 17 October 2008
Cost of Sizing
The cost of sizing ( excluding cost of sizing chemicals) is generally expressed as cost per unit length. Hence contribution of sizing cost can be calculated as:
cost of sizing= cost per unit length x tape length
cost of sizing chemcials is expressed as cost per unit length of size mixture. The cost per piece of fabric can be calculated as:
Cost of sizing chemicals per piece length= cost/kg x (warp weight per piece length x size add on %)
Basic Stitches Animations
This site talks about how sewing machine works. It is replete with animations. It starts by saying that it was inefficient to mechanically copy the process of hand sewing. This site has animations for the following stitches:
1. Basic chain stitch
2. Twisted chain stitch
3. Lock stitch
4. Oscillating hook lockstitch
5. Rotating hook lockstitch
6. Double locking chainstitch
A very nice site to visit !
Should I mention that on the same parent site there is this amazing guitar tutorial !!
Thursday, 16 October 2008
Efficiency of Sizing Department
The major causes of loss of machine efficiency are:
1. Creeling, which includes removing the exhausted beams, mounting new beams, denting, leasing etc.
2. Replacement of weaver's beam on consumption
Efficiency in sizing
Let yarn count= 34
Set length on warper's beam= 18000 m
length of yarn on weavers beam= 1500m
Total number of ends= 4000
Full running speed= 50 m/min
No of lappers per 3000 ends per 1000 m = 3
Time to cut a lapper = 90 sec
Time to doff a beam and put new lease rods = 600 seconds
time to change a set = 6300 sec
Time loss/1000 m due to miscellaneous causes= 60 sec
Sizing time of one beam with no stops : R = (1500x60)/50 = 1800 seconds
Lappers per beam of 1500 m per 4000 ends = 6
time lost in cuttin glappers per beam = 540 seconds
Number of weavers beam per set= 12
time lost per beam in a set change = 6300/12=525 seconds
time loss in beam doffing and leasing per beam = 600 seconds
Miscellaneous losses per beam of 1500 m = 90 sec
total time to size one beam = 3555 seconds
Machine efficiency = (1800 x 100)/3555 = 50.6%
Wednesday, 15 October 2008
Control of Yarn Stretch
During sizing, the yarns are under tension, this results in a slight permanent stretch in the yarn. It leads to a decrease in extensibility or elongation at break of the sized yarn, which leads to more breakage at the loom shed.
The various zones of stretch control on modern sizing machines are:
1. Creel zone: start- last warper beam, end-Dry nip
2. Wet Zone; Start- dry nip, end- first drying cylinder
3. Drying Zone: start- first drying cylinder, end- last drying cylinder
5. Splitting Zone: start-last drying cylinder, end- drag roll
6. Winding Zone: start- drag roll, end- loom beam
Control of Stretch in Creel Zone
The creel stretch on the existing type of sizing machines has to be controlled manually. The yarn tension in the creel zone increases gradually with reduction in diameter of the warper's beam. To counter this, the tightening of the beam is required to be adjusted suitably as the sizing progresses.
Control of Stretch in the Wet Zone
The control of stretch in this zone can be done with the help of 'positive dry nip'.
On multicylinder sizing machines, stretch can be controlled by synchronising the PIV gear during the cylinders with that driving he finishing squeeze roller in the wet zone.
Control of Moisture in sized yarns
A moisture control of 8-10% should be maintained in the sized cotton yarns. With excessive drying, the size film becomes brittle and harsh.
Very high moisture content is also undesirable because it makes the size films soft and the yarn sticky.
Quality of Sized Beams
A satisfactory weaver's beam should unwind well on the loom. These are some of the important package faults:
1. Density of sized beams: A loosly packed weaver's beam does not work well. The density is mainly influenced by two factors:
a. effectiveness of the friction clutch or the DC drive
b. effectiveness of the bream pressing motion.
2. Broken ends, missing ends, crossed ends, sticky ends
The major sources of all these faults are
b. invisible breaks during sizing
A lapper is an accumulaiton of layers of yarn on the warper's beam.
Those end breaks during sizing that do not form lappers are called invisible breaks.
Both lappers and invisible breaks result in missing and broken ends in the sized beams.
Crossed Ends- these are formed during weaving whenever the leading end is not available in the appropriate place on the beam,and, therefore, the weaver has to knot the trailing end to an end that is far away. This happens because in some cases the leading end of an invisible break migrates to a distant place.
Sticky ends - These are caused when broken ends from the warper's beam migrate to the yarn of another warper's beam.
In order to control these faults, it is necessary to control the incidence of lappers and invisible breaks.
Factors affecting lappers:
- End breakage rate at warping
- Efficiency of warp stop motion at warping
- condition of beam flanges (warper's)
Factors affecting invisible breaks
- High stretch at sizing
- weak places in the yarn
There are two types of defective selvedges that cause more difficulty in unwinding during weaving than the ends of the beam of thebeam. These are:
1. Sunken selvedges
2. Bulging selvedges
These defects can be controlled by
a. correctly setting the expandable comb at the headstock
b. Using the correct size of beam pressing roller so that it reaches both the beam flanges.
c. Ensuring that beam flanges are true.
Formation of ridges on the Beam
Ridges on the beam are formed when the ends that are taken in one dent of the comb do not spread out. To minimise the falut the eccentric dancing rollers at the headstock should be adjusted properly.
Tuesday, 14 October 2008
Control of size pickup
For control on variation of size pick up , the two steps required are:
a. determination of average size pick up on the beam
b. Suitable adjustment in sizing conditions
a. Determination of average size pick-up
Example: The weight of sized yarn on a beam was found to be 82.5 lbs. The beam contains 1050 yards of warp, whose count before sizing was 50s cotton.If the number of ends in the warp is 3000, calculate the following:
a. The weight of size on the yarn
b. The % of size put on the yarn
c. The count of sized yarn
a. Weight of size on warp= weight of sized warp- weight of same length of unsized warp
Now weight of unsized warp= (No of ends x length of warp in yds)/(count of unsized yarn x 840)= (3000x1050)/(50x840) = 75 lbs
Therefore weight of size on warp = 82.5 -75 = 7.5 lbs
b. Percentage of size on warp = (wt of size x 100)/ wt of unsized warp
= (7.5x1000)/75 = 10%
c. Count of sized yarn = (No of ends of the warp x length of warp in yds)/(wt of lbs of warp x 840) = (3000x1050)/(82.5x840)= 45.5s cotton
b. Control on sizing condition
1. Viscosity of size paste in size box: Any variation in the concentration or temperature alters the viscosity of the paste which in turn affects both the level of size pick up and extent of penetration. Initially as the viscosity increases, the size pick-up also increases. But as the viscosity increases beyond a point, the size pick up is reduced.
2. Sqeezing pressure and condition of squeezing nip: The squeesing pressure determines the extent of penetration of the size paste between the fibres of the yarn and also of the removal of excess size paste and hence the level of the size pick up.
3. Speed of the sizing machine: Other sizing conditions remaining unchanged, the size pick up increases with increasing sizing speed and vice versa. This is because the time available to squeeze the surplus size from the yarn is less at high speeds.
4. Depth of immersion roller in size paste: the depth of immersion roller in the paste determines the duration for which the yarn remains immersed in the paste. this duration in turn influences both the level of size pick up and the extent of size penetration.
5. Level of size paste in the size box: Variation in the level of size paste is an important source of size pick-up variations both within and between beams.
6. Density of ends: When the density of ends is high, difficulties are encountered in obtaining adequate and uniform size penetration. Therefore size pick up may vary at these fabrics.
Monday, 13 October 2008
Choice of Size Receipe
The suitability of size receipe for the type of yarn should take into account, fabric construction, and end use as follows:
1. Cotton Yarn- Starch Based
Polyester etc.- Polyvinyl Alcohol (PVA) based
2. Fine and Superfine cotton- thin boiling Starches
Coarse Count- ordinary starch
3. Heavy Fabrics- Modified starches
Light and Medium- Ordinary starches
4. conventional sizing Machines- Low viscosity starch
High speed sizing machines- High viscosity starches
5. Unlbleached calendered sort of fabrics- More weighting agents, antiseptic softners etc. are used.
Bleached sorts- ordinary starches
6. Finer Counts and Heavier Constructions- More size pickups
Coarse counts- Less size pickups
7. Plied yarns- low size pick up or nil even
Ingredients for water Based Sizes
1. Adhesives- Potato starch, starch from cereals ( corn, wheat, rice etc0, carboxy methyl cellulose (CMC), Polyviny alcohol (PVA), Polyviny Chloride (PVC)
2. Lubricants- Mineral Waxes, vegetable waxes, animal fats, mineral oils, vegetable oils
3. Additives- Salicylic Acid, Zinc Chloride, Chloride emulsifiers.
Suggested Size Receipe
Mutton tallow= 7.5
Preparation of Size Receipe
Modified Starch = 50 kg
CMC= 5 kg
PVA= 10 kg
Gum = 1.5 kg
Softner= 1.2 kg
Antistat= 0.8 kg
Mixing: Took 17" water. Added Starch, Gum, CMC and PVA slowly and one by one as the slurry is stirred. Softner and antistat added in storage kettle.
1. cold stirring at 50 rpm = 12 min
2. Transfer into pressure cooker through sieve=== 45 deg C
3. Stirrer rpm in cooker== 55
4. Close lid, open steam inlet, open air vent
5. Close air vent valve when steam is seen escaping through it, temperature = 96 deg C, Pressure = 10 PSI
6. time between point 3 and 4 == 15 min
7. Cooking starts, steam continued till temperature = 130 deg c, Pressure = 40 PSI
8. Time for getting 130 deg C after closing air vent valve = 25 min
9. Stem in-let closed
10. 10 minutes after closing steam, Temp= 124 deg C, Pressure = 32 PSI
11. Total cooking time after getting 130 deg C= 35 min
12. Flow time of paste taken through sample valve= 24 seconds
13. Transferred to storage beck
14. Final volume = 18.5 "
15. Stirrer RPM in storage beck = 20
16. Temperature after 10 min. of transfer = 100 deg C
17. Refrectometer reading= 16
1. Size add on = 18 %
2. Increase in strength % = 5.2
3. Elongation at break % os sized yarn = 6.8%
Saturday, 11 October 2008
The process consists of laying warp yarn parallel and sizing the yarn with a mixture to strengthen it to withstand the rigours of weaving.
Warp yarn is withdrawn in sheet from from warp beams which are placed at the back of the sizing machine. The yarn is then passed through sow box. Size solution is applied by immersion. After removing surplus solution that occurs at this state, the yarn is dried and arranged on a loom beam.
The objective of sizing is RESISTANCE to ABRASION
This objective is achieved by applying on the yarn a unifrom and smooth protective film of suitable sizing material.
We also want that in the sized yarn there should be
- Some increase in tensile strength in the yarn
- Minimum loss of extensibility in yarn ( about 4.4-4.6% elongation at break is required for cotton)
-Required moisture content ( 8-10% of cotton)
- Good quality of sized beam (neither too soft nor too firm + free from yarn defects)
- Good productivity and efficiency
- Reduced Cost
Process Control in Sizing
The process control programme in sizing should, therefore, comprise of the following aspects:
1. Selecting the correct size receipe and size pick -up level
2. Ensuring correct preparatio of size paste
3. Control of
- size pick up
-quality of beam
-a method to calculate the expected level of productivity
Friday, 10 October 2008
Warping process is required exclusively for preparing warp yarn for weaving. Hence warping cost should be calculated for warp yarn.
Unit costs in this section can be developed on weight basis or on length basis.
Warping cost per piece length of fabric= weight of warp yarn per length x cost per unit weight.
If unit costs are developed on length basis, they are expressed with reference to specific number of ends (generally 400-500 ends). It follows , therefore, that about four to eight beams ( some time even more) would be required to made one beam for weaving.
In other words, unit cost in terms of length will have to be multiplied by the number of warp beams required per weaving beam. Then warping cost per piece length of a fabric can be calculated as shown:
warping cost per piece length of fabric = cost per meter x tape length x no of warp beams per weaving beam.
If the warp beam is partly colored and partly greige, warping cost should be calculated for greige warp yarn and coloured warp yarn. Generally coloured yarn is processed on slow speed warping frame. Hence cost of color warping usually works out higher as compared to the cost of greige warping.
Friday, 3 October 2008
Minimising end breaks in warping involves four steps namely:
1. Control of tension in the yarn
2. Satisfactory maintenance of those machines
3. Minimising the defects on packages produced at winding
4. A regular check on the end breakage rate for comparison with the norm.
1. conrol of tension in the yarn
On the warping machine, there are two types of variation in yarn tension
1. Between different stages of unwinding of a package. This can be detected after the first thread guide.
2. Between ends. It can be detected at the head stock.
The tension variation that occurs during the unwinding of a package can be minimised if you design the creel such that the distance between the package and the first thread guide is shortest, it will avoid the yarn balloon rubbing the nose of the package.
The tension variation between the ends at the headstock is minimised if the groups of neighbouring ends on the beam are taken from the same column of packages in the creel.
2. Condition of Machine
a. Alignment of the package at the creel
Non alignment of the creel package with respect to the first guide is often seen to be a cause of high end breakage rate at warping. This alignment is done with the help of a gauge.
b. Eccentric Guide rollers
On machines with mechanical stop motions, there are several guide rollers at the headstock which are positioned very near to one another. Eccentricity in those rollers can introduce short term tension variations of high amplitude.
c. Thread Guides
Deep cuts in thread guides can significantly increase yarn tension and hence deteriorate warping performance. If found dirty, the thread guides should be cleaned with CCl4.
d. Relative humidity and temperature
For satisfactory working at warping, about 60% RH should be maintained. The dry bulb temperature should be kept at about 29 o C (84 o F). Lower humidity may increase yarn hairiness, end breaks and liberation of fluff. The fluff ultimately passes to the beam and given difficulty during sizing. Higher humidity is unnecessary; in fact relative humidity higher than 70% may increase end breakage rate.
Thursday, 2 October 2008
Process Control in Warping-3
Maintenance Check points at Warping
1. Clean with compressed air at every creel change-per shift
2. Clean with compressed air and cleaning waste- weekly
Package Alignment at the Creel
1. Look for incorrectly aligned packages, correct if the non-alignment is too severe- regularly
2. completely guage the creel with the help of a gauge- half yearly
In case of high speed warping machine, check tension weights at every count change- regularly
Check the tension levels with tension meter- Monthly
Stop Motion and Brake
1. Ensure that the machine stops within 1 1/2 revolutions fo the drum in case of high speed warping- regularly
2. Check with condition of drop pins and replace those with cut marks- regularly.
1. Check for concentricity- half yearly
1. Check for the conditions of flanges and beam shafts, repair damaged beams- regularly
1. Check that creel fans oscillate properly and are not chocked with fluff- regularly.
Parts in yarn path
1. Check for cuts in parts of machine in yarns parts regularly.
2. repair/replace the parts with cut marks- weekly