Warp Knitting Preparation | DS 21/30 EC Karl Mayer

The DS 21/30 EC – a new computer-controlled direct warping machine developed
by KARL MAYER for the warp knitting sector.

Source KWP 1/2009

KARL MAYER’s DS machine series represents highly efficient technology for use in warp preparation
for warp knitting. A well-thought-out construction and intelligent design features enable high speeds of up to 1,200 m/min to be achieved when producing sectional warp beams having identical circumferences and lengths, whilst guaranteeing accurate and reliable operation at the same time.
KARL MAYER's high-speed direct warping machines operate using optimally coordinated creel systems, feed units and synchronised braking systems. All the operating conditions, start/stop and running phases are 100 % computer-controlled,and any variations in the circumference of the sectional warp beams are extremely small. The maximum variation is no more than a millimetre, even when extremely delicate yarns are being processed. If the machine has to be braked, highly innovative synchronized braking systems stop the
machine in just 0.6 seconds, and the running of the yarn sheet is fully controlled,even when the machine has been operating at high speed. These performance features can all be utilised very easily via the KAMCOS® machine control system.
The Operator Interface with touch screen facility gives a clear view of what is happening, and enables all the machine functions to be accessed easily. An Ethernet interface permits the data acquisition and Teleservice
modules to be connected up. These performance features have ensured that all the models in KARL MAYER’s range of direct warping machines have become real bestsellers on the market.
DS 21/30 EC A new model in the successful DS series is the DS 21/30 EC. This new warping machine
is based on a rational design concept, is relatively cheap, and is designed to produce standard articles on a price-oriented market. These features mean that it is perfectly matched to suit the requirements of
KARL MAYER’s TM2 and TM3 machines.
The performance features of these two basic tricot machines, which are designed to appeal to manufacturers who are new to this sector, can be fully utilised by using them in combination with the DS 21/30 EC.
The construction of the DS 21/30 EC has been logically designed to provide practical solutions. The technology for producing the sectional warp beams enables a warping speed of up to 1,000 m/min to be achieved, and yarn tension values up to a maximum of 200 N to be processed. The special technical
features include computer-controlled band build-up, a master beam/successive beam control system, an integrated MMI operator console, an intelligent, synchronized braking system, the tried-and-tested
KAMCOS® control system, and facilities for connecting-up additional units. The touch screen monitor is an easy-to-use man/ machine interface and can be used to display the process parameters and input the
beam data.
A range of different functions can also be activated and master lists can be stored - simply by pressing buttons.
The DS 21/30 EC is a rational, robust production machine, which meets all the requirements of conventional warp preparation and is another contribution from KARL MAYER for producing standard articles economically. When used in conjunction with the TM2 or TM3 machines especially, the efficiency, synergistic effects and performance features of all the machines from this renowned manufacturer can be utilized to the full in warp knitting.
This new model in the DS range has been used successfully on the Asian market since
August 2008, and has been available on the world market since January of this year.

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Electro Static on The Yarn Sheet During Warping Process

The surface of  isolated material such like polyester yarn,nylon yarn,elastomeric yarn or others synthetic material is normally not charged. When the yarn surface moves towards another material, or get frictions with others parts surface on warping machine during warping process , e.g :a yarn sheet moving on  reed  ,tension tube or ceramic eyelet , electrons can be transported from the surface layer of these part  to the yarn sheet. This is called triboelectric effect and causes an imbalance of the electric charge of the material, the surface layer of one material becomes positively charged and the other one negatively charged. As the yarn sheet  and warping parts is isolated, the charge cannot be conducted away through the yarn or parts which get friction with the yarn sheet itself, the charge is then called static electricity. The ability of the electric charge to attract one with the opposite polarity or to repel another with the same polarity may then cause problems,  e.g.:Broken filaments on the yarns,hairness or the yarn sticky together.Different hardness and outer circumference in one set of warp beam when warp a textured yarn often occurred due static electricity or electro static.The most problem due electro static on the yarn sheet during warping process are :

• Broken filament.
• Un-even warp beam surface.
• Different outer circumference in one set of warp beam,mostly for textured yarn.
• Yarn hainess.
• Short life time of the latch needle for the warp knitting machine used latch needle.

The charged surface of the yarn sheet can be neutralized by ionizing the air uses anti static equipment  or electro static discharger (ESD),i.e. air particles are charged by positive and negative polarity.
The negatively charged air particles can then give off an electron to a positively charged particle in the surface of an isolated material, thereby neutralizing particles both in air and material. In the same way the positive air particles are neutralized by the negative particles in a charged material.
The anti static equipments uses a high voltage electrode to ionize air particles through corona discharge to both positive and negative polarity.

 Picture 1,showing the ESD rod installed below the yarn sheet after every separator reed on warping machine.

Picture 2,showing the ESD installed below the yarn sheet before and after main reed ,before the yarn sheet warp onto  the beam.





Wherever ESD are used to control static discharge,the effectiveness of an ESD system depends on the type of ionizers used and how they are installed on warp knitting machines. Measuring the static in the area
before and after a ESD is installed helps determine how well the system performs.
It’s also important to periodically monitor the area or process to detect unacceptable levels of charge accumulation and verify that the system is working properly.

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Warp Knitting Preparation for Technical Yarns

Warp Knitting Preparation Technology with Advantages for Yarn Guiding/Feeding

Technical modifications on creels and warping machines for processing technical yarns

Fig 1.:Horizontal balloon limiter

Out of all the textile materials, technical yarns are the most responsible for performance. They must match the end-use requirements exactly, can be processed into geogrids, tarpaulins, advertising substrates, 3D textiles, all kinds of nets, and reinforcement substrates for example, and, above all, they are extremely strong. Yams with counts of 1100 dtex and above provide maximum strength characteristics, but they also require special handling throughout all the processing stages. Yarn guiding forms the focus of steps taken to modify and adapt the warp  preparation technology developed by KARL MAYER.

In contrast to their large circumference, the thick yarns have a relatively small contact area on the package surface, and therefore do not adhere well to each other. The result is that individual yarn layers can slide between the back wall of the package and the package disc at the take-off points. They become entangled there, and can cause yarn breakages. This problem can be solved by having a foam rubber cover on the package disc and the spring-loaded contact points at the package (Fig. 2).

The high weight of the technical yarns also makes it necessary to make further    

                   Fig.2 : Package  

 disk with foam rubber cover

design modifications. Projecting yarn balloons are produced during take-off at high speeds, and these can catch on each other. If the machine stops as a result of a yarn breakage, the yarn ends fall to the floor and pull the entire wound package along with them. This can be avoided by using balloon limiters. The horizontal limiters consist of intermediate plates arranged horizontally between the rows of packages for catching the yarn ends (Fig. 1). The vertical balloon limiters prevent the yams from jumping uncontrollably Into the yarn guide of the yarn tensioners. KARL MAYER's top balloon limiting devices have a cylindrical shape, completely surround each package, and ensure that the yams do not become entangled with each other or in the yam guides of the yam tensioner (Fig. 3),

 Consequently, as soon as the machine is switched on, it can be run at maximum speed and the yams are delivered in an orderly manner to the yam tensioner. The KFD-AIR is used in this case (Fig. 4). This yam tensioner is designed especially for processing filament 'yarns and technical yams from 50 to 3000 dtex or 167 to 1000 dtex, it can produce yam tension levels of 10 to 90, M or from 30 to 230 M when processing these types of yams, absorbs yam tension peaks by air damping of the compensating lever, and is resistant to contamination. When processing coarse monofilament yarns with diameters above 0.3 mm, the KFD-AIR should also be fitted with a special cover. This prevents the rigid yarns from jumping out of the guide devices during take-off. If the yarn is too heavy for overhead take-off, the use of a special take-off roller is recommended. This guarantees tangential unwinding and controls the yarn tension as well, and thus replaces the KFD yarn tensioner. The principle of tension compensation is based on the increase and decrease of the braking force during take-off, by the rise and fall of a metal ring moving in a magnetic field (Fig. 5). This system operates extremely accurately and permits take-off speeds of up to 400 m/min for a maximum package weight of 6 kg to be achieved.

In addition to ancillary equipment needed for guiding the technical yarns, the machine used for warping them also has to be equipped with special devices. These include a roller unit with a more efficient motor and larger roller diameters. The resulting larger contact area of the yarns on the roller surface, in combination with the higher motor efficiency, enables the high tension level needed between the roller unit and the warping machine to be established. A pressure roller also ensures that the warp beam produced has a smooth, uniform surface. KARL MAYER Textilmaschinen GmbH offers a variety of raschel and high-performance tricot machines with and without weft insertion facility for processing the beams into custom-made technical textiles. Table 1 gives an overview of the warp preparation technology recommended for the specific warp knitting machines.

All in all, this represents custom-made technical expertise from one and the same manufacturer!

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Warping Calculations for Warp Knitting

The warping Length of Small Yarn Packages
When small yarn cones or leftovers are used in warping operation,these cones can be used efficiently if the warping length is precalculated.
The weight of the yarn on the cones is measured (in case of varying weights,the lowest should be used since it will run out first).The length of the yarn on the cone can then calculated by the formula
as follows :

I = w x 1000 /tex
for example : the length of the 100 tex yarn weighing 250 g is :


250 x 1000 /100 = 2500 metres


To calculated the weight of certain length of the yarn when the tex is known,the following formula is used:


w = I x tex / 1000
for example : the weight of the yarn on the warp beam containing 27.000 km of 7 tex yarn is :


27000 x 7 / 1000 = 189 kg

The dtex unit is such a variation.The unit can be defined as the weight in decigram  (dg) of the 1000 metre long yarn or filament (or the weight in gram of 10000 m length of the yarn).
To calculate the different parameter in different situations,the following formula are used :


dtex = w x 10000 / I


I = w x 10000/ dtex


w = I x dtex / 10000

According to the number of warp sections which required,the warping length of  is deducted.
For example : 42 inch wide of warp beam are to be warped for 168 inch tricot machine for production of lock knitt constructions (run-in ratio of 1.38 : 1).
I the creel ,the required number of 77 dtex cones are accommodated each weighing 1 kg ( net weight of the yarn).The yarn length per cones is :

1 x 10000 / 77 = 129.87 km , the number of section beams for each guide bar is : 168 / 42 = 4
According to the run-in ratio,the length of the warp on the front of beam should be 1.38 times longer than the yarn length of the back beam section can thus be considered as one unit while lenght  of the warp on the front section as 1.38 units.The number of units which required is :

4 x 1 + 4 x 1.38 = 9.52 units

he length for each unit is :

129.87 / 9.52 = 13.64 km

so that maximum warp length available for the back beam sections is 13.64 km and the available length  of  the front sections is 13.64 x 1.38 = 18.83 km.Thus the correct length of the yarn to be warped on each section can be pre-calculated for maximum usage of available yarn.

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Warp Knitting | Yarn Tension Compensation Device | WA II 4 Q

This device attached on Karl Mayer direct warping machine type DS 21/30 or DS 30/52 NC or DNC.
To understand how this device work is very importance in order to get good quality of warp beam,
This article purpose is give some more knowledge to people who involve on warp knitting business and user of
Karl Mayer's warping machine.
This article taken from many sources and the experience of the writer.
Hope fully will be use full for reader who involve at warp knitting business and the people who involve directly as the operator
or technicians of warping machine build by Karl Mayer Company.



Purpose:

This unit serves to created the desired yarn tension in the front of warp beam, to stabilize a yarn sheet and to compensate the yarns tension differences.
Function:
The yarns sheet runs through a pair of rollers. The stabilizing and compensating effect increases by raising deviation angle of the rollers pair, but at the same time also the yarns tension and tension peaks when the machine stopped due some reasons.
The ideal deviation angle of the rollers varies according to the various materials used and has to be determined in practice.

What Does 4Q means?
4 Q= 4 quadrant drive, driving and braking in both turning directions.(operating all four quadrants).
The possible operating mode of the drive can be represented by means of the four quadrants of the torque and number of revolution diagram ( operating diagram).



Operation

The warping tension results from the following four factors;
F0 = Tension caused by the package draw off.
F1 = Tension caused by the yarn tensioner.
F2= Tension caused by general friction.
F3 = Tension caused on the leveling roller unit (increase or decrease).



1- Yarn package in the creel.
2- Yarn tensioner.
3- Leveling roller unit.
4- Yarn tension regulator.
5- Warping machine.

The total tension is equal to the sum of the factors F0 through F3.In general, the package draw-off tension F0 increases as the package diameter decreases. The factor F1 doesn’t depend of the warping speed. The factor F2 depend of the warping speed and remains constants at equal speed ,In order to keep the total yarn tension constant ,increasing factor F0 (package draw-off tension) has to be compensated. This compensation done by drive regulation (driving or braking) on the leveling roller unit (WA).

Regulating Unit of the Leveling Roller

The 4 Q drive allows to increase total yarn tension by 70 Newton or to reduce it by 80 Newton .
When producing the master beam or working without computer (non NC type),
the desired total yarn tensions is set on a potentiometer at the machine and monitored automatically by electronic control over the entire warping process.

The Essential Advantage of This System;

1. Permanent control of the yarn sheet tension (white master beam or when working without computer).
2. Constant yarn tension regardless of the warping speed.
3. Equal beams circumference at equal number of revolutions.
4. Simple handling of tension change.
5. Permanent control of the layer thicknesses of the beams.
6. Driving and braking.
7. Constant yarn tension immediately after start-up of the machine.

Taking into Operation of WA roller

1. Yarn Tension of the Creel.

The yarn tension caused by the creel mainly the result of two changing factors :
Braking – The braking force of the yarn tensioners can be change depend of the machine construction and the respective warping task .
Yarn Package – The yarn tension change in the functions of yarn package diameter.

Advantages resulting from the use of KFD yarn tensioner.
- Yarn tension difference occurring with the large and small yarn package diameter are compensate.
- The same yarn tension is ensure at different production speed.

2. Regulating range of the leveling roller unit

The regulating unit must compensate the changing yarn tensions coming from the creel. Therefore ,it always to be adjusted in away that there is sufficient regulating reserve.

Total Yarn Tension Required

This must be know when warping is started. It is determined in the instructions of the yarn manufactures or by the requirements in the processing sectional beam.
Actual Total Yarn Tension
The yarn tension is measured shortly before the sectional beam on at least 10 yarns and the average yarns tension is determined in this way. The average yarn tension multiplied by the number of the yarns is the actual total yarn tension.
Setting the Required Yarn Tension
Turn the regulator on the switch cabinet carefully until the desired yarn tensions is reached .
Measure the yarn tension continually during the setting increasing.

3. Working Range |Pressure Pick-up|DMD Load Cell|Positions:200 N|1000N

The tasks to determine the DMD load cell position through the total yarn tension. The total yarn tension is calculated on the basis of trite thickness (dtex) and the number of the yarns:

Example 1 : 44 dtex ,1000 yarns
Formula : (0,2 * X 44 dtex ) X 1000 yarns = 8.800 grams = approx 88 Newton
DMD load cell position: 200 Newton

Example 2 : 167 dtex,1000 yarns
Formula : (0,2* x 167 dtex) X 1000 yarns = 33.400 grams = approx 334 Newton
DMD load cell position:1000 Newton
*0,2 is conversion factor and recommended by Karl Mayer.

The following conversion factors are suggested :
Polyamide (Nylon): 0,15.....0,2
Polyester : 0,2.....0,3
Monofilament: 0,12.....0,2


This table provide a theoretical guide line only and doesn't considering slippage (yarn properties).

Example :
Total yarn tension required 8,8 kg
Yarn tension regulator on position 4
a. Switch on the main switch of the warping plant.
b. Set the yarn tension regulator to the value taken from the table above.
c. Start the warping plant and wait until the present warping speed is reached.
d. Measure the actual total yarn tension.
e. Set the desire yarn tension by means of the yarn tension regulator by turning it slowly.
Turning to the right = higher yarn tension.
Turning to the left = less yarn tension.

4. Mechanical Basic Setting

Check the position of the pressure pick-up (1) .Is the pressure pick-up within the desired working range (see working range)?

A change has to be done as follows:
- Remove the screw (2).
- Reposition of the pressure pick-up(1) and fasten its by means of screw (2).
- Carry out the null balance of the pressure pick-up,(see electrical basic setting).




Check the parallelism of the yarn tension rail :e.g. improper transport of the leveling roller unit.

- Check the parallelism of the tension rail at both tension rail ends by means of the gauge (3),the gauge is supplied with the unit.
- If the corrections is required ,loosen the screw (4) ,align the tension rail and tighten the screw (4) again.

5. Electrical Basic Setting
The electrical setting need carry out by service personnel of Karl Mayer company,please leave a comment for further assistance.

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Common Problem on Warp Beam Process 1 for Warp Knitting

Various outer circumferences in one set of beam.

On the modern warping machine most of them equipped with yarn tension compensating roller or roller aggregate drive with AC motor. The function of this roller is to iron out various yarns tension on warp sheet ,the speed of the roller drive by AC motor synchronize with the speed of the motor which drive a beam to wound a yarn sheet on it. The speed of the roller should synchronize and slower + - 3% against speed of over-run roller on the machine head to get same length ,warped with same number of revolutions, the same outer circumference and the most importance is the individual ends of the yarn must be under the same required tension.
On the warping machine equipped with Numeric computer controller (NC) has facility to make a copy or duplicate for each beam in one set, for example for produce a fabric on tricot machine with 130” on the width, for one bar that will be need 6 warp beam with width 21”.With NC warping can be produce 6 warp beams with a same winding, a same length of the yarn and same outer circumference without any difficultly from beginning of beaming process until the end of beaming process.
However the problem with various outer circumferences also can be happen on machine equipped with NC control if the system of roller aggregate was malfunctions.
Next posting will explain how WA roller is work.

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Warp Preparation for Warp Knitting

To produce a warp knitting fabric on the warp knitting machines its require a yarn which feed on the beams, although in some case the ends of the yarn from the cone or cheese can be feed directly into warp knitting machine using creel, mostly this method only for pattern yarn on the lace machines, however for the ground yarn always using the yarn on the warp beam.
Warp beams produce at various warping machine, in this case for warp knitting, the warp beams produce on direct warping machines. Direct warping can be defined as produce in which ends of the yarn are wrapped in one operation from the yarn packages onto the warp beam.
Since the creel must supply the required number of the ends of the warp, there are two possibilities; either the creel can be very large or the width of the warp can be smaller. In order enable the use of moderate creel size and to simplify warp handling, section beams are warped. Each section its own flanges and number of section beams are placed on the common shaft to make up required number of ends for the warp.
Most of modern warping machine, can be work with 21” beam to 42”, these size of the beam mostly use on the warp knitting machine now a day.

The direct warping machine consists of the following parts:
1. The warping machine or machine head which use to turn the beam so that the warp or yarn sheet from the creel are wound onto it.
2. A front reed which separated a yarns and spaces to fit the width of the beam.
3. Oiling device to lubricants the yarn and reduce electro static on the yarn.
4. Backward device allows the beam to turn backward to repair and knots the broken yarn or remove the fluff.
5. Electro static eliminator which remove the electric static on the yarn due yarn friction with others parts of warping machine i.e. reed, separator etc.
6. Tension roller or roller aggregate to iron out differences yarn tension on the yarn sheet.
7. An eyelet- board or back reed to gather the yarns coming off the creel.
8. The creel accommodating the yarn packages.

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