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Electronic Control Systems in Weaving

ABSTRACT:

Today, data acquisition, automatic monitoring and display of trends can be performed with personal computers. This allows us to quickly identify and systematically eliminate weak points in the production process. There is need for quality product, which gives high standard, which is possible by use of automation in textiles. The automation has done a drastic change in textiles by the use of electronics and computers in it. Since the use of it has given economically feasible for many mills, a major part of the new plants will be equipped with such systems. Electronics & computers has given some the benefits in the textile industry, Such as high production rates, consistency in quality, and ease in monitoring, reduced maintenance, flexibility, reduction in man power, etc. Now day’s modern weaving machines are equipped with the various control systems like electronic take up and let off, permanent insertion control (PIC), slim through-light sensor, electronic color selector, ECOWEAVE /RTC, automatic picks finding, electronic yarn tension control, automatic pre winder switch off, automatic start-mark prevention, E-shed, CAN-bus , etc. Some of them are discussed briefly in this paper.

1. INTRODUCTION

The world is bright & cheerful, full of color, constantly changing fashion demands and rapid response in the industry, has given a new image to it. There is need for quality product, which gives high standard; same applies for all textile products with new fields of application. Which is possible by use of automation in textiles? The automation has done a drastic change in textiles by the use of electronics and computers in it.

1.1 Why Electronics and Control Systems in Textiles?

Electronics & computer control systems in the textile industry include primarily the machine panels, the systems for regulating, controlling and the data recording. Productivity, quality, operational profit of the industry and therefore the competitiveness depends on the technology. Due to the increase in performance of electronic systems in recent years, it is now possible to realize solutions, which in the past had to be rejected for cost reasons. Today, data acquisition, automatic monitoring and display of trends can be performed with personal computers. This allows us to quickly identify and systematically eliminate weak points in the production process. Since the use of it has given economically feasible for many mills, a major part of the new plants will be equipped with such systems. Electronics & computers has given some the following benefits in the textile industry,

1.1.1 High Production Rates:

A better utilization of the production equipment will result in cash profit. But without a data system, this would be a laborious, error prone and costly undertaking. An operator-oriented way of data preparation makes it possible to quickly identify problems, recognize trends and then take the appropriate measures.

1.1.2 Consistency in Quality:

The production of the finest quality product with a consistency is a demand of a modern era. Quality and reliability plays a major role in the textile industry, if they have to compete in the market. The involvement of it gives the on-line monitoring & controlling of the quality.

1.1.3 Reduced Maintenance:

The uses of mechanical operating parts are unable to get high speed. The worn out of the parts is a major problem & so the machine stoppage for the maintenance is a critical & time-consuming job. It is reduced in the modern automated textile machines.

1.1.4 Flexibility:

The supplied functions leave almost nothing to be desired, demanding customers can create their own applications by accessing the database. In addition, the data can be transferred to spreadsheet programs in a very simple way. In a similar simple way, the PCs can be interconnected to a network. Via the Windows functions and commercial components, can be operated in a network, even via modem and cellular telephone systems.

1.1.5 Reduction in Man Power:

The applications were realized when a higher quantity and a better quality was produced with the reduction in personnel. On the other side, it must be noted that the personnel definitely reacts to the presence of data systems and that its efforts and attentiveness increases. The automated work has given the reduction in manpower.

Following are the some of the applications of electronics and control systems in weaving machines.

2. Modern Electronic Control Systems in Weaving Machines:

2.1 Electronic Take Up and Let Off:

The take-up is used to keep the required thread density in the fabric and wind the fabric on the cloth roll and let off release the required amount of warp. The electronic system provides important time saving the required pick density is electronically set (no pick wheels are required to change pick density). The accuracy of settings makes it easy to adjust the pick density of the fabric for optimum fabric weight and minimum yarn consumption. The take up and let off are driven by separate motors.

Let-off and take-up motions are identical in construction, each motion utilizes a resolver as the measuring system, connected together with the sensor to a control circuit. Electronic fabric take-up and warp let-off is not only controlling and reacting, but also acting with regard to the future. Absolute sensors measure the warp tension – independently of the position of back-rest roller and mechanical element motion – keeping it constant, even when weaving with splitted warp beams. The accuracy of warp beam settings on the display amounts to 1 cN/end with a filling density resolution of 0.01 picks/cm. Exactly reproducible values for filling density, machine speed, warp tension and contraction support start-mark prevention. 

Figure 2.1 Electronic Take Up and Let Off
Figure 2.1 Electronic Take Up and Let Off

2.2 Permanent Insertion Control (PIC®) with Servo Control®

PIC®-system of DORNIER permanently monitors the most important electrical filling insertion elements. It recognizes imprecise operation of filling insertion elements. It sets new standards for process reliability and quality consistency. Feeders with reliable layer separation activated via CAN interface, support exact feed length measuring for insertion. 

Flow optimized main and relay nozzles as well as short reaction times and low pressure volumes in the regulation circuit of ServoControl® provide gentle, low tension force application on filling threads. This allows higher speeds with a lower thread break figure combined with less yarn napping and therefore better final fabric quality. 
Figure 2.2 Permanent Insertion Control (PIC®) System
Figure 2.2 Permanent Insertion Control (PIC®) System
Combined with electronic controlled switching times and nozzle timing, these devices guarantee high flexibility with lower air consumption. The modular, patented Triple Weft Sensor with deflection and stretching nozzles opens up a new dimension in reliable filling monitoring.
The permanent control of the relay nozzle jetting sequence with a continuous standard value comparison (PIC®) assures weaving quality and precludes machine downtime. Defective or worn magnets are indicated immediately. Yarn-, speed- and width-related parameters for the control of the nozzles pick and pick are supplied from a data library. The timing of the electronically controlled filling scissor can be set on the display with the machine running.
Figure 2.3 ServoControl® unit
The new ServoControl® unit regulates the pressure in one control circuit for all main and tandem nozzles depending on the specified thread arrival time. This raises the machine automation level. For processing of new, unknown yarns only a few settings are still required and can be attained fast and reproducible. Absolute pressure values are shown as digital values on the machine display for the first time. A precisely dimensioned air supply unit serves the main, tandem, relay and stretching nozzles.

2.3 Slim Through-Light Sensor (STS)

The new, patented filling stop sensor DORNIER STS (Slim Through light Sensor) is based on the through light principle. It provides highest functional and quality reliability for dark filling colors and finest threads up to 20den. It can be easily positioned anywhere on the reed with a clip-on attachment according to filling insertion width. The compact design prevents damage to reed teeth.

Figure 2.4 Slim Through-light Sensor
Figure 2.4 Slim Through-light Sensor

2.4 Electronic Color Selector (ECS)

During weaving various colors are used in the fabric in warp & weft direction. In this system the weft colors are changed electronically instead of mechanical slow speed system. The electronic filling tensioner maintains optimum tension on the weft throughout the weaving.

Figure 2.5 Electronic Color Selectors (ECS)
Figure 2.5 Electronic Color Selectors (ECS)
The electronic color selector, ECS, and the electronic filling tension EFT device with integrated filling stop motion, is based on a new type of stepping motor distinguished by its sturdy construction, extremely small control increment of 0.9o and high torque Setting and function relative to the weaving process are precisely programmable on the machine display. Due to the modular concept individual modules can be added or removed easily. In this way, a single color machine can be inexpensively upgraded to handle 12 colors. The powerful stepping motors are of a very compact design and permit very small graduated increments which in turn help to perfect sequence in the weaving process. The motors are controlled via a microprocessor. Needle position can be set individually on the color selector via the display.
The needle´s smoothly controlled movement allows gentle yarn presentation with reduced yarn tension peaks. Low tensile strength yarns and also heavy yarns with high yarn tension, like 2400 Tex glass for example, can be processed without difficulty.

2.5 Energy Consumption Optimized Weaving with Real Time Control (ECOWEAVE /RTC)

Figure 2.6 ECOWEAVE /RTC
Figure 2.6 ECOWEAVE /RTC

2.5.1 Technical Information

  1. Optimized Valve Timing: shorter blowing times for relay nozzles due to patented real time controlled valve timing. 
  2. Advanced Design: new dedicated micro-controller design for high speed valve timing corrections; continuously actuated during weft insertion. Based on changing weft speed and actual weft tip position. 
  3. Self-Adjusting: no more tedious setting of relay nozzle timing – most settings are adjusted automatically during auto tune procedure. 
  4. Failure Detection: hardware failures (missing pulses, valve failure) are immediately detected. 
  5. Patent: based on previously approved L5500 patent with improved reliability and precise weft insertion. 

2.5.2 Advantages

  1. Cost Savings: up to € 500 – € 2’000/year depending on weft yarn and machine width. 
  2. Reduced Air Consumption: less CO² emissions and 10% – 20% less air consumption provides immediate energy cost reduction.
  3. Reduced Weft Stops: weft stops due to improper valve timing and variation in arrival time are eliminated by precise & continuous adjustment of the relay nozzles and specific control of the weft tip. 
  4. Ease of Use: simplified system with few parameters allows easy integration for weavers. 
  5. Energy Consumption Optimized Weaving with Real Time Control.

2.6 Prewinder Switch off (PSO)

GamMax has a Piezo-electric filling detector that stops the machine in case of a filling break. With its Prewinder Switch off (PSO) system, the machine continues weaving even if a filling break occurs on the packages or the Prewinder. The Prewinder signals the filling breaks and simply switches to single-channel operation instead of weaving with two channels. PSO is a patented Picanol development.

At a filling break the machine stops and only the harnesses are moved automatically to free the broken pick for removal by the weaver. The automatic pick finder and the slow motion movements are not driven by a separate motor; instead, the pick finding is simply done by the Sumo at slow speed. The required pick finding position is reached with a minimum of reed movements through the beat-up line.

2.7 Automatic Picks Finding

The GTX plus machine is equipped with an automatic pick finding device and with slow forward and backward motion. In case of a filling stop, the pick finder opens the shed on the broken pick for removal by the operator. The microprocessor synchronizes all mechanisms in this process. The automatic pick finding system makes repairing a filling break much easier for the operator and it shortens the time lost by filling stops.

2.8 Electronic Yarn Tension Control

Each pre-winder can be equipped with a new type of Programmable Filling Tensioner. This PFT is microprocessor controlled and ensures optimum yarn tension during the complete insertion cycle. Reducing the basic tension is an important advantage when picking up weak yarns, while adding tension is an advantage at transfer of the yarns and avoids the formation of loops. The tension control enables you to weave strong or weak yarns at even higher speeds. It also drastically reduces the amount of filling stops, and enables you to set an individual waste length per channel and reduce the waste length for some channels.

The Yarn Tension Meter is a portable and precise sensor between Prewinder and filling detector to measure and display the filling tension on the microprocessor quickly. Thanks to the immediate feedback, the sensor allows very easy fine-tuning of the yarn tension, which is very helpful when sensitive yarns need to be woven, such as wool. Instead of “trial and error”, you can “measure and act”. This has a direct impact on the productivity and the quality.

2.9 Automatic Start-mark Prevention (ASP)

ASP: Preventing start-marks at the source. The simple functionality of automatic start-mark prevention saves time and significantly contributes toward quality improvement. All the functions outlined in the illustration can be simply called up on the machine display and changed as required, including the patented AE-function (dynamic start-up) and automatic single pick mode. All settings are reproducible.

Figure 2.7 Automatic Start-mark Prevention
Figure 2.7 Automatic Start-mark Prevention

2.10 Mobile, Multi-functional Axis Control

The new mobile warp change key pad significantly facilitates the warp changing process. It can even be carried out by one person on double width weaving machines. The operator can control warp and fabric take-up with it from any point around the weaving machine. 

Figure 2.8 Mobile Warp Change Key Pad
Figure 2.8 Mobile Warp Change Key Pad

2.11 E-SHED

Toyoda’s electronics technology has created the E-shed, yet another breakthrough in the weaving industry. Its ultimate shedding motion makes weaving easy, even with textile fabrics difficult to weave with conventional shedding motions. Based on the settings from the function panel, the E-shed’s main 32-bit CPU controls independent servo-motors that drive individual shedding frames with perfect ease. This flexible system enables not only shedding patterns but also cross-timing and dwell angle to beset from the function panel. All of which leads to greater efficiency, easier operation and higher fabric quality.

Figure 2.8 Schematic of E-Shed
Figure 2.8 Schematic of E-Shed

2.11.1 Ultimate Flexibility

The E-shed combines the optimum cross-timing and dwell angle for each shedding curve, making It easy to weave various kinds of fabrics such as high density fabrics traditionally woven by cam shedding,

Complex fabrics with a dobby and even fabrics difficult to weave with conventional shedding motions because of loose warp yarn or incomplete shedding.

2.11.2 Greater Fabric Quality

Unlike existing shedding devices, the E-shed allows separate upper and lower dwell angles to be set, which improves beating-up performance and fabric quality. Meanwhile, combined variations in cross-timing prevent warp entanglement and minimize problems caused by warp yarn. And since the shedding and beating motions are not synchronized, there are fewer stop marks during start-up. High Efficiency freely controllable warp leads to increased warp shedding ability and minimal miss picks in weft insertion. And this means greater efficiency.

2.11.3 Easy Operation

Settings can be changed by a touch of the function panel. This makes it much quicker and easier to be flexible when manufacturing many different kinds of articles in small quantities. 

2.11.4 Not Affected by Upper/Lower Frame Imbalance

The E-shed is not affected by any difference between the numbers of upper and lower heaId frames unlike in dobby shedding, which enables wider range of patterns to be woven with great ease.

2.11.5 Pick Finding with Shedding Motion Only

Shedding and beating are not synchronized, which enables pick finding while moving the heald frame and keeping the reed fixed. The result is higher quality fabric with fewer stop marks. (With the Optional electronic take up motion installed).

2.12 CAN-Bus – The Backbone Weaving Machine Control

Electronic Control Technology the electronics of modern weaving machine are based on multiprocessor architecture with 32-bit technology. Data transfer between the various sub units of the machine is via a CAN- BUS, permitting fast and reliable exchange of data both internally and externally. The terminal has a graphic display in which various functions of the warp let-off, cloth take-up, weft feeder, etc. can be programmed easily and clearly. The modern CAN-Bus System gives the following advantages: 

  1. Ease of operation. 
  2. High fabric quality irrespective of speed. 
  3. Pick density alterable while the machine is in operation. 
  4. Immediate help trouble-shooting problem. 
  5. Self-adjusting stop position of the machine. 
  6. Microprocessor controlled central forced lubrication system. 
  7. Storage and monitoring of all the production data, efficiently. 
  8. Machine function control, pattern weave, warps tension, pick density. 
  9. Pick finding control and the elimination of stop marks by means of preset programs. 
  10. Control and report of style change timing. 
  11. Quick control of the electronic functions (self-diagnostics and auto checkup) and monitoring of the machinery functions for protection. 
  12. Bi-directional communication between the weaving machine and the central production computer. 
  13. Speed set-up. 
  14. Electronic weaving speed variation depending on the characteristic of the yarn being used. 
  15. Control of warp let-off and fabric take-up. 
  16. Electronic control of the filling tension. 
  17. Transfer of setting and production parameters of a fabric style, to other machine with the help of memory cards. 
In Picanol GamMax, most of the machine functions are digitally controlled. All the machine settings can be digitally stored and transferred. The electronic terminal on GamMax monitors and controls all machine functions. Its LCD screen has self-explanatory menus and enables the weaver to set the weaving parameters in a very user-friendly way. GamMax is also Internet- enabled. The GamMax terminal features wireless communication through a USB memory stick or key tag, permitting robust, flexible, handy and reliable operation. Sulzer G6500 offers “Smart Weave” – intelligent pattern data programming. “Smart Weave” offers fabric designer intelligent support in the preparation of weaves design and picks repeats. The G6500 control interface is a user-friendly, Internet-ready touch screen terminals. The logical structuring with self-explanatory Pictogram guides the operators to the desired function simply and with a minimum of keying. In Leonardo, the computer system is based on the CAN-BUS system. This drives and controls all the main textile and mechanical function. With the CAN-BUS in mind, a new controller has been developed, called the FULLTRONIC. This co-ordinate all loom functions instant by instant, from the operating conditions of the various mechanisms to each individual response: heald movement, color to be selected, warp tension, density of the weft in the fabric, plus the messages describing the status of the lubrication circuit. Monitoring takes place at a frequency of more than 700 messages/sec. The Dornier rapier-weaving machine, type PS, has control cabinet with integrated CANBUS and various modules for start, stop, warp let-off and fabric take-up as well as start mark prevention. The Dornier Customer Service Department can directly access machine displays – trouble shooting online. The DoNet Global Communication Network offers quick location and transportation of setting instructions, remote diagnostics.

Figure 2.9 CAN-BUS Connections
Figure 2.9 CAN-BUS Connections

2.12.1 DISPLAY

Evidence of how advanced electronics high quality and perfect repeatability can be found in the many functions accessed via the microprocessor. These include integrated setting screens with preset ranges for shedding, filling insertion, pick density and warp tension values. Pre-programmed procedures to prevent starting marks in sensitive fabrics are included as a standard feature.

Standard – color-graphic display. Ergonomic navigation through only a few menu levels has been drastically simplified. Shortcut keys support rapid, direct access to important menus and data for machine control. Weaving parameters such as speed, filling density and warp tension can be freely selected and stored as style data. The electronic terminal monitors and controls all machine functions. Its LCD screen has self-explanatory menus and enables the weaver to set the weaving parameters in a very user-friendly way. The display advises which action to take when a stop occurs. Pre-programmed procedures to prevent starting marks are standard. 
Figure-2.10 Display of modern weaving machine
Figure-2.10 Display of modern weaving machine
Important settings normally done by the fixer under difficult conditions, such as setting the selvedge crossing time or the shed crossing, are now done by simply typing in the required values. The settings are accurate and easily transferable to other machines, and the result of slight adjustments can be checked immediately in the fabric. For the weaver, all this means great ease of operation and higher weaving productivity.

CONCLUSION

Many times in the past it was argued that projectile and Rapier systems have attained maximum speed limit. However, these machines continue to enhance the speed limit and are not far behind Airjet machines. Most of the developments are in the area of attaining better fabric quality, gentle treatment to warp and weft and reduced breakages. Another interesting trend is in the type of selvedge formation and waste reduction. Weft waste has been reduced to zero even in Rapier and Airjet machines. The future trend in developments would, probably, be in similar lines.

REFERENCES

1. Model development; Textile Magazine; Issue4; 2008; pp36-39

2. Amit A Jadhav, Modern development in weaving; The Indian Textile Journal; July 2007; pp22-25
3. Yueyang Guo, Ruiqi C, A new type of microprocessor con-trolled positive dobby, Indian Journal of Fibre and Textile Research, vol. 28, pp. 275, (2003).
4. Subhankar Maity, Kunal Singha, Mrinal Singha, Recent Developments in Rapier Weaving Machines in Textiles, American Journal of Systems Science, 1(1): pp7-16, 2012
5. DORNIER Machinery Brochures
a) Air-Jet AS type
b) Air-Jet A1 Type 
c) Air-Jet Tire Cord
d) Rapier P1Type 
6. Picanol Machinery Brochures
a) GTXplus
b) GamMax
7. TOYODA E-SHED Brochures

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