Anyone who wants to produce top quality woven goods in high volume, and wants to stay competitive in the bidding for orders, must first and foremost have their planning and organization under control. An additional criterion is thorough familiarity with the entire production process, from fibre to fabric, to ensure that fabric production is profitable.
A precondition of optimum production in the weaveroom is meticulous planning. It is at the planning stage that process parameters, sequences of operations and working conditions are defined, all of which are relevant to profitability. The basis for these is optimal installation of the weaving machines, with appropriate transport routes and equipment. Additionally, capacities must be planned and the necessary infrastructure and resources created, including buffer store, air conditioning, lighting, personnel, quality control etc. This article spotlights key points that it is essential to take into account in the planning and organization of a weaving facility.
High yarn quality ought to be a matter of course. But its importance has to be pointed out repeatedly, because 80% of weaving machine stoppages originates in upstream process stages. In non-verticalized mills, all yarns supplied should be inspected on receipt. Not only the uniformity of the yarn is important; damaged packages are a sign of poor transport quality, and on the weaving machine they not only impair productivity but also cause waste. If there are no yarn reserves in the weft packages the result will be a weft stoppage. Thread breaks in weaving are the largest cost factor in the entire production process, because they always involve a machine stoppage.
Proportion of the different departments in the total thread break costs
In the textile manufacturing process, thread break costs in weaving are far higher than in all other stages of production. Every stoppage prevented directly improves the company's profits.
The basis for good warp running characteristics on the weaving machine is created in warp production. Faultlessly produced warp beams and precision work on the sizing machine, in combination with the right sizing agent and size application, are the conditions that have to be fulfilled. According to an old German proverb in the textile industry, "well sized is half woven".
Machine configuration (weaver-room layout)
In weaving mills, large quantities of materials are moved every day. Correctly dimensioned transport routes and good transport equipment are essential to ensure efficiency. With sufficient stockage space between the weaving machines, the number of movements needed to transport weft yarn can be reduced. A customized configuration developed by Sultex experts takes all these considerations into account. The condition of the floor also has a crucial influence on the speed of transport. On a level, well finished floor any vehicle can move faster and with less wear.
Air conditioning serves to create an optimal climate for weaving. Conditions in the weaveroom will depend on the yarn to be processed and the sizing agents used. Correctly adjusted relative humidity is crucial for the running characteristics. Good air conditioning also fulfils other tasks: it purifies the ambient air by extracting dust, and by cooling the air it creates the right working conditions. Room air conditioning is used above all where cotton and cotton blends are woven. In some cases, process zone air conditioning may also satisfy requirements - a system used in particular where manmade fibres are woven.
Efficient and effective cleaning of weaving machines and the weaveroom is an important factor in achieving flawless fabric production. When weaving staple fibre yarns, the air conditioning system alone is not capable of keeping the weaving machine and the weaveroom sufficiently clean. In this case the only solution is to use travelling cleaners. It is advisable to use units that blow off while simultaneously vacuum-cleaning the floor. However, for thorough cleaning of weaving machines, there is no alternative to using vacuum cleaners and compressed air. Compressed air is efficient but simply blows the dust somewhere else. For this reason, suctioning off is a far more effective method. Central vacuum systems have the advantage that they simultaneously remove dust and waste. Heavy soiling increases wear on machine components and causes stoppages. With scheduled cleaning work, unnecessary costs - of spare parts, stoppages and maintenance can be avoided.
Weaving machine stoppages
Every weaving machine stoppage, whatever its cause, harbors the risk of a fabric defect. Weaving machine stoppages adversely affect the weaving mill's productivity, reduce machine allocation per weaver and increase costs. If possible, such interruptions of production should be avoided. In order to eliminate stoppages, their cause and frequency must be known. Modern weaving machine terminals and mill management systems provide information on the number of stoppages but not about their exact causes. The efficiencies and stoppage times recorded by these systems are important as benchmarks, in order to detect sudden and gradual changes and thus conclude what action to take. The causes can only be identified by specific, manually conducted stoppage analyses (The results of these studies form the basis for process related and organizational changes and optimization. The improvements introduced must also be checked. A control loop is thus created, of action taken and verification thereof. In order to correctly evaluate these standstill analyses, in-depth knowledge of the entire textile production process is needed, because the causes are often in upstream process stages. At the same time, mistakes made by the operator and incorrect machine settings can be identified.
The duration of a stoppage is not only important with regard to productivity; it also crucially influences fabric quality. Stop marks after a weaving machine stoppage can be prevented if the machine is restarted quickly. If a machine is stopped for too long, the width of fabrics woven from critical materials may be reduced. For this reason, complicated yarn breaks or multiple breaks must be avoided at all costs. The weaver's workload can be calculated from the downtime and the number of stoppages. From this data it can be seen how many weaving machines one weaver can look after, which in turn provides information on personnel costs.
Long-term stoppages include style and warp changes, machine servicing and repairs. In contrast to stoppages for mechanical reasons, they can be planned and can be reduced to a minimum. For these interruptions, planning with foresight, teamwork and personnel training are indispensable. Keeping sufficient quantities of spare and wearing parts in stock to cover consumption will help minimize long-term downtimes and save costs by avoiding rush orders.
We distinguish two types of efficiency. Weaver efficiency provides information on the weaver's workload. It takes the frequency of stoppages (broken ends and weft breaks), downtime and productivity into account. Plant efficiency includes all stoppages (broken ends and weft breaks, warp changes, repairs etc.). The difference between the two figures can be traced back to the long-term stoppages. The plant efficiency reflects the productivity of the weaving facility and can be improved by reducing short-term (yarn breaks) and long-term (organizational) stoppages. Depending on the style mix, increasing efficiency by one percent results in an increase in earnings of up to 1000 Euros or more per weaving machine and year.
Correct lighting of production facilities creates good working conditions, makes work easier and helps prevent mistakes. The lighting must be such that parts of machines or installations do not cast shadows on the cloth. Depending on the weaving machine configuration - with or without batch winder and inspection unit - it makes good sense to install a light source behind or below the fabric in order to detect defects quickly and easily.
Maintenance of the machines must be planned with care and carried out in accordance with the manufacturers' instructions. Unnecessary repairs and long-term stoppages can thus be avoided, and spare parts costs reduced. Maintenance is carried out on the basis of a checklist, making a record of the condition of parts and of parts replaced. The machine file will allow deficiencies and excessive wear of individual weaving machines to be identified. Lubrication and greasing require special care and must be carried out by qualified personnel in accordance with the manufacturer's instructions. Machine cleaning is an important part of maintenance and must not be neglected under any circumstances.
Style and warp changes
Style and warp changes can easily be planned in advance. It is important to make sure that besides the warp beams, weft yarn and harness, all other necessary materials (temples, cams, weft feeder brushes etc.) are put ready in the order they will be needed. Checklists are very helpful and thorough job preparation helps to avoid wasting time. In addition, machine reports ensure that all machines weaving the same article have the same settings.
Preparation of materials
Good planning benefits the production process, helping to avoid unnecessary waiting time. By keeping adequate quantities of warp beams and weft material at intermediate storage points, as close as possible to the weaving machines, production losses can be minimized. For the sake of good running characteristics, the weft yarn should be acclimatized for at least 24 hours under the climatic conditions in the weaveroom.
Inspection of the cloth immediately after weaving avoids the production of further faulty goods. Avoiding defects is the prime objective. If they occur, it is vitally important to detect and remedy them quickly. For this reason the cloth should always be inspected directly on the weaving machine. It makes sense to document all defects, so that a subsequent inspection can be carried out efficiently.