Knitting Productivity

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Knitting Department Productivity Dr Muhammad Mushtaq Mangat www.mushtaqmangat.org Knitting is the first process in the battery of whole process to convert greige yarn into a value added garment. In this department, yarn is converted into fabric with the help of knitting machines. This department plays a crucial role in the productivity of knitted garment manufacturing mills. It has been observed during survey that at the time of panel inspection in cutting department, more than 50% rejection of panels is due to knitting faults. Knitting department has also more than 20% share in the rejection of garments at the time of final inspection before packing. It is believed that more than 50% improvement is possible in knitting which includes, less share in garment rejection, more production per machine, better fabric quality, less consumption of knitting parts, improve labor productivity etc. This article is aimed to identify the improvement areas in knitting and discussion how we can improve knitting productivity. In the first part, we will give introduction of knitting technology, second part have reserved to explain the areas where we can have improvement and finally in third part we will suggest how we can make improvements. Knitting History It is quite difficult to say about the start of knitting with confidence. Many authors and researchers have different views. However, researchers are generally agreed that the art of hand knitting has been practiced since thousands of years. How ancient human learned this art is still a mystery and so is the country and time of its origin. However, some believe that this art originated in Persia. Others claim Israel, Jordan and Syria belt as its origin, and still others claim mountains of North Africa. Knitted socks discovered in Egyptian tombs have been dated between the 3rd and 6th centuries BC. First knitting frame was invented four hundreds years back and that frame could knit 600 courses per minute and today the latest machine can knit more than 15 million stitches per minute. While a skilled hand knitter can produce only 120-150 stitches per minute. Furthermore, until 1980 majority of the knitting machines were controlled mechanically. Nevertheless, today more electronics are used to control machine working and application of computer is becoming high every day. Jacquard knitting machines were equipped with

designs wheels and drums to produce a certain design in fabric but today computer is attached with the machines for designing purpose. Same is the case with stripper knitting machine. There were manual controls to change the yarn supplied but today whole machine is equipped with electronic controls and all setting are done on computer.

Before the invention of knitting frame by William in 1589, hand knitting was the main source of knitted fabric and a skilled person could knit 120 –150 stitches in minute and still this hand knitting is popular but mainly for to pass their leisure time and mainly ladies are doing this business, particularly in old ages this is their hobby. In some cases hand knitted sweaters are sold in the market but its share in the total business is negligible. Knitting in 2006 There are machines which can run at speed of plus 50 revolution per minute, gauge more than 40, diameter plus 60 inches and feeders up to 316, fully garment knitting machines, stripers and jacquard on same machine, interchangeable structure, totally computerized etc. In addition to that people have made machine (still not commercially used), on which we can feed sliver (align fibres) and machine will convert this sliver into yarn. In this way no need of full fledged spinning mills. Furthermore, machine will make yarn as per the requirement.

Just 20 years back maximum production from one machine was 300 Kgs per day and today we can have more than 1500 Kgs per day. This scenario forces our industry to keep pace with the new technology. Unfortunately, in our industry we have old machines, which are not capable to make us competitive in the international market. Furthermore, we are still having old facilities in knitting department]. In addition to that we are still stick to old management practices. There is a dire need to have modern technology as well as modern management theories in practice.

Knitting Process Explanation Knitting is a process in which fabric is made by inserting loop into loop. In this process yarn loops are made with the help of needle hook and these loops are passed through previously made loops already hold by the needle. From the above-mentioned definition it is clear that

knitted fabric is mainly composed of loops. These loops are formed with the help of needle by providing them yarn from any warp sheet or feeding through a feeder. Loops formation is the basic and fundamental differentiation from woven fabrics. All knitted fabric characteristics are based upon loop structure. Loops are mainly responsible for elasticity and resilience of the fabric.

Knitting Fabric Production Process As discussed in the first part of the chapter that knitting is one way of making fabric. For this purpose yarn is supplied to knitting machine and machine converts this yarn into fabric with the help of various parts. There are many factors involve in production process which have a significant impact on productivity of the knitting. Some of the factors are mentioned below:-

1. Controlled environment in knitting hall (moisture and temperature) 2. Machine maintenance 3. Quality of compressed air 4. Skill of workers 5. Yarn storage place and methods 6. Fabric storage 7. Lubricants quality 8. Quality of needles and sinkers 9. Fluff level in the environment

In this part of the article, we will discuss different factors affecting productivity and ways how we enhance their positive impact on productivity.

Controlled Moisture Percentage and Temperature In Pakistan, knitting industry is confined only in three major cities of Pakistan; Lahore, Faisalabad (Punjab) and Karachi (Sind). There is a significance difference in climate of Punjab and Sind. Even in Punjab, temperature varies from -2 to above 50 C° in different parts of the year. Same is the case with moisture %. In rainy season it crosses 80% and in dry season it reduces to 20% and sometime less than it.

Cotton is highly absorbent. It can absorb up to 8.5 % moisture. Tensile strength of cotton increases with the increase of moisture. Furthermore, it gains weight, which is quite logical. To avoid problem of variation in the strength and weight, which change with the change in moisture and temperature, international standards of moisture and temperature have been set.

As per standards, moisture must be 65% ± 2 (Relative Humidity) and temperature must be 20C° ±1.

All knitting machines manufacturers recommend controlling environment in the knitting hall. Mayer and Cie, one of the largest and most aggressive knitting machine manufactures recommends maintaining 20 C° temperature and 65 % RH humidity in knitting hall. They have given these recommendations in the book, “Knitting Technology“, published by Mayer and Cie. There is a direct impact of moisture and temperature on knitting productivity. It was observed during survey of the industry that only one mill in Lahore and one mill in Faisalabad have installed air condition plant. Both are having better production from the same types of machines. Air conditioning system provides the required temperature and humidity along with controls the fluff (visible and invisible fly) in the air. There is an air circulation system attached with water chillier and humidifiers, which provide filtered air to the knitting hall. Based on expert’s opinion, claims of air conditioning plant manufactories and observation during survey of the industry, it is expected that 20-25% production of the knitting mill can be improved by putting an air conditioning plant. In addition to that 50% less faults and 50% less consumption (breakage) of needles and sinkers is expected. Above all we will be fulfilling our moral duty by providing a healthy environment to workers, which keeps them healthy. As per doctor’s opinion, fly can damage our aspiratory system. And finally we have a neat, clean, free from fly and healthy environment, which definitely improver our productivity. It is presumed that pay back period of all investment is les than six months. In addition to that there is a 50% less consumption of needles and sinkers, along with better fabric quality, above all healthy, pollution free environment for workers. Other than increase in production, we can have following benefits:1. No tripping of electronic parts, which is quite common at high temperature 2. Less breakage of needles due to low temperature 3. Satisfied operator since environment is neat and clean along with suitable temperature and humidity

4. Better knitted fabric quality due to less yarn breakage and low machine stoppage frequency 5. Better health of workers 6. Less yarn wastage 7. Conducive environment for creativity

From all above discussion, it is quite clear that air conditioning plant is one of the most important investments in a knitting mill. Based on all discussion, it is recommended that all knitting mills should have air conditioning plant to improve their productivity. It is not an expense rather it is investment. Its pay back period is less than a year. In our view, instead of a big knitting hall, we should focus to have an efficient hall. Cool and Dry Compressed Air Compressed air of 125-150 pounds per square inch pressure is used in knitting for cleaning and oiling purpose. It goes into the deeper parts of the knitting machine to remove fly from the machine. Furthermore, it is used along with oil to make inner parts of the machine fully lubricant to avoid any friction. It is one of the most important inputs in knitting productivity factor. When air is compressed in a vessel its temperature increases and at the same time, moisture percentage in the compressed air also increases. High temperature and high level of moisture both are dangerous for knitting process. High temperature further raises the machine temperature, which is already too high due movement of the machine at high speed. High level of moisture reduces the lubrication efficiency. Since all lubricants (mainly white oil) are water-soluble. Moisture present in the compressed air gets dissolves the oils and ultimately its reduces its lubrication. Which occurs in shape of less lubrication and ultimately there is breakage of knitting elements, particularly, needles and sinkers are the main victim of high moisture. To avoid it, it is recommended by all machine manufacturers that we should use compressed air free from moisture and it should have low temperature (less than 20C°). In our knitting industry, in most of the cases, people use compressed air without treating. There are machine and equipment, available to reduce the moisture level and keep air temperate low. Based on this discussion, it is recommended to have a cool and moisture free compressed air for knitting.

We can have following advantages of cool, free from contaminant in and dry air: 1. Helps reduction in needle breakage 2. Avoiding rust on machine 3. Smooth running of machine 4. Reduction in accidents

Other than the two above-mentioned areas, knitter should focus on the following points: • • • Yarn and greige fabric storage Machine maintenance Lifter to move yarn and fabric in knitting hall

It is expected that by focusing these points one can have the following advantages: 1. Avoiding Mixing of yarn 2. Less yarn variation 3. Less left over yarn 4. Less yarn wastage 5. Better machine maintenance helps in better production …. A Universal Truth

Adopting al above recommendation it is expected that knitter can increases its profitability more than 25% along with a better image of the firm in the minds of the customers, internal and external both.

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