Effect of spindle lift in ring frames on productivity and energy
Power consumption plays a major role in the yarn manufacturing cost. In this article, Dr Nagarajan Ganapathy & Rajesh Pandiyan highlight the effect of spindle lift in ring frames on productivity and energy.
In spinning mills, power consumption plays a major role in the yarn manufacturing cost. Ring frames consume power of around 42 -55% when compared to that of the other preparatory machineries. Furthermore, the yarn content in the cop is around 55 to 60 gms only depending upon the count spun. To produce this weight of yarn, more power is required to drive the spindles to run at the maximum speed and efficiency with acceptable waste levels. Nevertheless, with those disadvantages, ring spinning system is universally applicable that most of the fibres can be spun to required fineness.
The yarn spun from this machine demonstrates excellent quality features like structure and good strength satisfactory for downstream processes. Many efforts has been taken to reduce the power consumption and higher productivity by modifications in the spindle design, reduced wharve diameter and in electrical components. In this article, an attempt has been made on lift conversion in a modern ring frame. Subsequent benefits gained out of it like higher productivity & savings in energy is also discussed in this paper.
In general, spun yarns can be manufactured by using ring, rotor and vortex spinning systems. Ring spinning is versatile in all aspects except productivity and energy consumption. Rotor spinning is commercially more widely used because a wider range of yarn counts can be spun with appropriate yarn properties. Since its commercial introduction in 1969, rotor spinning has developed continuously. Rotor speeds have increased from around 30,000 rpm to over 150,000 rpm. Vortex spinning was introduced by Murata Machinery Ltd. Japan in 1997. This technology is a development of air jet spinning, making use of air jets for twisting fibres to produce yarns. The features of Vortex spinning is the delivery speed is around 500 m/min production rate which means that the production rate is around 20 times higher than that of the ring spinning machine. In addition, other advantages like low maintenance costs, fully automated piecing system and elimination of speed frame. The yarn quality is also comparable to that of the ring spun yarns.
Materials and methods
A study was conducted on a modern ring frame producing Ne 30 combed hosiery yarns from medium staple length cotton. The mills were producing the yarns on ring frames on 40mm ring diameter, HPS spindle with auto doffing arrangement. The process parameters maintained are spindle speed 17500 rpm, twist multiplier 3.6 and ring traveler of 5/0 respectively. The scope of the study was to increase the ring frame productivity and also to reduce the power consumption. The first part of the study was to convert the normal lift of the ring rail traverse from the existing 195mm to 175mm. With this conversion in lift, lower ring tube length of 190mm could be conveniently used for winding the yarn instead of the existing 210mm. Before the conversion process, end breakages, quality and power study were conducted at five spindle speeds, viz, 17500, 18000, 18500, 19000 & 19500 rpm respectively.
The same study was repeated again after the ring tube length is changed from 210mm to 190mm. The second part of the study is to analyse the benefits from the lift conversion. Comparisons on Ends down/100 spindle hours, quality and power study in terms of power consumed in units consumed between 210mm & 190mm under identical process conditions. Ends down study were conducted for the full doff. On line monitoring of yarn clearer cuts /100 km was done on a modern Auto coner machine equipped with Uster Quantum 3 yarn clearer.
The produced yarns at five spindle speeds from both 210mm & 190mm ring tube length were tested for their quality characteristics like unevenness, imperfections on Uster tester– 3. The following are the changes effected on the machine for converting the lift from 210mm to 190mm.
- Ring rail traverse was lowered from the existing 195mm to 175mm
- Simultaneously, a reduction of 20mm on Lappet, ABC Rings and doffing bar height was done.
- Ring tube empties which changed to 190 mm from the existing 210 mm.
- Adjusted the magazine width of bobbin loader according to 190mm ring tube size.
- Rotary arrangement for Bobbin feed was modified according to 190mm ring tube empties requirements.
Results and discussions
- Effect of lift conversion on production per spindle / day: Ring tube length of the lift converted 190mm and the existing 210 mm tube length is shown in Figure 1.