Seminar OnDevelopment in Card Wire And Wire geometry BY:- MUKUL CHANDEL M.TECH T.T
WHAT IS ALL ABOUT ?• INTRODUCTION• CLOTHING AREA• IMPORTANT PERAMETERS• POSSIBLE ACTION BETWEEN TWO SUFACES• USE OF STEEL ALLOY
INTRODUCTION• There are two rules of carding• The fibre must enter the carding machine, be efficiently carded and taken from it in as little time as possible• The fibre must be under control from entry to exit• Control of fibres in a carding machine is the responsibility of the card clothing
Following Are The Five Types Of Clothing Used In a Carding Machine• Cylinder wire• Doffer wire• Flat tops• Licker-in wire• Stationary flats
CYLINDER WIRE• Cylinder clothing play a major role in cotton processing when it comes to optimal reduction of neps and dirt particles. The quality of a cylinder wire itself, in turn, is primarily determined by a high precision during manufacturing and the selection of optimum tooth geometries.
DOFFER WIRES• The doffer is a collector and it needs to have a sharp tooth to pick up the condensed mass of fibres circulating on the cylinder. It also requires sufficient space between the teeth to be efficient in fibre transfer from the cylinder, consistent in the transfer rate and capable of holding the fibre under control until the doffers stripping motion takes control.
LICKERIN WIRES• Licker-in with its comparatively small surface area and small number of carding teeth, suffers the hardest wear of all in opening the tangled mass of material fed to it.
FLAT TOPS• Flats fabric and hooks - simply a clever design• Flat tops mainly consist of the flats fabric and of the hooks. Both of them have an enormous influence on carding quality.
IMPORTANT PERAMETERS• Tooth depth• Carding angle• Base width• Wire height• Tooth pitch• Tooth point dimensions
TOOTH DEPTH 1. Shallowness of tooth depth reduces fibre loading and holds thefibre on the cylinder in the ideal position under the carding action ofthe tops. The space a fibre needs within the cylinder wire dependsupon its Micronaire/denier value and staple length. should have to bereduced. 2. The recent cylinder wires have a profile called "NO SPACE FORLOADING PROFILE"(NSL).With this new profile, the tooth depth isshallower than the standard one and the overall wire height isreduced to 2mm , which eliminates the free blade in the wire. Thisfree blade is responsible for fibre loading.
TOOTH PITCH1. Each fibre has a linear density determined by its diameter to length ratio. Fine fibres and long fibres necessitates more control during the carding process. This control is obtained by selecting the tooth pitch which gives the correct contact ratio of the number of teeth to fibre length.2. Exceptionally short fibres too require more control, in this case , it is not because of the stiffness but because it is more difficult to parallelise the fibres with an open tooth pitch giving a low contact ratio.
BASE THICKNESS1. The rib thickness of the cylinder wire controls the carding "front" and thus the carding power. Generally the finer the fibre, the finer the rib width. The number of points across the carding machine is determined by the carding machines design, production rate and the fibre dimensions. General trend is towards finer rib thicknesses, especially for high and very low production machines.2. Rib thickness should be selected properly, if there are too many wire points across the machine for a given cylinder speed, production rate and fibre fineness, "BLOCKAGE" takes place with disastrous results from the point of view of carding quality. In such cases, either the cylinder speed has to be Increased .
FRONT ANGLE1. Front angle not only affects the carding action but controls the lift of the fibre under the action of centrifugal force. The higher the cylinder speed , the lower the angle for a given fibre.2. If the front angle is more, then it is insufficient to overcome the centrifugal lift of the fibre created by cylinder speed. Therefore the fibre control is lost, this will result in increasing flat waste.3. If the front angle is less, then it will hold the fibres and create excessive recycling within the carding machine with resulting over carding and therefore increased fibre damage and nep generation.
BACK ANGLE• A lower back angle reduces fibre loading, but a higher value of back angle assists fibre penetration.• Between the two extremes is an angle which facilitates both the reduction in loading and assists fibre penetration and at the same time gives the tooth sufficient strength to do the job for which it was designed.
HARDNESS OF WIRE• The cylinder wire needs to be hard at the tip of the tooth where the carding action takes place.• The hardness is graded from the hard tip to the soft rib.• High carbon alloy steel is used to manufacture a cylinder wire and it is flame hardened.• Rib should not be hardened, otherwise, it will lead to mounting problems.
POSSIBLE ACTION BETWEEN TWO SUFACES WITH CARDING WIRE
USE OF STEEL ALLOY IN MANUFACTURING OF CARD WIRE• BASED UPON APPLICATION AND DEMAND CARD WIRE IS MANUFACTURED FROM DIFFERENT ALLOY STEEL :- ULTIMA (TUNGSTEN,VANADIUM ALLOY STEEL) CHROMA (CHROMINU ALLOY STEEL) PERFORMA (HIGH TENSILE SPECIAL ALLOY)
CONCLUSION• Fact that carding is heart of spinning line.• With the demand and requirement geometry of card wires is changed in different parameter.• If quality of wire is good better will be carding and then better will be the product.