Yarn Lab
LabExperiment no: 01
Experiment name: STUDY ON THE PASSAGE DIAGRAM AND GENERAL DESCRIPTION OF ROVING FRAME MACHINE.
Introduction :
A roving is a long and narrow bundle of fiber. Rovings are produced during the process of making spun yarn from wool fleece, raw cotton, or other fibres. Their main use is as fibre prepared for spinning, but they may also be used for specialised kinds of knitting or other textile arts.
After carding, the fibres lie roughly parallel in smooth bundles. These are drawn out, by hand or machine, and slightly twisted to form lengths suitable for spinning. These unspun strands of fibre are the rovings. Roving can also mean a roll of these strands, the strands in general (as a mass noun), or the process of creating them.
Because it is carded, the fibres are less parallel than top (which is combed) and are not of uniform length. Carded rovings look fluffier than combed top, which looks smooth and has a high lustre. The fibres in combed top tend to be of a fairly uniform length due to the method of preparation. Though drawing it into strips may line the fibres up a bit.Roving is not to be confused with sliver as there is twist in roving.
Pencil roving is a type of roving that has been drawn until it is the size of a fat pencil. It can be used by spinners with minimal drafting (withdrawing fibers from a clump). Knitters also use pencil roving, similar to Lopi style yarns, or when making a thrummed item. (Regular roving can also be used in thrummed knitting.)
Objectives:
⦁ To draft the sliver to reduce weight per unit length.
⦁ To insert small amount of twist to strengthen the roving to prevent breakage during next processing.
⦁ To make conical or tapper shape of the bobbin.
⦁ To wind twisted strand on the bobbin.
M/c specification:
⦁ Platts.
⦁ The United Kingdom.
Main parts:
⦁ Separators
⦁ Guide rollers
⦁ Drafting rollers
⦁ Dead weight
⦁ Flyers
⦁ Spindles
⦁ Motor
Working principle
The roving bobbins (1) are inserted in holders (3) on the creel. Guide bars (4) guide the rovings (2) into the drafting system (5), where they are drawn to their final count. The drafting system is at an angle of 45-60° and is one of the most important units on the machine, since it exerts a very considerable influence on the uniformity of the yarn in particular.
After the resulting thin ribbon of fibers (6) leaves the delivery roller, the twist necessary for imparting strength is provided by spindle (8) rotating at high speed. In the process each rotation of the traveler on the spinning ring (10) produces a twist in the yarn. Ring traveler (9) is also necessary for taking up this yarn onto a tube mounted on the spindle. This traveler - a remnant of the flyer on the roving frame - moves on a guide rail around the spindle, the so-called ring (10). The ring traveler has no drive of its own, it is dragged with spindle (8) via the yarn attached to it. The rotation of the ring traveler lags somewhat behind that of the spindle due to the relatively high friction of the ring traveler on the ring and the atmospheric resistance of the traveler and the thread balloon between yarn guide eyelet (7) and traveler (9).
This difference in speed between the spindle and the traveler results in the thread being wound onto the tube. In contrast to the roving frame, the ring spinning machine spindle operates with at higher speed than the traveller (9). The yarn is wound up into a cylindrical cop form by raising and lowering of the rings, which are mounted on a continuous ring rail. The layer traverse of the ring rail is also less than the full winding height of the tube. The ring rail therefore has to be raised slightly (shift traverse) after each layer has been wound. For a time, machines were also built featuring shift traverse produced by lowering the spindle bearing plate rather than raising the ring rail. These machines are no longer available today.
.
Conclusion:
The passage of material through the simplex m/c is easy. During this passage, three works are done on the sliver: drafting, twisting and winding. The output of this machine is roving which is then fed into the Ring frame .
Experiment No: 2
Name of the experiment: Study on TPI of twist constant of the Roving frame machine.
Introduction:
Twist is the spiral turns given to a yarn to increase the strength of the yarn. But in speed frame machine vary small amount of twist is given to the roving to make it able to wound onto a bobbin. For a fibrous material twist is measured by the parameter twist per inch (TPI), twist per centimeter or twist per meter (TPM). For the cotton sample twist is measured by TPI.
In speed frame machines twist per unit is varied with the variation of raw material and its different parameters. This variation of twist is inserted by changing a wheel that is connected with the main driving shaft named twist change pinion (TCP). And the multiply of TCP and TPI, present in a machine is called twist constant. This value is applicable for any required twist with corresponding TCP. So we can find out the required TCP to get a given TPI. The generalize formulae is as below:
Objects:
i) To find out twist per inch of the ring frame.
ii) To find out twist constant of the ring frame.
Specification:
⦁ Front roller carrier wheel :81T(A)
⦁ Twist constant change pinion carrier:30T(B)
⦁ Twist constant change pinion:30T(C)
⦁ Twist change pinion:28T(D)
⦁ Sprocket wheel:34T(E)
⦁ Sprocket pinion:36T(F)
Spindle carrier wheel:40T(G)
⦁ Spindle wheel:22T(H)
GEARING DIAGRAM:
Fig: Gearing diagram of speed frame
Calculation:
Result:
Twist per inch TPI → 1.56
Twist constant → 33
Conclusion:
Speed frame is the first machine which enables the winding of the fibrous material on to a package. From this machine the fibre gets a circular shape which is very advantageous to be used in ring spinning. So the importance of this machine is very much. In this experiment we indicate different gearing diagram of the twist inserting portion; specify it and calculate twist and twist constant. We found a satisfactory result. So the experiment is a successful one.
Experiment No: 3
Experiment name: Study on drafting zone of Roving frame machine.
Speed Frame Sections:
A standard type of a speed frame has following sections:
1. Creel section
2. Drafting section
3. Twisting section
4. Winding section
Creel section:
Creel is the place situated at the back of the machine where the raw material is placed to be fed to the drafting zone.
The draw frame sliver cans are arranged in four or six rows in the creel zone.
Since the fibers in the drawn sliver have less coherence so it is necessary to keep the surface speed of the guide rollers equal to the surface speed of the back drafting rollers so that any false drafting may be avoided that can damage the sliver.
In modern fly frames, the creel transport rollers are arranged without vertical supporting rods, and these types of creels are called telescopic creels.
Just before the drafting section a photo-electric stop motion is used which detects the presence of the sliver and as the sliver breaks it automatically stops the machine.
Drafting section/Drafting system
The drafting section of the roving frame may be 3 over 3 or 4 over 4 with or without apron roller arrangement. Only the 3-over-3 or 4 over 4 roller with double apron drafting system are still to be found in modern machines offered by manufacturers. In general 3/3 drafting system is used, but for higher draft applications 4/4 drafting system is used. The draft often has limits not only at the upper limit (15 to 20), but also at lower limit. It is around 5 for cotton and 6 for synthetic fibers.
4-over-4 double apron drafting system:
❶ In production of a roving, a 4-over-4s roller with double apron drafting system is commonly used to attenuate the sliver.
❷ In a system of three pairs of rollers, there are two drafting zones. The first or back zone is designated the “break draft,” while the second or front zone is called the “main draft”.
❸ A pair of endless aprons is positioned in the high-draft front zone and made to move at the surface speed of the middle-roller pair.
❹ As fibers enter the high-draft front zone, the aprons will hold them and assist in keeping them moving at the surface speed of the middle rollers, while preventing the short-fibers being dragged forward by those fibers nipped and accelerated by the front rollers.
❺ The magnitude of break draft is usually small, varying between 1.1 and 1.5; therefore the front draft (i.e. main draft) is responsible for the major part of the total attenuation desired.
❻ The total draft is defined as the ratio of the surface speed of the front rolls to the surface speed of the back rolls and is a product of the break draft and the main draft:
❶ In 4-over-4 double apron drafting system, there are three drafting zones such as break draft, middle draft and front draft (or main draft).
❷ Back draft is apply in back zone which affects roving evenness. Less amount of draft is apply in middle zone where the condenser is used to condense sheet like sliver. Maximum amount of draft is apply in front zone where the apron is used to move at the surface speed of the middle-roller pair.
❸ The total draft is defined as the ratio of the surface speed of the front rolls to the surface speed of the back rolls and is a product of the break draft, middle draft and the main draft:
Draft distribution:
An important consideration of the drafting zone is the draft distribution i.e. how much draft should be given in the back and front zones. In a 3-over-3 drafting system, there are two drafting zones such as break draft, and main draft. The first or back zone is designated the “break draft,” while the second or front zone is called the “main draft”. The total draft is the product of break and main draft. The break draft is in the range of 1.03 to 2.03 and all the remaining draft is given at the main drafting zone, generally ranging from about 5 to 18.
Table: Recommended total draft range
Fiber Type Recommended Possible Range
Short staple cotton 6-9 5-10
Medium staple cotton 7-12 6-14
Long staple cotton 9-18 8-18
Manmade Fibers & it’s blends 8-13 8-14
If the break draft is increased beyond an optimum value then the evenness of the spun yarn drastically reduces due to the formation of thick and thin places. It is recommended to keep the break draft as low as possible. The problems associated with the higher break draft than recommended are given as follows:
Requires higher drafting forces that can create vibrations in the back zone of the drafting system. Break draft may have to be as low as 1.022 to prevent roller vibrations.
Tends to create roving irregularities such as thick and thin places.
Table: Fiber and Machine Parameters Influencing Drafting Force
Fiber parameters influencing drafting force Machine parameters influencing Drafting Force
Fiber length
Fiber fineness
Fiber to fiber friction
Fiber parallelization
Fiber irregularity
Packing factor
twist Drafting ratio
Drafting speed
Roller setting
Comments: In roving frame draft level often has its over and upper levels of drafting the drafting is done in between this limits if not each of the case tends to change high masses through the nips. So that the drafting resistance is high and difficult to get controlled draft. All the time the break draft kept in low level because it only improves the evenness of the sliver.
Experiment no: 04
Experiment name: STUDY ON THE PASSAGE DIAGRAM AND GENERAL DESCRIPTION OF RING FRAME MACHINE.
Introduction :
The ring spinning machine was first invented in 1828 by the American Thorp. In 1830, another American scientist, Jenk, contributed the traveler rotating on the ring. There have been many development has done in ring spinning machine for the last years but the basic concept remained unchanged.
Objectives:
1.To know aboyt the material passage of the ring frame.
2. To draw the yarn path diagram of the ring frame.
3.To know about the different parts of the ring frame.
4. To know about the functioning of the different parts of the ring frame machine.
5.To study the machine in ordar to improve our technical
Machine patrs:
1.Creel
2.bobbin holder
3.Roving guide roller
4.Pressure arm
5.Trumpet
6.Bottom roller
7.Top roller
8.Apron
9.Knowles bar
10.Cradle
11.Spacer
12.Pnewmatic waste collector
13.Pnewmatic waste
14.Lappet
15.Lappet arm
16.Lappet eye
17.Separator
18.Ring dia
19.Ring flange
20.Traveller
21.Cops
22.Spindle
23.Wrave
24.Spindle break
Working principle :
A ring frame was constructed from cast iron, and later pressed steel. On each side of the frame are the spindles, above them are draughting (drafting) rollers and on top is a creel loaded with bobbins of roving. The roving (unspun thread) passes downwards from the bobbins to the draughting rollers. Here the back roller steadied the incoming thread, while the front rollers rotated faster, pulling the roving out and making the fibres more parallel. The rollers are individually adjustable, originally by mean of levers and weights. The attenuated roving now passes through a thread guide that is adjusted to be centred above the spindle. Thread guides are on a thread rail which allows them to be hinged out of the way for doffing or piecing a broken thread. The attenuated roving passes down to the spindle assembly, where it is threaded though a small D ring called the traveller. The traveller moves along the ring. It is this that gives the ring frame its name. From here the thread is attached to the existing thread on the spindle.
The traveller, and the spindle share the same axis but rotate at different speeds. The spindle is driven and the traveller drags behind thus distributing the rotation between winding up on the spindle and twist into the yarn. The bobbin is fixed on the spindle. In a ring frames, the different speed was achieved by drag caused by air resistance and friction (lubrication of the contact surface between the traveller and the ring was a necessity). Spindles could rotate at speeds up to 25,000 rpm,[citation needed] this spins the yarn. The up and down ring rail motion guides the thread onto the bobbin into the shape required: i.e. a cop. The lifting must be adjusted for different yarn counts.
Doffing is a separate process. An attendant (or robot in an automated system) winds down the ring rails to the bottom. The machine stops. The thread guides are hinged up. The completed bobbin coils (yarn packages) are removed from the spindles. The new bobbin tube is placed on the spindle trapping the thread between it and the cup in the wharf of the spindle, the thread guides are lowered and the machine restarted. Now all the processes are done automatically. The yarn is taken to a cone winder. Currently, machines are manufactured by Rieter (Switzerland), ToyoTa (Japan), Zinser, Suessen, (Germany) and Marzoli (Italy). The Rieter compact K45 system, has 1632 spindles, while the ToyoTa has a machine with 1824 spindles. All require controlled atmospheric conditions.
Passage diagram of ring frame machine:
Fig : Ring frame machine .
Conclusions:
In Ring Spinning, the Spinning Geometry plays a vital role regarding to the quality of yarn and performance of machine. Spinning geometry has a significant influence on spinning operation and the resulting yarn primarily on: Tension conditions, Binding-in of the fibers, Number of End Breakages, Yarn Hairiness, Yarn Irregularity, and Generation of Fly. Turn the spinning width, should be as close as possible to spinning triangle width to minimize high loss of fiber, minimize hairiness in the yarn. In Compact Ring Spinning system, the width of spinning triangle get reduces the integration of edge fibers in yarn cross section increases. The inclination of the drafting arrangement in modern ring spinning machine now lies between 45° to 60°, very often 45° to get optimum spinning triangle. Roller overhang must not be too large
Experiment No: 05
Experiment Name: Study on T.P.I & Twist Constant of Ring Frame .
Objects:
⦁ To find out twist per inch of the ring frame.
⦁ To find out twist constant of the ring frame.
Specification:
⦁ Front roller diameter = 1"
⦁ Tin cylinder diameter = 10"
⦁ Whrave diameter = 1.125"
⦁ Twist change pinion = 48T
Gearing diagram:
Figure: Gearing diagram for calculating twist and twist constant of ring frame.
Calculation:
Tin cylinder dia :
r=
=3.98
d=2×3.98
=7.96
Spindle dia, D =0.954
T.P.I=
=
=
T.P.I=1××
=1×5.26×0.57×2.916×1.85×0.714×0.56
=6.468 inch/min
For 1” T.P.I =6.468×
=2.055 inch/min
Twist constant= T.P.I×T.C.P
=2.055×48
=98.64
Result:
TPI= 6.468
Twist constant= 98.64
Conclusion:
Ring frame is the final and very important machine for build the yarn onto bobbin in a form suitable for storage, transportation and processing. It is used to twist the drafted strand to form yarn of required count and strength. In this practical we calculate twist, twist constant of the ring frame. By this practical we come to know about the gearing diagram of ring frame. Special thanks to our teacher and his assistance for helping us.
