Comparative Study between Engineering Stripe and Feeder Stripe

When maximum 2-3 colours are used to knit a stripe fabric where the stripe pattern length lower then it is called feeder stripe. The feeder stripe designs are knitted on general circular knitting machine. The main principle is to feed 2-3 colours on the feeders according to design and let the machine knit the reqd. design. The knitting machine has a capacity for 108 cones of yarn. If you have inserted 8 black yarns to the feeder, with 100 cones white yarn next. When knitting starts you will see within the 2” repeat there is a black and white horizontal stripe. Feeder stripe designs can be made on Single jersey, Rib and Interlock machines (Figure 1).


Introduction
Yarn dyed knit fabrics are one of exclusive fabric highly recommended by buyer. In knitwear section yarn dyed fabric is very popular and expensive rather than regular solid dyed fabric. There are two type of yarn dyed fabric used in knitwear garments.

Feeder stripe fabric
When maximum 2-3 colours are used to knit a stripe fabric where the stripe pattern length lower then it is called feeder stripe. The feeder stripe designs are knitted on general circular knitting machine. The main principle is to feed 2-3 colours on the feeders according to design and let the machine knit the reqd. design. The knitting machine has a capacity for 108 cones of yarn. If you have inserted 8 black yarns to the feeder, with 100 cones white yarn next. When knitting starts you will see within the 2" repeat there is a black and white horizontal stripe. Feeder stripe designs can be made on Single jersey, Rib and Interlock machines ( Figure 1).

Engineering stripe fabric
When the size of the stripe repeat of the fabric is bigger than 2" which is beyond what the feeder stripe method can do, it is called Engineering stripe. Engineering stripe designs are produced on special type of circular knitting machine named as auto stripe/ engineering stripe machine ( Figure 2).
In engineered stripe method, the machine is set to change threads at certain time to from a big repeat. This way the repeat can be of almost any size. However, the price of engineered stripe fabric is substantially higher. the order of yarn by selector and forms coloured striped fabric. The development of computerized striper circular knitting machine enhances the growth of our knitting industry as well as makes an interaction with the modern knitting technology. Moreover, it's also necessary to be able to put the control theory into practice by the use of numeric control, electronic driving, etc. Nowadays, engineering stripe has been used more frequently than the feeder stripe for big repeat [1,2]. Eventually, the main work of this paper is to identify the limitations of feeder stripe and how Engineering stripe minimize those limitations. Special attentions were given on the machine set up mechanism with stripe pattern processing on the control panel [1].

Feeder stripe knitting machine
In case of feeder stripe machine yarn is fed to the needle directly via a feeder without any finger device. One coloured yarn can be fed at one time by a feeder during the revolution of cylinder. Special design of Cam, heat-radiation and dust-removal are easy, speed and wear proof are high. RPM is above 20 when Lycra units are applied.

Types of engg. stripe machine
Machine type depends on the number of fingers opposite to a feeder ( Figure 3):

Type of stripe according to its size
i. Micro Stripe: An ultra-fine stripe that is knitted by maximum 4 courses with stripe width of 1-4 mm.
ii. Medium Stripe: A moderate stripe that is knitted by 5-20 courses with stripe width of 4.1-14 mm.
iii. Long Stripe: A thick stripe that is knitted by more than 20 courses with stripe width of more than 14 mm ( Figure 4).

Main issues of project
The Auto stripers are used on both single and double bed machines. The experiment will include the functions of various important parts of Auto stripe machine, its additional features. The experiment will also include the thread path diagram with brief analysis of its feeding mechanism, finger controlling and changing process. The main aim of this work is to identify the differences between Engineering Stripe and Feeder Stripe as well as calculating the maximum no. of courses per repeat that can be produced on 4, 5 and 6 finger engineering stripe machine [2]. In the result and analysis chapter, the tension variation will be analysed between the feeding system of feeder stripe and auto stripe machine. Then there will be a representation of the major differences between auto stripe and feeder stripe fabric. The striping limit of 4 and 6 finger machines will be analysed and an idea will be given about their limitations [2][3][4].     Feeding principle: The striper feeder is based on the friction principle. The income yarn is guided through ceramic eyelets and a torsion rod and wound around the feed wheel for 1-2 circles. For 6 finger m/c, there are 2 feeding device with 3 yarn wheel. These yarn feeders present torsion rod. By means of the friction between yarn and the wheel, the striper feeder provides a reliable yarn transport. Whenever a yarn is selected, it twists and moves away from wheel and thus gives sufficient tension for feeding. Other deselected rods remain close to wheel and where yarn tension is lower [5].

Finger:
The yarn is fed with the help of finger motion. There are 4-6 fingers against each feeder. The finger works with the help of actuator. Selection of each finger is effected from control panel in which the design is fed. It has an individual clamping and cutting of yarn at each finger ( Figure 6). Piezoelectric data actuator: An electronic actuator activates the powerful yet swift mechanical movement of finger in yarn change [2]. The actuator has 4-6 selectors for four to six finger machines. The actuator is situated below the finger box and rotated with cylinder rpm. For 6 finger machine, 5 selectors will beat the 5 finger box butts. These 5 fingers will disable, only one finger will active. This one finger will take the selected thread. According to the program predetermined courses will be formed. Thus another predetermined course will form (

Additional features of auto stripe m/c
Control panel for auto-striper: Data acquisition system for machine control, recording and displaying the machine functions. Controller with 8 MB memory capacity and easy to select coloured yarn by means of the control panel, it is easy to change or select coloured yarn, and modifies the stripe width. Error messages are shown on the display and can quickly be localized.

Production of auto stripe fabric from sample Materials
Machine specification: Following specification of machine is shown below ( Table 1).

Typical M/C selection data:
Typical M/C selection data is shown into the following tables (Tables 2-4).

Machine set-up process: [Fukuhara]
Step 1: At first a new file is started or existing file is opened.
Step 2: A file no. is selected which is given input through a pen drive or an existing file for editing. After touching ENT it will skip to finger specification.
Step 3: Total No. of Course is edited and press ENT for the full pattern.
Step 4: No. of Total stripe is edited for the full pattern and press ENT.
Step 5: For 1st stripe of the pattern total no. of course is edited and press ENT.
Step 6: For 1st stripe of the pattern the yarn colour is selected as A, B, C based on finger, edited, press ENT and confirm the finger specification.    Step 7: Follow step-6 for the remaining stripes of the pattern.
Step 8: After entering the repeat, the folder has to save. As a result, the finger will work according to the program.

Knitting Operation:
• The control panel sends control pulses to the actuator for the yarn insertion of selected yarn.
• There is a butt below every finger box • An actuator selector disconnects other butts and only one finger of finger box is selected.
• Actuator selects the finger according to the control panel command • There is a cutter with every finger box that cuts yarn after the completion of a course • The insertion process is implemented mechanically by means of cams • Optimally designed transmission ensures accurate insertion, clamping and cutting of the yarn, even at high machine working speeds.

Yarn changing process through finger
Figure gives the aspect of a 4 fingers striper. We can see that the finger 1 is being selected and the finger 4 is being deselected. A cutting blade cuts the deselected yarn [3]. Yarn change occurs in small zone (about 7 cm width) because in this zone 2 yarns work simultaneously during yarn change ( Figure 10) [8].

Formula creation and commanding the control panel (Figure 11)
Yarn changing with electronic control: The electronic control unit contains the programmed pattern information of the striped pattern. This is recalled from the unit through a rotary code transmitter synchronous to the machine movement and passed on to the magnets of the yarn change fingers in the stripers. The yarn change on a S/J circular knitting machine is illustrated in the figures. a.
Yarn C completes a stripe and it is cut by the clamping cutter. Finger C is in base position. The yarn guide is in top position and the clamp is opened.

b.
New yarn D is selected and the finger D moves close to the needle and clamp is closed. Yarn cutter moves upward.

Mechanism of producing feeder stripe
In a 108 feeder m/c, active feeder would be=108/26=4 with remainder 4. 4 patterns produced for 1 revolution of the cylinder. The rest 4 feeders will be needle dropped or, all miss cam for 1 repeat Feeder arrangement (Table 6 and Figure 13).

Feeder stripe pattern limitation
Normal range of Feeder stripe was analysed and it is 2-7.5 cm In KCL, there are two large dia machines available of LISKY. 44" and 52" diameter feeder stripe machine is possible. Total feeders are 312 possible with 6 feeders/ inch. If the yarn count is 30s, stitch length is 2.60, CPCM is 20. So, 312/20=15.6 cm; so maximum 6.14 inch is possible (Table 7).
Where, Total feeders are 264 possible with 6 feeders/inch. If the yarn count is 30s, stitch length is 2.60, CPCM is 20. So, 264/20=13.2 cm; so maximum 5.2 inch is possible.
So, it can be defined that the feeder stripe, if the course is less than 6.14 inch called feeder stripe. If the course is more than 6.14 inch called engineering stripe. In feeder stripe, to produce big repeat is not possible. By calculating the colour of thread this design is produced. The feeder stripe pattern ranges depend on the no. of feeder, count of yarn, big stitch length and big diameter machine.

Reasons for not Producing 15.2 cm Stripe Pattern on Feeder Stripe machine
• The main reason is the amount of stripes in one revolution of cylinder. The main object in feeder stripe is to get sufficient stripes in one revolution.
• If more than 2-3 colour is used than there is a possibility of spirality since spirality increases with the no. of feeders.
• If more than 2-3 colours is used then there is a possibility of yarn breakage. Since coloured yarn breaks more than grey yarn and in case of auto stripe machine multiple tensioner and stop motions are used.
• It is easy to set the design on auto stripe and getting the production start. But in feeder stripe for 15.2 cm pattern yarns should be passed through feeder accordingly and should set the cone packages serially in the creel. This makes the process more time consuming. But, it is true that we can make this stripe pattern on 312F machine.
• RPM of feeder stripe is more. That's why more breakage to make 1 pattern and the process becomes economically difficult.

Differences between feeder stripe and engineering stripe
The basic difference between the Feeder stripe and engineering stripe is described in the following Table 8.

Case study
Four finger machine: A fabric sample is analysed where total individual colour is five; black colour used for 4 times. As a result, total no. of courses is 240 which exceed 192 courses (48 × 4) in four finger machines (Tables 9 and 9a).
If different eight colours used and more than eight colour, total no. of courses will not exceed 192 courses in 4 finger machine (Table 9b and 9c).
In 4 finger machine, we can use more colour when the no. of courses is limited. In this study, we can produce more coloured striper design by reducing the no. of courses in single colour. If we want to create a big courses repeat in more than four colour with each stripe contains different colour, it is not possible in four finger Engg. striper machine with 1 revolution of cylinder only (Table 9d).
In this case no. of courses will also be increased as per wish against four colours only. For this reason, above example each colour contains 96 courses. The total course is 384. Generally, our machines contain 48 feeders. The feeder no. is equivalent to the no. of cam box. Every feeder contains four fingers. Where, machine will rotate one time then it produces 48 courses. 384/48=8 Revolution; so, we can see that total repeat complete in 8 revolutions. If we add a new colour such as Red, it will be not possible to produce in four finger machine. So we have to produce this repeat in 5 finger machine.
Five finger engineering stripe machine: At first it reduces the limitation of 4 finger machine in making 5 colour large stripes. Each stripe contains different colour (Table 10 and 10a).
When machine revolute one times then produce 48 courses. 480/48=10 revolution. So, we can see that total repeat complete in 10 revolutions. We can use more colours when the no of courses is limited or do not exceed 48 × 5=240 course limit (Table 10b).

1.
Feeder stripe is the term been used when stripe is manufactured on normal Single Jersey m/c.
Engg. stripe is the fabric knitted on special Engg. stripe m/c.

2.
Smaller stripe repeat is produced. Bigger stripe repeat is produced.

3.
We can use a limited stripe or courses. Practically 5 cm repeat length is knitted. Maximum stripe repeat width is 15.6 cm.
We can use unlimited stripe or courses. Bigger than 5 cm like 165 cm, 120cm pattern can be easily made. Theoretically capacity: 16000 Stripes; Practically: max. 500 Stripes can be made.

4.
Maximum 3 colors are used. No color limitation.

5.
There is no extra device on feeder stripe. There is an extra device named "Finger" that can feed extra thread for knitting.

6.
Repeat size largely depends on the no. of feeder of m/c. Depends on the no. of finger opposite to a feeder.

7.
Every yarn is fed continuously without any break or cutting after stripe completion.
Every yarn is cut after completion of a course of a same color in a stripe. There is a cutter below finger which cuts the completed course.

8.
Feeder Stripe depends on the dia of the machine. If dia increase the size of stripe pattern can be extended.
Engg. Stripe is finger dependent. It can knit any no. of courses of any color. Say, 500 courses of blue; actuator only selects blue color fingers during rotation until the completion of 500 courses.

9.
Positive Feeding System is used. Semi Positive feeding system is used.

10.
Feeder stripe pattern is normally repeated multiple times to complete the body panel of a garment.
1 stripe pattern can complete the full body panel of a garment without repeating.

11.
Production cost is low. The price of feeder stripe fabric is lower. Production cost high approximately 7-10 times higher. The price of engineered stripe fabrics is substantially higher.

12.
Productivity is high. Low productivity.

13.
Only 1 tensioner is used during yarn feeding. More than 2 tensioners are used to avoid more breakage.

14.
Oil drops can be more than 80. That's why RPM is more. Up to 80 oil drops per minute. RPM is less.

15.
No. of feeders are normally very higher, more than 60 F Less than 50 F

16.
The strength of yarn is more. The colored yarn is less strong

17.
Tension variation is less during yarn feeding. Tension variation is more during yarn feeding.

18.
Fewer faults occur during sample stripe fabric production.
More faults occur during sample stripe fabric production.

19.
Less yarn breakage. The possibility of breakage of yarn will increase

20.
One stop motion is used in feeder stripe machine during yarn feeding. Several stop motion is used in Engg. Stripe machine.

21.
No slippage of yarn in feeding device due to multiple coil wrapping. The slippage for semi-positive feeder is about 5-8% during friction between yarn wheel and yarn.     When we use more than five different colours the total no. of courses will be 240. But any colour use more than 48 courses then total no. of courses exceeds the 240 courses (Table 10c).
Here 11 individual colours are used but black colour used eight times (30 × 8=240 courses). As a result, 240-48=192 black colour courses are excess used in five finger Engineering stripe machine.

Six finger machine:
We analyse the following sample where 6 colours are used. Grey colour is inserted for finger A, White for B, Red for C, Yellow for D, Sky for E and Green for F. Actuator will select the yarn from the fingers until completing a stripe automatically. A practical fingering sequence is given below where some fingers will not be selected (Tables 11 and 11a).

Summary of case study
• Four, five and six finger machine means each feeder contains four, five and six finger respectively. In four, five and six finger machine four, five and six colours stripe designs can be produced as long course as possible.
• Normally multiple coloured yarns are fed for different fingers and control panel gives command while actuator selects the desired colour from any finger until it completes a stripe.
• If fingering sequence is followed then less wastage, otherwise some fingers will never be selected and yarn remains idle.
• In 4 finger machine, we can use more colour when the no. of courses is limited. In this study, we can produce more coloured stripe design by reducing the no. of courses in single colour.
• If we want to create a big courses repeat in more than four colours, it is not possible in four finger Engg. Striper machine with 1 revolution of cylinder only.
• But this analysis use more different colourise; eight, ten, twelve and so on then you cannot be exceeded 192 (48 × 4) courses per repeat for four finger machine, 240 (48 × 5) courses for five finger machine and 252 (42 × 6) courses for six finger machine.
• Six finger machines give more flexibility in colour selection than 4 and 5 finger machines.
• Pattern width in 6 finger machine is more than other two and usually over 15 cm.
• The work also revealed that any colour use more than 48 courses per repeat then exceeds 192 courses for four finger, 240 for five finger machine and show similar effect on other finger machine.

S. No Color Courses
Sequence Finger       • Practically, if 3-4 colours are used with pattern width of 10-25 cm, 4 finger machine is used. But, theoretically up to 8 colours can be used.
• Practically, if 3-4 colours are used with pattern width over 25 cm, 6 finger machine is used. But, theoretically more than 8 colours can be used.

Calculation for auto stripe fabric (1 × 1 Rib)
Calculation for auto stripe fabric is shown below with proper table and figure (Table 12) and (Figure 14).

Conclusion
Four, five and six finger machine means each feeder contains four, five and six finger respectively and each machine contains 48 feeders. In four, five and six finger machine four, five and six colours stripe designs can be produced as long course as possible. The work revealed that any colour use more than 48 courses per repeat then exceeds 192 courses for four finger, 240 for five finger machine and show similar effect on other finger machine.