Broken twill and Transposed twill.pptx

Different Types of Fabric structures produced in the loom and this is the basic structure used for producing various woven fabric structures

1. Broken Twill, Transposed Twill Topic-4

2. Alpha breathing

3. Branch: B.Tech (TT) Semester: S5 Subject code & Title: 18TT503- Fabric Structure and Design Unit/Lesson No: Unit I, Lesson 5 T-L tools: Chalk and Talk, PPT Presentation, Online Presentation Faculty Name: Dr.M.Janarthanan MICRO PLANNING Pre requisite knowledge: Weave, Repeat, Design, Draft and Peg plan

4. Topic for Learning through Evocation:

5. 2. Topic Introduction: Broken Twill weave and Transposed twill weaves 2.1. General Objective: Students will be able to understand the design of broken and transposed twill weaves. 2.2 . Specific Objectives: 1. SO1: To explain the construction of broken twill weave. 2. SO2: To explain the significance and construction of transposed twill weave. 3. SO3: To explain the fibre, loom requirement, properties and applications of broken twill and transposed twill weaves .

6. Taxonomy of Objectives Knowledge Dimension The Cognitive Process Dimension Remember Understand Apply Analyse Evaluate Create Factual Knowledge Conceptual Knowledge 1,2,3 Procedural Knowledge Meta Cognitive Knowledge

7. 2.4. Key words: Design , Broken draft, Peg plan, Twill angle 2.5. Reference book Fabric Structure and Design by N.Gokernasan, PP-46-48 2.6. Key diagrams (if any): - Broken Twill Weave Transposed Twill

8. BROKEN TWILL These twills are constr u cted by breaking the c on t inuity of any continuous twill weave. The co n tin u ity c an be broken in e ither a reg u lar or an irregular order. Generally somewhat similar in appearance to herring bone twills, can be produced by breaking a regular twill. There are two ways of obtaining broken twills. Break and reversal method Entering and skipping method Break and Reversal method: In this method first decide the break unit. (after how many threads the twill will be broken) Generally, it is half the number of threads in the repeat. And then reverse the thread.

9. Example: 2/2 twill (Break point: half the number of threads) 2. 4 /4 twill (Break point: 2 threads)

10. Entering and skipping method: This method is applicable to twills that are composed of equal warp and weft floats. The first step is calculating the number of treads that will be taken in order to enter. For n / n twill, it will be (n + n) x 3 And then skipping a suitable thread in a repeat of the twill. The most suitable number to skip is one less than half the number of threads in the repeat of the twill. (N/2 –1), W here, N is the nu m ber of th r ea ds in t h e repeat of the twill. Example: 2/2 twill, No. of threads will be enter = (2+2) x 3 = 12

11. No. of threads will be enter = (2+2) x 3 = 12 No. of threads will be skip = 4/2 – 1=1 Prepare another design from this by taking 2 ends and then skipping one alternately.

12. Broken Twill - It is produced by breaking a regular twill. 1 2 3 4 1 2 4 3 2/2 Regular Twill 2/2 Broken Twill at a break of 2 1 2 3 4 5 6 3/3 Regular Twill 1 2 3 6 5 4 3/3 Broken Twill at a break of 3 1 2 3 4 5 6 7 8 1 2 4 3 5 6 8 7 2 1 4 3 6 5 8 7 4/4 Regular Twill 4/4 Broken Twill at a break of2 4/4 Broken Twill at a break of2

13. 1 2 3 6 5 4 7 8 1 4 3 2 5 6 7 2 1 8 3 4 5 8 7 6 4/4 Broken Twill at a Break of 3 (24x8) 1 2 3 4 5 2 1 8 7 6 3 4 5 6 7 4 3 2 1 8 5 6 7 8 1 6 5 4 3 2 7 8 1 2 3 8 7 6 5 4 4/4 Broken Twill at a Break of 5 (40x8)

14. COMBINATION TWILL In these types of weaves two different types of twills are combined together alternately. The combination may be warp way or weft way. Accordingly warp or weft faced twills may be used suitably . These twills are constructed by two methods: End and end combination Pick and pick combination In the first method the twill weaves are combined end way and in the second method twill weaves are combined in pick way. The type of draft used here is the skipped draft. The heald shafts are divided into two groups, The first group controls the first design and the second heald shaft controls the second design.

15. Transposed twill In the case of these twills the diagonal effect is broken by transposition of the original order of the threads . This type of construction produces attractive designs . A number of methods can be adopted in the transposition of the regular twills .

16. As shown in the figure above, the transposed twill is constructed in three stages. In the figure A the repeat size of the design is shown. The design adopted here is a base twill of 3/3 transposed on a repeat of 2. The repeat size is 6 ×6 . In the figure , B is shown the base marks that are made on repeat size of 2 × 2, the squares of which are thickly lined. In the figure 4.16 C is shown the design of the transposed twill where the 3/3 twill is transposed in the thickly lined squares .

17. SUMMARY These twills are constr u cted by breaking the c on t inuity of any continuous twill weave. There are two ways of obtaining broken twills. Break and reversal method Entering and skipping method In these types of weaves two different types of twills are combined together alternately. The combination may be warp way or weft way. Accordingly warp or weft faced twills may be used suitably . In the case of these twills the diagonal effect is broken by transposition of the original order of the threads .

18. Formative Assessment Questions 1. _________ draft is used for producing transposed twill weave structure. (a) Straight draft . (b) Pointed draft (c) Divided draft (d) Skip draft (e) Grouped draft (f) Broken draft 2. Which weave the twill line is skipping a suitable warp thread in a repeat of the twill? (a) Pointed twill (b) Broken twill. (c) Elongated twill (d) Steep twill (e) Cork screw twill (f) Diamond twill

19. Formative Assessment Questions 3. Which twills are constructed by breaking the continuity of any continuous twill weave? Transposed twill Broken twill. Pointed twill Balanced twill Herringbone twill Combined twill 4 . Does the broken draft is suitable for producing broken twill structure. Yes. No