Single Jersey Plain. Single Lacoste. Needle set out. Cam arrangement F K. Needle set out. Cam arrangement F1 F2 F3 F4 K T K K K K K T

Transcription

1 Structure Single Jersey Plain Sample Needle set out 1 1 Cam arrangement F K Single Lacoste Needle set out 1 2 Cam arrangement F1 F2 F3 F4 K T K K K K K T

2 Double Lacoste Needle set out 1 2 Cam arrangement F1 F2 F3 F4 F5 F6 K T T K K K K K K K T T Polo Pique Needle set out 1 2 Cam arrangement F1 F2 F3 F4 K K T T T T K K

3 Terry Needle set out Cam arrangement F1 F2 F3 F4 K T K M K M K M K M K T 1X1 Rib Needle set out D 1 1 C 1 1 Cam arrangement D C K F K

4 Single Jersey Plain With Full Feeder Spandex Needle set out 1 1 Cam arrangement F K Single Jersey Plain( Feeder Stripe) With Full Feeder Spandex Needle set out 1 1 Cam arrangement F K.

5 Single Jersey Plain (Engineering Stripe) Needle set out 1 1 Cam arrangement F K Plain Interlock Needle set out D 1 2 C 1 2 Cam arrangement D K M M K F1 F2 C K M M K

6 Quality Management System: Knitted Fabric Faults: Many types of fault may be found in knitted fabric due to many reasons. These faults occurred sometimes due to defective parts of machine, or sometimes due to use of defective raw materials. Some faults occur very frequently and some faults occur rarely. Here some frequently occurring faults in knitted fabric are given below; Faults Hole Sample 1 Causes: The main cause is yarn breakage which happens due to; Too tight take down tension Yarn with weak spot. Clogged surface of yarn guide or feeder. Defective or damaged needles. Remedies: Main remedy is avoiding yarn breakage and using defect free needles. Other than these the followings may help; Use of fault free yarn. Using smooth surface of yarn passage to needle. Properly adjusting take down tension. Sample

7 Sample 2 Causes: It happened because, the needle is broken. It can also happen due to; Worn or old needle. High take down tension. Dirty or faulty tricks. Remedies: It can be avoided by using faultless needle. Proper take down tension will help. Clean needle tricks will also reduce risk. Sample 3 Causes: It is another type of hole of very small size. It is called loop in the factory. It is created due to yarn breakage or faulty needle. Too tight take down tension Yarn with weak spot. Clogged surface of yarn guide or feeder. Too high yarn tension. Remedies: Main remedy is avoiding yarn breakage and using defect free needles. Other than these the followings may help; Use of fault free yarn. Using smooth surface of yarn passage to needle. Properly adjusting take down and yarn tension.

8 Fly Causes: If dyed yarn, melange yarn and grey yarn are used in knitting at the same floor, colored fly may be found in the fabric. It happens because of; Improper covering of the machine. Careless air blowing. Insufficient cleaning. Remedies: To avoid this; The knitting machines should be covered or divided by some covering which would help reducing fly contamination. Cleaning has to be done carefully. Thick Place Causes: It happens due to faulty yarn or slub yarn which creates thick horizontal line in the fabric of small length. Remedies: By using fault free yarn, this fault can be avoided.

9 Needle Line Causes: It happens due to one and only reason, that is needle breakage. Needle breakage can happen due to; Too high take up tension. High yarn tension Old needle. Large knots or slub in the yarn. Remedies: It can be avoided by using needles which are not defected. To do so; Old needles should be replaced. Fault free yarn should be used Take down tension should be adjusted correctly. Oil Spot Sample 1 Causes: It happened due to too much oiling of the machine parts. Remedies: Proper amount of oiling may help avoiding this fault.

10 Sample 2 Causes: It happens due to; Too much lubrication. Dirty tricks and sinker. Use of improper needle oil. Remedies: It can be avoided by; Avoiding excessive oiling of machine parts. Proper cleaning of needles, sinkers, tricks etc. Use of proper needle oil. Press Off Causes: It happens when; The yarns are not properly laid in needle hooks. Too loose take down tension is applied. Defective needles are used. Needle timing is wrong. Improper yarn tension is set. Remedies: It can be avoided by; Using defect free needles. Using correct needle timing. Applying correct take down and yarn tension.

11 Fault Detection System: Fabric faults are detected in fault detection machine. The faults are marked and cut off from the fabric. Fabric fault is detected by mainly two ways; 4 point system and 10 point system. But for knitted fabric, 4 point system is mainly used. 4 point system: Theoretical definition: The 4-Point System is a standardized test method for fabric visually inspecting and grading. The 4-Point System assigns 1, 2, 3 and 4 penalty points according to the size and significance of the defect. No more than 4 penalty points can be assigned for any single defect. Defect can be in either length or width direction, the system remains the same. Only major defects are considered. No penalty points are assigned to minor defects. In this system, one should inspect at least 10 per cent of the total rolls in the shipment and make sure to select at least one roll of each colour way. Fabric defects are assigned points based on the following: Size of defect Penalty 3 inches or less 1 points Over 3 but not over 6 2 points Over 6 but nor over 9 3 points Over 9 inches 4 points Total defect points per 100 square yards of fabric are calculated and the acceptance criterion is not more than 40 points. Individual rolls exceeding the specified point count level shall be graded as second quality. A shipment shall be failed the inspection if the shipment penalty count points exceed the specified point count level. Any roll having a running or repeating defect through more than ten continuous yards shall be rejected regardless of point count. No roll that contains more than four full width defects per one hundred linear yards shall be accepted as first quality. Any roll found to contain defects, in any increment of one hundred yards, with an average of more than one major defect per ten linear yards will be rejected. No roll shall be accepted that contains a major defect in the first or last three yards of the rolls. A major defect is considered to be any three or four point defect.

12 Inspection: For different knitting faults, the following table is followed for assigning points. Procedure In this system fabric quality is evaluated by penalty points per 100 square yards. Formula: Points / 100 sq. yd. = (Total points in roll X 36 X 100)/ (Total length in yards X width in inches) So, to evaluate fabric quality you need to know fabric width and length of the inspected roll. In knits; fabrics are sourced in weight and supplier does not mention length. That's why when it comes to use 4 point system in knits fabric, inspector finds it difficult to use given formula for calculating penalty points. To use the 4 point system for fabric inspection it is needed to calculate length of the fabric in a roll. Evaluation of fabric quality of Knitted fabric in 4 point system Step#1: Measuring fabric length in a roll. Generally the following specification in knitted fabric roll found Weight of the roll (in Kgs) Fabric weight Grams per square meter (GSM) and Fabric width (inches)

13 For example, fabric weight of a roll is 50 kgs, fabric GSM 250 and fabric width (W) 46 inches. The following formula is used to know approx. length of the roll with above information. Fabric length (in meters) = Fabric weight X 1000 / (Fabric GSM X Fabric Width X ) Using data from above example Fabric length (L) = (50 X1000)/ (250 X 46 X0.0254) = Meters Step#2: Converting fabric length into yards. Multiplying factor is Fabric length in yards = X = Step#3: Calculating total penalty points. Suppose total 34 penalty points are given to the above roll. Once the length is found of each fabric roll, the above formula can be used to calculate points per 100 square yards. Point /100 square yards = (Total penalty points X 36 X 100)/ (Roll length X Width in inches) = (34X36 X 100)/(187.2 X 46) = Check sheet or inspection format: To record or to collects defects during inspection simple check sheet is used. A check sheet includes general details, details of fabric lot, fabric defects according their sizes, summary of fabric defects, quantity inspected and total penalty points and result of the fabric lot after inspection. Tally marking can be used for recording of number of defects. A sample 4 point system fabric inspection format has been attached at the bottom.

14 Image: Sample format for 4-Point system for fabric inspection. Practically Used Procedure in the Factory Practically the fabric roll of 20kg is taken and inspected in the fabric inspection machine where the fabric is passed over a lighten surface as lights are placed under the inclined surface. The fabric is passed at a uniform speed. The inspector looks for any types of faults and when he finds any, he stops the machine and marks the faulty area with yellow color or cuts off the faulty area. The faults are detected in 4 point system which is already mentioned. But in factory, the process differs from the theoretical process. Here the faults are detected in the following way; If a fault is found, for example; a fly, then it is marked and given 1 point. If another fly is found within 3-6 inches, another point is increased for it, so 2 points in total. If another fly is found in the next 3 inches, then again 1 more point is increased and 3 points in total is given. If any fly is found after 9 inches, another point is increased and 4 points in total is given. If more than one fly is found in the 0-3 inches area, it is given 1 more point. But if any fly is found in same line in any position of the fabric, no point is given. But a fly can be found at any position along the full width of the fabric, for that reason, the full width is considered in case of taking the range of 0-3 inches or 3-6 inches and point is given to any faults according to the range given above. If any fly is found after 9 inches, it is given 4 points in total. But it is not applicable for full length of the fabric. If a fly is found after 3-4 meter of the previous one, the whole procedure is restarted from there as the 1 st one is given 1 point and the followings are done as described before. Some very commonly found knitting faults and the points are given below; Knitting faults Hole Fly Press off Slub Star mark Needle line/ Sinker line/ Vertical line Barre mark/ Horizontal line Points Total points are calculated from the following formula;

15 Points= Total pointsx 36X 100 Roll lengthx Actual width in inches Up to 20 points points Above 30 points Acceptance criteria A grade B grade Rejected But actually this formula is not used always. All points are summed and then the acceptance criterion is considered. This summation is done for total points found in 100 meter of fabric. If the sum goes beyond 30 points, then the fabric is rejected. The whole rejection is done depending on this calculation. For example, if the fabric roll is shorter than 100 meter, say, 50 meter, and total points found sums 20, then the fabric is not cleared, instead it is taken as on hold.

16 Maintenance: Maintenance is defined as a process which is used to retain a product or restoring a product to a satisfactory operational condition. It is very essential in every part of textile factory as the machines need better care for smooth and continuous running. The main objectives of maintenance programme are; Retaining equipment at maximum operating speed and productivity. Ensuring best possible level of quality of product. Minimizing idle time. Cleaning the equipment. Maintenance mainly of two types; 1. Planned maintenance 2. Breakdown maintenance Planned Maintenance: It is a more technical approach as maintenance is done to avoid any possible breakdown. It requires a planning, scheduling section for maintenance. A routine is made for this type of maintenance and it is done on daily or weekly or monthly basis. It is a type of routine maintenance where the maintenance is done according a routine or schedule and steps are taken to ensure any avoidance of breakdown. The procedure of routine maintenance is described below; Routine Maintenance: Routine maintenance usually denotes those activities of maintenance which are bare minimum to ensure efficient working of machines. These activities have to be performed according to predetermined frequencies which are based on technical and quality considerations. Routine Maintenance Tasks Followed In The Factory: Daily work Positive feeder checking. Oil line checking. Take up roller checking. Needle, cam box, sinker cleaning. The yarn guides, tensioners, feeders cleaning. Cleaning the floors in every 30 minutes.

17 In every 15 days Gear box checking. All bearing greasing. All needles, cam, sinker cleaning by oil. Full machine checking. Breakdown Maintenance: This system is used only when the machine breaks down. It is unplanned system, but since there is no planning, scheduling etc, not much concern has to be given on maintenance department when only this system is used. Examples of breakdown maintenance done in the factory are given below; For any breakage of needles, it is replaced immediately. In case of any mechanical or electrical problem, technician is called. Other than these, the machine parts are cleaned every time before setting up the machine for a new product.

18 Setting the Machine: The needle set out and cam arrangements are set as planned before for different fabric structures. The machine used in this factory contain latch needle. For single jersey machine, latch needles are a bit longer while the latch needle of double jersey machine is a bit shorter. The single jersey machines contain sinker along with every needle which is the second primary knitting element of a knitting machine. It holds down the old loop during the needle making the new loop. In double jersey machine, here is no sinker, instead the needles of alternate beds help holding down the old loop. To set up the knitting elements and the whole machine, some tools are required. Some of them are shown below; Equipment Uses It is used to adjust VDQ pulley diameter of the machine. Pulley Key or Allen Key It is used to adjust yarn tension and to rotate the cylinder for one or a couple of times if required when the machine is stopped. Handle

19 It is used to put Lycra package at its creel. 1 no T-L key It is used for feeder spring adjustments. 2.5 no L-L key It is used for yarn tension adjustments. 3 no L-L key It is used for feeder ring. 4 no L-L key

20 It is used for cam box. 5 no T-L key It is used in auto striper machine to adjust striper fingers. 6 no T-L key It is used for adjusting the dial. 10 no L-L key It is used as the motor key. 15 no L-L key

21 There are some other tools used for various purposes. Some of those tools are given below; Use: To set different type of nuts and bolts Tightening & loosening of nuts & bolts. Adjustable Wrench Use: To set nuts and bolts. Tightening & loosening of nuts & bolts. Double Head Spanner Use: To set nuts and bolts. Tightening & loosening of nuts & bolts. Single Head Spanner Use: To fitting varies type screw. Tightening & loosening of nuts & bolts. Flat Screw Driver Use: To beat metal parts. Hammer

22 Use: To hold m/c parts, Cut metal wire, Set nuts and bolts. Multi-Pliers Use: To cut metal wire. Use: To hold and set m/c parts in thin or narrow space. Cutting-Pliers Long Nose-Pliers