STARFISH Technology Introduction and Overview STARFISH Workshop Manufacturers

STARFISH Technology Introduction and Overview STARFISH Workshop

Manufacturers of Cotton Knits Are faced with Ø Intensified global competition Ø Demands for better quality and reliability One of the key demands is Ø Ever lower levels of potential shrinkage STARFISH Workshop

Achieving Low Shrinkage Levels Is not the main problem Low shrinkage has to be combined with Ø A specific fabric width Ø A specific area weight Ø Consistency between deliveries Finding the right combination of materials, machine settings, and processing conditions is not always a simple matter STARFISH Workshop

An Important Consequence Of lowered maximum shrinkage levels Is a drastic reduction in the possible margin for errors STARFISH Workshop

Margin For Error fabric dimensions longer length Ø higher shrinkage Ø lower weight shorter length Ø lower shrinkage Ø higher weight after dyeing margin weight and length shrinkage controlled by adjusting the length width is fixed customer allowance plant capability Allowed weight and length shrinkage must lie within this region STARFISH Workshop

Traditional Methods Of Product Development & Quality Control are no longer adequate They are too slow They are too unreliable They are too costly STARFISH Workshop

Modern Quality Management “Right First Time and Every Time” Products have to be engineered Ø for specific performance requirements Performance has to be guaranteed by Ø strict specification of materials Ø continuous control of processes STARFISH Workshop

Shrinkage - Definition Shrinkage Sample Original Dimensions Lo, Xo LS Relaxed Dimensions Lr, Xr LS = 100. ( Lo - Lr ) / Lo WS WS = 100. ( Xo - Xr ) / Xo STARFISH Workshop

Shrinkage Measurement Is not very useful for process control Large quantities of fabric can be processed during the time it takes to measure shrinkage We need an on-line measurement STARFISH Workshop

Fabric Dimensions Are a reflection of stitch density Length is inversely proportional to the density of Courses ( CPI, C/cm ) Width is inversely proportional to the density of Wales ( WPI, W/cm ) STARFISH Workshop

It Follows That Shrinkage can be calculated From differences in the densities of Courses and Wales in the Original and Relaxed fabrics LS = 100. ( Cr - Co ) / Cr WS = 100. ( Wr - Wo ) / Wr STARFISH Workshop

Measured vs Calculated Shrinkage 10 fabric types, 20 test procedures 30 Calculated Shrinkage 25 Each data point is the mean of 5 replications 20 15 10 5 0 y = 1. 0162 x - 1. 0613 R 2 = 0. 95 -5 -10 -5 0 5 10 15 Measured Shrinkage 20 25 30 STARFISH Workshop

For a Fixed Fabric Width In the as-delivered fabric There is a fixed number of Wales per cm depending on the knitting machine that was used to make the fabric Wales / cm = Needles / Width STARFISH Workshop

Fabric Area Weight Can also be calculated. . . The number of loops per unit area multiplied by the weight of each loop Wt = C * W * tex * loop length number of loops weight per loop STARFISH Workshop

For a Fixed Area Weight and a given fabric construction If the fabric width is fixed then the fabric length is also fixed Therefore the number of Courses per cm is also fixed STARFISH Workshop

Control of Fabric Dimensions by the dyer and finisher Can be achieved by controlling the density of Courses and Wales Wale density is easily controlled through the fabric width Control of Course density requires electronic sensors & feedback control at the final finishing machine STARFISH Workshop

The First Requirement Relaxed Dimensions Is that the Relaxed Dimensions must be appropriate for the target Weight & Width and Shrinkages Relaxed Dimensions can be predicted STARFISH Workshop

Relaxed Fabric Dimensions Are determined by Knitting variables Ø average loop length Ø yarn specification Ø size of knitting machine Wet processing type Ø preparation / dyeing machinery Ø loading / speed / tension Ø depth of shade STARFISH Workshop

Courses & Wales vs 1 / Loop Length Courses or Wales / cm 27 Relaxed Plain Jersey, Ne 18 to Ne 50 24 Courses = 5. 50 / L R 2 = 0. 97 21 Courses Kc = 5. 5 18 Wales 15 Wales = 4. 44 / L R 2 = 0. 93 12 Kw = 4. 44 9 2. 0 2. 5 3. 0 3. 5 4. 0 Reciprocal Loop Length 1/L 4. 5 5. 0 STARFISH Workshop

K Factors Are Not Accurate Enough Courses or Wales / cm 27 Relaxed Plain Jersey, Ne 18 to Ne 50 24 Kc = 5. 5 21 Courses Kw = 4. 44 18 15 Wales 12 9 2. 0 2. 5 3. 0 3. 5 4. 0 Reciprocal Loop Length 1/L 4. 5 5. 0 STARFISH Workshop

Effect of Yarn Count & Loop Length 24 Relaxed Plain Jersey, dyed & finished Courses or Wales / cm 22 Courses 20 18 n Ne 18 s Ne 28 l Ne 38 16 14 Wales 12 10 2. 2 2. 4 2. 6 2. 8 3. 0 3. 2 3. 4 Loop Length mm 3. 6 3. 8 4. 0 4. 2 STARFISH Workshop

Effect of Wet Process on Course Density Finished Courses / cm 27 Relaxed Plain Jersey, dyed & finished 24 Y=X Winch = 0. 96 x Grey R 2 = 0. 99 21 18 Pad-Batch = 0. 89 x Grey R 2 = 0. 98 15 12 12 15 18 21 Grey Courses / cm 24 27 30 STARFISH Workshop

Effect of Wet Process on Wale Density Finished Wales / cm 21 Relaxed Plain Jersey, dyed & finished Pad-Batch = 1. 02 x Grey R 2 = 0. 98 18 Y=X 15 Winch = 0. 996 x Grey R 2 = 0. 99 12 9 9 12 15 Grey Wales / cm 18 21 STARFISH Workshop

The Finisher’s Dilemma LS For a given product, the Wet Process is fixed … … so, Relaxed Dimensions WS are determined by the knitter Delivered Dimensions (Weight & Width) are fixed by the Customer Therefore SHRINKAGE is pre-determined STARFISH Workshop

The Finisher Can Deliver Either The target Weight and Width Or The target Length and Width Shrinkages He can not control all four simultaneously STARFISH Workshop

Practical Process Control The Finisher should concentrate on controlling only two parameters Width and Course Density Ideally, the final finishing machine should be equipped with electronic sensors to monitor and adjust the Course Density STARFISH Workshop

The Knitter Must Ensure The basic fabric construction is properly specified and manufactured so that. . . When the target Courses and Width are actually delivered by the Finisher. . . Then the Weight and Shrinkages will also be correct STARFISH Workshop

Low Shrinkage By Design Requires Correctly engineered fabric Ø yarn quality and knitting conditions Appropriate finishing targets Ø course density and width Automatic control of machinery Ø sensors for course density STARFISH Workshop

Correctly Engineered Fabric Is an indispensable requirement The basic Fabric Dimensions are Subject to strict mathematical rules. . . that govern the relationships between weight, width, and shrinkage Predetermined by the knitter. . . and modified by the wet process STARFISH Workshop

The Manufacturer Must be Able To check for himself that the fabric is correctly engineered To calculate the proper finishing targets STARFISH Workshop

STARFISH Simulation Program Enables the manufacturer to make Generalised predictions of weight, width and shrinkage assuming average conditions Individual calibrations for particular conditions existing in a given dyeing and finishing plant STARFISH Workshop

Courses / cm Predicted by STARFISH Predicted C / cm 27 Starfish Standard Processes (no calibration) 24 Starfish (Cont) = 1. 03 x Pad. Batch R 2 = 0. 990 Y=X 21 18 Starfish (Winch) = 1. 01 x Winch R 2 = 0. 989 15 Single Jersey Ne 18 to 50 12 12 15 18 21 Measured C / cm 24 27 STARFISH Workshop

Courses / cm Predicted by STARFISH Predicted C / cm 27 Partial Calibration - Processes only 24 Calibration (2) = 0. 999 x Pad. Batch R 2 = 0. 989 21 18 Calibration (1) = 0. 998 x Winch R 2 = 0. 990 15 Single Jersey Ne 18 to 50 12 12 15 18 21 Measured C / cm 24 27 STARFISH Workshop

Wales / cm Predicted by STARFISH Predicted W / cm 21 Starfish Standard Processes 18 Starfish (Cont) = 1. 01 x Pad. Batch R 2 = 0. 989 15 Starfish (Winch) = 1. 004 x Winch R 2 = 0. 990 12 Single Jersey Ne 18 to 50 9 9 12 15 Measured W / cm 18 21 STARFISH Workshop

Wales / cm Predicted by STARFISH Predicted W / cm 21 Partial Calibration - Processes only 18 Calibration (2) = 1. 001 x Pad. Batch R 2 = 0. 989 15 Calibration (1) = 1. 0003 x Winch R 2 = 0. 990 12 Single Jersey Ne 18 to 50 9 9 12 15 Measured W / cm 18 21 STARFISH Workshop

Computer Program is a Good Start But we also need Good quality assurance procedures. . . targeted on key control variables Latest finishing technology. . . and corresponding know-how STARFISH Workshop

Targeted Quality Assurance STARFISH predictions are averages Variation must be contained by systematic control of. . . Ø raw materials Ø key production parameters STARFISH Workshop

Finishing Technology STARFISH sets the Targets but the FINISHER has to achieve them He needs the latest equipment and know-how STARFISH Workshop

The Total STARFISH System Fabric Engineering by Computer Targeted Quality Assurance Application Know-how STARFISH Workshop

STARFISH Workshop