UPMSP Weaving Technology flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Tex count
- Weight in grams of 1000 metres of yarn. A direct system, so a higher Tex number means a coarser yarn.
- Cotton count Ne
- Number of 840-yard hanks in one pound of yarn. An indirect system, so a higher Ne means a finer yarn.
- Twist multiplier
- Twist per inch divided by the square root of the English cotton count. It indicates how hard-spun the yarn is.
- Moisture regain
- Percentage of moisture in a textile material expressed on its oven-dry weight. Cotton is about 8.5 percent and viscose about 13 percent.
- Plain weave
- A 2 by 2 repeat where each warp end interlaces alternately over and under each pick. It gives the firmest, most interlaced fabric.
- Twill weave
- A weave with a repeat of three or more where the interlacing point steps by one or more ends each pick, producing diagonal lines.
- Satin weave
- A warp-faced weave with a repeat of five or more and long floats, giving a smooth lustrous face and poor abrasion resistance.
- Fabric crimp
- The waviness of a yarn in fabric, expressed as the percentage excess of yarn length over fabric length.
- Cover factor
- Threads per inch divided by the square root of the yarn count. It measures how much of the fabric surface is covered by yarn.
- Primary loom motions
- Shedding, picking and beat-up. These three motions are essential for any fabric to be woven on a loom.
- Dobby shedding
- A shedding mechanism using pattern chains and levers to control a small number of heald shafts, suitable for small weave repeats.
- Jacquard shedding
- A mechanism where each individual end is controlled by a hook, allowing unlimited design size for complex figured fabrics.
- Positive let-off
- A warp let-off motion driven by gears or a motor that delivers warp at a controlled rate to keep tension nearly constant.
- Take-up motion
- The mechanism that draws fabric forward at a set rate after each pick, determining the picks per inch in the woven cloth.
- Warp stop motion
- A device using drop wires that halts the loom immediately when a warp end breaks, preventing a long missing-end defect.
- Sectional warping
- A warping method where yarn is wound in sections on a drum and then beamed, used for short runs and patterned warps.
- Size add-on
- The percentage increase in warp yarn weight after sizing, calculated from sized and unsized weights. Cotton warps usually get 6 to 12 percent.
- Squeeze roller pressure
- The nip pressure after the size box that controls wet pick-up. Higher pressure reduces add-on and drying load.
- Size migration
- Movement of size to the yarn surface during drying, which causes hairiness, shedding at drop wires and weak yarn interior.
- Loom efficiency
- Actual picks delivered divided by calculated picks at running time, expressed as a percentage. Typical shed values are 85 to 95 percent.
- Warp break rate
- Warp breaks per 100,000 ends per hour. It is a standard measure of warp quality and sizing performance.
- Loom allocation
- The number of looms one weaver can attend, calculated from stoppage time and attendance time per loom per shift.
- Warp tie-in
- Joining a new warp to the old one behind the heald shafts, which avoids re-drawing and cuts gaiting time sharply.
- Reed mark
- A warp-way streak caused by incorrect denting or a damaged reed wire, appearing at regular intervals across the fabric width.
- Weft crack
- A visible line across the fabric where picks are crowded or spaced unevenly, often from faulty take-up or let-off.
- Starting mark
- A visible thick or thin place at the point where the loom restarts after a stoppage, caused by uneven pick spacing.
- Four-point system
- A fabric grading method assigning one to four points by defect length, with holes scored two points regardless of size.
- AQL
- Acceptable quality level used with sampling plans. It is the quality level that is the worst tolerable process average.
- Standard test atmosphere
- The controlled condition of 20 plus or minus 2 degrees Celsius and 65 plus or minus 2 percent relative humidity for textile testing.
- Fabric weight formula
- Grams per square metre equals warp tex times ends per metre plus weft tex times picks per metre, divided by 1000.
- Loom-hour cost
- Total of depreciation, power, labour and maintenance divided by available loom hours. It sets the conversion charge per metre.
- Air-jet weft insertion
- Weft insertion by a main nozzle and relay nozzles using timed air jets, giving the highest commercial speeds for staple fabrics.