Estimate dry fabric mass from 144 loops/cm², 3.2 mm per loop and 20 tex, ignoring finish and waste.
A 92.16 g/m²
B 288 g/m²
C 9.216 g/m²
D 460.8 g/m²
Answer: A. 92.16 g/m². One square meter contains 1.44 million loops and 4,608 m of yarn. At 0.020 g/m, the mass is 92.16 g.
Production runs at 30 rpm with 48 active feeds and 1,680 needles knitting at every feed. How many stitches form per minute?
A 80,640
B 2,419,200
C 1,451,520
D 50,400
Answer: B. 2,419,200. Multiply the speed by active feeds and needles per feed: 30 × 48 × 1,680.
Using 2,000 needles, 28 rpm and a 3.0 mm loop length, estimate yarn use at one fully knitting feed.
A 168 m/min
B 1,680 m/min
C 6 m/min
D 56 m/min
Answer: A. 168 m/min. The feed forms 56,000 stitches per minute. Multiplying by 0.003 m per stitch gives 168 m/min.
At 65 m/min yarn delivery, 1,000 needles knit once per revolution at a feed on a machine running 25 rpm. What is the delivered yarn per stitch?
A 0.26 mm
B 26 mm
C 2.6 mm
D 6.5 mm
Answer: C. 2.6 mm. The feed forms 25,000 stitches per minute. Dividing 65 m/min by that rate gives 0.0026 m per stitch.
Delivered yarn is 120 m/min per feed across 40 feeds. For 18 tex and no waste, find hourly production mass.
A 2.592 kg/h
B 0.5184 kg/h
C 51.84 kg/h
D 5.184 kg/h
Answer: D. 5.184 kg/h. Yarn use is 4,800 m/min. Multiply by 18 g per 1,000 m and by 60 min/h, then convert to kilograms.
Over an eight-hour shift, theoretical output is 6 kg/h and effective running time is 85%. Find actual output.
A 34.0 kg
B 40.8 kg
C 48.0 kg
D 42.5 kg
Answer: B. 40.8 kg. Multiply 6 kg/h by 8 h and by 0.85 to obtain 40.8 kg.
Which loop length maintains tightness factor when yarn changes from 16 tex at 2.8 mm to 25 tex?
A 2.24 cm
B 4.375 mm
C 3.5 mm
D 2.24 mm
Answer: C. 3.5 mm. To hold the factor constant, scale length by the ratio of square roots: 2.8 × 5/4.
Tightness factor is 14 when loop length is 0.30 cm. Compute yarn linear density under the square-root convention.
A 17.64 tex
B 19.60 tex
C 4.20 tex
D 46.67 tex
Answer: A. 17.64 tex. The square root of tex equals 14 × 0.30 = 4.2. Squaring gives 17.64 tex.
Reduce loop length by 10% with yarn tex fixed. By approximately what percentage does tightness factor rise?
A 11.1%
B 9.0%
C 10.0%
D 21.0%
Answer: A. 11.1%. The new factor is 1/0.90 times the old factor, or about 11.1% greater.
Suppose stitch density stays fixed while yarn linear density doubles and loop length falls by one quarter. Find the new-to-old mass ratio.
A 1.25
B 2.00
C 1.50
D 0.75
Answer: C. 1.50. For a fixed number of stitches, mass is proportional to loop length times tex. The ratio is 0.75 × 2.
After relaxation the width falls 8% and length falls 5%, with mass conserved. About how much does mass per unit area rise?
A 13.0%
B 7.6%
C 14.4%
D 12.6%
Answer: C. 14.4%. The area ratio is 0.92 × 0.95 = 0.874. Its inverse is 1.144, corresponding to a 14.4% rise.
Consider a tube with 1,800 uniformly spaced wales and a laid-flat width of 45 cm. What is wale density around its circumference?
A 20 wales/cm
B 30 wales/cm
C 40 wales/cm
D 10 wales/cm
Answer: A. 20 wales/cm. The circumference is twice the laid-flat width, or 90 cm. Divide 1,800 by 90.
Draw-down fabric measures 18 courses/cm and later relaxes to 20 courses/cm. How does a fixed set of courses change in length?
A It becomes 11.1% shorter
B It becomes 10% longer
C It keeps its length
D It becomes 10% shorter
Answer: D. It becomes 10% shorter. Length is inversely proportional to courses per centimeter for a fixed course count. The new length is 18/20 of the original.
Areal loop density increases from 150 to 180 loops/cm² while density along the width is unchanged. What is the change in course spacing?
A 16.7% increase
B 20% decrease
C 20% increase
D 16.7% decrease
Answer: D. 16.7% decrease. Course density rises by a factor of 180/150. Its reciprocal, course spacing, falls to 150/180 of the original.
Two guide bars fully thread 600 positions each and use 4 mm and 6 mm per end per course. Find total yarn use for 500 courses.
A 6,000 m
B 3,000 m
C 1,800 m
D 300 m
Answer: B. 3,000 m. Each course uses 600 × (0.004 + 0.006) = 6 m across both guide bars. Multiply by 500.
Guide bar 1 feeds 1,000 ends at 4 m/min each, using 15 tex. Guide bar 2 feeds 1,000 ends at 3 m/min each, using 20 tex. What fraction of mass comes from guide bar 1?
A 57.1%
B 75%
C 42.9%
D 50%
Answer: D. 50%. Both bars deliver 60 g/min. Yarn length multiplied by linear density gives equal mass rates.
Specified guide-bar run-in is 1,600 mm per rack of 480 courses. Find the average yarn length per end per course.
A 33.3 mm
B 7.68 mm
C 3.33 mm
D 0.30 mm
Answer: C. 3.33 mm. Divide 1,600 mm of yarn per end by 480 courses.
One guide bar is threaded one in and one out on 1,200 positions. With 3.6 mm yarn per active end per course, what length does it feed in 800 courses?
A 172.8 m
B 2,160 m
C 3,456 m
D 1,728 m
Answer: D. 1,728 m. Half the positions carry yarn. Multiply 600 active ends by 0.0036 m and by 800 courses.
Four hundred needles knit in the first pass, and 25 edge needles on each side become inactive every time shaping occurs. How many remain after three shaping steps?
A 325
B 350
C 250
D 275
Answer: C. 250. Each narrowing step removes 50 active needles. After three steps, 400 − 3 × 50 = 250 remain.
Which effect best explains why needle draw depth alone can overestimate true loop length?
A Warp beam flanging
B Yarn robbing back
C Fabric width rounding
D Needle gauge conversion
Answer: B. Yarn robbing back. Tension differences can pull yarn out of a newly formed loop into neighboring loops.
An 18 tex body yarn and a 6 tex plating yarn form each stitch. Per stitch they contribute 3.0 mm and 3.3 mm respectively. Find the plating yarn mass share.
A 33.3%
B 36.7%
C 25.0%
D 26.8%
Answer: D. 26.8%. The mass share is proportional to length times tex: 6 × 3.3 divided by (18 × 3.0 + 6 × 3.3).
Compare two warp knits identical except for a longer underlap on one guide bar. Which yarn path changes directly?
A Inside the yarn package
B Through the take-down roll
C Around the needle hook
D Between successive needle loops
Answer: D. Between successive needle loops. Underlap length changes the lateral connection between successive needle loops.
Interlock knitting needs two feeds to complete one structural course in the stated machine setup. At 22 rpm with 48 fully operating feeds, calculate the structural course rate.
A 264 courses/min
B 528 courses/min
C 1,056 courses/min
D 96 courses/min
Answer: B. 528 courses/min. There are 22 × 48 feed actions per minute. Divide by two feed actions per structural course.
One feeder in a 48-feeder circular machine delivers a different tension each revolution. Where is the fabric fault most likely to recur?
A In one fixed wale
B At a repeating course interval
C At random needle positions
D Only at the tubular fold
Answer: B. At a repeating course interval. The feeder affects successive needles as they pass and repeats in the courses produced by that feeder.
Pattern repeat is 18 needles around the cylinder and 12 courses along the fabric. A 1,440-needle cylinder knits 360 courses. How many complete pattern repeats are in this area?
A 2,400
B 3,600
C 1,800
D 120
Answer: A. 2,400. The area holds 1,440/18 = 80 repeats around the cylinder and 360/12 = 30 along the length. Their product is 2,400.