A) Circular Knitting
Find out the production rate (kg/hour) for the following
knitted structure on a fine gauge circular knitting machine.
Knitted structure Plain
Fabric Weight 120
g/m
Courses per centimeter 18
Number of feeders 100
Machine speed 30
rpm
Working efficiency 90%
B) Flat-bed Knitting
Calculate the production rate (pieces/hour) for the
following knitted structures of a V-bed knitting machine using different number
of feeders.
Knitted structure Plain
Courses per piece 250
courses
Number of cam systems 3
No of strokes per minute 25
Working efficiency 90%
Find out the production rate (pieces/hour) if a) only use ONE feeder per stroke; and
b)
Two feeders per stroke.
Answer
A) Circular Knitting
Production (courses/hour) = 100 x 30 x 60 x 0.9 =162,000
courses/hour
Production (meters/hour) = 162,000 / (18 x 100) = 90
meters/hour
Production (kg /hour) = 90 x 120 g/m /1000 = 10.8 kg/hour
B) Flat Bed Knitting
One feeder
production:
One stroke = TWO courses
Production (courses/hour) = 25 x 2 x 60 x 0.9 = 2700
courses/hour
Production (pieces /hour) = 2700/250 = 10.8 pieces/hour
TWO feeder production
Production (courses/hour) = 25 x 2 x2 x 60 x 0.9 = 5400
courses/hour
Production (pieces/ hour) =5400/250 =21.6 pieces/hour
Knitting Instruction
for Flat-bed Machine
Apart from production calculation (pieces/hour) on V-bed
machine, one of the key elements for the knitting factory (sweater factory) is
to prepare knitting instruction.
What is knitting
instruction?
Knitting instruction is the statement used to knit the
garment parts and expressed in terms of courses (fabric length), needles width
(fabric width) and fashioning frequencies.
In other words, if a fabric piece is given with how many
inches in length and width, you need to find out the correct number of courses
to produce the required length and correct number of needles width to produce
the required fabric width.
A swatch (a small piece of fabric) in correct knitting
instruction and knitting tension is normally prepared before bulk production.
One of the common methods used by industry to determine the stitch tension is
to stretch the fabric course wise to its utmost limits manually and measure the
dimension of 10 wales board.
Example
Find out the widening (Part A in diagram) and narrowing
(Part B in the diagram) of the sleeve panel as shown.
Given
Courses per inch : 6
No. of needles at bottom : 64 needles
Height of A = 13 inches
Height of B = 3 inches
Fabric narrowing by 2 needles each time on each side
Each small square is 1 square inch.
A) Widening (for each
side) of A:
Number of needles to be added (on each side)
((16 x 8) – 64) /2 = 32 needles (width)
Number of turns for widening: 13 inches x 6 = 72 turns (height)
72 turns / 32 needles = 2 turns ……14 needles
ie every 2 turns add 1 needles for 32 times, we will have 14
needles left.
( 2 + 1 + 32 ….14)
To make such adjustment, we modify as follows: every 3 turns
we add 1 needle for 14 times.
The widening will have two parts:
2 + 1 + 18 (part 1) and 3 + 1 + 14 (part 2)
Check : Part 1 we add 18 needles on 36 courses (2 x 18)
Part 2 we
add 14 needles on 42 courses (3 x 14)
Total we
add 32 needles (18 + 14) on 72 courses (36 + 42)
B) Narrowing (on each
side) for B
No. of needles on each side to be narrowed: (16-12) /2 x 8 =
16 needles
Number of turns for narrowing: 3” x 6 =18 turns
If narrowing by 2 needles each time, number of times will be
16 needles/2 =8
Dividing 18 turns by 8 times = 2 turns…..2
which means 2 turns will be less if every 2 turns less 2
needles by 8 times ( 2-2-8 ).
To make the adjustment, the last 2 turns will have 3 turns
instead. The answer should be
2-2-6 (Part 1) and 3-2-2 (part 2)
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