Circular
Knitting m/cs are widely used through out the knitting industry to produce
fabric. This m/c can be built in almost any reasonable diameter and the small diameter
of up to five, which are used for wear.
Plain circular m/c uses only
onsets of needles, circular rib m/c uses two sets of needles i.e. Cylinder
needle and Dial needle, interlock circular knitting m/c also uses two sets of
needles by needles are long and short respectively for both dial and cylinder,
that is why multiple design and thick fabric can be produce with that m/c. That
m/c is also called double Jersey m/c.
M/c.
Gauge: Needle / inch (varies
according to diameter)
Needle
Type: Latch.
Needle
bed type: Single cylinder, Double
Cylinder, Cylinder and Dial long or short needles
for
cylinder and dial
Two
principle operations exist:
English
system: Where the cams and yarns
strands revolve by the needle and fabric take down is stationery.
American
system: Where the needles and fabric
take down revolves by cams and yarn strands are stationery.
DIFFERENT PARTS OF CIRCULAR KNITTING M/C:
1.
Yarn strand
2.
Wheel
3.
Tension wire
4.
Belt
5.
VDQ pulley
6.
Feeder
7.
Cam
8.
Cam box
9.
Sinker & sinker cam (For single jersey m/c)
10.
Needle
11.
Fan
12.
Take up roller
13.
Cloth roller
14.
Cylinder
15.
Dial (For double jersey m/c)
IMPORTANTANT EQUIPMENT OF CICULAR KNITTING M/C.
1.
START/ STOP/INCH BUTTONS:
Complete set of easily accessible
start/ stop/inch buttons
at top in each leg.
2. RATCHET LEVER:
Permit hand movement of the M/C.
3. AUTO STOP MOTION:
Automatic three stage 24v yarn
motion, positive feed tapes &
knitting zone. Indicator lamps are on
individual stop motion & on the
main control panel. While the yarn is
broken we can find the location
which is broken as well as
to repair , meanwhile the motor can
brake
and stop operation at once to
keep the security of M/C.
4.
FREE STANDING SIDE CREEL:
Reserve package for each feed.
5. AUTO – COUNTER:
Two shift revolutions with display
counter with predetermined stop
settle freely the weight or
yardage of fabric.
Transistor inverter provide
for free controlled, the process of “V.S. motor – drive” from slow operation to
normal operation is quite & fast brake to prevent damages in case of
needles or yarn breakage.
7. FABRIC TASKE UP SYSTEM:
With variable speed control by a
belt drive set can be adjusted the speed
for different course of fabric-
constant and uniform fabric tension.
8.
SEFTY GUARD SWITCH:
Machine can not be Started with
guard open, these guard have
reinforced fiberglass window for easy fabric inspection.
9.
AUTO LUBRICATION:
The automatic central pressurized
oil sprayer can be adjusted at cycling time and quantity to make cylinder ,
dial,, sinker ring’s cam, needles and sinkers lubricated enough , besides it has the function cooling
and clearing.
10.
AUTO-LINE REMOVAL SYSTEMS:
Three fans on each rotating arm
for clearing off any dust of creel and knitting
zone.
Adjustment of VDQ pulley:
There are 3 disc plates in VDQ
pulley arrangements. Central plate contains scale & plastic segments on
both sides. The plastic segment can move outwards & inwards which increase
& decrease the dia of the VDQ pulley.
The central disc which is the main
disc of VDQ pulley . It has a straight
track for the plasic segment which goes from the center to outwards. The
central disc has marked point on its wall by a grooved scale.
picture
And the outer disc has a round track/ spiral
track or complicated round track. It has a marking point to the scale of
central disc for the adjustment of stitch length and GSM.
When the track of outer disc rotates,
then the plastic segment moves on the track of central disc. And thus the Dia
of VDQ pulley changes. Here central disc is
fixed & the two outer disc can rotates . when the
outer disc rotates anti- clockwise, then the Dia of VDQ pulley increase &
vice versa . The outer disc is rotated by the nut bolt system.
Gearing of take down mechanism.
Ø Motor drives cylinder by pulley or gear mechanism.
Ø As cylinder rotates, it rotates cylinder take
down frame.
Ø A ring is adjusted at the base of the machine &
adjusted with the take down frame. It also rotates with the frame rotation.
Ø A fixed position is adjusted inside the ring which
gives rotation to a bevel gear with it own teeth.
Ø Bevel ger transfer motion to a sprocket wheel by a
horizontal shaft.
Ø Sprocket wheel drives a pulley which again transferred
motion to the pinion attached to the takedown tensioning roller.
Ø Thus the take down rollers tension is adjusted &
the production is continued.
Central stitching:
Ø A device named central stitching point t is attached on the machine frame .
Ø A gear is adjusted just below to this point .This
point is rotated by key & gives motion to the gear.
Ø The gear transfer motion to the cylinder gear train & thus cylinder can rotates
either anti clockwise direction at a slight motion.
Ø Thus cylinder base is threaded such as nut bolt
system.
Ø When cylinder rotates anticlochwise it rises upwards
& vice versa.
Ø Rising of cylinder means tension decrease . Lowering
of cylinder means tension increase.
Ø Thus central stitching is complete.
Synchronized timing Delayed timing:
Synchronized & delayed
timing is used in knitting for loop formation principle.Usually fore
synchronized & delayed timing two typed of cam is used.
One
is synchronized cam and other is delayed cam. The nose of delayed rises much
time is required for loop formation. On the other hand the nose of synchronized
cam is lower in position on comparing to the nose of delayed cam. For this here the time of needle
movement reduce on comparing to delayed
cam.
There is device on the dial at
the central of cylinder circle which used to move the dial left & right.
There are two screws on the
device. If we rotate the left screw then the dial will move to the left side.
This mechanism is required because if we change the synchronized cam to
the delayed cam then the needle move more forward in dial. So there is a possibility to have a
friction between the needle and the feeder .
And
thus there is a possibility of needle breakage . So if we can move the dial to
left side then needles will also moved to the left . So we should be able to
avoid friction.
Picture
Uses:
Synchronized
cam: Synchronized cam can be used for all types of fabric.
Delayed
cam: Delayed cam is used for Lycra ,1X1 Rib etc. Because it produce elasticity
to this type of fabnric. In delayed cam the needle move much forward so the
yarn like lycra extend and after this production the the length of lycra again
decrease and thus it produce elasticity to the fbric.
Inverter:
Invertger is a device which
controls / adjusts the motor rpm according to requirement . A motor can provide
rpm more than 1000 . But the knitting machines don’t need such more rpm.
Cylinder rotates not more than
30
rpm for better quality opf fabrics & inspection purpose & also for
resisting sparking or explosion due to
friction . This 30 rpm can be provided by inverter from supply.
Inverter
can also stop m/c instantaneously if there is any yarn breakage or another
problem. Inverter performs this action as a breaking system.
Inverter
mainly acts by using voltage differentiation & variation of current
frequency. This voltage variation actually controls motor rpm.
Inverter
is of following types:
·
Yaskawa
·
Mitsubishi
·
LG
·
Shihlin
Oil mechanism:
Oil card is uniwave types in mondol
fabrics ltd.-
UNIWAVE-Mechanically
controlled.
Uniwave:
This
one is mechanical oil controller. Here a pipe of air is connected to oil box.
The downward pressure of air from air compressor creates the upward
Oil classification:
SAE=22-Standard
<22-low viscosity
>22-high viscosity
Operating instruction of single jersey & double jersey m/c:
1.
Auto counters LED display:
The led display can show the
massage:
§ No. of revolution per shift.
§ Error massage.
2.
RPM meter:
This meter shows actual rpm of the
m/c.
Function
keys:
1.
Set up:
This key is used for setting the
total desired revolution per production batch. For example, to set 1500
revolution as the desired no. of revolutions,
Step1:
Press set up key
Step2:
Use key to key in 1500
Step3:
Press enter key
To
change setting it will repeat same steps but with new figure.
2.
READ key:
This key is used for reading the
no. of revolutions recorded by each shift while shift indicator light is on.
3.
TOTAL key:
Hold down total key to show the sum
of A shift, B shift, C shift.
4.
Forced jog:
If the m/c needs to run slowly then
jogging motion is needed. Before activating this function, ensure that all
needle latches are their in correct position. When any of yarn fault stop
motion is activated, the JOG & STOP functions will be automatically disable
in order to run m/c electrically at jogging speed to retain the yarn, hold down
the JOG & STOP key simultaneously. This function is meant to protect light
bulb of MER by preventing them from overheating.
5.
RESET key:
This
key is for zeroing the record on total no. of revolution per batch and total
no. of revolutions of each shift.
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