Analysis of some problems in actual use of domestic frame twister
Jul 23, 2021
1) Take-up and pay-off device
In
order to improve the quality of the stranded wire, reduce labor
intensity, and shorten the estimated ground length of the frame
stranding machine, walking type take-up and pay-off devices have been
generally used to replace the past fixed take-up and pay-off racks.
2) Threading die
The
threading die is a vulnerable part in the Rigid Frame Strander. The original
bakelite material has been gradually changed to nylon and ceramics over
the years.
In Danggang steel materials, the current life of aluminum
steel materials is 4-5 times longer than that of the previous Taolu
materials.
3) Supporting components
In recent years, equipment
manufacturers have paid more and more attention to the quality of their
products. In order to solve the air leakage and oil leakage of the frame
twister and improve the stability and reliability of the system,
domestic famous brand products or Sino-foreign joint ventures should be
selected as much as possible in the design. Pneumatic components and
hydraulic components; now there are also imported components, but the
price of the equipment should be higher. At the same time, improve the
precision of machining, select the supporting factory for heat
treatment, and ensure the quality of heat treatment of parts, so as to
continuously improve the equipment The quality of manufacture and use
reduces unnecessary maintenance.
4) Twisting cage body drive
In
the frame stranding machine, the drive of each section of the frame
stranding cage generally has two forms: one is that the frame stranding
cage body is driven by the ground axis, the stranding cage gearbox
drives the stranding cage body to rotate, and the operating handle can
realize the reversing and idling rotation of the stranding cage. ,
Reliable, simple, low cost, in line with the traditional operating
methods of cable manufacturers, accepted by the majority of cable
manufacturers: in recent years, more and more equipment manufacturers
have digested and absorbed the advanced level of foreign frame stranding
machines and adopted Each section of the winch cage is driven by a
separate DC motor. The DC motor is decelerated and driven by the
secondary synchronous belt, and the frame winch starts slowly and
smoothly; the operating parameters of the whole machine are set by the
computer, and a pair of switches control automatically increase and
decrease the speed slowly to ensure the frame , Traction and take-up are
synchronized to ensure that the wire pitch remains unchanged when the
equipment starts, accelerates, decelerates and stops. The split
transmission frame twister has no shaft and gearbox, which simplifies
the structure and greatly smoothes the production site. At the same
time, it also greatly reduces the mechanical maintenance cost of the
equipment. It is the development direction of the domestic frame
twister.
5) Safety device
With the gradual promotion of mechanical
upper and lower reels, the automatic winding has adopted an air thimble
to tighten the upper reel. After the winding reel is tightened, a
mechanical safety device is installed. At the same time, a limit control
main motor is set on the mechanical safety device. When in the safety
position, the main motor can be started. After continuous improvement
and perfection, the rotary air joint and its sealing device in the frame
twister now have a fairly good use effect.
6) Tension control
The
single wire tension of the traditional stranding machine is uneven, and
the pay-off tension on each pay-off reel is also inconsistent, which
seriously affects the quality of the stranded wire. The frame winch is
mostly pneumatically controlled, and the tension of the wire reel is
controlled by pneumatic tension. The tension is automatically controlled
by the pressure regulating proportional valve to ensure that the
tension of the wire reel is even from the full reel to the empty reel.
There is an uninterrupted air source device on the twisting cage.
7) Disconnection control
With
the continuous increase of the speed of the frame winch, the
instruction of the disconnection stop device is required to be agile,
and the winch cage brakes quickly and smoothly. The disconnection
parking device of the new frame twister adopts a non-contact probe to
directly control each spool. As long as one of the spools is
disconnected and stops, the broken frame number can be displayed on the
console and the machine will stop in time. The length of the broken wire
is about 1.5-2 meters to ensure the repair after the broken wire. The
impact and damage of emergency braking to the equipment is very severe
and should be minimized; therefore, the braking of the frame winch is
usually divided into emergency braking and normal braking, and the
normal braking time is longer.
8) Traction device
Frame stranding
machine usually adopts double-wheel traction, and there are several
structures of double-wheel traction, such as single-active,
double-active, single-slotted wheel and double-slotted wheel, which
should be selected according to the maximum traction of the stranded
product. Among them, the line splitter is a natural line splitting to
avoid wire core scratches during the line splitting process; the
traction sheave uses an R groove and is equipped with a pneumatic
crimping device to prevent the cable from loosening to prevent the cable
from slipping when driving after parking.
9) Pre-deformation device
The
frame stranding machine cannot be twisted back. When stranding the
wire, internal stress is generated inside the single wire, which causes
the wire to be twisted not tightly, and it is easy to loose strands,
which brings trouble to construction. Therefore, in the production of
overhead conductors, a single-wire pre-deformation device should be
installed in front of the splitter plate of the stranding cage to
eliminate the internal stress of the single-wire, and it can be removed
at any time when not in use.
10) Compression device
In order to
reduce the diameter of the conductive core and save materials, power
cables, especially cross-linked cables, usually use compacted cores,
with a compaction coefficient of about 0.85 to 0.9. The process of each
factory is different, and it can be pressed by a mold or a roller. In
order to facilitate layered compaction, after each section of the
stranding cage, a set of paralleling mold bases and pressing devices are
equipped, and the paralleling mold bases can be adjusted back and
forth; the paralleling mold bases can be twisted or pulled at one time.
Compression stranding; the rolling press roller frame is used to produce
the rolling compaction of the sector-shaped conductor.
11) Pre-twisting device
The
frame twister can be equipped with a pre-twisting device according to
the needs of users, and the cable cores with a cross-section greater
than 800mmz should use split conductors to reduce the skin effect of the
cable. The transmission system of the traditional twisting machine's
pre-twisting device is quite complicated, and the advance speed is
driven by the earth axis, and the pitch adjustment will cause
accumulated errors; the single DC motor drive frame twisting machine
uses a separate DC electric drive pre-twisting device, pre-twisting
joints The pitch is steplessly adjusted, and the high-precision
electrical synchronization technology is used to automatically track the
change of linear speed to ensure the stability of the pre-twist pitch.
Our requirement for the pre-twisting device is that the pre-twisting
pitch should be the same as the cable pitch after splitting the wires.
12) Centralized upper and lower disks
In
order to reduce auxiliary time, reduce labor intensity, and improve
productivity, more and more factories choose frame twisting units with
centralized upper and lower disks. The centralized upper and lower
devices can automatically complete the entire process of grabbing,
turning, walking, and loading in sequence. Convenient and reliable.
Common forms of upper and lower trays include top hoisting, bottom
jacking, ground level flipping, and side bottom 30° flipping. At
present, two forms of horizontal flipping on the ground and 30° flipping
on the side are commonly used; the former is faster than the latter,
but the estimated land area of the upper and lower parts is about twice
as large. The factory can choose according to its actual situation. .
13) Wire reel configuration
In
order to greatly improve the production capacity of the equipment, give
full play to the variable speed function of the existing frame winch
gearbox; some equipment manufacturers, in view of the frame winch in
production and use, the speed of the front winch cage is faster, and the
speed of the rear winch cage is slower. Phenomenon, the product design
has been improved, and the number of spools on the front and rear frames
of the frame twister has been appropriately changed. For example, some
of the first three sections of the 18-reel (including 18-reels)
frame-type winch cage are equipped with three wire reels (that is, 120°
uniform distribution) on each level of each segment, and the frame-type
winch cage after 18 reels In the above, each section of each section is
equipped with four wire reels (that is, 90° uniformly distributed);
there are also the first four sections of the 24 reels (including 24
reels) frame-type winch cage, all of which are on each section of each
section. Equipped with four wire reels (i.e. 90° uniformly distributed),
and the frame-type stranding cage after 24 reels is equipped with five
wire reels on each level of each section (ie 72° uniformly distributed);
the above two kinds of wire reel configurations The structure has been
proved to be feasible in practical applications.
