Ptfe teflon tube extrusion machine is divided
into many kinds, exactly say ptfe
tube forming process has push and pressure method, extrusion method, hydraulic method, welding
method, winding method, etc., which is mainly push and pressure
method.Generally dispersed PTFE resin with particle size of 500 microns and
apparent density of 0.45g/ml ~ 0.55g/ml is adopted.The small diameter tube
chooses the compression quite big resin, the medium and large diameter tube
chooses the compression quite small resin.Extruder usually choose 200 and 260
solvent oil.PTFE thermal shrinkage tube, PTFE spiral tube, PTFE steel wire
reinforced hydraulic tube and so on can be produced by the secondary processing
of PTFE tube.
1.1 common ptfe teflon pipe
Ptfe ordinary tube is made of ptfe
dispersion resin at room temperature with organic solvent as extruder, and then
through drying and sintering.According to the size of the pipe diameter can be
divided into two types of ordinary pipe and micro pipe.Ordinary tube inner
diameter > 4mm, micro tube inner diameter ≤4mm.
Typical formula for PTFE tube production:
Dispersed PTFE resin: 100 (weight)
Extruder: 18 ~ 24
Production process:
PTFE, extruder - mixing - pushing -
pressing - drying - sintering - cooling - products.
Production process parameters:
Mixing: temperature ≤19 ℃, time 10min
~ 20min, mixed at 25 ℃ ~ 30 ℃ for more than 24h.
Blank: compression rate is about 50mm/ min,
pressure is 0 ~ 3MPa.
Pushing pressure: the cavity temperature is
30 ℃ ~ 50 ℃, and the die temperature is 50 ℃ ~ 60 ℃.
Drying: under 210 ℃,2h ~ 3h
Sintering: batch sintering, temperature
rise rate of 60 ℃/ h,375 ℃±5 ℃ insulation for 4h.
Continuous sintering, dry area 100 ℃ ~ 250 ℃, preheating
area 250 ℃ ~ 330 ℃, sintering area 380 ℃ ~ 420 ℃, cooling area less than 300 ℃.
Main equipment: mixing machine, preforming
machine, vertical pushing press, drying and sintering furnace.
USES: as insulation and fluid conduit.
1.2 polytetrafluoroethylene heat-shrinkable
tube
PTFE thermal shrinkable tube has the
property of being heat-shrinkable, so it can be tightly coated on the surface
of other workpieces, making the workpieces resistant to corrosion, electrical
insulation and viscosity.Widely used in electrical, chemical, mechanical,
printing and other industries.The maximum shrinkage of PTFE shrink tubes is
reported to be more than 75%.
It is processed by disperse PTFE resin. The
principle is that PTFE is subjected to stress during processing and produces
forced high-elastic deformation, which is reversible and freezes at low
temperature. If the forced high-elastic deformation is reheated, it will
gradually disappear and return to the original state.
Typical formula for PTFE thermal shrinkable
tube production:
Disperse PTFE resin 100 (weight)
Extruder 20 ~ 22
Production process:
PTFE resin, extrusion aid → mixing → storage → pre-molding
→ pushing and pressing → drying → sintering → cooling → heat treatment → blowing → cooling → product.
Production process parameters:
The front part is the same as ordinary PTFE
tube.
Heat treatment: the quenching process of
the dried and sintered pipes after further full sintering at high temperature,
the temperature is 390 ℃±2 ℃, and the coolant is -5 ℃.
Blowing: at 310 ℃ or so, fill
the compressed gas below 0198MPa, the blowing rate is 200% ~ 400%.
Main equipment: blowing machine, other PTFE
tube and the same.
1.3 ptfe teflon steel wire reinforced hydraulic
pipe
The common PTFE pipe will break under the
pressure of about 40kg/ cm2. When it is combined with steel wire, the pressure
resistance will be greatly improved. The maximum working pressure abroad
reaches 700kg/ cm2.The results show that the compressive strength and pulse
strength of the hose are related not only to the steel wire strength but also
to the weaving Angle.When the braiding Angle is 54°44 "for single-layer
braiding, the steel wire does not extend under internal pressure, the length
and diameter of the hose do not change, and the pressure resistance is the
best.
When used as hose for hydraulic system in
aviation industry, in order to prevent electrostatic breakdown of inner tube
caused by hydraulic oil flow, trace conductive carbon black should be added in
the manufacture of PTFE inner tube.However, it was found that adding carbon black
could not completely prevent electrostatic discharge from passing through the
tube wall and increase the gap.
In the 1960s, Attas manufactured composite
tubes, in which the inner layer of the tubes was a uniform mixture of
conductive carbon black and PTFE, and the outer layer of the tubes was pure
PTFE.This form of tube body layer has axial conductivity, so it can not only
eliminate static electricity, but also prevent seepage.
The process:
Inner resin (including conductive carbon
black), outer resin → blank → pushing → drying → cooling → testing → weaving → fitting joints → testing.
PTFE steel wire composite hose is mainly
used in aircraft hydraulic system, air conditioning system, fuel system,
lubricating oil system.In civil industry, it is suitable for soft connection of
hydraulic pressure, steam pressure and steam transportation in rubber, plastic,
pharmacy, clothing, shipbuilding, automobile, machine tool, motor, diesel
engine and paper making industries.
PTFE spiral tube, also known as PTFE
flexible hose, has not only all the excellent properties of PTFE, but also
flexible properties.At present, there are two kinds of PTFE spiral tube and
chemical fiber, stainless steel wire and plastic coated glass fiber woven
reinforcement.
It is made of PTFE through secondary
processing. The process is that PTFE thin-walled tube continuously rotates
forward through a combination mold with a temperature of 270 ℃ ~ 280 ℃ at a
certain speed.
It
is mainly used for the inlet and outlet pipes of the shock parts such as the
soft connection dislocation connection, serpentine pipes, pump engines and so
on.Used for shielding cable and protecting cable sleeve of aircraft engine.
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