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♦ PTFE sheet molding and sintering of
Contour-parallel spin
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Fault Name
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Causes and Countermeasures
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Pre-mold platen surface, and crack patterns
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(1) resin poor thermal stability. Should use a
better thermal stability properties of the resin.
(2) different batches of resin mix. Should use
the same batch of resin. (3) pre-forming pressure
is too high. Should be appropriately reduced. (4)
improper pressure process control. Pressure
should be slowly and evenly, does not allow the
impact-type pressure. (5) mold mismatch. Mold
with the structure should be improved. In
addition, the mold should be placed in the press
center of the table, a solid and reliable
connection
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Pre-mold platen surface roughness and the white
spots
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(1) pre-forming pressure is too low. Per unit
area should increase the pressure to maintain
sufficient holding pressure time. (2) resin
particle size too large. A smaller particle size
of resin should be used to require an average
particle size of resin, 25,200 pm
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Pre-mold platen surface discoloration and
depression
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(1) resin components of low impurity content is
too high. Impurities should use less resin and to
prevent the operation of foreign impurity
entrainment. (2) Feeding uneven. Feeding should
be uniform, dense line. (3) compression method is
incorrect. Both sides should be pressurized. (4)
The holding pressure time is insufficient. Should
be an appropriate extension of time for holding
pressure
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Pre-Mold platen dimension inaccurate
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(1) resin molecular weight is too small or
unevenly distributed. Should use the same batch
number, performance, consistent resin. (2)
pre-compression molding uneven. Should be evenly
slowly pressurized. (3) non-uniform feeding. Mold
kit should be uniform feeding, add ingredients
Calibrating finished. (4) improper packing. At
different pressure, must be given certain amount
of holding pressure time, to ensure that all
parts of the pressure delivered to the resin, the
pressure the greater the pressure more slowly,
holding pressure time should be longer
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Sintered plate crack
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(1) heating or cooling too fast. Should be
properly controlled rate of temperature rise.
Typically, the heating rate of 0.4-1/
shelter no products the greater the heating rate
should be slower when the temperature rose to
about 330 ℃, the plate outside the first began
to melt, and then gradually penetrate inward. The
use of a 1.5-3t / and n, heating rate, inward
penetration of the melting rate of about 5-6 per
mm thickness and no order for the entire A sheet
to melt, we must control a certain time of
heating rate and temperature. (2) The sintering
temperature is too high. Should be appropriately
reduced. (3) The holding time is too long. Should
be appropriately reduced. (4), when the
pre-manufactured Stripping bumps, leading to
sintering cracks. Stripping should be careful to
avoid collisions. Preform, the pressure slowly
after pressure relief to prevent the product
burst
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Peeling thickness and uneven surface of the
transverse wave
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(1) installation of non-performing blades. Should
be adjusted appropriately. General peeling
thickness 0.5-3mm plate, the knife sharp corners
and 38 '; spin Cutting thickness o. 5mm, the
knife sharp corners 34 ', the latter angle is
generally not more than 5'. Tip height should be
slightly more suitable than the spindle
centerline. (2) Mandrel bad installation. Mandrel
shall be adjusted or replaced. (3) clip knife
device nut loose. Should be re-commissioning and
installation of rotary knife knife block. (4) The
cutting edge is not straight. Grinding should be
carried out, or ATC
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Peeled surface vertical scratches or cracks
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(1) parison contain metal impurities. Parking
should be removed. (2) there are gaps in the
blade. Should be grinding or tool change. (3),
when peeling the hard impurities stuck in between
the blade and peeling surfaces. Should stop
processing, and should always clear the plates
and the blade between the impurities
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Sintered plate deformation
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(1) The holding time is too short. Should be
appropriately extended. In order to sintering
temperature uniform inside and outside pieces
should be 300-330 ℃ under the conditions of
heat for some time. (2) cooling down too fast.
Should be properly slow down. Cooling rate
related to the crystallization plates, is
affecting the physical properties of the
important parameters, cooling too fast, plate
easily lead to strain and crack. -50 ℃
generally increases the speed of cooling the
cooling of several more appropriate. "3) The
furnace temperature unevenly distributed. Should
increase the accuracy of temperature measurement
points and temperature control, so that furnace
temperature distributed evenly, it may be
appropriate to extend the cooling time
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Opaque sintered plate
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(1) The sintering temperature is too low. Should
be appropriately increased. (2) The holding time
is too short. Should be appropriately extended.
It is noteworthy that in the resin thermal
stability should be a good case can be extended
appropriately increasing the sintering
temperature and holding time
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Board or intermediate raised on both sides of
unequal length at both ends of Matsube
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(1) The sintering conditions unreasonable.
Sintering conditions should be adjusted. Such as
sintering temperature, heat and cooling times.
(2) the blade is not parallel with the mandrel
axis. Should be adjusted to parallel
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