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PTFE sheet molding and sintering
of Contour-parallel spin
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| Fault Name |
Causes and Countermeasures |
| Pre-mold platen surface, and crack patterns |
(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 |
| Pre-mold platen surface roughness and the white spots |
(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 |
| Pre-mold platen surface discoloration and depression |
(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 |
| Pre-Mold platen dimension inaccurate |
(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 |
| Sintered plate crack |
(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 |
| Peeling thickness and uneven surface of the transverse
wave |
(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 |
| Peeled surface vertical scratches or cracks |
(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 |
| Sintered plate deformation |
(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 |
| Opaque sintered plate |
(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 |
| Board or intermediate raised on both sides of unequal
length at both ends of Matsube |
(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 |
