7 solutions to PC and ABS problems

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7 solutions to PC And ABS problems
Written By Jasmine HL
1. Silver wire problem
Poor silver wire is the most common problem of PC / ABS materials. Silver wire, also known as
silver streaks, water splashes, material flowers, etc., is a phenomenon of silvery-white silky
stripes on the surface of the product along the flow direction.
The main reason is because of the interference of gas, and the generated gas is mainly divided
into three components:
Air: air involved in the melt and injection phase;
Moisture: the moisture contained in the material itself;
Pyrolysis gas: Gas produced by high-temperature hydrolysis / thermal decomposition.
Solution: First check whether the material is sufficiently dry. After confirming that the material is
sufficiently dry, adjust the injection molding process to improve the silver wire defect. At the
same time, poor injection silver wire is also related to mold venting.
2. Flow mark problem
The flow mark is generated when the material is injected. The reason is that the material has
poor fluidity. The flow mark is different from silver streaks. It is not caused by moisture or
material decomposition, and the appearance is also different.
Solution: It can be avoided by increasing the temperature of the material to improve the fluidity.
Properly increasing the mold problem to increase the fluidity of the material in the mold and
reducing the injection speed can also be solved.
3. Shrinkage and dent problems
Shrinkage is caused by the insufficient filling of the material in the mold cavity.
Solution: Properly increase the mold temperature and material temperature to improve the

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fluidity of the material, extend the injection pressure holding time, increase the injection
pressure, increase the injection speed to improve mold filling performance, or increase the size
of the gate and heat the gate flow. To reduce and eliminate product shrinkage;
Dent is caused by improper material temperature and improper product design. When the
material temperature is too low, not only shrinkage will occur, but also the problem of dents. The
material temperature is too high and the mold temperature is too high, which will cause the melt
to cool. Shrinks excessively, causing dents.
Solution: Use appropriate processing problems to increase injection speed and measures.
4. Warping and deformation
The warpage and deformation of the injection-molded part is due to the irrational design of the
part, improper gate location and unreasonable injection processing conditions, which results in
internal stress, uneven or excessive shrinkage, excessive mold temperature or uneven mold
temperature It may cause difficulty in demolding of the mucous membrane of the product, or
uneven cooling, which will also cause warping deformation;
Solution:
Processing technology: lengthen the injection molding cycle, reduce the injection temperature,
properly adjust the injection pressure and injection speed, at the same time slow the ejection
speed, increase the ejection area, and maintain the ejection force balance;
Product design: increasing wall thickness, adding reinforcement and reinforcement at rounded
corners can reduce warping deformation;
5. Streaks
Usually caused by melt expansion into the mold cavity during high-speed injection, resulting in
"melt rupture".
Solution:
In terms of molding process: take measures to increase the material temperature, increase the
nozzle temperature, and slow down the injection speed to reduce the appearance of streaks;
In terms of mold: increase the mold temperature, add overflow grooves, increase the size of the
gate, and modify the shape of the gate.
6. Pockmark
Solution:
Poor dispersibility, add dispersant or oil, increase temperature, and add backpressure.
Watch for mold problems. Try something else.
Is the baking temperature-time sufficient?
Mold temperature adjustment.
7. "Peeling" of Products
The peeling problem of plastic products is greatly related to the fluid rupture caused by high
shear force. At low shear stress or rate, small disturbances caused by various factors are
suppressed by the melt; while at high shear Under stress or velocity, the disturbance in the fluid
is difficult to suppress and develops into an unstable flow; when a critical shear force is reached,
the fluid will rupture.

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Solution:
In terms of materials: The PC and ABS components are partially compatible, so it is necessary to
add an appropriate compatibilizer in the modification process to improve its compatibility. Of
course, the bad peeling caused by the mixture is the first step we need to eliminate;
Mould: The principle of mold design should follow the direction of minimizing shear. Generally
speaking, products with dense skin texture surface are more prone to peeling (caused by
frictional shear of the melt in the cavity and the inner wall of the cavity during high-speed filling);
at the same time, the gate design is too small, Will cause excessive shear when the melt passes
through the gate, which in turn will cause the product surface to peel;
Injection process: the main direction is to avoid excessive shearing. When product filling is
difficult, high-speed and high-pressure methods can be used to improve it. Therefore, in the
actual injection molding process, you can also consider increasing the injection
temperature/mold temperature and improving the material fluidity to reduce the flow resistance
during the actual filling process, thereby Avoid excessive shearing caused by high speed and high
pressure.