TPE injection molding defect analysis and solution

unpleasant sight

Possible Causes

Approach

Finished product variant

Cooling time is too short, the finished product is not cooled enough

Extend cooling time

Open mold speed is too fast, strong pull variant

Slow down mold opening speed

Finished product structure is defective

Modify the mold

The mold temperature is too high and the finished product is not cooled.

Reduce the mold temperature

Finished product is easy to break

Material temperature is too low or mold temperature is too low

Increase barrel temperature and mold temperature

Improper drafting or improper ejection

Modify the mold

The gate is too small

Modify the mold

Insufficient draft angle

Modify the mold

The finished product has a grain after the mold is released.

The rate of fire is too fast, and the air in the cavity cannot be instantaneously discharged.

Reduce the rate of fire, so that the air in the cavity is smoothly discharged

Raw material contains water

Baking material

The molding temperature is too high, and the degranulation is decomposed by high temperature.

Reduce molding temperature

Air in the barrel

Reduce the temperature in the back of the tube and increase the pressure

Finished product with burrs

Excessive pressure, the parting force is greater than the clamping force, and the mold is forced to open.

Reduce the pressure, fly the mold, increase the clamping force

Injection pressure and overpressure

Reduce the pressure and pressure

The shot is too fast, the material temperature is high

Reduce the rate of fire and material temperature

Mold vent clogging

Cleaning the mold

Insufficient filling of products

Insufficient pressure, slow rate of fire or debris in the die

Increase injection pressure, increase firing rate and clean the die nozzle

The molding temperature is too low and the gate flow path is too small

Increase molding temperature and modify flow path

The air in the cavity cannot be completely discharged

Add or enlarge vents

Shooting time is too short, insufficient shot

Extend the injection time and increase the injection volume

Products have a bonding line

Insufficient injection pressure, too fast, the gate and runner are too small
Another: the nozzle temperature is low, the molding cycle is long, the color masterbatch titanium dioxide is too much, and the color masterbatch is not well dispersed.

Improve injection pressure, rate of fire, and modify gate flow path

Molding temperature and mold temperature are too low

Increase molding temperature and mold temperature, increase back pressure or accelerate screw speed

Poor exhaust at the junction or no overflow tank (cold well)

Increase the vent hole or increase the overflow pool at the junction

Use too much release agent

Reduce the amount of release agent used

Poor gloss of the product

The rate of fire is too slow, the injection pressure is too low, and the mold temperature is low.

Increase injection pressure, rate of fire, and mold temperature

Moisture or grease contamination in the cavity

Wipe clean

Poor surface grinding or too small gates and runners

Modify the mold

Insufficient injection volume or moisture in raw materials

Increase jet fire rate, extend injection time and baking material

Flow on the surface of the product

The injection pressure is too high or too low, the rate of fire is too fast or too slow

Adjust the appropriate injection pressure or rate of fire

The holding time is too short or the gate is too small

Increase the holding time or change the gate

Mold temperature and gate temperature are too low

Improve mold and gate temperature

Poor material melting

Increase temperature, back pressure or speed up the screw

Extrusion finished surface rough

Low molding temperature

Increase temperature, back pressure and screw speed

Mode temperature is too low

Increase mold temperature

The surface of the product is blocky

The tube is not cleaned or has debris

Reclean the tube

Additives such as color masterbatch or carrier are not required

Find the corresponding color masterbatch

After the product is molded, it will be swollen.

The die temperature is too low, or the screw speed is too fast

Increase die temperature and reduce screw speed

Limit too fast

Adjusting the limiter

Produces a large amount of gas during extrusion

Overall temperature is too high

Reduce the temperature

There is debris in the material tube

Cleaning the tube

The product has shrinkage

Raw materials contain water

Baking material

The melt temperature is too high and the screw speed is too fast

Reduce temperature and reduce screw speed