Problem & Solution

Practical answers to common plastic material challenges

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Q

Die buildup / die lip buildup

A

The essence of die buildup is the precipitation, adhesion, and accumulation of low-molecular substances and degradation products in the melt at the die outlet. The core of the solution is "cool down + clean die + optimize formulation": appropriately reduce die temperature to reduce precipitation ...

Extrusion & Post degradation yellowingprocessing temperatureresidence timeheat stabilizerPVC dehydrochlorination

Q

Gel particles / fish eyes

A

The essence of gel particles (fish eyes) is ultra-high molecular weight components or cross-linked gels in the resin that are not completely melted. The solution approach is "heat up + filter + change material": increase plastication temperature to ensure full melting, use screens to filter gel p...

Extrusion & Post gel particles fish eyeshigh molecular weight componentsplastication temperaturescreen filtrationresin purity

Q

Discoloration / burnt / black specks

A

This problem is a typical manifestation of discoloration / burnt / black specks in extrusion molding. The core of the solution lies in eliminating the root cause of the defect through systematic optimization of process parameters (temperature, speed, pressure) and precision correction of the die/...

Extrusion & Post degradation yellowingprocessing temperatureresidence timeheat stabilizerPVC dehydrochlorination

Q

Bubbles / air holes

A

The three major causes of extrusion bubbles (raw material moisture, gas from thermal decomposition, air entrainment by the screw) must be treated differently: moisture type — fully dry to the specified moisture content; decomposition type — reduce processing temperature to avoid degradation; air ...

Material Drying extrusion bubblesraw '2079851475616104451melt degradationvent vacuumscrew compression ratio

Q

Bamboo pattern / pulsating extrusion

A

The essence of the bamboo pattern is periodic instability in the matching of extrusion and haul-off speeds. The core of the solution is to eliminate speed fluctuation sources — stabilize the screw rotation speed transmission system, optimize the temperature control PID to eliminate periodic tempe...

Extrusion & Post bamboo patternextrusion-haul-off matchingscrew rotation speed fluctuationtemperature control PIDuniform feeding

Q

Rough surface / matte surface

A

This problem is a typical manifestation of rough surface / matte surface in extrusion molding. The core of the solution lies in eliminating the root cause of the defect through systematic optimization of process parameters (temperature, speed, pressure) and precision correction of the die/sizing ...

Material Drying poor plasticationfeed temperaturemixing timeplasticizer dosageresin particle size

Q

Melt fracture/sharkskin

A

The essence of melt fracture is that the die wall shear stress exceeds the critical shear stress of the polymer melt. The solution idea is 'reduce shear + modify interface': lower the extrusion speed or raise the die temperature to reduce the shear rate, and use PPA processing aids to improve the...

Extrusion & Post melt fractureshear stressdie temperatureextrusion speedPPA processing aid

Q

Pipe bending/not straight

A

The essence of pipe bending is that longitudinal cooling asymmetry or axis deviation causes inconsistent shrinkage rates on each side. The core of the solution is to ensure that the cooling system is coaxial with the extrusion axis and that circumferential cooling is uniform, while eliminating tr...

Extrusion & Post pipe bendingcooling uniformitytraction deflectiondie temperaturecoaxiality

Q

Uneven pipe wall thickness

A

The essence of uneven pipe wall thickness is that the die-mandrel geometric deviation and poor alignment of the sizing system cause the melt to be distributed unevenly in the circumferential direction. The core solution idea is 'precise calibration + online monitoring': calibrate the die concentr...

Molds & Tooling pipe wall thicknessdie concentricitysizing sleeve alignmentvacuum sizingonline thickness measurement

Q

Product post-curing deformation

A

The core of curing abnormality is that the rate and degree of the crosslinking reaction deviate from the optimal window. The adjustment idea is the 'three-element method': formulation (precise metering of catalyst/curing agent), temperature (precise control of mold and material temperature), time...

Molds & Tooling draft anglemold polishingholding pressurecooling timerelease agent

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