Problem & Solution

Practical answers to common plastic material challenges

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Q

PP '2079851475616104452 Silver Streak

A

When silver streaks appear on PP, don't rush to blame drying—first check regrind, masterbatch, and additive volatilization, then shear heat; PP silver streaks are more a 'volatiles and shear' problem than the raw material itself absorbing water.

Material Drying PP;silver streak;regrind;additive volatilization;shear heat;venting

Q

PP Part Color Difference

A

For PP color difference, check 'dispersion and metering stability' first, then temperature; color difference often drifts with regrind ratio and feeding fluctuation—fixing these two variables is more effective than repeatedly adjusting masterbatch ratio.

Material Analysis PP;color difference;masterbatch dispersion;back pressure;gravimetric feeding

Q

PP Injection Cycle Fluctuation Material Shortage

A

For alternating shortage, check the metering system.

Injection Molding PP;short shot;metering;check ring;bridging

Q

PP Part Post-demolding Deformation

A

PP 'demolding before setting' is the root of deformation: thick-walled parts need sufficient cooling time and balanced ejection; post-demolding storage and packaging are also high-incidence deformation stages—stacking hot parts equals secondary molding.

Molds & Tooling PP;demolding deformation;cooling time;ejection;setting

Q

PP '2079851475616104452 Cold Slug Mark

A

The antidote for PP cold slug marks is 'cold slug well + nozzle temperature': first guide cold material into the cold slug well, then ensure nozzle temperature is not low; recurring fixed-position small spots are mostly due to inadequate cold slug well design.

Injection Molding PP;cold slug mark;cold slug well;nozzle temperature;gate

Q

PP Film MD Thickness Deviation

A

For MD thickness variation, first stabilize extrusion output and haul-off.

Extrusion & Post PP;film;thickness deviation;MD;extrusion fluctuation

Q

PP Cast Film Gel Particle (Fisheye)

A

CPP gel particles must be distinguished into 'unplasticized' and 'contamination/crosslinking' types: the former relies on plasticization and screens, the latter on cleaning and dead-spot control; transparent film demands extremely high melt uniformity—plasticization and filtration must both be in...

Extrusion & Post PP;cast film;gel particle;fisheye;screen;plasticization

Q

PP Flat Filament Drawing Breakage

A

For PP flat filament breakage, first check the film's 'innate quality' (gel particles, impurities, thickness), then adjust drawing temperature and ratio; drawing amplifies film defects—if the film fails, it breaks no matter how you adjust afterward.

Extrusion & Post PP;flat filament;drawing;filament breakage;gel particle;draw ratio

Q

PP Pipe Extrusion Inner Wall Ripples

A

For inner wall ripples, check die head distribution and pressure stability.

Extrusion & Post PP-R;pipe;inner wall ripple;die head;sizing

Q

PP Extruded Sheet/Plate Uneven Thickness

A

PP sheet thickness relies on the three-in-one stability of 'die lip + melt temperature + haul-off', preferably with thickness closed-loop; for transverse deviation, first use the thickness profile to locate which die lip section has the problem, then adjust targetedly—don't randomly adjust bolts ...

Thermoforming PP;extrusion;sheet;uneven thickness;die lip;haul-off

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All Topics 11636 Material Drying 1439 Injection Molding 1506 Molding Process 740 Molds & Tooling 1506 Processing Machinery 2025 Extrusion & Post 2239 Blow Molding 315 Thermoforming 141 Material Analysis 1343 Production & Quality 382