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Technical Resource

Molding Defect Troubleshooting

A structured diagnostic resource for identifying and addressing production molding defects. Search by defect name, symptom, or common terminology — across injection molding, blow molding, compression molding, die casting, and stamping.

Injection Molding

(27)

Black Spots, Brown streaks.

Injection

Blisters (Air Entrapment).

Injection

Brittleness

Injection

Bubbles

Injection

Burn Marks, Dieseling.

Injection

Cracking, Crazing

Injection

Delaminating

Injection

Discoloration

Injection

Flash

Injection

Flow, Halo, Blush Marks.

Injection

Gate Stringing, Drooling

Injection

Gels.

Injection

Jetting.

Injection

Material Leakage

Injection

Oversized Part.

Injection

Part Sticking.

Injection

Short Shot (Incomplete Filled Parts).

Injection

Sink Marks.

Injection

Splay Marks, Silver Streaks.

Injection

Sprue Sticking

Injection

Surface Finish (Low Gloss).

Injection

Surface Finish (Scars, Wrinkles).

Injection

Undersized Part

Injection

Valve Pin Does Not Close.

Injection

Voids.

Injection

Warping, Part Distortion

Injection

Weld Lines.

Injection

Extrusion Blow Molding (EBM)

(19)

BLOW-OUTS & HOLES

EBM

BUBBLES

EBM

CAP LEAKAGE

EBM

CURTAINING & WEBBING

EBM

DIE LINES & STREAKING

EBM

DIRT & CONTAMINATION

EBM

DULL OR ROUGH MELT APPEARANCE

EBM

EXCESSIVE SHRINKAGE

EBM

INCOMPLETE INFLATION

EBM

LOW ENVIRONMENTAL STRESS CRACK RESISTANCE

EBM

LOW GLOSS

EBM

PART VOLUME TOO HIGH

EBM

PART VOLUME TOO LOW

EBM

POOR PART SURFACE

EBM

POOR WELD OR PINCH-OFF

EBM

STREAKING OR DIE LINES

EBM

THIN PARTING LINE

EBM

UNMELTED PELLETS IN PART

EBM

WEBBING

EBM

Injection Blow Molding (IBM)

(18)

BOTTOM PUSH-UP DEPTH

IBM

DIMENSIONS "h", "s", "t" and "e"

IBM

HEAVY CENTER

IBM

NECK PROBLEMS COCKED NECKS

IBM

DISTORTED SHOULDERDISTORTED SHOULDER

IBM

IMCOMPLETE THREADS

IBM

NECK FOLDS & SHOULDER CUTS

IBM

NOZZLE FREEZE OFF

IBM

PARISON FLASHING

IBM

SHORT SHOTS

IBM

POLYMER STICKING

IBM

SURFACE DEFECTS

IBM

PITTED OR NICKED SURFACE

IBM

POOR GATES ('FISH EYES', FLASH, TAILS)

IBM

POOR TEXTURE OR ENGRAVING REPRODUCTION

IBM

STREAKS & FLOW LINES

IBM

SUNKEN AREA OR DIVOTS

IBM

WARPAGE

IBM

Injection Stretch Blow Molding (ISBM)

(10)

HORIZONTAL BANDS

ISBM

LONG GATES

ISBM

KNIT LINES ON PRE-FORM

ISBM

MATERIAL IN BOTTOM - TOO MUCH

ISBM

MISMATCHED PARTING LINE

ISBM

PRE-FORM DROOLING

ISBM

VERTICAL BANDS

ISBM

DIMENSIONAL PROBLEMS DEFORMED NECKS

ISBM

FOLDS IN NECK

ISBM

UNDERSIZED PARTS

ISBM

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