JOMAR PRODUCT TROUBLESHOOTING

1. Flash in Bottom and Neck

Reason:a. Foreign material inside core rod bearing

area in neck ring(s) or on mold surface, or on core rod.

b. Melt temperature too high.c. Preform mold temperature(s) too high.

(Water temperature control unit)d. Injection pressure too high.e. Holding pressure too high.f. Damaged mold.g. Nozzles not seated properly or are

damaged, mold nozzle seats damaged.h. High pressure preform time too long.i. Mold and/or hose passages plugged.

2. Short shots in preform molds will show as short necks or half filled preforms.

Reason:a. Loss of heat in one or more zones in the

preform mold. (Water temperature control unit)

b. Loss of heat in one or more zones in the extruder or manifold.

c. Loss of injection pressure, or injection pressure too low.

d. Loss of holding pressure.e. Loss of screw RPM.f. Foreign material blocking the nozzle

orifice(s).g. Nozzle “Frozen off” from low

temperature in base or manifold being too cold.

h. Nozzle orifices too small.i. Hopper out of material.j. Not enough low pressure preform time.k. Partially melted material blocking throat

in hopper.

3. Unblown Bottom

Reason:a. Check and Clean Foreign particle on

the BOTTOM BUSH of Blow mold cavity

b. Check and Oil Lubricate below the moving part of the bottom bush

4. Plastic sticking to preform molds will show as “pulls” or “stringing” of the plastic as the molds open. Common causes of plastic sticking to the core rods are:

Reason:a. Melt temperature too highb. Preform mold temperature(s) too high.c. Packing or holding pressure too low or

too high.d. Core rods too hot (use internal cooling).e. Core rod tip too hot (use external

cooling).f. Insufficient lubricant in material.g. Split time or cure time too short

5. Rocker bottoms show up as bulges in the bottom of the bottle or as “warped” bottomsin ovals. The bottoms are usually still hot and soft in either case.

Reason:a. Not enough exhaust time.b. Poor blow mold venting.c. Insufficient cooling of blow mold bottom.d. Melt temperature too hot.e. Cycle too fast for mold or bottle.

6. Wall Thickness Variation

Reason:a. Increase melt temperatureb. Increase/decrease CURE TIMEc. Increase/decrease BLOW DELAYd. Check and clean core rod blow air valve;

all gaps must be the samee. Raise “BODY” temperature in MTCf. Check and clean MTC water linesg. Check MTC operationh. Check core rod alignmenti. Change Core Rod

7. B lack Spots

Reason:a. Foreign particles in raw material or

Masterbatchb. Purging through the entire systemc. Making sure the nozzle split is cleand. Making sure the nozzle contact area at

the manifold back is cleane. Making sure the machine nozzle is

aligned with the manifold radiusf. Cleaning and re-seating all nozzle tipsg. Cleaning the manifold faceh. Burnt Material in Manifold, open end

plugs and purge

8. Bottom Weak

Reason;a. Lower gate MTC temperature – parison

moldb. Move external cooling point on tip of core

rodc. Move nozzle outd. Increase LOW PREFORM Timee. Change Nozzlef. Check MTC operationg. Decrease DECOMPRESS time

9. Shifting of Parting line

JOMAR PRODUCT TROUBLESHOOTING

Reason:a. Decrease Melt temperatureb. Requires better balance of MTC linesc. Pack parison temperatured. Cool the core rod temperaturee. Check for proper MTC operation

NOTE

As a rule of thumb, thin or thick areas in the bottle wall are where the preform has not been

conditioned correctly.

Clean and polish mold surfaces and check flow of the correct temperature water through ALL

lines in the preform mold.