Problem

Common Causes

Solution / Approach

Ejectors won't retract

dry tool lacking grease, broken ejector pin, water off,broken spring, galling

Inspect mold for above problems, check water set up, pull mold in halves when applicable

Slide sticking; mold with slides won't lock up

galled slide surface,burrs, dry slide surface, tool overheating

inspect tool for above conditions, review water set up, pull mold in halves if applicable

Sink/pin push

galled surface, tool overheating, cure time too low, Mold open speeds and pressures too high

check for above conditions, and review velocities for slow filling over these areas

stringing

tip too large for bushing, hot runner drop temps too high, low decompressure after rotation setup (position)>

Install smaller tip, lower drop heats, increase decompression after (position), add screw delay time to compensate for long cure time (screw should recover
prior to cure time setpoint)

Parting line flash

Drop hold/ pack to 0; assess part in shortshot state and see if flash still exists

flash on shortshot condition reflects tool problem..blue parting line and inspect for proper seal off

Tool binds during ejection

too few knockouts, galling, broken ejector pin, improper grease, poor water setup

pyrometer tool heat schematic, inspect for above conditions, pull mold in halves if
unable to retract to zero position

stress/cracking

Galled surfaces, overpacking, slow fill, poor cure time, poor watering

Lower pressure, faster fill in affected area,inspect for tooling issue,longer cure, inspect for tooling issues
listed above

drag marks

broken spring, galled surfaces,overpacking, early mold open, too much on ejection speed/ pressure
fast open break, parting line burr, poor watering

inspect for above conditions and respond per the situation

color swirls

tool related: hot runner temps too high/low, velocity too high for tooling(sheer burn)
application, tip not matched to bushing, cracked check ring, heater band/ thermocouple failure

check melt temp, inspect for above failures/issues

pin push marks

lower ejection pressure, slower ejection speed, more cure time, faster fill

flow lines

tool related: hot runner temps too high/low, velocity too high for tooling(sheer burn)
application, tip not matched to bushing, cracked check ring, heater band/ thermocouple failure

higher/lower cut-off, faster/slower velocities, higher/lower temperatures(barrel/mold)
inspect heater bands/thermocouples (hot runner),inspect for improper setups listed above

burns

tool related: hot runner temps too high/low, velocity too high for tooling(sheer burn)
application, tip not matched to bushing, cracked check ring, heater band/ thermocouple failure

slower fill affected area,lower barrel temp, higher mold temp,check water flow

cold slug

increase decompression after position, increase/decrease drop temp, slower beginning velocities, confirm tip size