I M THANKFUL TO ALL WHO HELPED ME TO SOLVE BLACK LINE PROBLEM BY REDUCING BARREL LAST TWO ZONE TEMPS BY 25~30* I WANT U R EXPERT OPINIONS ON MY LOGIC FOR THE CULPRIT. PLZ!! SHARE U R VIEWS !! AS THE BOTTLE WAS HEAVY WALL >1mm NEEDED BLOW TIME LONGER THAN 10 s. SO INJECTION DELAY TIME WAS MAX. TO COMPENSATE RESIDENCE TIME OF PREFORM IN INJ. MOLD. THIS WAS ADDING TEMP. FOR LONGER TIME TO THE FEED ZONE MATERIAL TO REACH TO METERING ZONE TILL IT GETS INJECTED.

AND THIS WAS THE CAUSE OF COLOR MASTER BATCH GETTING DEGRADED GIVING BLACK LINE IN THE SHORTEST RUNNER PATH i.e. THE FIRST ENTERED MATERIAL IN NEXT SHOT

Sanjay, It's great that you took the time to report on the outcome, as well as comment throughout the discussion. This proves to me that when this happens, people asking the questions get solutions and contributors are encouraged to keep contributing. Well done!

Thanx John. John i iwsh some one should come forward to create a group for troubleshooting and solutions for inj. blow molding , inj. molding & blow molding industry!!
This will by all means provide a wide!! useful knowledge to the members as well visitors & followers!!

Interesting. Usually there is always some material in the barrel - the next few shots so it couldn't be from just sitting there, it would have to have been a combination of pressure, screw speed, barrel temp, etc.? Unless it was sitting for a long time.

My dear friend!! I will like to draw u r kind attention!! To the basic
diff. Of inj. Blow molding with horizntal plastifier!!

In this case!! Screw always returns back to its home position back!! I.e.
Always screw remains at the end position (home position) so the Temp of
hopper throat zone as well its preceding zone!! Which mainly covers a feed
zone!! Has the Most effect on the Melt!! And this is the culprit only!!

So only by changing Temp of these last Two zones could solve the problem!!
Rest all parameters e.g. Inj. P/F, screw speed etc. Remained same!!

In case of any further clarification!! We can surely!! Discuss more!! If,
require any.

Ahh... that may explain my confusion. I didn't realize it was blow molding.

I m sorry!! For u r oversight!! In fact Right from the first discussion!!
I hv surely mentioned about Injection Blow Molding!!

Any how!! Thanx for ur participation!!

Will u like to be a part of New Trouble shooting group for inj blow
molding, inj. Molding & blow molding?? If, we create a new group??

You probably have, and I probably overlooked it. My blow molding experience is none.

Sure I would love to be a part of the group.