PET Injection Molding on a Haitian 1600

Hi just wondering if anyone else does injection molding on a Haitian 1600 and could give some advise, I need to no the procedure you would use if you are making a white 45lt Laundry tub.
The company I work for has done this for years but overtime people have forgotten the procedure as it doesn't run that much anymore any help would be appreciated.
We currently use PET and PET master batch at 4% dry that for at least 8hrs in a drier have barrel temps and mold heats up high with injection fast screw back speed slow and back pressure up really high, we get lots of burns black specs and under packing.
Maybe if someone could point me in the direction of a trouble shooting sheet or information would help lots too
Thanks in advance
Warren Hinds

Just a quick update
We have ran this machine for the past 2 weeks touch and go, we've had about 500 rejects to about 2000 good parts.The machine it self has blown 4 hoses, 2 being the same one 24 hours apart from each other, I believe that the company who supplied the hose didn't crimp it probably. We have also had the mold heats stop working at 100%, they usually are up at 350oC but could only run them up at 290 - 310oC, which caused a lot of shorts which can be expected. Other then that we had a pretty good run with it this time around, as we usually have 2000 rejects and 500 good parts.
The mold should be coming out today and we will be doing 35Lt bowls which are a lot easier to run for some reason, easier start up and easier to maintain.

Thanks
Warren Hinds

just try ...

probable cause from machine is injection (speed/pressure/flow) or back pressure too high. and the melt temperature also can affect for this cause and you can reduce it.

best regards,
hendrich

I also think that it depends on the machine injection speed, flow of the plastic and plastic melting temperature. These things can affect the molding part