Re: non return valve leaking
This could be the result of simply running the barrel heats too high for the PA6. You don't mention if either of these resins are glass filled. You also didn't mention decompression settings either. The PA job may run very little compared to the PP one.
BTW I know on an Engel the sealing ring can be turned backwards and not seal properly against the seat. So confirm if it's properly assembled. Also when the refurbishment occurred was the screw tip assembly replaced?
Rick
Re: non return valve leaking
Different resins flow differently, like sometimes flash where others don't. So some may show a "bad' NRV,where others don't. LCP can really uncover even micro NRV defects!
KOM
brent
Re: non return valve leaking
Rick,
The PA6 melt temperature was 265 deg C - I measured that. None of the resins are glass filled. I played with decompression for PA6, but it didn't work. The one thing that I didn't check was moisture content. The resin was dried 5 hours in a dehumidifying dryer with dew point set at -40 deg C. When purging I saw the melt to be normal, not watery.
I will confirm the assembly when they take the screw out. I know that the screw tip assembly was refurbished.
Robert
Re: non return valve leaking
Robert,
My maintenance guy showed me a spec sheet for barrel clearance guidelines......for a 2 1/2 " screw, the new part clearance is .007-.010", and max wear clearance is .030".
Hope that helps,
Joel
1 Attachment(s)
Re: non return valve leaking
Go to Reiloy's website. They have a lot of good information about screws and barrels. I have attached a file for spec's on screw and barrel wear.