June 15, 2022

Cracked Ring: Excessive barrel wear in the metering area. Unmelted plastic in the valve can cause a situation where the ring will not seat against the rear seat. This is usually due to a poor start up or shut down.

Broken Stud: This is usually due to a poor start up or shut down procedures. Failure to make sure barrel is up to operating temperature at start up or failure to properly purge barrel and screw at shut down.

Slow Recovery: Excessive back pressure is the most common cause. However, if there is excessive wear between the front seat and ring it can impede the movement of plasticized material and screw recovery can be drastically affected.

Failure To Hold Cushion: Excessive wear on the seating areas can allow material to pass back over the valve or ball check.

Poor Quality Consistency: Excessive wear on the seating areas can allow material to pass back over the valve or ball check.

D-2 Tool Steel
Heat treated to Rc 58-60, D-2 is a relatively inexpensive, high carbon-high chromium steel with proven, uniform wear resistance surpassing most other steels.

H-13 Nitrided
Tool steel with good strength that is thru-hardened and ground dimensionally then nitrided for 72 hours.
A tough material good for general applications.

CPM9V
Highly wear resistant tool steel with a high percentage of vanadium carbide. Excellent for abrasive applications.

CPM420V
Ideal for highly corrosive applications. 420V also has significant wear resistant characteristics.

NOTE: If your screw is turning during injection, it’s a good indication that your non return valve is leaking.