Tip of the Day 142: 1st Stage + 2nd Stage = Injection Forward

Tip # 137 explained how to correctly name “First Stage” instead of Injection Forward because Injection Forward, in eDART land, is supposed to go off at the end of hold. Naming First Stage correctly lets the eDART create Machine Sequence / Injection Forward from the start of first stage until the fall of injection pressure. However this is not very reliable when you are making fill-only parts or have other variations in hold pressure.

Some machines (e.g. the Arburg and Sumitomo in our lab) have a second digital output that is on during hold or “Second Stage” pressure. If there is no complete Injection Forward signal from the machine then the eDART can use the Seq. Module Input / First Stage and Seq. Module Input / Second Stage signals to create its internal Machine Sequence / Injection Forward. This is more reliable than letting the eDART search for the fall of injection pressure. Furthermore it is “real time” because the eDART sequence engine does not need to look backwards from screw run to find the fall of pressure after it happened.

Here is the graphical depiction showing how the setup in Sensor Locations appears on the Cycle Graph: