In the previous tip (# 171) you read why the eDART™ needs to know the correct fill volume. Tip #53 shows specific examples of what can happen if it is not set. But I neglected to explain HOW to set it. Mea culpa. So here goes.
Two initial notes: Always verify the fill volume is correct after you have set it‡. And re-set it if you change the machine position settings.
Cycle Graph: “Set Fill Volume at Cursor” (for “short”… ?!)
The most visual and precise way to set fill volume is using the cycle graph cursor.
Place the cursor as close as you can to the point where the machine slows down to pack†. Usually this is the injection pressure peak. But not always (see tip # 53 or ‡ below). You may want to zoom in to see the detail (right mouse & drag). Then…
Using a Fill Only Part (no graph manipulation required)
You can make a fill-only part (pack and hold turned off) and mark that as the fill volume. When the correct fill-only part comes out of the machine, proceed as follows:
1. On the tool bar, press: . Then…
Entering the Value Directly
In the rare case where you actually know the fill volume (perhaps from simulation) you can simply type it into the box on the Sequence Settings “Fill” tab (# 4. above).
If you do nothing at all on a new process the eDART will try to set the fill volume automatically for you. It does this by watching for the first dramatic slow-down in injection speed. After 10 similar shots it assumes that the slow-down point is the fill volume and it sets it as you would by typing it in. If you wish to re-start the automatic fill setting process, click the button. After 10 stable shots the button will pop up and the new volume will appear.
‡Verify the Fill is Correct
After setting the fill volume, always wait a cycle and check the “Machine Sequence / Fill” trace at the bottom of the graph. It should go low (off) when the machine slows to pack†. If it does not then you will need to set it again. The graph below shows a correct setting.
†“Machine Slows to Pack” will be velocity to pressure transfer in decoupled 2 and fill speed to pack speed transition in decoupled 3. As far as the plastic knows it is the slow-down to pack, whether by pressure or speed.