Runaway Acti-Feed occurs when the amount of thread the machine feeds keeps increasing until it reaches the Upper Limit. To identify Runaway set the Minimum/Preset to the material thickness, and make sure the Maximum is unchecked and watch the Acti-Feed graph while the machine sews. The Upper Limit (typically around 80) can depend on software version. A related issue is Flatline Acti-Feed.
If you are encountering Runaway Acti-Feed, follow the steps below.
The Red thread had the presser foot too high, however the presser foot being set too low can also cause this issue.
The blue thread had the presser foot too low.
Some fabrics might be thick enough to reach the Upper Limit, so it is recommended to test for Runaway Acti-Feed on a T-shirt-like fabric with 1 layer of cut-away.
1. Check the Bobbin.
2. Check the Presser Foot.
3. Run the Determining Acti-Feed Test.
4. Check the Rotary Hook Support (Retaining Finger).
5. Check the Digitizing. If the Column Width of a satin stitch is too small, it can lead to sew quality issues. The fabric type can exacerbate this issue, for example on stretchy materials.
Example of small satin stitches
6. Check for Loopy Top Thread.
7. Consider if the application needs a Maximum Acti-feed. This might be more common on unusually thick fabrics/applications, for example while sewing 3D foam.
8. If the situation remains unresolved, the Thread Sensor might need to be replaced. You will need additional technical assistance. Here are the available Melco Technical Support options.
9. If the situation remains unresolved, you will need additional technical assistance. Here are the available Melco Technical Support options.
- Verify if the symptom started after the Main-PCB was replaced
- Refresh the Registry
- Refresh the Jobs And Machines Folders