Bernette b68 AIRLOCK - 2-Thread Flatlock Narrow (RN); 2-Thread Rolled Hem; 2-Thread Overlock Wide (LN)

Sewing Test
83
2022-05 EN 50400685.00A.04
2-Thread Flatlock Narrow (RN)
Stitch Formation Measures
Lower looper thread (red) extends
over the fabric edge to the bottom.
> Increase LL-thread tension (red).
> Reduce RN-thread tension (green).
Needle thread (green) doesn't reach
the fabric edge.
> Reduce RN-thread tension (green).
> Increase LL-thread tension (red).
Lower looper thread (red) doesn't
reach the fabric edge.
> Reduce LL-thread tension (red).
> Increase RN-thread tension (green).
Needle thread (green) extends over
the fabric edge to the top.
> Reduce LL-thread tension (red).
> Increase RN-thread tension (green).
The fabric edge forms a tunnel or
curls.
> Increase the mtc micro thread control.
> Reduce the cutting width CW.
> Reduce the stitch length SL.
> Check the rolled hem selection N/R position.
2-Thread Rolled Hem
Stitch Formation Measures
Looper thread (red) wraps fabric
edge too loosely.
> Increase LL-thread tension (red).
> Increase the cutting width CW.
Looper thread (red) wraps fabric
edge too tightly.
> Reduce LL-thread tension (red).
> Reduce the cutting width CW.
> Check the rolled hem selection N/R position.
The fabric edge doesn't curl as
intended.
> Increase the cutting width CW.
> Reduce the stitch length SL.
> Increase LL-thread tension (red).
> Check the rolled hem selection N/R position.
Needle thread (green) forms loops
on bottom side of the fabric.
> Increase RN-thread tension (green).
The seam puckers.
> Set the differential feed between 1 and 0.6 (stretching).
> Reduce RN-thread tension (green).
> Reduce the stitch length SL.
2-Thread Overlock Wide (LN)
Stitch Formation Measures
Lower looper thread (red) extends
over the fabric edge to the bottom.
> Increase LL-thread tension (red).
> Reduce LN-thread tension (yellow).