Bernette b68 AIRLOCK - 3-Thread Flatlock Wide (LN); 3-Thread Flatlock Narrow (RN)

Sewing Test
79
2022-05 EN 50400685.00A.04
Stitch Formation Measures
The seam puckers.
> Reduce RN-thread tension (green).
> Set the differential feed between 1 and 0.6 (stretching).
> Reduce the stitch length SL.
3-Thread Flatlock Wide (LN)
Stitch Formation Measures
Upper looper thread (blue) extends
over the fabric edge towards the
bottom.
> Reduce LN-thread tension (yellow).
> Increase UL-thread tension (blue).
Upper looper thread (blue) doesn't
reach the fabric edge.
> Reduce UL-thread tension (blue).
> Increase LN-thread tension (yellow).
Lower looper thread (red) not
straight along the fabric edge.
> Increase LL-thread tension (red).
> Reduce LN-thread tension (yellow).
> Reduce UL-thread tension (blue).
The seam puckers. Lower looper
thread (red) too tight.
> Reduce LL-thread tension (red).
Needle thread (yellow) doesn't
reach the fabric edge.
> Reduce LN-thread tension (yellow).
> Increase UL-thread tension (blue).
> Increase LL-thread tension (red).
Needle thread (yellow) extends over
the fabric edge to the top.
> Reduce UL-thread tension (blue).
> Increase LN-thread tension (yellow).
The fabric edge forms a tunnel or
curls.
> Reduce LN-thread tension (yellow).
> Reduce UL-thread tension (blue).
> Increase the mtc micro thread control.
> Reduce the cutting width CW.
> Check the rolled hem selection N/R position.
3-Thread Flatlock Narrow (RN)
Stitch Formation Measures
Upper looper thread (blue) extends
over the fabric edge towards the
bottom.
> Reduce RN-thread tension (green).
> Increase UL-thread tension (blue).
Upper looper thread (blue) doesn't
reach the fabric edge.
> Reduce UL-thread tension (blue).
> Increase RN-thread tension (green).
Lower looper thread (red) not
straight along the fabric edge.
> Increase LL-thread tension (red).
> Reduce RN-thread tension (green).
> Reduce UL-thread tension (blue).