Differential Feed - ELNA 683 Gebrauchsanweisung

Differential Feed

Differential feed on an overlock is a two-part
feed dog which feeds in the fabric at different
ratios. The front part of the feed dog pushes
more or less fabric under the foot than the rear
part of the feed dog is feeding out. There are
two kinds of differential feed: negative and
positive.
Standard Feeding
1
The front and rear feed dogs feed the
fabric in and out at the same ratio when
DF is set at 1.
2 Positive Feeding
Set DF higher than 1 when sewing fabrics
which have a tendency to stretch and create
waves (knits, for example). The looser and
stretchier the fabric, the more the front part
of the feed dog must feed in and the less the
rear part of the feed dog must feed out.
Waves are eliminated.
Positive feeding may also be used for
gathering or ruffling light to medium weight
woven fabrics. See Gathering 4 on page 14.
Negative Feeding
3
Set DF lower than 1 when sewing sheer
fabrics which tend to pucker. The front part
of the feed dog feeds in less fabric than the
rear part feeds out. The fabric is held taut by
the feed dogs. Puckering is eliminated.
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