JUKI LH-4128-7, Руководство инженера

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2. Loose stitches are produced Same as the aforementioned causes given in the “Thread breaking”. Other causes are described below in addition to them.
2-1) Bobbin fails to move smoothly. Replace the bobbin with a new one.
2-2) The clearance provided between Adjust the clearance provided between the hook and the
the hook and the bobbin case bobbin case opener to 0.2mm.
opener is too large.
2-3) The feed dog is positioned too high. Adjust the height of the feed dog to 1mm.
2-4) The thread path is poorly finished. Buff it up.
2-5) The clearance provided between Adjust the clearance provided between the bobbin case
the bobbin case and the throat and the throat plate to 0.9mm.
plate is not properly adjusted.
3. Puckering frequently occurs. 3-1) The needle thread tension is too Minimize the needle thread tension as long as stitches are
high. neatly finished.
3-2) The bobbin thread tension is Minimize the bobbin thread tension as long as stitches are
too high. neatly finished.
3-3) The tension of thread take-up Minimize the thread take-up spring tension as long as
spring is too high. stitches are neatly finished.
3-4) Operating range of the thread Minimize the operating range of the thread take-up spring as
take-up spring too large. long as stitches are neatly finished.
3-5) Presser foot pressure is too low. Increase the presser foot pressure.
3-6) Sewing speed is too high. Reduce the sewing sped.
(The number of revolutions of the
motor is too large.)
Trouble Case (1) Case (2) Check and Corrective measures