Concetti Chiave
- Equal tension in upper and lower threads is crucial for perfect stitching, preventing loops and fabric wrinkles.
- Skipped stitches can result from a bent or blunt needle, incorrect needle length, or unsuitable needle size.
- Fabric puckering may occur due to a blunt needle or overly tight tension settings.
- Machine needles can break from improper needle settings, pulling fabric incorrectly, or sewing over pins and thick layers.
- Thread breakage issues often arise from mismatched bobbin and upper threads, tight tension, poor quality threads, or incorrect machine threading.
1. Regulating the thread tension: For perfect stitching the tension of the upper and lower threads should be equal. The needle and bobbin threads will be locked at the centre of the thickness of the fabric.
Imperfect stitching occurs when one tension ( needle or bobbin) is stronger than the other as follows:
- when the upper tension is too tight, loops appear on the upper surface of the work.
- when the lower tension is too tight, loops appear in the lower surface is the work.
- when both threads are too loose, floating stitches are the result.
- when upper and lower threads are too tight, the fabric will become wrinkled.
To regulate the tension
- when the upper thread is too tight, loosen the tension disc.
- when the upper thread is too loose, tighten the tension disc.
- when the under thread is too tight, lift out the bobbin case and loosen the screw if the tension spring leaf outside the bobbin case with screw driver.
- if under thread is too loose tighten the screw driver of the bobbin case.
2. Skipped stitches: This may be caused by:
- a bent or blunt needle.
- a needle of incorrect length.
- an improperly set needle.
- a needle not suitable to size of thread.
3. Puckers in fabric: This may be caused by:
- a blunt needle.
- a very right tension.
4. Breaking of machine needle: This may be caused by:
- improper setting of needle.
- pulling fabric without raising needle.
- sewing over a pin on fabric.
- sewing over many layers of fabric.
5. Constant breaking of thread: This may be caused by:
- bobbin thread different from the upper thread.
- tension of the thread too tight.
- use of poor quality thread.
- incorrect threading of machine.
- uneven winding of the bobbin.
- bobbin thread too full.
Domande da interrogazione
- ¿Cómo se puede lograr una costura perfecta regulando la tensión del hilo?
- ¿Cuáles son las causas comunes de las puntadas saltadas?
- ¿Qué factores pueden provocar el rompimiento constante del hilo de la máquina?
Para una costura perfecta, la tensión de los hilos superior e inferior debe ser igual, de modo que se bloqueen en el centro del grosor de la tela. Ajustar la tensión del disco o el tornillo del estuche de la bobina puede ayudar a equilibrar la tensión.
Las puntadas saltadas pueden ser causadas por una aguja doblada o desafilada, una aguja de longitud incorrecta, una aguja mal colocada o una aguja no adecuada para el tamaño del hilo.
El rompimiento constante del hilo puede deberse a que el hilo de la bobina es diferente al hilo superior, la tensión del hilo es demasiado apretada, el uso de hilo de mala calidad, un enhebrado incorrecto de la máquina, un bobinado desigual de la bobina o una bobina demasiado llena.
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