The bobbin case is not installed correctly. Put the notched part upwards, put it into the slot and turn it by hand to see if the needle is in this neutral position. In addition, when the bobbin is installed, the bobbin thread inside the bobbin is pulled out longer, so that the general bobbin thread is handled well Can hook up.
It is also necessary to determine whether the model has the function of free bobbin thread. If there is, the bottom line is also installed normally, it is a jumper. Quickly change the needle of the corresponding material. If this function is not available, reinstall the lower thread, manually guide the lower thread to the top of the needle plate before starting the needle, keep the upper thread and the bottom thread above the needle plate before starting sewing. Of course, you still have to use a needle that corresponds to the fabric, otherwise the effect will not be good.
