Understanding the Sewing Process I Embroidery Project

The upper thread starts at the thread cones located on top of the machine. The thread follows a specific path through tensioners and guides down to the take-up lever, then continues through additional guides until it reaches the sewing needle. The sewing needle carries the upper thread down through the needle plate into the bobbin hook area.

The bobbin is stored inside of a bobbin case which is installed into the bobbin hook. The bobbin hook rotates around the bobbin and guides the bobbin thread to a point where it can mate with the upper thread.

The sewing sequence is as follows. The needle and the presser foot descend together. The presser foot reaches the fabric being sewn first and presses if firmly against the needle plate to hold it steady when it’s penetrated by the needle. The needle comes down through the presser foot, through the fabric, through the needle plate and then down to its lowest point in the cycle. Upon reaching this point, the take-up lever continues moving downward, causing the tension on the upper thread to relax. This allows a small loop of thread to form behind the needle. The point of the bobbin hook rotates behind the needle and catches this small loop. The bobbin hook pulls the upper thread down and wraps it around the bobbin thread as it rotates through one revolution. The needle begins to rise up and pulls the bobbin thread and upper thread tightly together and a stitch is formed.

The needle then rises back up to its highest point, along with the presser foot and the process is repeated.

NOTE: The Bobbin hook rotates twice for each needle penetration.