Seam Puckering, often appearing when sewing synthetic fabrics, is a distortion of yarn fibers and thread along the seam. To avoid or reduce puckering we recommend the following : Use the smallest size of thread and needle possible Use a smaller ball point needle. Use the same type of material in the thread and fabrics. Use minimum pressure on the presser foot. Tension of the needle thread and the bobbin or looper thread should be minimal. Use feed dogs with finer teeth. Reduce the number of stitches.