In sewing, puckers occur when the material along the seam starts to look bunched and rippled. It can completely destroy the look of the garment and happens most frequently when sewing fine fabrics like silk, satin or tulle. Fortunately, puckered seams can easily be avoided by keeping a few helpful hints in mind whenever you sew.
Pin together all fabric pieces evenly. Place pins at intervals of approximately 1 inch.
Guide the fabric layers evenly through the sewing machine. Do not push, pull, or tug on the fabric.
Set your machine stitch length so it is appropriate to the fabric. A stitch that's too short or too long will cause the fabric to pull or pucker. You'll find a stitch-length guide in your sewing machine manual.
Handle thin or single layers of fabric with extreme care. Some very thin fabrics will pucker if the stitch length is too long.
Stitch using the appropriate needle for the fabric and make sure that the needle is not damaged in any way. A needle that is the incorrect size may cause your fabric to pucker, as will a nicked or worn needle.
Exert the appropriate amount of pressure on the fabric with the presser foot. Most machines regulate this automatically; however, some older machines require you to make this adjustment manually.
Check the machine's tension. A too-tight tension device may cause puckers, especially with a zigzag stitch. Your machine's tension device may also be out of balance.
Wind your bobbin evenly.
Have your machine serviced professionally on a regular basis. This should eliminate any balance problems with the tension- or pressure-regulation devices on your machine.
Experiment with stitch length and tension on a sample piece or pieces of fabric.
Check the sewing machine needle package for a guide to which needles are appropriate for which fabrics.