SOLUTIONS: 1) Use a quality thread with consistent frictional characteristics; 2) Properly balance the stitch so that the needle and bobbin threads meet in the middle of the seam. Always start by checking the bobbin thread tension to make sure it is set correctly, so that the minimum thread tension is required to get a balanced stitch.

Poor Stitch Balance - Too Loose

Proper Stitch Balance

SOLUTIONS: 1) Use a quality thread with consistent frictional characteristics; 2) Properly balance the stitch so that when the looper thread is unraveled, the needle loop lays over half way to the next needle loop on the underside of the seam.

Stitch Too Loose

Proper Stitch Balance


Proper Stitch Balance

DESCRIPTION: Where the needle loop is not pulled up to the underside of the seam and the "purl" is not on the edge of the seam.

SOLUTIONS: 1) Use a quality thread with consistent frictional characteristics; 2) Properly balance the stitch so that when the looper thread is unraveled, the needle loop lays over half way to the next needle loop on the underside of the seam.

DESCRIPTION: Where needle holes appear along the stitchline that will eventually turn into a "run". Generally caused by the needle damaging the fabric as it is penetrating the seam.

MINIMIZING NEEDLE CUTTING ON KNITS: 1) Make sure the proper thread size and needle type and size are being used for the fabric (See Reducing Needle Cutting.); 2) Make sure the fabric has been properly stored to prevent drying out and has been finished properly; 3) Check with your fabric manufacturer.

DESCRIPTION: Where the stitch line is still intact but the yarns in the fabric have ruptured.

MINIMIZING SEAM FAILURES - FABRIC: 1) Reinforce stress points with Bartacks. Make sure the bartacks are the proper length and width for the application; 2) Check to make sure the patterns have been designed for proper fit; 3) Make sure the ideal seam construction is being used; 4) Contact your fabric supplier.

Open Seam Failure - Fabric

Bartacks Used to Reinforce Fly Seam

DESCRIPTION:  Where the threads in the seam have ruptured leaving a hole in the stitchline. Caused by 1) Improper stitch for application; 2) Inadequate thread strength for seam; 3) Not enough stitches per inch.

MINIMIZING SEAM FAILURES - STITCH: 1) Use a better quality sewing thread. This may include going to a higher performance thread designed to give greater seam performance.  (See the Thread Selection Guide.); 2) Use the proper size thread for the application; 3) For knit fabrics, check for "Stitch Cracking". Stitch Cracking can be caused by any of the following: not enough stitches per inch; improper seam width or needle spacing for application; improper stitch balance; and improper thread selection.

DESCRIPTION: Where the seam does not lay flat after stitching.

SOLUTIONS: 1) If sewing machines are equipped with differential feed, set them properly for the fabric; 2) Use minimum presser foot pressure during sewing; and 3) Observe operator for correct handling techniques. Too much stretching of the fabric by the sewing operator will cause this problem. (See Sewing Stretch Knits.)

Stretch Denim - Wavy Seams

DESCRIPTION: Where the seam does not lay flat and smooth along the stitchline. Caused by one of the following:

1) Feed Puckering - where the plies of fabric in the seam are not being aligned properly during sewing; 2) Tension Puckering - where the thread has been stretched and sewn into the seam. The thread then causes the seam to draw back and pucker; 3) Yarn Displacement or structural jamming - caused by sewing seams with too large of thread that causes the yarns in the seam to be displaced, giving a puckered appearance.

MINIMIZING EXCESSIVE SEAM PUCKERING: 1) Use the correct thread type and size for the fabric. In many cases, a smaller, higher tenacity thread is required to minimize seam puckering but maintain seam strength (See the Thread Selection Guide or Minimizing Seam Puckering); 2) Sew with minimum sewing tension to get a balanced stitch; 3) Make sure machines are set up properly for the fabric being sewn; 4) Check for proper operator handling techniques.

DESCRIPTION: Where the yarns in the fabric pull out of the seam from the edge. This often occurs on fabrics constructed of continuous filament yarns that are very smooth and have a slick surface. Also caused by loosely constructed fabrics.

MINIMIZING SEAM FAILURES - SEAM SLIPPAGE: 1) Consider changing the seam construction to a French seam construction; 2) Increase the seam width or width of bite; 3) Optimize the stitches per inch; 4) Contact your fabric supplier.