How to Avoid Sewing Defects

Avoiding stitching defects is one of the most basic aspects to consider when making clothing. This might happen due to the following factors:

  • the fabric quality
  • type of thread
  • the conditions of the needle 
  • the maintenance of the sewing machine
  • the stitch density

These circumstances, or a combination of them, can create different types of stitch defects. Let’s see what kind of problems they cause and how to avoid them.

Seam Puckering

Seam puckering can occur at the time of sewing or after washing it. It consists of a fabric gathering right on the stitch. It happens more often in woven fabrics, rather than knits. And mainly on heavy-weight fabrics.

The seam Puckering can be due to:

  • fabric slippage
  • the tension of the thread is too tight
  • retention produced by the sewing machine

Fabric slippage

The fabric slides under the stitching when sewing. This occurs when the fabric structure is too tight, so the needle can’t pass through. This mainly happens when the stitch goes either in the same direction as the weft, or to the bias.

To know if the stitching retention is due to the type of fabric, after sewing, cut the thread stitch. If the fabric is still gathered, then you know the stitching retention occurs due to the type of fabric.

How to prevent fabric slippage:

  • use a thinner thread
  • use a thread with greater tenacity
  • use a smaller needle size.
  • try a sharp, long-pointed needle, so it reduces the resistance
  • use a needle plate with a smaller hole
  • reduce the number of stitches per centimeter

High thread tension

If the tension of the thread is too high, the stitch pulls the fabric and it creates puckers. You will see this either as soon as it comes out of the presser foot, or after washing it.
To identify if this is the problem, cut a stitching. If the fabric goes flat and stops shirring, then you know the thread tension was too tight.

How to adjust the tension of the thread:

  • lower the thread tension. Start by lowering the tension of the bobbin, or the tension of the anchor, maintaining the tension of the thread. If it is not enough, lower the tension of the thread maintaining a balanced stitch and a firm stitching
  • use a thread with low elongation capacity to minimize stretchiness
  • use a thread with better lubrication to improve the stitch elongation
  • use a thinner thread to help the penetration into the fabric and reduce the tension of the machine
  • if possible, use a thicker needle. Or use a needle with a round tip to make a larger hole, so it will lower the tension
  • keep the machine clean and free of dust to avoid friction of the thread

 

Retention produced by the sewing machine

The seam is retained by the sewing machine when the stitching is made by an unbalanced feed dog dragging. This means that the top and bottom tension of the feed dog creates an uneven movement of the layers.
It usually happens when the press foot pressure is different from the feed dog or when the operator retains the fabric.
This problem can be identified when, after cutting a stitch, there is a displacement of the fabric.

How to solve this:

  • lower the pressure of the presser foot as much as possible
  • adjust the feed drop according to the thickness and characteristics of the fabric
  • use a type of feed dog according to the type of fabric. For lightweight fabrics, use a feed dog with a density of 20-24 teeth per inch. For heavyweight fabrics, lower the density to 8-12 teeth
  • adjust the plate to the needle size. Use a small hole plate for thin needles. As a general rule, the hole of the plate should be approximately twice larger than the needle size
  • help the sliding of some fabrics by using a Teflon foot
  • improve the feeding system by using a differential feed
  • improve the fabric manipulation when sewing
  • when using fabrics with different stretchiness, place the layer that stretches the most facing the feed dog

Stitch Slippage

The stitch slippage is made by a mismatch at the stitch loop. When the loop is finished, it slides towards the upper or lower side of the seam, so that the edges of the seam are separate when pulling and releasing.
The circumstances that produce this problem can be:

  • an unbalanced stitch tension
  • the stitch length is too long

Due to excess tension in the bobbin case.
If the lower tension is too high the loop stitch moves towards the lower layer of the fabric.

Due to excess tension in the needle.
If the upper tension is too high the loop stitch moves towards the upper layer of the fabric.

How to solve it.
Adjust the tension of the bobbin or thread until a regular stitch is obtained. The knot must be is centered.

Thread Breakage

The thread break occurs during the sewing process. The needle or bobbin thread breaks when the stitch is completed.
The causes can vary from:

  • poor thread quality
  • the thread thickness is not matched with the needle size: the thread is too thin
  • the thread tension too high
  • the stitch density too low
  • the needle is wrongly placed
  • a mismatch or poor lubrication in the bobbin mechanism
  • an overheating of the needle
  • a poorly adjusted sewing machine
  • an inappropriate handling of the operator

To solve this problem, check these points and adjust it accordingly.

Loose Stitches

The loose stitching is caused by a lack of thread in the formation of the stitch.
This happens due to:

  • a poorly adjusted bobbin case or the thread is not properly threaded
  • a low-quality thread
  • deteriorated machine pieces
  • poor tension of the thread
  • the sewing speed is too high
  • the needle type is incorrect or the needle wears away
  • the needle is too thick.
  • the needle is not a ballpoint needle (knit fabrics)
  • an obstruction at the needle eye due to a melting thread or material

To solve this problem, check these points and adjust it accordingly.

Skipped Stitches

The Skipped Stitches are those stitches that the length of the stitch irregular. Most stitches have a regular length but a few of them are longer, usually twice longer than a regular stitch. This can happen due to:

  • a problem when making the loop (bad adjustment or maintenance of the sewing machine)
  • a mismatching between the needle and thread size
  • a defective, poor quality or damaged needle
  • an inappropriate thread size
  • an inadequate twisting of the thread
  • poor needle thread tension
  • the stitch is too long
  • poor press foot tension, or the feed dog dragging is too long
  • the fabric is too heavy (the sewing speed needs to be reduced, and the stitching must be longer)

To solve this problem, check these points and adjust it accordingly.

 

Fabric Perforation

This happens when the needle makes a hole in the fabric. Some causes can be:

  • the type or size of needle is inappropriate for the fabric
  • a poor fabric quality (badly finished or it was burnt with the iron)

To solve this problem, check these points and adjust it accordingly.

Uneven Stitches

The stitch is not set in a straight and regular line. Some stitches remain displaced on the seam line. The uneven stitches can occur when using a poor thread quality.
To solve this problem, you might need to improve the thread quality.

Clogged stitches

It happens when there is a resistance on the fabric slippage along the stitching process, so the stitch length becomes irregular. The reasons could be due to:

  • a bad synchronization of the mechanisms of the feed dog
  • an inadequate presser foot height for the weight of the fabric
  • the presser foot is not appropriated for the material 
  • the type of feed drop is unsuitable for the fabric, either by the type and size of the teeth, or because it requires a supplementary feed dog such as puller feed, and impeller needle
  • the fabrics do not have the same stretching properties. In that case, place the most elastic fabric facing the feed dog
  • an inappropriate handling of the operator (dragging or retaining one of the layers of the fabric)

To solve this problem, check these points and adjust it accordingly.

As we can see, analyzing sewing defects involves several elements that directly affect the result. Knowing and mastering the use of these elements will help you to get the stitch quality that you want.

Olga Fuenmayor

Olga Fuenmayor

Editor at Seampedia.
Fashion Technical Management / Consulting
Model development / Quality control / Production control.

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