How to prevent seam puckering: causes and solutions

Seam puckering is one of the most common processing problems in the sewing industry. Immediately during or shortly after processing, unwanted waves – known as puckering – appear along the seam. These can only be removed temporarily by ironing or pressing and reappear after the next care treatment at the latest.
A basic distinction is made between the following three types of puckering:

Transport puckering
Tension puckering
Displacement puckering

Depending on the structure of the fabric, one or more types of puckering may occur simultaneously. Other causes of puckering can include design features or poor processing parameters.

Smooth fabrics tend to pucker due to transport, dense fabrics tend to pucker due to displacement, and particularly fine, lightweight fabrics often show tension puckering along the seams. Seam puckering is also increased by creative combinations, such as coarse decorative seams on thin materials.

To prevent seam puckering or improve seam appearance, the puckering phenomenon must first be analysed to determine the cause. Depending on the type of puckering, different approaches are needed to improve the situation.

Feed puckering

Feed puckering is a common processing issue that affects seam appearance and overall garment quality. It occurs when one fabric layer is transported differently from the other during sewing. Understanding its characteristic appearance helps to identify the root cause and select the appropriate corrective action.

Puckering is asymmetrical to the seam.
Only one fabric layer shows visible wrinkles.
The opposite fabric layer remains smooth, making feed puckering easy to distinguish from other seam defects.

Uneven transport of the upper and lower fabric layers during sewing. This creates a length difference between the two layers, resulting in visible puckering after the seam is formed.

With a sewing machine, the lower layer of fabric is pushed forward by the feed dog during simple bottom feed. The presser foot presses down on the fabric and creates static friction, which causes the upper layer of fabric to be pulled along. This leads to transport puckering, especially with smooth fabrics. Excessive presser foot pressure intensifies this effect.

Set the presser foot pressure as low as possible (even fabric feed must still be ensured)
Select the feed type appropriate for the application (e.g. needle feed, roller feed, top feed, pinch feed, differential feed)
Select the teeth of the bottom feed according to the top material (e.g. fine teeth for fine materials, coarse teeth for heavy fabrics)

The teeth of the lower feed dog should only protrude approx. 1 mm above the stitch plate during the lifting movement.
Replace worn feed dogs (rounded teeth).

Plastic roller presser foot (gummed, smooth feed surface) for challenging materials

Use Teflon feet
For seam constructions with multiple seams, always maintain the seam direction if possible
Reduce sewing speed
Use a hinged presser foot (only the presser foot must be moved in rhythm with the feed dog, not the entire presser foot system)

Tension puckering

Tension puckering is one of the most common seam appearance defects. It is caused by an imbalance between the forces acting on the sewing threads during stitch formation. Recognising its characteristic appearance helps to identify the underlying cause and choose the appropriate corrective action.

Puckering appears on both sides of the seam.
The fabric relaxes after cutting the stitch bridge
This beahviour distinguishes tension puckering from feed puckering und structural fabric distortion.

Tension puckering is generally caused by two key factors: incorrect thread balance and an unsuitable amount of thread within the stitch. The following sections explain both causes and their respective solutions.

False thread balance is a primary cause of tension puckering, occurring when the needle and bobbin threads are not evenly distributed within the fabric layers. This imbalance creates uneven stress along the seam, leading to visible wrinkles and distortion that compromise both the appearance and structural integrity of the stitched material.

Unfavourable thread balance between needle thread and bobbin thread in double lockstitch

If one of the two threads (needle thread or bobbin thread) is significantly shorter than the other, the stitch formation will not be optimal. Depending on the material, the seam may be compressed and puckering may occur. The amount of thread must be distributed correctly.

Unfavourable thread balance:

To check the thread balance, it is helpful to unpick a section of the seam. If the thread balance is unfavourable, one thread system will be significantly shorter than the other.

Optimal thread balance:

Unfavourable needle and thread balance with the double chain stitch

As soon as one of the thread systems is significantly shortened, the stitch feed is no longer optimal. Depending on the material properties, the seam may become compressed and puckering may occur. The thread quantity must be distributed correctly.

Unfavorable thread balance:

To check the thread balance, it is helpful to unpick a section of the seam. If the needle thread tension is too loose, the needle thread heads are clearly visible on the bottom of the seam. Long loops can be seen after unpicking the seam.

If the needle thread tension is too tight, the needle thread heads disappear into the fabric after unpicking the seam and are no longer visible on the bottom of the seam.

Optimal thread balance:

With optimal thread balance, the needle thread heads are visible as small dots (approx. 1–1.5 mm high) after the seam has been pulled.

Incorrect thread amount refers to an imbalance in the quantity of thread used during stitch formation, resulting in inconsistent and unstable seams. This misbalance can increase stress on the fabric and is a key contributing factor to defects such as tension puckering.

Tightening the thread tension devices too much causes the needle and/or underthread to be too tight in the seam. The total amount of thread is too small in relation to the length of the seam. This causes the fabric to pucker.

General rule of thumb: ‘As little as possible, as much as necessary’. To ensure sufficient thread balance in the seam, the thread tension of the needle and underthreads must be set as low as possible. However, a certain minimum thread tension is necessary for controlled thread guidance. With extremely thin and delicate fabrics, slight waves often cannot be completely avoided.

The following applies to double lockstitch machines:

Wind the bobbin evenly with as little tension as possible.
Set the bobbin tension as low as possible (yo-yo effect).
Adjust the needle thread tension accordingly.
It is advisable to check the thread tension values regularly. Simple and inexpensive spring scales (e.g. www.pesola.com) or specially developed thread tension measuring devices (e.g. www.zugspannungsmesser.de) are suitable for this purpose. The thread tension values determined depend on the type, condition, maintenance and care of the machine.

To get an idea of the optimum amount of thread in the seam, the following formulas can be used to calculate the theoretically sufficient thread requirement per stitch. The results should be regarded as rough guidelines.

* variable, depending on various parameters (e.g. sewing thread ticket, thread tension)

Displacement puckering

Displacement puckering is a seam appearance defect caused by the displacement of fabric yarns rather than by incorrect thread tension or fabric feeding. Recognising its characteristic appearance helps to distinguish it from other types of seam puckering and identify suitable corrective measures.

Puckering appears on both sides of the seam.
The puckering remains visible even after cutting the stitch bridge.
This indicates permanent displacement of the fabric yarns rather than temporary seam compression.

Displacement of individual warp or weft threads by the needle penetration (without sewing thread). The effect is intensified when sewing thread is used.

The extent of the displacement depends on various factors:

Type of weave (plain weave fabrics generally tend to pucker more than satin or twill weave fabrics due to their structure)
Fabric density (the denser the weave, the more prone to puckering)
Stitch density (the more stitches, the stronger the puckering)
Needle and sewing thread ticket (the thicker, the stronger the puckering)
Fabric finish (highly refined fabrics, e.g. easy-care finishes, only allow limited movement of the warp or weft threads)

Displacement puckering usually cannot be completely avoided during processing. Under certain circumstances, the following suggested solutions may reduce the visual impairment to some extent.

Use the finest sewing thread ticket possible, but suitable for the application (the use of core spuns or continuous filaments is more favourable than the use of spuns due to their smaller optical diameter and comparable tensile strength).

Select needles that are as fine as possible for the sewing thread strength (reducing the needle size by Nm 5 can already result in a visible improvement).
Use suitable needle tips and blade types (due to the different behaviour of the fabrics, carry out your own needle tests if necessary).
With the double chain stitch (stitch type 401), fewer warp and weft threads are displaced due to the seam construction (thread looping on the bottom of the fabric).

Balanced stitch length (the fewer stitches, the less displacement; but be careful: pay attention to seam strength!)
Rotation of the seam line by approx. 5° from the grain (slightly diagonal to the warp direction so that the fabric thread displacement is distributed over several warp and weft threads)

Rotate the cut pattern by 90° so that the grain runs in the weft direction (the fabric thread density is usually lower in the weft direction, which means that the seam may be less prone to puckering in this direction).

Other causes of puckering

In addition to the most important types of puckering already explained in detail, other factors can also have a negative effect on the appearance of the seam. A selection of these is listed below.

Uneven feeding and pulling during sewing can lead to unwanted puckering of the seam. Manual processes are subjective and therefore not reproducible. This can be remedied by additional machine equipment, which can be provided by the respective machine manufacturers depending on the machine type and class.

Particular attention should be paid to the coordination between the machine and the material. For example, if the top feed is set too slow or too fast, a puckered seam can easily occur. When piping edges or sewing in zips, it is also quickly apparent if the piping tension has been set too tight. See also the following image.

Some fabrics that are prone to puckering cannot tolerate multiple topstitched seams. This exacerbates the issues of tension and displacement puckering. The only way to achieve a smooth seam appearance is to omit any topstitching. See the photos below.

In the case of non-congruent seam lines, such as the Viennese seam or sleeve insertion seams, pucker-free topstitching is technically not possible. In this case, it makes most sense to avoid topstitching. Where topstitching is still desired, it is recommended to stitch as close as possible to the closing seam, where the excess fabric is still as small as possible.

The same applies to hems on curved cut edges ( curved hems, etc.). One way to achieve pucker-free seams in such cases is to bind the edges with a matching facing.

If seam puckering occurs due to the properties of the outer fabric, such as density, weave, raw material or finish, sewing tests prior to production are strongly recommended. This is the only way to determine whether this material can be processed to achieve the desired look.