T-shirts are made of a light fabric and have an extreme elasticity, this makes them problematic to embroidery. They can often pucker and embroidery designs can distort.
There are a variety of methods that can be used to accommodate these problems.

Digitizing
Firstly a suitable design should be chosen. If the embroidery design is detailed and involves a lot of stitches it will cause the embroidery to be hard and uncomfortable to wear. It will also make holes in the T-shirt and cause the lightweight fabric to stretch.
It is a good idea to increase the pull compensation especially when two different coloured columns meet. A embroidery design with no pull compensation will look good on the screen but will distort and leave gaps in the design once embroidered.
If you open up the density, especially on fill areas then the embroidery design is less likely to pucker. If puckering becomes too much of a problem then use an appliqué for large areas.

 

Underlay
Underlay is very important when using a fabric with stretch. Using the correct underlay will prevent the design from shifting. It is best to avoid using long stitches which will pull the fabric inwards and distort the design.

 

Backing
Backing also stabilises the embroidery and stops the fabric moving or stretching in the frame. The backing should match the weight of the fabric.
It is best to use a cutaway backing for a knit fabric, cutting as close to the embroidery design as possible. The more backing left on the more likely it is to pull when washed.

 

Topping
Topping is used on the top of the fabric to hold down the weave of the fabric. The main benefit of using a topping on a knit fabric is that it prevents the stitches from sinking into the fabric.

 

Framing
To reduce the chances of the design distorting you should use the smallest frame possible. The larger the frame the more the fabric will stretch and distort during embroidering.
The fabric should be secure so that the embroidery design won’t shift, it is a good idea to frame the backing with the T-shirt.

 

Stitching
Use a 75/11 needle and sew at a slower speed for more control.