If you were given the choice of sewing on a denim shirt or a t-shirt, which would you choose? That’s a no-brainer! Most Embroiderers would choose the denim shirt, as it is typically easier to hoop and yields higher embroidery quality. Of course, that is no accident as denim is a very stable fabric, while a t-shirt is a knitted fabric, which generally is “stretchy” and flexible in nature, making it much more difficult to hoop and sew. But knit fabrics are a staple of the Embroidery Industry, so the challenges must be overcome in order to be successful in this business.

The characteristics that make sewing on knits so difficult are the same ones that make the material so popular with consumers. Knits are composed of interlocking looped stitches, which provide a fair degree of stretch and flex, making them the ideal choice for creating comfortable clothing. In addition, knits tend to shed wrinkles well and don’t unravel when embroidered.

However, knit fabrics are not all created equally and come in a variety of textures, weights and fiber contents. Here are some examples:

Firm Knits – These knits are not very stretchy and can almost be treated like wovens. Examples include double knits and Raschel knits.

Lightweight Single Knits – These have a moderate stretch. Examples include tricot and jersey knits. Jersey knits are commonly used in lightweight polo’s and t-shirts.

Interlock Knits – These knits are heavier and thicker than single knits and have a fair amount of stretch. They are used in heavier grade polo shirts and t-shirts.

Textured Knits – These knits tend to be heavyweight with textured surfaces and have a moderate amount of stretch. Examples include knitted terry and velour, sweater knits and fleece.

Two-way Stretch Knits – These are unique in that they stretch both in length and width, whereas the other categories of knit have considerably more stretch in one direction than the other. Two way stretch knits tend to have a large amount of spandex fibers and are usually selected for activewear such as bathing suits and dancewear.

On a daily basis, most Embroiderers have close encounters with products that fall into the lightweight, interlock and/or textured knit categories. Though these fabrics are different in construction, the processes for dealing with them are the same. But before you can sew them, you need to know how they respond to embroidery.

During the sewing process there several physical forces that are applied to the fabric, three of which will be discussed here. The first is a downward pressure on the fabric, caused by the needle piercing the fabric. Each time that the needle encounters the fabric, it pushes it down towards the bobbin before breaking through. As the needle pushes goes through the fabric, it also pushes the fibers apart. This of course causes a tiny, almost imperceptible amount of distortion in the surface of the knit. But when you compound this by the thousands of needle penetrations that can occur when sewing a design, the distortion can be significant.

A second force is a downward pull caused by the stitch formation process. As the bobbin and upper threads are joined underneath the fabric, a small amount of force is placed on the fabric, such that it is pulled towards the hole in the needle plate. Once again, the possibility exists for a small amount of distortion in the fabric.

Finally, there is a force that is caused by the movement of the pantograph. After a stitch is formed, the needle rises up and away from the surface of the fabric trailing the upper thread, which is still joined to the bobbin thread by virtue of the last stitch that was formed. As the pantograph moves to the next position it has to pull against the upper thread and the bobbin thread, which causes the fabric to be pulled in the same direction as the pantograph movement.   This places a significant amount of force on the fabric.