Underneath It All Embroidery Project

Underlay is perhaps the single most important aspect of digitizing for embroidery, yet it’s the least visible part of a design. Properly applied, it can add a three-dimensional texture, flatten unruly fabrics and minimize puckers and waves. On the other hand, improper underlay can ruin a design and cause poor quality stitching. Despite that, few digitizers fully understand or appreciate the critical role that underlay has on the embroidery process.

Underlay has four basic purposes:

To better understand how underlay is used, we will address each one separately.

Garment Stabilization

The primary purpose of underlay is to provide stability to the garment during sewing, such that any unwanted movement is minimized. There are two parts to proper stabilization:

You already know that the purpose of backing is to offer stability to the item being sewn. The concept is that backing doesn’t stretch or shift, whereas garments do. Thus, by hooping a piece of backing with a garment, you add a solid base for the stitching, while minimizing any unwanted movement. However, none of the stabilizing characteristics of the backing are imparted upon the garment until the two are joined via the stitching process. But jumping right into a design is not going to offer much, if any, stabilizing force.

For example, if you were sewing a large soccer ball on the front of a t-shirt, you would need to stabilize the entire area that would be covered with the ball, rather than going straight into sewing each of the black and white sections. While you may wish to use a separate underlay for each of those individual areas, you should still apply an underlay for the entire design before sewing any individual element. (Of course, if you use the wrong backing or don’t hoop properly, no amount of underlay is ever going to save the design.)

Minimize Push-Pull Problems

At this point, it may seem like all you need to do is just click on the automatic underlay function of your software and have the program generate something for you at the beginning of the design. But that is a very dangerous supposition! Randomly applying underlay can lead to a whole host of sewing problems. In fact, the very goal of achieving fabric stabilization can be thwarted by improper underlay. Here’s why: push-pull.

Push-pull issues exist with every design and every fabric, some more than others. It’s a function of the mechanics of the sewing process versus the characteristics of the fabric being sewn. The end result is puckering and distortion.

To understand the source of push-pull problems, go back and think about the stitch formation process and try to picture in your mind what takes place during sewing. The force exerted by the movement of the pantograph (in conjunction with the thread protruding up through the fabric to the needle), pulls the fabric in the opposite direction of the pantograph movement. If you were sewing a satin stitch, which causes a well-defined zigzag motion, on a knit fabric you would see that the material is constantly pulled inward towards the center of the column. Simply stated, anything that zigzags back and forth PULLS causes a force that pulls in towards the center of the sewing area.

PUSH is caused by the physical forces present when the upper thread is joined to the lower thread to form a stitch. Because the process happens below the material, there is a slight downward pull of the upper thread, such that it is forced to lie securely on the top of the material. When you place multiple parallel stitches side-by-side, there is a large amount of pushing downward.

To better understand this, lay a piece of fleece fabric on a table. Pick a spot and push down with the palm of your hand. You will see that the fabric (along the edges of your hand) push upward forming what looks like a “wave” in the fabric. During sewing, this wave pushes out in front of the design in the direction that the stitches are moving. If you are covering an area with stitches (that zigzag back and forth) starting on the left side and moving to the right, the fabric will be pushed out in front of the embroidery towards the right. The further you go, the larger the wave becomes.

As you can see (in regards to push-pull), stitch patterns which move back and forth are the underlying culprit. In contrast, stitches that move in a straight line have virtually no effect on the fabric in regards to shifting or distortion. And here is where improper underlay can cause more problems than it solves.

The majority of automatic underlay patterns are composed of zigzagging stitches which produce push-pull problems. Thus, the very underlay applications which are used to prevent the problem may actually be a contributing source.

To remedy this problem, it’s better to manually create an underlay pattern that uses the following basic sequence:

Steps 1,2 and 3 all utilize run stitch segments that are more or less linear, rather than back and forth. This provides excellent stabilization, by tacking the garment to the backing with no push-pull pressures. Steps 4 and 5 apply low impact zigzags which equally distribute any push-pull forces away from the center out to the edges. However, any push-pull forces generated will be minimized due to the stabilization provided by the initial linear stitches.

Support

Underlay stitches also provide support for the top stitches as well as stabilization for the fabric. This is especially useful when dealing with textured fabrics which have an uneven surface. A carefully laid grid of underlay stitches, properly applied, will help to flatten the fabric, yielding a smoother surface for the rest of the stitches to lie on. In addition, this will lift the design itself slightly higher than the fabric surface, such that it doesn’t sink down into the fabric, which can cause distortion and loss of detail.

Click on the image to see an example of good and bad underlay patterns. When creating a support (underlay) pattern, special attention must be paid to creating an even grid of stitches so the top stitches are equally supported. The underlay should be precise and balanced rather than random and scattered, as illustrated here. Of course, care must be taken to ensure any push-pull forces generated by the pattern are minimized by applying linear underlay stitches prior to the zigzag underlay stitches.