Why do thread breaks occur? Not quite as intriguing a question as what is the meaning of life or why did the chicken cross the road. It is, however, a much easier question to answer.
Nothing is more frustrating (or costly) than a thread break. Frequent thread breaks will shred through all profitability of a job. Too often, thread breaks are considered a norm and the solution is to re-thread the needle rather than find a solution. The following indicators will help embroiderers troubleshoot and avoid expensive thread breaks.
One of the first places to look when dealing with an excessive thread breaks is the travel path of the thread from the cone or spool itself to the needle. Each embroidery machine has its own method of getting the thread to the needle that often involves a series of twists and turns through an intricate maze. If the thread is out of the normal travel path, it can rub against a machine part and begin to fray and, ultimately, lead to a break.
Another source of thread break issues can be the needle. A slight burr in the eye can wear the thread to a breaking point. A bent needle tip can also be a thread-breaking source. This can happen to either a ball or sharp point needle.
The causes are too numerous to mention in this space, but suffice it to say that the bent tip acts like a fishhook barb and either tears up the garment or cuts the thread as it withdraws from the fabric. Needles are extremely inexpensive; damaged garments and production downtime are extremely expensive. Replace needles that have a lot of use.
An embroidery machine is capable of moving in .1mm increments. However, there is not a machine in the world that can actually stitch at that value. Once you break the 1mm threshold, the diameter of the needle is such that you can’t place the next stitch without rubbing against a previous stitch, which can weaken the thread and cause it to break. This very common problem not only leads to thread breaks, but potential holes in garments as well.
Excessive thread trims
Every time the embroidery machine has to trim, the continuity between the thread cone and the garment is broken. Thus, every time the machine starts up again, the chances of a thread break increases. While this is a result of the needle simply becoming unthreaded, the bottom line is that the machine stops and the result is downtime.
Too much density will yield too many stitches in too small of an area, with the obvious result being thread breaks. Density needs to be carefully chosen based on the material being sewn in order to assure proper coverage without overdoing it. In addition, large segments usually require more density, while smaller ones may need less density. The standard setting is 63.5 spi or 4 points.
When sewing a thread color that contrasts with the fabric color, such as white on black, it may be virtually impossible to get enough density to ensure uniform coverage without getting thread breaks. Rather than increasing density, consider using two layers of thread segments at 45 degree angles, with slightly reduced density settings.
Stitching over stitching
How many layers of thread can a needle pass through? It is not something that you want to find out. Multiple layers of stitching create another potential thread-break scenario. The first layer of thread only has the needle passing through the material. Each subsequent layer adds more for the needle to pass through, which damages the overall integrity of the thread fibers.
Anything more than three layers of embroidery can spell disaster. The density settings typically need to decrease with each successive layer that is added.