1. Change the needle.
2. There are 3 needle plates, one is for tubular frames, one is for caps, one is for border frames/table. If you use the wrong needle plate for the job you may get looping.
3. The relationship between the upper tension and the main tension is touchy. If the upper tension is too loose it may allow looping to occur. Tighten the upper tension slightly, a bit at a time to see if this solves the problem.
You'll also want to check the settings for the Angle area "A" and "B" are set to. If your machine is one of the newer versions than you have a setting called the frame angle for area A and frame angle for area B, this setting corresponds to the entry and the exit of the needle at a certain degree. Normally for polyester thread on a single head we set this setting to 260 degrees, but if you are sewing rayon which has no stretchability to it, then you will want to make the setting on these frame angles to about 230 or 240 angle.
To get to the setting go to SETTING, then go to M/C PARAMETERS, and then Hit the NEXT button twice to get to page three, there towards the bottom you will see these two angle settings. Make the change and also lighten up the tensions on your machine since you are sewing with rayon, and she should sew fine.
Now if your machine is an older type then you need the press the FRAME button and then select 0 for frame A and then 0 for frame B, for Polyester types threads you want to make sure these setting in Frame are set to 10 for both A and B.