If you are embroidering, you will only want to use embroidery thread. Regular all purpose thread is too heavy for embroidery. When you are sewing however, you don't want to use embroidery thread because it isn't as sturdy as sewing thread. With both types of thread, you only want to use a high quality thread. You will have fewer issues and your machine will thank you for it.

I also have problem with embroidery threads. Is polyester thread better than rayon? I used rayon threads to do embroidery but they keep breaking off. Has it anything to do with tension? How is it my new rayon threads break all the time?

Poly is more durable and fades less. But good quality rayon really shouldn't be breaking like that either. hmmmm....

Does the rayon thread you pull off the spool/cone look like it's linty, or have rough spots? It may just be bad thread, or you may need a different type of needle.
I use almost all poly, never used much rayon, but do I know the needles made just for embroidery do have a larger hole and a special scarf to allow for all the thousands of stitches being made. I use either one, but maybe you could try a pack of embroidery needles?
Sorry I can't be more help.

Cheri

You also need bobbin fil for the bobbin. Brother Finishing Touch bobbin fil is usually recommended.