Had the same thing happen to me this weekend while quilting. Checked tensions, re-threaded machine (several times) changed needles, cleaned machine....finally figured out that the material itself was the cause. Even after washing and drying the material, it seemed to have a slight 'rubber-like' feel to it. It was causing just enough friction to wear the thread thin and break it. It was the 'licensed' Transformers material. Worked through it, despite breaking 3 needles.