塑料焊条是基本于塑料而出来的一个东西，原理跟焊条一样。
1.焊接时未往下压，焊条拉伸太大。一般都是这个原因。
2.焊条质量不好。为了降低焊条生产成本，加有填充剂。
3.温度未掌握好。
4.焊工技术问题。

A plastic electrode is something that comes out of plastic basically, just like a electrode.
1. The welding rod is stretched too much without pressing down during welding. That's usually the reason.
2. The quality of the electrode is not good. In order to reduce the production cost of the electrode, a filler is added.
3. The temperature was not properly controlled.
4. Technical problem of welder.