Most mining machine manufacturers in Zhengzhou have such a bad name, which is not so good. Zhao Yang, a foreign trade teacher, pointed out that Henan's machinery was broken, fraudulent and dishonest. The output required by customers can't be reached, and the after-sales can't keep up. In order to reduce the cost and steel plate thickness, the machine life is short and the output is low. To make matters worse, some manufacturers don't insist on long-term operation at all, that is, they sell one machine at a time and leave after earning more money in a year or two. Most people in Zhengzhou machinery industry know it.