I'm not surprised... When I was working as manager and optometrist/optician, the owner (he started his career selling lenses, after open a glass frame factory and a the end optic stores) of the optic stores told me that in the 80's when they start to export work and open factories in Japan, and later in China, they ship some German made equipment, at that time the best for make glasses frame, with a crew and some technician, to teach a the workers how to use these machine end eventually repair them. Later on, they start to copy those machine, and build them under different names. The quality was not like the German machine, but also the price was totally different. And because of the huge demand of glasses and frame, they sold.
This also happen on glasses and frames, I remember go to international show, where you can find all the new fashion glasses, frame from all the big company, and after you can spot company with "weird" name that sell a exactly copy of the brand one super super cheaper. I remember some Christian Dior sunglasses/mask, with black lens, and the body was black or white, that were a brand new thing (in 2003) and in other stands of this show, Chinese company sell the exact copy in different colors.