Processing other people's goods, in principle, can not apply for patents, can only belong to technology introduction and new product development! Because in essence, the invention right of this product you processed does not belong to you! Of course, there are exceptions: when you introduce other people's technology, you make substantial design changes to the original product, improve the technical performance, and you can apply for patents for some functions that the original product does not have!
Of course, if you apply for a patent on a processed product without a patent, it is legally established, but it is disgraceful from the moral level and an indirect theft!