The sentence structure of the following sentence
零部件的更换
零部件=(mechanical, electrical, etc) part; 更换 = replace/replacement (it can be a noun), so 零部件的更换 = replacement of parts
坚固性= ruggedness
Have you noticed the structure 在...上 used here? It means &quot;with respect to; regarding; in terms of&quot;, so the sentence may be split into (I think 零部件的 modifies 更换以及坚固性 here):

在[零部件的(更换/以及/坚固性)]上也有所优化
There are some optimizations regarding the replacement and ruggedness of parts.