Plastic cannot completely replace the mirror for the following reasons
1. requires very good mold steel to produce molds
2. requires very good polished mold surfaces
3. requires very clean injection molding machines to produce
4. needs very good maintenance because whatever material is easy to scratch
But some products need plastic to mirror. That is to find experienced transparent products.
find a trustable injection molding company is most important for any new customer invest a mirrow plastic part.
The following videos may help you
