What time Do postmen come in the evening to deliver robotic things?

Generally the postman does not know what he is delivering unless the contents is written on the outside of the package. Even then, packaging is often re-used.

If the package was sent by regular mail, it should arrive at the regular time; whatever time you typically receive your mail

If the package was sent by a parcel service (FEDEX/UPS) it will be delivered when it's most convenient for the driver, meaning that a route will be calculated for him that minimizes the amount of driving thereby reducing both time and fuel costs.