About this 3D model

This is a battery compartment which can hold up to four AA and AAA batteries and a SD card. Unfortunately the lid does not fit very well when printed on a Replicator2x. The walls of the lid are not thick enough. I was not able to simply increase wall thickness in AutoCAD. Advice on how to do it is very welcome. This model is a result of an assignment trying to satisfy the following requirements: * Hold either 4 AA or 4 AAA batteries * Hold a SD card * Can be attached to belt or camera bag * Protect batteries against splash water