Bans only work when the demand for or availability of the banned item isn't high. 
Where demand is high, there will be a black market.  It will be lucrative, violent, and likely lead to more of whatever it is you tried to ban.  See:  alcohol prohibition, war on drugs, prostitution, etc....
Where availability and/or private ownership is high, it will be enormously challenging (or even impossible) to eliminate whatever it is that you are banning.  See:  guns in America.  There is no way to eliminate a significant proportion of privately owned guns in American outside of a draconian, infinitely expensive, and violent/deadly door to door search and seizure operation.  You can ban production and sale of guns, and presumably over 3-4 generations, you might be able to make progress as older guns break/stop functioning.  But by then a lot of malfunctioning parts might be 3D printed anyways.  And as always, if there is demand, there will be a supplier, whether it is government, legitimate business, or black market.