Here are versions of other minecraft sword and axe designs I've seen. They are solid body which means it's easier to shell and fill or leave empty.

Check out editable models of the sword and axe

best results are default low settings with 10-20% fill and 2 shells. I scale it to 85% and center it on the platform. I've also done two-up side-by-side on in a build with good results. rotate the object to lay flat on the bed for best prints. Recently uploaded a v2 of the sword that may print with a little better definition.