Wall thickness for large objects in FD

I've had a customer write to me and tell me that one of my models he ordered in FD printed OK but shattered in transit.



Now this is quite a large piece 200mm long by 35mm wide. My design thickness was .75mm-.8mm - it had to be printable in WSF as well as FD though in fact I find is a little thinner in a few places - it's messy as it curves in multiple directions, though this should also make it stronger.

So what thickness should I make this so it does not break?

Will attach stl file in separate post .

Tom

STL file for above

Avoid those 90° edgings.
Use small 45° chamfers, or (even better) a small radius.

And, instead of making the whole thing thicker, "just" add some internal struts.