Morning all,

I am in need of some stiffening rib design advice.  I am not sure if I am in any violation of asking design advice here vs SW advice but I am going to ask anyway.  I am molding a hopefully flat cover to a battery case.  It will be molded from PC/ABS (Cycoloy).  Gated in the middle bottom surface of the part.  the part is 10" long x 5.5" wide x .100 thk.  I am concerned about the orientation of the ribs with regards to the part.  I will be running the ribs parallel to the direction of flow (length wise on the underside of the cover).  I will size them to be no more than .040 thk at the base of the rib with a .5 degree draft and no taller than 2 times the width of the adjoining wall ie .2" tall.  The question I am asking is should I connect the ribs running lengthwise with some interconnecting cross ribs or diagnol ribs as well?  I know it is easier to add ribs later if need be by machining additional pockets in the core, but what would be a good spacing length and width wise given the parts dimensions do you think?  I am attaching some pdfs for reference.

Thanks

Sid