The issue came up this morning with a customer of mine as to why I 
would want  to deviate from his specification calling for alternating 
the grain direction in the layup of a  6 layer MLB. I could'nt give 
him  the answer he was looking for. It seems that in all his 
experiences,  other vendors require cross graining to avoid warp and 
twist and that  keeping grain direction constant was a no, no.
     In all of my experiences the case has been just the opposite. WE 
go out of our way to assure that materials are cut to order in the 
proper direction so we can avoid cross graining. Maybe this practice 
started years ago by recommendation of our laminate supplier, or 
maybe after making many orders of  "potato chip" boards we decided to 
watch the grain directions of our layups.
     My thoughts on the advantages of  NOT cross graining are:
1. Predicable  shrinkage compensated by scaling the artwork.
2. No built in stresses from lamination thus less twist, warp in 
subsequent processes.


Can anyone  please ellaborate on this issue.

Thank You.

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