Stan, I feel the best way to go is to use 3/4" Baltic Birch (BB) plywood with high pressure plastic laminate glued to the top and bottom. This is how the most popular router tables in the US and Canada are built. Another option is to use regular 3/4" plywood with two layers of 1/4" high density tempered fiberboard stacked on top of it and then the plastic laminate top and bottom; this would be for larger table tops.
Melamine is a poor choice since the plastic laminate is paper thin and can be damaged easily and the core is just high density particle board which does not stand up well to humidity and weight. (3/4" is about the same as 19mm, 1/4" is about the same as 6MM)
"Living in the D" (this means Detroit!)
"It's fine to disagree with other members as long as you respect their opinions"