Toying with getting a cost system out of spreadsheets and into access. Most
the tables are simple and easy to set up, but I'm debating our material
blends table. We have multiple plants, about 10 materials, and each product
may contain any percentage of 1, 2 or 3 of those materials. Each plant
currently has its own spreadsheet with the blend lookup as follows:
code mat1 mat1% mat1waste mat2 etc...
A X X% Xwaste Y
Putting this into an access table though I'm guessing I would need to have
the following columns
Code Plant mat Mat% matwaste
A 1 X X% Xwaste
A 1 Y Y% Ywaste
and so on

Is this the correct and effecient way to set this table up or is there a
better way?

I noticed that nobody answered.

This is a structure question. You really need to explain what your real
world "entities" that you want to DB are, are and what you are trying to do
(to make sure you really do that, do it without using any access or
spreadsheet terminology :-) )

For example, is your mission to database all of the different products that
you make? And if so, what do plants have to do with product variations?
Is each product unique to one plant?

You started out well in the first 3-4 sentences but then went south.

Hope that helps a little.