Speed up VBA code for Excel

I have a VBA code that I run which helps me divide up a larger spreadsheet for customer orders. We have one customer with two sub-units that order multiple parts from multiple locations at once. I would like the macro to look up the parts in our inventory spreadsheet to determine what we have available to ship, look up the sales order number, purchase order number, and sub-unit before creating individual excel files for each location. Right now I am putting the look-ups in before I run the macro to separate into individual files because when I had it do everything it took hours to finish. It does what I need it to do in its current form but it takes about 15-20 minutes to run so I need to find a way to speed it up. Ideally, the macro would create the look ups and separate into individual files without taking more than a few minutes or shorter. I have attached a sample in its raw form and a sample with the formulas and macro. I actually took the formulas out and pasted them into the first row of the columns they would be in because they wont work anyway if not on our server.