It would be helpful to have some additional info on your line and process. Lets make some assumptions...
Consider: re-tooling costs for your fab supplier. Can your supplier hold the additional tollerences for a larger panel. Can your supplier fab in your required dimensions. Any unused board material (loss / waste) will be charged to you as: cost of waste divided by # of images per panel size added to each image. In fact due to loss (X'd out boards + panel waste) it may cost you more for a panelized version (vendor and product design specific){I have experienced this first hand}
Additionally: Is this a stand alone machine or a 100 yard line? If a line you don't want to wait 20 minutes to begin filling the "pipeline". Also consider exposure time for solder paste. No clean or organic? Could make a difference. Operator idleness?
Is the cost of depanelizing offset by the reduction of handling / machine idleness (waiting for next board). Will you need special depanel equipment?
The larger the panel, you typically see an increase in "droop" on edge hold conveyor reflow ovens. Can you compensate for this? What will it cost? It may add process time in other depts. Not just your own.
What are your volumes? 1, 10, 1,000 or 1,000,000 units per month? Prototype? One time shot? Stable forecasting from planning dept. ?
How effective is your optimizer? Larger panels may take longer to process as your pick to place distance increases linearly from the feeder(s). Some machine types are more susceptible to this than others (fixed feeder vs moving feeder banks).
Hope this helps.
Dean
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