If all you want to do is punch copper bars, the Boschert machine is gonna blow away the router from a speed perspective. If you don't need high speed and the router would fulfill other needs, it may be closer to a wash. For a fixture I am imagining a wood or aluminum sheet with grooves in it to hold the bars. You could have hold downs that swing parallel to the bars so you can insert the parts, then rotate the hold downs 90 degrees and tighten them down. The hold downs would be placed between holes. Drilling is probably the most effective way to do the holes on a router but you probably need a high torque low speed spindle whereas most routers have a high speed relatively low torque spindle.