Sometimes you just have to lay down a lot of filament. I make large structures for my boys, where details aren’t really that important and it’s ok if you can see layer lines in the print. When I print these, I like to switch from the 0.4mm nozzle to a 0.6mm nozzle to accommodate more filament being put down. However, there are a couple of adjustments that need to be made.

• Slow down the speed a little bit. The bigger cross-section of the extruded filament takes a little longer to heat up. Slow down to give it time to heat. Even with a slightly slower move speed, you are still putting down 1.5 times as much filament so your net speed is still much higher.
• Increase the temperature at the nozzle. You have increased the nozzle diameter by 1.5x. The center is going to cool down a little bit faster than with a 0.4mm nozzle.