I use a Nemco vegetable slicer for onions I grill up. Takes about 20 minutes to do 50 lbs…of course I’m not counting the hour it takes to peel em. I have used a food processor for the raw onions…just pulse it a few times gets them about right. But to tell you the truth I will only go through about an onion a day for raw ones. I’ll just dice it up with a knife…takes less than a minute…once again not counting the peeling time. I like the uniformity of diced onions more than food processed onions.