The week that made me reconsider dry running every new tool

Ngl, I always thought it was a waste of time to dry run a new fixture or program for more than one cycle. Just get the part in there and go, right? Last month I was running a job on our Haas VF-2 at Miller Machine in Denver. Third part of the run, I hear this grinding noise that made my stomach drop. The tool change arm was a hair off and it had caught the edge of a collet nut. If I had just let it run one slow dry cycle with the doors open, I would have seen it. Cost the shop about 400 bucks in tooling and a whole afternoon of downtime. My foreman didn't even yell, he just said 'that's why we check, kid.' Now I'm that guy who watches every single move the machine makes for the first five parts. Has anyone else had a close call that made you change up your whole routine?

3 comments

3 Comments

michael6931mo ago

That's why we check, kid" - I felt that one right in my gut. I had a similar wake up call years ago on a Bridgeport CNC where I got lazy and a through spindle coolant hose caught on a tool changer. Let's just say I learned the hard way that saving two minutes on a dry run costs you three hours and a lot of explaining to the boss. Now I'm the old timer who makes new guys stand there with me and watch the first cycle like it's a nature documentary. If they give me a funny look I just point at my eyeglasses and say "I learned to wear these after the crash too.

the_wyatt1mo ago

And exactly what @michael693 said about making the new guys watch the first cycle like a nature documentary, that's brilliant. I do the same thing now, but I make them stand close enough to hear the machine, not just see it. That grinding noise I heard was like a fork on a dinner plate but louder. Now I bring a folding chair and a coffee for that first dry run, settle in like I'm watching a ball game, and I don't move until the machine's done with part five.

fox.jesse2h ago

Four hours into a dry run once and I had to call it because the coolant pump sounded funny. That was a Friday night, everyone gone, just me and a machine that decided to act up. I get why people do the coffee and folding chair thing, but honestly I think that approach works against the whole point. @the_wyatt, you're basically telling a new guy that he's just a spectator, not a student. If they stand there staring at a machine for an hour with no engagement, they stop listening for the small stuff and just wait for it to be over. Better to put them on a stool nearby with a notebook and make them write down every weird noise and vibration they hear, then explain it after. Sitting back like a ball game teaches them to be bored, not careful.