c/cnc-operators

16

viola_lopez30•3d ago

Caught myself arguing both sides of coolant vs mist today

I was reading through a thread on Practical Machinist and found out that some shops are running flood coolant on aluminum with zero issues while others swear by mist to keep thermal shock down. It blew my mind because I always thought flood was the default for aluminum, but apparently it depends on your tool coating and feed rate. One guy said he cracked 3 inserts in a row switching from mist to flood on a 6061 part. Has anyone else run into this split where the 'right' way changes based on who you ask?

22

lewis.mila•3d ago

Vent: That one engineer who told me to 'just watch the red light' still makes me mad

I was 3 months into running a Haas VF-2 at a shop in Cleveland, trying to set up a new part for a rush job. This older engineer walked over, saw me double-checking the offsets, and goes 'you new guys overthink everything, just watch the red light on the probe and go.' So I did, and it crashed the tool into the vise, scrapping a $350 billet of 6061. The light was for a different sensor they never updated the sticker for. He shrugged and said 'well, now you know.' I still think about that dude every time I set up a job. Has anyone else had a senior guy give you bad advice that you followed and regretted?

23

fiona_kim•4d ago

That $30 end mill I swore by was actually junk - 3 broken parts later

I used to think cheap HSS end mills were fine for aluminum. Bought a 10 pack for $30 on Amazon, figured it was a deal. Broke 3 of them in one afternoon cutting some 6061 parts. Then a guy at the shop let me try his $12 single carbide end mill. It cut clean, no chatter, and is still going after 40 parts. Has anyone else found that spending more on tooling actually saves money in the long run?

30

murphy.tessa•5d ago

Spindle bearing went out on a Friday at 4pm

Was running some aluminum parts for a rush job two weeks ago and heard that telltale grinding noise. Knew right away it was the spindle bearing. Took me all weekend to tear it down and replace it, got it running again Monday morning. Lost about 16 hours of production time. Anyone else keep a spare bearing set on hand or just me?

5

jasonf35•6d ago

Serious question about tool wear tracking methods

I keep seeing everyone on here swear by tracking tool life with spreadsheets and manual logs. Been doing that for about 18 months at my shop in Phoenix and I think it actually made things worse. The difference I saw was around month 6 - my insert life started dropping by about 12% because guys were forgetting to log changes or fudging the numbers. What really opened my eyes was watching a new kid just eyeball his tool changes based on sound and finish quality, and his scrap rate was half of mine. I think we got so caught up in data that we forgot the basics of paying attention to the machine. Has anyone else had their production go sideways after switching to a strict tracking system?

18

john_fisher•12d ago

Old timer at the shop swore by roughing with HSS before finishing with carbide

I ignored him for six months and kept blowing through expensive inserts on hardened D2, so I finally tried his method last week and got 40% longer tool life on a single job - has anyone else found that combo actually saves money in the long run?

14

moore.beth•12d ago

Stick with HSS tooling or switch to carbide for aluminum? Split shop on this one.

I work in a job shop where half the guys swear by HSS for aluminum. Say it's cheaper, easier to sharpen. The other half run carbide inserts, claim they get better surface finish and longer runs between changes. I got stuck in the middle last week on a 200 part job. Tried HSS first. Got good results but had to stop and touch up tools after 30 parts. Carbide cut faster but chipped on a deep pocket. What side do you lean toward for production aluminum work?

6

adams.uma•12d ago

Old way of setting tool offsets vs a simple trick I picked up

I used to spend half my shift jogging the tool down to touch off the part, then manually typing in the offset. Took forever and I'd mess it up at least once a shift. About 3 months ago, an old timer showed me to use a 0.001 shim and touch off to that instead of the part surface. Now I just do the math in my head, subtract the shim, and punch it in. Has anyone else got a quick trick for tool offsets that saved them time?

0

gavin228•1mo ago

I finally figured out why my fixturing was off after 4 months

Was getting random deviations on a simple aluminum part for weeks. Kept adjusting offsets, re-leveling the vise, checked tram. Turns out I was clamping way too hard on thin wall sections. The part was flexing during the cut and springing back after. My lead guy walked over one day, watched me clamp down, goes "bro you're crushing it." Took maybe 10% off the clamping force and my parts have been spot on ever since. Anyone else have a dumb simple fix that took way too long to find?

19

gray875•1mo ago

Hot take: Should you dial in speeds and feeds by the book or by ear?

I spent 3 hours last week trying to get a finish pass right on a 6061 aluminum part. Book said run at 8000 RPM with a .003 chipload, but the chatter was so bad I thought the spindle was gonna walk off the machine. So I dropped it to 6500 and bumped the feed by 10%, and it cut like butter. But now I'm second guessing myself because the guy who trained me always said to trust the manufacturer's numbers. On the other hand, my old boss would say every machine is different and you gotta feel it out. How do you guys handle this when the specs just don't work? Do you stick to the chart or go with your gut and adjust on the fly?

1

mianelson•1mo ago

Shelled out $250 for a fancy 5-axis post processor and it crashed my machine on the first test run

I bought this expensive post processor from a guy online who claimed it was magic for my Haas VF-2. Hooked it up last Friday, loaded a simple part file, and the thing sent the spindle straight into the table at 80% rapid. Scared the crap out of me and left a nice little divot in my fixture plate. Took me three hours to re-level the head and get everything trammed back in. Has anyone else gotten burned by a post processor that wasn't worth the money?

24

diana_kim66•1mo ago

Switched to HSM toolpaths for roughing last month

I used to just run standard trochoidal paths for my roughing passes on aluminum. Then I tried high speed machining toolpaths in Fusion 360 on a job at my shop in Detroit. Now I'm cutting cycle times by about 30 percent on the Haas VF-2 with way less tool wear. Any of you guys use HSM for steel or just aluminum?

4

ray_williams•1mo ago

Found a scrap bin full of aluminum chips from 1987 in the back of the shop

I was cleaning out an old cabinet last Tuesday and found a bin of aluminum chips that someone labeled 'December 1987 - Grade 6061'. Turns out those chips were still perfectly good to recycle, and the shop I work at now in Ohio gets paid $0.45 a pound for them. Has anyone else stumbled across old material that was still usable?

25

ward.jamie•1mo ago

Vent: That time a coolant line sprayed my whole station during a rush job

Honestly, I was running a Haas VF-2 in a shop outside Cleveland about two years ago. We had a huge order for some automotive brackets, and the foreman was breathing down my neck to hit the deadline. About halfway through the third part, I heard this weird hissing sound and then a spray of coolant hit me right in the face. I panicked at first and hit the feed hold, but the line was busted near the back of the enclosure. I had to shut everything down, grab some rags, and clamp off the line with a vise grip just to stop the flood. Took me 45 minutes to swap out the hose and clean up the mess, and the foreman was not happy. Has anyone else had a coolant line blow on them during a tight deadline?

23

shanef34•1mo ago

Crashed my Okuma lathe because I ignored a worn insert

Was running a batch of 304 stainless at my shop in Detroit last Thursday, and the finish started looking rough on part 87. Figured I could push it one more cycle to finish the job, but the insert shattered on the next pass and the turret slammed into the chuck. Anyone else ever cheap out on tooling and end up paying way more in repairs?

36

sean_green44•1mo ago

Rant: Hit 10,000 parts on my Haas and nobody warned me about the spindle

I ran my VF-2 for like 4 years straight, never thought about the spindle bearings much. Last week the machine just started screaming at 8,000 RPM and I realized I crossed 10,000 parts without ever doing a maintenance check on it. Now I'm down for a week waiting on a rebuild kit. Has anyone else had their spindle give out way earlier than you expected?

20

corap21•1mo ago

That old timer told me to trust my ears over the readout and he was dead wrong

I had a guy named Pete who's been running CNC since the 80s tell me last year that I should ignore the digital readout for chatter detection and just listen to the machine. He said the readouts lie sometimes and your ears know better after enough time. So I tried his way on a big 304 stainless job for a local aerospace supplier, running a 3/4 inch four flute end mill at 3500 RPM. Machine sounded fine to me, no screaming or weird harmonics, but the readout showed a 0.0025 inch deflection spike every few passes. I kept going because I trusted Pete and ended up scrapping four parts worth about $800 each because the surface finish went to hell on the last pass. Next time I ran the same job I set up a vibration sensor and split the difference between the readout alerts and my ears, zero issues. Has anyone else ever been given advice by a veteran that just plain backfired on a specific part or material?

3

wyatt135•1mo ago

Was team flood coolant for years, finally switched to mist and I get it now

I used to think mist systems were just for people who didn't want to clean up puddles. Then my shop got a new Haas VF-2 last month and the flood coolant kept blowing chips everywhere on a tight tolerance part. Switched to a mist setup with a Kool Mist unit and my surface finish went from 63 to 32 microinches on aluminum. Anyone else make the switch and notice a difference on their end mills?

26

the_wendy•1mo ago

Pro tip: I was skeptical about using a tool presetter but it saved me 45 minutes on a job last week

Always thought they were a waste of money until I had to set up 12 tools for a complex aluminum part. Has anyone else found tool presetters worth the investment for their shop?

27

vera195•1mo ago

Blew $80 on a fancy edge finder and it was a dud

Picked up a brand name electronic edge finder from a tool truck last month for $80. The first few times it worked fine but then it started giving false readings on aluminum parts. Ended up going back to my old mechanical edge finder that cost me like $15. Has anyone else had bad luck with the fancy electronic ones or did I just get a lemon?

24

ivan774•1mo ago

Why does nobody talk about how long it takes to dial in a new fixture plate?

Spent 6 hours chasing tenths on a simple aluminum bracket because the plate wasn't trammed from the factory. Anyone else get burned by that?

9

jamie804•1mo ago

Just hit 50,000 parts on a single tool insert and I'm still shocked

Running a batch of 4140 steel brackets on the old Haas, I swapped in a fresh CNMG insert expecting the usual 8,000 part life. That was six months ago. I just passed 50,000 pieces and it's still cutting within spec, with no chatter or major wear. I've never seen anything like it in my 12 years on the floor. I'm running it at 650 SFM with a 0.012" feed, and the coolant mix is just our shop's standard stuff. Has anyone else ever pushed a tool this far past its supposed limit on a tough material?

31

cooper.drew•1mo ago

Update: I saw a guy run a job without a tool offset at the trade show in Chicago

He was making a demo part on a Haas VF-2 and just used the machine coordinates, arguing it was faster for one-offs. The part came out fine, but watching it made me question if we're all too rigid about our setup routines. When does sticking to the book actually slow you down?

23

john_fisher•1mo ago

Question about a trick for spotting chatter before it wrecks a part

I used to just listen for that high pitched squeal and then react, which meant scrapping stuff a lot. Last month, an old timer at the shop showed me to put a tiny bit of layout dye on the tool holder. You run the program dry for a second, and if the dye smears, you've got vibration starting before you even hear it. I tried it on a tricky aluminum job and caught it early, saving a $400 blank. Anyone else got little tricks like that for catching problems before they happen?

16

nelson.vera•1mo ago

Showerthought: I just ran my 500th part on a single tool without a single crash

I was running a long job on a VF-2 last week, a bunch of aluminum brackets with a lot of pocketing. I had a 3/8" end mill in there and just kept an eye on it, cleaning chips and checking the finish. I didn't think much of it until the cycle finished and I saw the run count on the machine. Five hundred and twelve parts, all with the same tool. No regrind, no weird noises, just consistent cuts. It mattered because I used to baby tools and change them way too early, scared of a crash. This run proved that with good speeds and feeds and keeping things cool, you can push way further than the book says. Has anyone else had a tool last way longer than they expected on a specific material?