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c/cnc-operators

5

nathan_kim•1h ago

I finally had a 6mm end mill snap yesterday after 4 months of pushing it way too far

Was running some aluminum plates for a client in Portland and pushed the feed rate up to 150% to meet a deadline, and the tool just gave out mid-cut. Has anyone else ever gotten away with running tools way past their suggested specs for way longer than you should?

10

the_john•11h ago

Rant: I spent 8 months fighting with tool paths on a 3 axis mill before a buddy showed me how to rough with a bigger stepover

I used to baby my roughing passes, like .02 stepovers thinking I was saving the machine. Last year a machinist in Detroit watched me set up a job and just laughed. He told me to bump it to .06 on the first pass and let the coolant do the work. Cut my cycle time by 40% on that part and the finish was still fine. Anybody else get stuck in a habit that made zero sense after someone called them out?

18

robin896•2d ago

Grabbed the wrong tool offset last night and scrapped a $400 part

I was running a late shift at the shop in Cleveland, tired after about 10 hours, and punched in the wrong tool offset on a Haas VF-2. Instead of checking my G10 line I just hit cycle start on a finished aluminum bracket. Heard that awful grinding sound and realized I cut 0.050 inches too deep into the face. Boss wasn't happy but at least we caught it before the next part went through. Anyone else ever zone out and pay for it like that?

17

rowanw91•18d ago

Serious question, why does everyone at the Milwaukee shop love those carbide burr sets?

Stopped by the tool supply place on 3rd last tuesday and grabbed one of those 10-piece carbide burr sets everyone talks about. Tried it on some aluminum parts and the thing chattered like crazy compared to my old HSS bits. I get that carbide lasts longer but for the money I'd rather just swap out the cheaper bits more often. Am I missing something or is this just hype?

11

andrew_baker9•18d ago

Old timer warned me about coolant ratio at a job shop in Cleveland

I was setting up a new Haas VF-2 last year and this guy in his 60s who had been there since the 80s walked over. He just said 'your coolant looks thin, you're gonna eat those tool holders in about two months.' I brushed it off because I was running 5% concentration like the manual said. Sure enough seven weeks later I started getting chatter and found the turret had built up rust inside the taper. He was running 8% on all his programs and never had that issue. Has anyone else found that the factory recommended ratios are way too low for real production runs?

1

ross.kim•21d ago

Hit a nice little milestone at the shop today

Ran my first full week of production on that new 5-axis Haas we got in March. No crashes, no scrap parts, just smooth cuts all week. Anybody else find it takes a few months to really trust a new machine?

3

the_laura•23d ago

Picked up a tip from an old-timer about clamping thin aluminum

Guy at the supplier said to put a piece of plywood under the stock before clamping it down. Tried it on a .040 sheet job last Friday and the vibration almost disappeared. Anyone else do this or have another trick for thin material?

21

carr.luna•24d ago

An old timer in Detroit showed me a toolpath trick that cut my cycle time by 40% on a tough job

He saw me struggling with a complex aluminum part at the shop and just walked over, tapped the screen, changed one feed rate, and said 'try that instead of fighting the machine,' and I still use that same move every time I run 6061.

13

the_laura•25d ago

Spent $200 on fancy tool holders that didn't fit my machine

I bought a set of ER collet holders from a brand I'd never used before last month, thinking they'd save me time on tool changes. Turns out the pull studs were a different thread pitch than what my Haas VF-2 needs, so none of them would seat properly in the spindle. Anyone else get burned by assuming specs would match without double checking first?

18

zarag17•25d ago

TIL that 90% of coolant mist violations come from not checking the nozzle angle regularly

Saw it in a safety report from a shop in Detroit and after checking mine I found the mist was blowing straight into the vent, anyone else run into this with their Haas machines?

12

sullivan.quinn•27d ago

Ran into a phantom spindle issue on an old VMC last Thursday

I spent like 6 hours chasing a weird vibration on a 2001 Haas VF-2. Turns out it was just a loose setscrew on the drawbar coupler that had backed out maybe a quarter turn. I pulled the whole spindle drive apart before I even thought to check that simple thing. Anyone else get tunnel vision and waste half a shift on something dumb like that?

30

ryan_hart38•28d ago

That week everything ran perfect and I got suspicious

Last Tuesday every tool change landed within 0.001, the coolant never clogged, and I finished a 60 piece run in 4 hours flat, has anyone else had a shift so smooth you started waiting for the other shoe to drop?

11

kelly_rivera•29d ago

Old timer told me my feeds and speeds were way too conservative, changed everything

I always ran my CNC at safe slow settings to avoid crashes, but a retired machinist watched me one day and said 'you're babying it, push it harder.' He showed me how to bump up the feed by 30% on aluminum and the finish actually got better. Anyone else get feedback that made you totally change your approach?

10

dakota_miller93•1mo ago

Discovered setting my tool offsets while the spindle is stopped was costing me parts

Been running CNC lathes for 12 years and always zeroed my tools with the spindle off because that's how my first supervisor taught me. Last week I tried touching off with the spindle running at 500 RPM and my first part came out within 0.0005 inch of the print. Any other old-timers run offsets this way or is it just me?

24

dakota_miller93•1mo ago

Just hit 500 flawless parts on a single setup and I'm not celebrating

I thought hitting 500 parts without a rework would feel like a victory, but honestly it just makes me paranoid that the tool is about to fail and ruin my whole streak, has anyone else felt that way after a good run?

5

margaretc42•1mo ago

Got told I was programming my tool offsets all wrong - old timer vs new training

So I had this inspector come through last week on a big job we were doing for a medical parts company. He watched me set up a new endmill and asked why I was touching off with the tool setter at a different Z than the actual part surface. I said that's how I learned at the trade school up in Dayton, you use the table as a reference and then add your offset from there. He said no, that's gonna give you trouble with thermal growth on longer runs. He showed me his way where you touch off at the actual work surface height. I been doing this for 4 years the other way and never had issues. But he's got 25 years experience and does audits for a living. So which way do most of you guys do it? Touch off at table height or at the part surface? Is this just a preference thing or am I actually messing up my tolerances? Got a big run of 316 stainless coming up next month and don't want to scrap parts.

3

kai_ramirez38•1mo ago

Picked a 3-axis over a 5-axis mill for my garage shop and it fit my work better than I expected

I spent weeks going back and forth on dropping $8k on a used 5-axis CNC mill or sticking with a simpler 3-axis setup. I knew the 5-axis would let me do wild angles and complex parts without fixturing headaches, but the price tag and the space it needed in my garage scared me off. Ended up grabbing a 2018 Haas Mini Mill with a 3-axis config for $5,500 from a guy in Denver who was upgrading. First real job I ran on it was cutting aluminum brackets for a buddy's fabrication project, and I realized the 3-axis handled 90% of what I actually need. The extra money I saved went into a nice vise and a bunch of quality end mills from a local supplier. Anyone else decide to go simpler and find out it was the right call for their actual work load?

29

lee582•1mo ago

People keep ignoring the tool offset calibration at shift change

I walked into my machine at Precision Parts in Cleveland last Tuesday and found the last guy's offsets were off by 0.015 on the X axis. This is the third time this month I have caught it. Why can't people just run a quick test cut before they clock out? Has anyone else been dealing with this slack at their shop?

6

henryr45•1mo ago

Hit 10,000 parts on our old Mazak with zero scrap and it felt weird

So we have this Mazak VTC from like 2005 that runs a simple aluminum bracket, a job we do every month. I just cleared the counter after the last run and it hit exactly 10,000 pieces since the last major crash. Not a single scrapped part. At first I was proud, but then it got me thinking. I realized I've been babying that machine, running feeds and speeds from a sticky note the old lead left, probably way under what it can handle. I checked the cycle time and we're losing almost a minute per part being too safe. That 'perfect' number was actually hiding a cost in time. I bumped the feed up 15% on a test batch yesterday and it ran fine, no chatter, and saved us hours. Has anyone else had a 'good' number that was actually holding them back? How do you find the real limit without breaking stuff?

17

blake_kelly19•1mo ago

My wife's cousin who runs a fab shop said something about our job that got me thinking.

He was over for dinner and said, 'Honestly, the best operators I've hired are the ones who can read a print like a book and then argue with the engineer about it.' Ngl, that hit different because I've always just followed the print to the letter. How do you guys handle it when you see something on a drawing that just won't work?

2

the_faith•1mo ago

Pro tip: I tried two different ways to clean my machine's way covers and one was a disaster

Last week, I was cleaning my VF-2 and tried using a standard degreaser spray on the rubber way covers. It made them swell up and get stiff, almost like plastic. I had to order new ones, which cost about $300 and took five days to arrive. Then I switched to just using a rag with a bit of isopropyl alcohol, like an old-timer in the shop suggested. The covers stayed flexible and clean with no damage at all. Has anyone else found a simple cleaner that works better than the fancy stuff?

11

kellyr20•1mo ago

That one Friday I scrapped a $1200 part because of a decimal point

Fat-fingered a .05 instead of a .5 on the offset and didn't catch it until the final pass. Anyone else ever have a single typo ruin your whole day?

2

keith164•1mo ago

Choosing between a manual tool change and a pallet system for a 50-part run

Everyone said the pallet system was the only way to go for speed. I stuck with manual changes and finished the job in 8 hours, same as the quote. The extra setup time for the pallets would have eaten the profit. When do you guys decide a pallet system is actually worth it?

2

kevint47•1mo ago

Had a coolant line blow out on our old Haas VF-2 last Thursday

I mean, it's a 2007 model and the plastic just got brittle. Happened right as we were finishing a run of 50 aluminum brackets. Had to shut down, clean up about 5 gallons of coolant off the floor, and replace the whole line with some new hose from the supply shop. Anyone else had to deal with old coolant lines failing like that?

11

sam_cooper•1mo ago

Had a coolant line blow off at 3 AM during a long run

One side says you shut it down and clean up, the other says you clamp it and keep going to hit the deadline. What's your call?