CNC "Oops"

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Forum topic by lab7654 posted 01-09-2013 03:59 AM 1359 views 0 times favorited 6 replies Add to Favorites Watch
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266 posts in 2425 days

01-09-2013 03:59 AM

As some of you may know, I’m taking a woods manufacturing class that is actually a fully formed business, registered with the state. We make real money and turn out real projects. This year’s project relies almost exclusively on our school’s CNC Shark. Up until this week, we haven’t had many issues. I was working on other things in the shop when I heard a big squeal from the machine’s general direction. Apparently, the students operating it had to pause the run to adjust some loose clamps, and when they resumed, the bit plunged straight through the board and into the table. It was most likely a malfunction, as most things run fairly smooth and simple. Thankfully, the damage was minimal. The aluminum T-track is readily available from Rockler in individual sections, just in case we want to replace it. The bit also escaped with no damage, since the track was just aluminum.

We pretty much laughed it off, since there was no serious damage, but we hope it was just a one-time fluke. Thoughts on why this happened or just plain comments are always appreciated!

-- Tristin King -- When in doubt, sand it.

6 replies so far

View dannelson's profile


194 posts in 2549 days

#1 posted 01-09-2013 04:16 AM

Mistakes happen, ever try to run a cnc during a thunderstorm? Bad idea. Static discharge from dust collection. Bad results. White noise, I still don’t understand that one but it’s bad. Trip over the power cord unplugging the operating computer while running bad. Forget to x y z zero bad. But with all that said cnc sure is fun and a challenge and I wouldn’t want to woodwork without one. Dan Nelson Nelson Woodcrafters

-- nelson woodcrafters

View REO's profile


929 posts in 2252 days

#2 posted 01-09-2013 06:10 AM

started without homing? the machine didn’t know where it was and went to the first line of code.

View NiteWalker's profile


2738 posts in 2755 days

#3 posted 01-09-2013 06:54 AM

You can flip the damaged track over and no one will ever know… ;-p

-- He who dies with the most tools... dies with the emptiest wallet.

View djg's profile


160 posts in 2340 days

#4 posted 01-09-2013 11:27 AM

I put a sacrificial piece of MDF right on top my CNC bed just for this reason. Cheap and easy. If you ar concerned about how flat it is, make up a flatteniing routine tool path with a large straight bit to flatten the MDF bed.

-- DJG

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266 posts in 2425 days

#5 posted 01-09-2013 12:27 PM

Dan, We’ve had our fair share of mistakes… I myself have forgot to xyz zero a couple times.
REO, I think you may be right, but the machine is usually able to seamlessly pause and resume.
NiteWalker, That’s actually a brilliant idea!
djg, Another good idea. We’ve been running this thing all day for nearly every school day since September. I’m surprised this is the first big mistake. I’ll mention it to the class. Flattening a big piece of MDF would be more accurate than the current top, as it is slightly out of flat in the middle.

-- Tristin King -- When in doubt, sand it.

View djg's profile


160 posts in 2340 days

#6 posted 01-09-2013 01:02 PM

I use a flattening routine to even out the hills and valleys with respect to the gantry. No matter how much sag you have, this will fix it.

-- DJG

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