help with HD4 shark

[hunter62]

hello new to this so have patients I have a HD4 shark and I run a file
when roughing when it is almost finished it suddenly
out of nowhere plunges straight down has done about 4 times I have successfully completed about 15 projects with no problems
it is very random when it happens also all of a sudden once in a while it just goes where it wants and just sits there and spins
any help would be appreciated

[Rando]

Ouch! Definitely contact support; my understanding is that you're not alone in that experience....

Thom

[tpulley]

I would love to know what they say too. Although I am not experiencing a problem like that, its always good to know what could be and why...

[hunter62]

well this is what finally happened contacted nextwave getting the run around of course wife spent three days on phone with them they say
they are looking into problem

[Rando]

Correct me if I'm wrong, but THAT looks like a fire! What the...?

[SteveM]

I agree, something got so hot it melted the entire mount. I have no idea on how that could possibly happen.
Once Next Wave sees those pictures, you may have to explain to them how that happened.
For sure, all that plastic has to be replaces before you do anything. Looks like the entire assembly would need replacing.
Were you cutting something that actually caught fire?

[Rando]

Well, HDPE melts at 120 to 180 °C (248 to 356 °F), so whatever it was, there was an active flame; you can tell from the browning on the edges, especially the bottom. Isn't there supposed to be a probe on that nub? What's up with that? Where did that go, assuming one was there?

Both, given the size and shape of the damage, clearly a fire started. Normally, this would be in, say wood chips on the bed during an exceedingly slow cut where the bit is mostly just spinning against the wood.

I suspect it IS possible that the fire actually started INSIDE the router, and was blown out the bottom, and then over the plastic. Can you tell whether the burns at the bottom of the router look like flames lapping UP to it, or being blasted OUT of it (downward)?

Yikes, sounds like getting/checking/charging a nearby fire extinguisher should jump to the top of your "Monday morning todo list"...if not Sunday .

Either way, you're right that the z-asis carriage; the entire thing, not just the visibly burned parts, will have to be replaced. Even if it doesn't have apparent deformation, the other side would have gotten warm enough to "set" the creep of the router into the slowly-melting plastic. There's almost no way the other side can be dimensionally correct at this point.

Bummer! But for the....fact that I only cut Aluminum, go I. I suppose we're fortunate so far in having had few. Unofficially (of course), I think this is only the second one I've read about here, but a search might turn up more than my lazy self can muster .

Regards,

Thom

[SteveM]

It's hard to say, but it looks like it's melted to the router.
If only one side were to be replaced, I don't think he could never get it squared to the table top, without replacing the entire mount. the lump of melted plastic is the touch probe for the virtual zero setup. That sucker is gone. It might have gotten so hot, the lower bearing of the router may need replacing as well. I don't see how there could be any grease in that bearing anymore. It probably boiled out of the bottom of the router.

[cjablonski]

Based simply on operations alone and a bit of perception and experience I would think the fire was outside the router towards the lower right side facing the machine. It would seem somewhat unlikely to have started within the router itself as the motors fan blows air downward through the router while in operation at anywhere between 8-24 thousand rpm. With that rpm and CFM of movement it would've extinguished a small ember from its ignition point or moved the source away from the center of the router motor. Somethings I wonder.

Did the gantry stall on a fixed point? Even if this occurred the bit of the router, even with a downcut, would have expelled spoil., by default not leaving enough friction or materials to create the heat/fuel to start a fire.

Did it occur while running? Being that the majority of the viewed damage is fixed to the lower 1 side of the mount this too seems unlikely unless the cut was fixed within the are of the flame source for an extremely extended period of time.

Did this happen during the operation of the CNC? With all that I've said above, albeit plausible it seems unlikely.

I somewhat wonder if this is consequential damage from an unrelated circumstance that had nothing to do with the cnc operating at all.

Last one..... a question tagged on from the last statement. Was there an ignition source outside the envelope of the cnc that caught fire as the CNC was stopped? This potentially collateral damage from that?

Inquiring minds need to know

[Bob]

Were you monitoring the operation when the melting/fire was happening?
What did you observe?
Thanks,
Bob