Ok I’ve had my S5P for exactly one week (and loving it), have 7 hours on the machine so far, but new to it overall.
I setup a job that spans the entire 2x4 bed, and est cut times look like anywhere from 9 to 12 hours (depending if you look at Vectric or CM).
My question is… any precautions I should take with a long job? Im confident in my tool paths (I’ve done lots of samples), but new to CNC. I do feel comfortable in walking away from the machine as long as I can ensure work holding is proper (im planning threaded inserts).
I’d love to kick off most of the machining before I head out for work. Maybe Im naive…
I wouldn’t recommend it. Try to break your toolpaths into individual shorter actions. When I run stuff that takes a while, I find other things to do in the shop, so that I’m close. It’s easy for an offcut to pop up, snag the bit, drag the workpiece over, and then the fun starts. I wouldn’t leave my tablesaw alone while ripping lumber with a power feeder, same mentality with any power tool.
The time from “Huh, that was a funny noise” to “FIRE FIRE FIRE” can be, literally, less than one minute. Lots of people will tell “It’s fine, I do it all the time”, but it only takes ONCE for there to be a problem. It’s not fine, they are just lucky.
@mhotchin you beat me to the video hahaha. I will say i have looked away/stepped inside but never further than earshot, I have caught it so many times either bit slippage, motor skipdue to hang up, hit the workholding clamp ect. And could have caught fire. Plus @jer5091 what time of dust collection do you have set up, is there a chance of an obstruction in the hose ect? Fine dust catches on gire quickly as well so there is a potention of having a bit stuck with essentially kindling around it. I do have a friend who has remote access to his computer and a live feed camera and leaves his but again what happens if the remote access fails? Long story short break up toolpaths or pause and continue when you can be around or 3rd option can always edit gcode (search forum) to pick up where u leave off.
For long jobs I like to throw in tool changes to brake it up and have an opportunity to check my bit. I usually don’t change the bit but I may check the tightness and verify it hasn’t moved by marking a line on the bit where it meets the nut. It kind of sucks having to stop every so often but it sucks more to have a 9 hour project destroyed at 8 hours in. Plus the tool changes also gives me places to easily restart from if something does happen and the piece is salvageable. And the fires are real. I personally had a piece of oak climb the bit and get stuck against the collet nut long enough to start burning. Just as I seen it and went to shut it off I saw some of the glowing hot ash get sucked up in the dust collector. I got it all stopped and cleaned up at that point. I had stepped away maybe 10 minutes. Now if I step away I have a video camera and I still don’t go far.
With @mhotchin vid, I walked away from my machine cutting some MDF, It was the chip kind with lots of glue. The bit burnt with the glue used to hold it together, and it sent hot chips to the dust collector. On returning to the machine I detected smoke. I was coming from the dust collector.
These are hobby machines without the safety of commercial equipment. Be careful.
My Shapeoko 3XXL runs perfectly when I am near in the shop (or sitting on the shop deck). It seems that as soon as I walk for away for more than a couple of minutes, things always seem to go amiss.
Never leave the machine running unattended/unsupervised.
If a cut is taking a long while, look into why — adjust the tool used, the toolpaths, feeds, speeds, &c. The feeds and speeds in Carbide Create are quite conservative, see:
See
for concepts on this and see the series #MaterialMonday:
I’ll also add in the “DO NOT WALK AWAY” warning, especially with runs that long. Even with a perfect setup dust can get in the nut and collet possibly moving the bit (even pulling it completely out), causing all kinds of damage to both your machine and project. And as already mentioned, a fast turning bit can cause friction and ultimately a fire.
Generally not a good idea. Avoid it if at all possible.
That being said, i’ve got some projects right now taking 12 hours to cut, i can’t be down in my shop for that long. So what i’ve done is added a nest camera on the CNC and i have a nest protect smoke alarm right next to the machine as well as a fire extinguisher near the door into my shop. I usually keep the camera feed up so i can check it constantly. IF something were to happen, i would get notified pretty quick and can run down there. It’s not ideal, but on that long of a cut, not much I can do, 99% of the time i’m in the shop working on other things.
I also have a very large dust collection system, so chips aren’t an issue. That video above, cutting MDF and no DC, no wonder it started a fire so quickly.
I personally would not walk away from a running machine, cause it only takes a second for something bad to happen which could ruin your work and or worst yet your machine.
I don’t leave the house but I do step away from jobs that I have tested and have confidence in, however even then I have the following items setup for safety:
Smoke Detector (Connected to security system with central monitoring service)
My SPRO is enclosed and I mostly do aluminum jobs that take a while, so I don’t have as much concern with fire, but I run an ER20 spindle and had 1/2" bits pull up some projects in the past that can get kind of sketchy. The poster that mentioned would you leave any power tool running unattended was a good example…I never thought of it that way, but with the above items I feel confident enough I can go grab a bit to eat in the kitchen or work on programming the next job from my desk.
Not to mention stepover, DOC and z safe having a significant role in time taken. I see that the Carbide 3D tool library also has very conservative settings for their bits. Others are too aggressive for machines running regular routers. All of it takes practice, understanding, and testing. I find some of the better gains for me are setting conservative finishing passes, running larger DOC and stepover for roughing.
