Unnatended ShopBot

[mikejohn]

A question has arisen from comments made in a couple of recent threads thread.
People are starting their bots working, then locking the doors and going away, to come back when the file is finished.
Is this a common practice?
I recognise that you have to be certain the file will cut clean, but what safety features do you have in place?
What if the router/spindle stops but the shopbot carries on?
Or the vacuum/clamps fail?
If this is a common practice, and nobody is reporting huge problems, its something more to think about.
...............Mike

[elcruisr]

I will have to say that this is running a fire risk. I have had two instances in three years of having to put out a fire on the table. Both very small and easy to handle but that was because we were there in the shop with the machine. We NEVER leave ANY machine running alone. One instance was a computer error which stopped the cut and left the spindle running on some particle board. I was across the room and after crossing the room to see what was going on I had smoke and that wonderful orange glow that sent me for a water bucket! I never could repeat the error or the stop in the same file, let's hear it for Swindlz (Our local name for Windows). The second time my operator was at the machine and a reconstruction of the event and looking at the cutter and material is that the cutter hit a chunk of metal in a piece of wonderful cheap imported plywood which shattered the cutting edge and while the increased cutting resistance stalled the drivers in about 4 inches we had a great little fire started that sucked it's way into the spoil board and started on the plenum in the little time it took to shut down.

Since these incidents I have talked to others who are running "big iron" and have heard that this is not all that uncommon. Several places keep a buckt of water at the operators station for such an occurence! We have opted for a 10 pound CO2 extinguisher next to the e-stop.

Eric

[gerald_d]

I suppose that a big vacuum pump sucks all the smoke into the table, making a smoke-detector above the table useless. We've also had some smoke occasions - thank goodness we didn't have vacuums and dust collectors fanning them along.

I think you can walk away during probing, but not during cutting.

[mikejohn]

Even after 6 months I never am more than 5 metres away from the beast, which is why I was suprised to hear that others leave them unattended.
...............Mike

[gus]

Over the years I have seen more types of equipment self distruct (mechanical, electrical,electronic, you name it) to ever trust one like this to run in my shop unattended. They make automatic fire control system but boy do they make a mess. Also for those of you at home with someone living next door it is one thing to burn your own garage and house down but the guy next door may be somewhat upset when you take his with it.

Ted

[gene_marshall]

I am sooooooo reluctant to answer here.
As soon as I write this I'm sure to have a nuclear meltdown in the shop.

My remarks about unattended machines referred to operating without a man standing there.
Surely, if you are going to sit a guy on a barstool to watch the thing, then you should have somewhat better confidence in your programming.

We set up and run our botsin the morning and most often allow them to finish after we leave for the day.
We have had good luck( knock wood) with doing so in the 6 years since our origional purchase.

occaisionally, the brushes wear our unexpectedly and we break a bit or 2
A town wide power outage tested our UPS's andworked quite well, stopping the bot, turning of the routers and holding the position for restart in the morning.
We cut solid hardwoods almost exclusivly and very seldom see mdf. i understand the flash point for mdf dust is pretty low.

I am not advising anyone to do what I do.
And shopbot does not advise this either.

My point was that the legacy lathe requires an operator, where the bot does not.
i do routinely go for lunch and let it run.
as well as in my office to type these forum posts.
How far is close enough?

I suppose if I slept on a cot in the other room, then the bot would not technically be unattended.
But that could be more dangerous than anything.

I am quite comfortable with this machinery.
Maybe my way of thinking is not for everyone

gene

[marshawk]

The other part of the puzzle is that you have to know how to set up your toolpaths.

We routinely search through the file for deep plunges and slow the speed way down until the first plunged cut is performed.

Our usual cut shears off a small bit of the workpiece on every pass and does not get hot or smoke. The plunges do, but we have never caught a piece of wood on fire.. (Gene is now feverishly knocking wood)

Also, our bits are 1/4" tapered to 1/8". If the bit gets stuck in the wood, it breaks.

Know what you are cutting and how you are cutting it. Know your machines limits and ensure that you don't exceed them. If the machine is going to break, it's going to break whether you are watching it or not. After watching for the first few minutes you should have a pretty good idea of how the piece is going to cut and you can judge from there whether you need to keep a closer eye on it.

One of the nicest things about having a robot do your work is that you don't have to be there to watch it every split second.

[mikejohn]

I certainly do other things whilst the 'bot is cutting, I just don't have confidence in leaving it unnatended.
Only today I had a new happening.
Last week I was forced to change routers. I routed the cables exactly the same as the previous router.
Today it caught up whilst in the furthest x,y position, breaking the cable tie attaching it to the bendy plastic wire carrier, but did no other damage.
What, I ask myself, would have happened if the cable tie had not broken and I had been home in bed?
I recognise these huge car manufacturing robots happily work away with little supervision, but somehow I fear the ShopBot may not have the same failsafe devices.
................Mike

[gene_marshall]

Mike,
When we change out our routers... we leave the cord attached to the bot and change out the router from the switch. That way we don't have to replace a ton of cable ties.

Also, on the origional topic... SAFETY starts between your ears...( I am now saying the insanely simple and not directing this at anyone)
there is no substitute for being comfortable with your own procedures. Let NO ONE try to convince you to take a risk that you are unprepared for!
We have had these routers for quite a while and feel comfortable doing things our way. I am certain that there are other cuts on other projects that would convince me otherwise.
I doubt that I would leave mdf cutting unwatched ( even to run to the head)
decisions like these are best deliberated long and hard.
Cheers
Gene

[jay]

And I thought the original post was directed at me!

On jobs that I have cut before and on straight long tool path jobs that I have checked the file with the 'file editor' and or maybe run it through the 'preview mode', for the things that Chip and Gene mentioned above, I have no problem letting the Bot work merrily away on it own. In fact, it is currently running while I have come home for some well deserved supper. If I get back within the next couple of hours it will still be cutting, if not the router, dust collector, etc. will have shut off at the end of the file and the machine will be sitting there waiting for its' next instruction.

If you keep a maintenance log, your equipment should always be in top notch condition. I will concede that if something was to come to a service point in the middle of a file I would change out the part or do the maintenance early before I would leave anything unattended.

When you make the decision to multi-task it must be done with long and hard deliberation and one has to accept the consequences and limided risk if things do not go a planned.

Cheers,
Jay

[3imoh]

Has anyone tried monitoring the bot with a video camera? There are monitoring cameras out there that hook up to your local network...here is one that has a microphone as well:

http://www.axis.com/products/cam_207/

You could get a wireless PDA that you could carry around with you to monitor the video and sound...it may be enough of a babysitter to feel ok about letting the bot run while working on other things...

-Howie

[benchmark]

Hi Howie

I have a web cam over the Shopbot which I can monitor in my office.....I left the mike disconnected, I didn't fancy the screaming router. It works really well.


Paul

[jseiler]

I've done this as well. I bought a wireless 802b camera for about $60. (I think its a linksys and it has no microphone, a plus actually). I mounted in a box with a plastic front on it and have it aimed down toward the cutting area. That way I can monitor the bot and watch my daughters in the house. If there's an issue, I can run out the garage really quick. I'm working on a system to clear the plastic front of debris as it runs like they do with in-car race camera, but I haven't found time for that. I'm thinking a circle of plastic between a couple of pieces of cloth to clean the plastic. If I mounted the circle of plastic on a timing motor, it would slowly spin, cleaning the area in front of the camera. Right now, I just have to wipe it off after each job or during a long job.

John

[rcnewcomb]

For those who are successful in running unattended bots, what is your configuration? (i.e. why aren't you being plagued with communication loss problems like I am)?

What model Shopbot?
What version of Shopbot software?
What operating system?
What brand of computer?

[davidp]

Randall,

We run a PRT Alpha 96, SB 3.4.12, Windoze XP, Dell Laptop.

We were having communications problems particuarly late in the day. We found our control box was getting extremely hot around 55c we installed a huge heat sinks on the back cooled by a bank of fans that are thermostatically operated. The box now only gets about 5c above ambient temperature and we have not had a communications problem since.

And yes we leave the shopbot running by it self but we are never very far away.

David.

[jeff_rowley]

Randall,
You aren't by any chance running with a wireless network, (or for all I know, a wired network, too), are you? I was using a wireless network to transfer files from the design computer to the shopbot computer. I had a couple of lockups in the middle of cutting files. I've started disabling the wireless network while cutting and have had no further problems. It's a bit of a pain to enable the network, download the files, and then disable, but I guess it's all I've got for now. To be honest, it would probably be quicker and easier to just pick up a little USB flash drive and sneaker net it out there.

Oh and to stay on topic, my Shopbot (PRTAlpha 96) runs in my garage. I routinely leave it running and go back inside. I check on it fairly regularly, but to be honest have never run across a situation that would cause me concern. In fact, I was cutting a lithophane in some corian last night with a 1/32" bit. I just went to bed. Looks like it finally shut down around 2AM. Maybe just lucky I guess. All these tales of fire, etc. are starting to worry me a bit more.

Good luck!

[marshawk]

Hey Guys,

We ran our network to stop the sneakernetting.

The only thing that we can't do without a bunch of waiting is communicate to a 'Bot while it is cutting.

One thing that I had to do was delete mapping to the machines. Every time I opened Windows Explorer, the computer would go out and try to read the hard drive on the active ShopBots and that would take several minutes and sometimes pause the carving.

Turn off every kind of automatic update or scheduled maintenance that is run by the operating system or virus program. Do these manually.

Chip

[richards]

Jeff,

On the computer that runs the Shopbot, none of the drives are shared. When I transfer a file, I copy it from a shared drive on another computer to the Shopbot computer. To this point, I've had no problems with the network (other than a flakey wireless connection). Currently, I'm running wireless 24/7.

[jamesgilliam]

Randall, We have been running our PRT-96 down here for the last 4 years with no problems. Using the DOS based software, I just don't see the need to change, Windows ME, HP desktop that is dedicated to the machine. I will say that, like David, we are never too far away.

[richards]

Leaving my Alpha unattended is something that I could never do. A quick look at the spoil board shows many discolored spots where the spindle was turning to fast for the feed rate, especially sharp corners and tight curves. Those discolored spots show that the spoil board was getting hot enough to burn. Many times I set the feed rate to 6-8 ips second, and then adjust the spindle speed to get the desired chip load; however, ramping slows the feed speed down to the point that things get hot and scorching occurs. Depending on the parts being cut, my average feed rate might easily be closer to 3-4 ips rather than the programmed 6-8 ips.