Thread: How to wire emergency stops to shut down the whole shop

Could also prevent the actual E-Stop from working. If somebody was heads-up enough to hit it but power had already been removed then the person who cut power will be in for a whole new world of lawsuits.

This PDF discusses a networkable E-Stop controller:

http://info.bannerengineering.com/xp...ture/51246.pdf

If the OP desires to propose a nanny-state sort of safety system, perhaps I.D. cards would need to be swiped at each machine, before the controls would respond?

I will keep this short and to the point:

1: Cutting power is not an estop, and is very dangerous. This is not an option.
2: Wireless anything has no business functioning as an estop, nor does any computer or plc. Must be hardwired.
3: Estop circuits and wiring should be a logical 1 or voltage present in the non estop condition., This is for safety, if the system should fail because of a broken wire, or other problem the equipment down stream will go into estop.
4: a logical approach, wire in all of your estops around your shop in series, then parrallel a relay for each machine at the end of your estop chain. The relays are isolation for the machine. You would use a normally open contact from the relay, and then insert this in series with each machines estop circuit. Operation would be all estops out (estop contacts closed) energizes relay closing normally open contact(s) that are wired individually in series with a machines estop circuit. This would work fine if you had all cnc machines. On a manual machine, you would have to take a case by case analysis of how the machine can be controlled to stop. I.e. a warner and swasey 3a turret lathe has a hydraulic geared head, which uses a hydraulicly applied braking clutch. You would have to insert a directional valve to disengage the forward clutches and engage the braking clutch, and this directional valve would be wired into one of the estop relays. On a bridgeport milling machine, you probably would have to install a drive and parameterize it for a FAST_Stop. etc etc. These are the machines that will complicate and add expense to your idea. As i said, if you have all cnc machines, 7 estops and 7 relays, conduit and wiring , not too bad on the wallet., all others make it very complicated to do and to do correctly. An old monarch lathe coasting to stop after the power has been cut is far worse than having a properly trained operator know how to plug the spindle control to stop the machine. 30 seconds to stop the spindle is 29.99 seconds too many, so it makes implementing a safety that is effective very challenging. The "saw stop" system is a great idea on a low inertia table saw, and works well to keep people from sawing off their digits. To implement this idea on a lathe with a 20" chuck would probably take a forgin press the size of alcoas to pinch the spindle and stop it. My opinion is that a master "shop" estop does not solve any problem. Operator awareness and knowledge of the machine they are running does.

If the any of the machines you want to E-stop are fitted with an ON/OFF switch and not started through a relay system then you need to be sure that they will not start up when the power is restored. Such as a table saw in your home shop and the power goes out, when the powwer come back on the saw will start as the switch is in the run position.

Originally Posted by S_W_Bausch

This PDF discusses a networkable E-Stop controller:

http://info.bannerengineering.com/xp...ture/51246.pdf

If the OP desires to propose a nanny-state sort of safety system, perhaps I.D. cards would need to be swiped at each machine, before the controls would respond?

Hmmmmm . . . I'll see your requirement AND raise you that in a crash, the employees manager has to swipe his card to back the machine out of the mess and get it released for production again.\

Originally Posted by motion guru

Hmmmmm . . . I'll see your requirement AND raise you that in a crash, the employees manager has to swipe his card to back the machine out of the mess and get it released for production again.\

Why worry about any of this sorta thing... By the time it's implemented ALL Machines THAT;s EVERY ONE OF THEM of ALL BREEDS will be in CHINA and YOU wont have to worry about it....

OSHA and the EPA will have run ruffshod over ALL Congress Critters who have made new laws outlawing ANY AND ALL MACHINES in the USA.. er...USA division of CHINA..

My first thought when I read the OP was "Why the hell would anyone want that? It'd only take one person near a button or switch to panic and all hell would break loose.

Most places have a mains switch and that should be enough. In a thunderstorm all power could suddenly go and it's wise to use and work with caution at times like that.

I also notice that the OP asked a question and vanished into thin air.

When I first saw this topic, it made me think if a trip to a firehouse, with my son's kindergarten class a few years ago.

They had some switches that turned everything off it they had to leave and go to a fire.

The couldn't go around and shut off the television, radio, cook stove ( where they were cooking some great smelling chili while we were there), fan, etc. if there was a fire and they had to leave.

There was a master switch that shut it all of.

But, they didn't have any industrial equipment or were they using this for an E-stop.

JAckal

Every school shop that I've been in has had an "emergency stop" which shut the power to the whole shop. This was the common E stop technology at the time these shops were built. Of course for most machinery some automatic braking mechanism would be a huge safety benefit. On some school shop machinery there is a potential issue in a sudden stop for wheel or blade inertia wind the arbor nut off, a blade to jump off the wheel etc..

Going back to the original post the question should be "Why wouldn't you want someone to be able to quickly shut off the power or trip an automatic brake if your kid/grandchild was about to severely injure themselves or others?" A number of posters seem to forget that this is for a school shop.

Dave

Its common and std here in collage and school shops. As above though, in this day and age its far from the safest way of achieving what its trying to achieve. Most drives + VFD's can stop there motors, servos or spindles a lot quicker with power than with out.

Over here everything but the lights go off in the room with these kinda systems. There's also a easy key lock out for the instructor too. TO date i have seen it save more accidents than cause them. In a modern robotic - cnc shop that could be a diffrent story however!

I also notice that the OP asked a question and vanished into thin air.

Not the only person who doesn't stay around for the spirited dialog that ensues.

While this thread doesn't qualify for what I am about to discuss, there are many threads where the OP should have just used Google.

A few hours ago, I responded to someone who couldn't find high temperature paint.

Global Industrial seems to have 72 colors. OP could have / should have Googled "Engine Paint".

My attitude is typically helpful, but I do wonder if Milacron should set up a Mr. Obvious forum, where he could move all the "where do I find wire nuts?" queries.

I do credit the membership with being very tolerant of abuse of access to the experts of this website.

I took machine shop in high school during my junior/senior year and promise you there were no Estops on the walls and none on most the machinery.
This is were the the job of being an good shop instructor came into play.We spent the first 9 weeks in the class room learning basic machine shop math,how to read micrometers,blue print reading and most of all SAFE machine operation.It was the job of the instructor to weed out any dip shits who he thought could be a safty concern and send them to auto shop or what ever before we ever got to go into the machine area.

Machine shop trade is dangerous,we aren't playing with lego blocks,people get hurt/killed even after years and years of safly working.
I understand what the OP is trying to do,but like I said,it's the job of the instructor to INSTRUCT safe machine operation.If a kid was into horse play or stupid as a box of nails and couldn't make it past the first 9 weeks of book and hand work he never made it to the machinery.
We were tought to work safe at trade school and as much of the does and don't that the teacher could train us in the limited time he had,because once we were released into the work force he wanted to know in his heart we were trained to the best of his ability to work safe and smart.
At most shops the boss does not have an Estop under his desk or by the door any way.

Originally Posted by Dave D

Every school shop that I've been in has had an "emergency stop" which shut the power to the whole shop.

I've never been in a school with that kind of setup. Also, my home town just built a fantastic new high school equipped with a *huge* machine shop (CNC, manual, sheet metal, welding, even a paint booth!) and it does not have anything like that.

So, yeah, I kept that in mind. I think it's a good idea, just wanted to stress that it needs to be implemented properly. Cutting power to a half-horse SB is a lot different than cutting power to a multi-horsepower CNC spindle.

I took machine shop in high school during my junior/senior year and promise you there were no Estops on the walls and none on most the machinery.

If you lived with socialized medicine, you'd do your damnedest to stay out of the emergency room, also.

Check the locations.... I see a pattern.

I hear you have to schedule ripping your arm off, otherwise they just give you a roll of duct tape and tell you to sit down in the waiting room.

"Check the locations.... I see a pattern." Bingo

Dave

Originally Posted by doug8cat

You may think common sense would prevent the need for such a system but remember these are teeny boppers and some folks who just have no clue. I lost count of how many time I pulled a chuck key out of a lathe while the student was off doing somthing else, I then put the key in my office, most times after 15+ min of searching for it they would come and ask for another, get a lecture and there key back. Although hypocritical as it sounds that is my worst habit to this day.

Thats what he should he do.. make some sort of rally/switch if the chuck key is in the chuck the lathe wont start.

E-stops to shut down a whole production line are common.
E-stops to shut down a school shop are common.
E-stops to shut down all machines in a production or job shop are stupid.