E-Stop

[bkukowski]

Just curious if anyone has. I am currently designing my own e-stop for my phoenix cnc router.

[Sporqster]

Would fear for my life when the owner of the mill finds out I've milled a ridge in the top of the table count as 'for personal safety'?

[JFettig]

never for personal safety.... crap I dont even have estops on my machines I only use the estops at work to shut off the drives before I shut down the machines.
most of them are enclosed.

Jon

[stuart76]

depends what you mean as personal safety? Ive used it a few times while destroying tools and jobs (as you do). Also use it when working on or in machines to avoid any disasterous outcomes.

[Chris D]

I am surprised the safety police have not come running already about this thread. It seems as though many people believe that there should be absolutely no chance of being hurt no matter what they do.

E-Stops are good, they are highly visible and, if placed in a good spot, easy to HIT when needed. On my hobby machine, I have used it a couple of times to prevent the machine from doing something I didn't think it should - mostly during initial testing after construction.

On industrial machines, I don't recall hitting E-Stops for much of anything. It was always easier to hit Feed-Hold and or Reset to stop the machine and deal with the problems in that manor.

As for hitting E-Stop to prevent harm to myself, never. If I am near something that can hurt me (on my machine or on most industrial machines), chances are you can't get to the E-Stop button anyway.

If you look at industrial machines, the E-Stop is usually located outside the work area where, from operating the machine, you can see & hit the E-Stop. From that position, it is rare you could hurt yourself - you are not in the work area where things can hurt you. During setup, when your hands are inside the work area where there are moving parts and such, there is generally no E-stop that you can get at - doesn't make much sense for personal safety does it. So, my observation is that E-Stops are put on machinery not to protect the operator from harm, but to protect the machine from harm.

Kind of put's things into perspective as to what (rather than who) is being protected by the machinery builders and safety police.

[Al_The_Man]

The E-Stop is noted for being the hardest button to find on a machine
Here is the NFPA79 regulations for Industrial Machinery, all equipment manufacturers in N.A. at least are supposed to conform.
Al

[ghyman]

I grew up in a shop on a lathe that turned ø12"-18" shafts up to 9 feet long, and vertical machines with up to ø108" tables.
Big parts, big machines.
It's unfortunate that the machine manufacturers at that time (late eighties) chose to make the e-stop shut down EVERYTHING.
A broken clamp let a part come loose from a vertical turning center that a friend of mine was running, and he hit the e-stop.
After what seemed like minutes, but was probably less than five seconds, the table was still spinning at 200-300 RPM, (the e-stop killed the hydraulics, which provided braking for the table.) and the appx 1.5-ton part came out of the machine, killing my friend.

I hate the e-stop button, and would really prefer to see machine tools with a "stop" button that is as easy to find (and hit) in an emergency.

Granted, there should always be a perfect setup, and perfect tooling, perfect toolpaths, etc. And the operator should always be familiar enough with the control to know where all the buttons are.
But in the middle of a two-hour rough turning cycle (on the tenth part in the order), it's not always feasible for the operator to be right next to the control in the unlikely event that there will be an emergency!

Anyway, that's my two cent's worth.

Feel free to raise a glass in a toast to a fallen fellow machinist...

Here's to you, Joe.

[sbrpollock]

I'm Sorry to hear about your friend. I think I would have gone after the manufacturors of the machine with a vengence.

I work in very heavy industry. When commisioning equipment, we always run the machine up to its full design limits (such as speed or load, what ever is appropriate) and E-Stop it BEFORE we turn it over to production. This way we detect things like you have described and get them dealt with before the machine is in opperation producing a product.

I have seen many machines that had E-Stops that most certainly protected the opperator. For example some equipment I commisioned a couple years ago had a cable running the length of the machine, about waist high, right in front of where the opperator worked. If the opperator got caught and was being pulled in, the cable stopped the machine within a few hundred milliseconds. Of course the opperator would probably still have a miner injury, but at least he wouldn't be dead.

Have I ever hit an E-Stop to protect myself? Hell yes! I hit an E-Stop the other day that probably protected a whole crowd of people. I'm currently doing maintenance on a production machine that is about a quarter of a mile long and three stories high. I was in a position to see the product (Steel strip about eight feet wide traveling at about 800 feet per minute) that runs through this machine broke. I hit the nearest E-Stop as the loose end was making its way to about half way through the machine. If it had gonne much further, it would have really created a lot of havoc in an area where a lot of people work.

When things start comming apart or going wrong with this kind of machinery, being a couple hundred feet away isn't even safe!

The equipment and machinery I deal with has the potential to kill, injure, or scare the hell out of dozens of people at a time. I have seen E-Stops save a lot of people not just property.

[freak_brain]

Ghyman, I am very sorry to hear of the death of a friend.

I am not convinced however that e-stop is bad based on that problem. I have seen many situations where it did good. I personally work in very large machining. My machine, a horizontal Ingersoll, has nearly 30 feet of "X" travel. It has multiple interchangable spindle units. One day I accidentaly cycled started my machine while in a very bad situation--kind of hard to explain the real situation--. (The remote pendant can start the machine). Without the E-stop I would have been toast my friend. Now, this may be an rare situation but for me, it only took that one time. I'm not saying anything is 100% but I personally think it serves more good than bad.

Just my two cents
-AJames

[Al_The_Man]

In most countrys there are regulations in place for commercial machinery as far as E-stops, but the thing that really bugs me, fortunately it is rare, there are still manufacturers that shut the whole machine down with e-stop, including the CNC control
There is absolutly no need for this which makes trouble shooting a nightmare, when I install a system, I not only leave the CNC unit on, which reduces the work of re-zeroing the machine but I also leave the inputs active, they are mostly low voltage anyway, this way, on a CNC machine at least the input logic can be seen in its active state.
I just shut of the supply to the CNC outputs and supply to contactors, motors, and all moving parts, as per the code.
Al.

[CNCRob]

Originally Posted by Al_The_Man In most countrys there are regulations in place for commercial machinery as far as E-stops, but the thing that really bugs me, fortunately it is rare, there are still manufacturers that shut the whole machine down with e-stop, including the CNC control There is absolutly no need for this which makes trouble shooting a nightmare, when I install a system, I not only leave the CNC unit on, which reduces the work of re-zeroing the machine but I also leave the inputs active, they are mostly low voltage anyway, this way, on a CNC machine at least the input logic can be seen in its active state. I just shut of the supply to the CNC outputs and supply to contactors, motors, and all moving parts, as per the code. Al.

Thats the way my RYE machine is at work. If I hit the E-Stop, I pretty much have to restart the whole machine. If something minor happens I usually just hit the cycle stop. But if its something major I hit the E-Stop because cycle stop don't stop the bit. Fortunatly I have only had to use it a few times though.

[bobgerman]

Although I can't say that I specifically remember having to ever hit the E-stop in a panic for personal safety (I probably have) I have worn them out using it mostly for set-up/maintenance safety (the machines I work with (Amada) allow me to do this without shutting down). Anytime my personal safety is in jeopardy, i.e. when any part of my person is in harms way, I make sure the E-stop button is depressed and locked to prevent the machine (or somebody else) from making any kind of dangerous move. It just makes me feel better.....I kinda like my matching set of fingers.