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Author Topic: CNC safety system possibility for CNC machining and Mach  (Read 4016 times)

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Offline zealous

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CNC safety system possibility for CNC machining and Mach
« on: November 11, 2006, 01:51:13 PM »
CNC safety system possibility for CNC machining and Mach

I heard talk about a new table saw that is equipped with new type of safety system called SawStop.
I find this very interesting and a possibility for the CNC industry to climb on board and develop something similar.

So everything has tonal qualities, like an orchestra of sounds. Our machine might sound like a bunch of random chaos of sound but they actually have a continual tonal frequency (when functioning properly).
There is a distinct change in the electrical signal when a finger touched a spinning.

A couple things come to mind for possibilities:

-Stop a spindle or a machine from harming a person.
-Stop a machine from causing damage to it’s self.
-Accurately diagnose the physical health of a machine.
-Fine tune and adjust appropriate spindle speed by detecting the spindles frequency and having a program appropriately adjust the RPM’s on the fly.
-Feed rate changes can be made more efficiently and accurately on the fly.


Here’s how Sawstop work’s:

“SawStop safety system includes an electronic detection system that detects when a person contacts the blade. The system induces an electrical signal onto the blade and then monitors that signal for changes. The human body has a relatively large inherent electrical capacitance and conductivity which cause the signal to drop when a person contacts the blade. Wood has a relatively small inherent capacitance and conductivity and does not cause the signal to drop.
A fast-acting brake stops the blade when contact is detected. The brake includes a heavy-duty spring to push a block of aluminum, called a brake pawl, into the teeth of the blade to stop the blade from spinning. The spring is held in compression by a fuse wire until contact is detected. When contact is detected, the system sends a surge of electricity through the fuse wire to burn the wire and release the spring. The spring pushes the brake pawl into the teeth of the spinning blade, and the teeth cut into the aluminum and bind, thereby stopping the blade. All this happens in about 3–5 milliseconds, or 1/200th of a second. At the same time, the angular momentum of the blade causes the blade to retract below the table and the power to the motor is shut off.”
http://www.sawstop.com/index.htm



 ;D Just some thoughts on the possible future of CNC and Mach  ;D

Offline ger21

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Re: CNC safety system possibility for CNC machining and Mach
« Reply #1 on: November 11, 2006, 02:12:31 PM »
Saw Stop came out with this several years ago and tried to sell it to all the major saw manufacturers. None of them bought in, so Saw Stop developed their own saw, which sells for about 40% more than their competitors. There's a testimonial on their site from someone that boght a different brand of saw due to the price difference, but sold it and switched to the saw stop after cutting off the tip of their finger. I'm sure most users would not pay the 40% extra $$, and wonder how long the saw stop will be around. It's a great thing for school shop classes, though.

Another thing, is that this destroys the blade, and the stopping apparatus needs to be replaced when a stop ocurs. Although I doubt it would happen often. Once a blade hits your fingers, I'd guess you'd be more cautious in the future.
Gerry

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Offline zealous

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Re: CNC safety system possibility for CNC machining and Mach
« Reply #2 on: November 11, 2006, 02:21:13 PM »
Here is the idea for or CNC machines and Mach which might work better and for little cost.

A small pulse of electricity passes threw the machine, if the machine or router is touch the signal is broken and the Estop is tripped or a pause and shut off of the router is executed.

I actually had two idea's in one.
-The other is to pick up the tonal qualities of the machine and router.
-The user can fine tune a program to there normal ranges.
-The program will push the machine to these ranges.
-If out side the range the machine will slow down to meet the normal tonal range.

just a thought any idea's on how to make better would be great  ;D

Online Chaoticone

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Re: CNC safety system possibility for CNC machining and Mach
« Reply #3 on: November 11, 2006, 03:13:43 PM »
Hey Jason,
    On the safety side. Help me understand, in effect, the cutter would be wired as a piezo electric switch that would emulate an e-stop. I would think this would be very doable.


http://www.alliedelec.com/Search/ProductDetail.asp?SKU=948-0309&SEARCH=&ID=&DESC=37F1%2DBB2%2DAC1&R=948%2D0309&sid=4555128069A5E17F

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!