Felder "PCS", competing technology to SawStop

[ben_r_]

I find having the safety device actually makes me more careful.

Same. Now not only am I concerned about general safety, I also triple check everything to ensure I do not cause an accidental break trip and loose one of my expensive blades!

 

[ChuckM]

I shall add that when working with other machines like the bandsaw and mitre saw that don't have the extra finger saving protection, I'm extremely conscious of their safety needs. There're many accidents reported in the use of mitre saws.

The mitre saw is the next machine I hope they would introduce the finger-saving technology to (bandsaw finger-saving technology is already available in the meat-cutting industry).

 

[jeh]

Wow! Now if they or someone could put this technology in a similarly priced option to a SawStop PCS, we'd have something!

That said, I hope that someday when SawStop redoes their mechanism so the blade isnt damaged those of us that own one are offered some kind of retrofit kit to upgrade to the new mechanism!

SawStop led the way and makes a great product. Destroying a blade is a non-issue once you figure out you still have your finger(s) left. The quest for X feature on Y device is never ending and results in deadlock waiting for something that will never come to light or will, but by then your won't need or want it. If you like the saw then get the saw and move in. Hopefully you will never have it kick in and destroy your blade.

The concept of being able to press a button to reset a finger save device is insane. Once you have triggered it you need to stand down for the rest of the day and do something else. I realize there are cases with wet wood that could trigger it, but you can turn the safety feature off if that is a concern. I don't cut pressure treated materials on my PCS so I don't have any experience with issues related to that.

 

[Michael Kellough]

I’m with JimH2. Wrecking a blade as often as you would otherwise cut your finger on the tablesaw costs how much in a lifetime?

I’ve been using tablesaws for about 45 years and only cut a finger twice. The first time was so long ago that after the little slot in the end of my index finger healed I found that dialing (rotary) dial phones was much easier. The second time was superficial (I’m learning).

So if I’d had a SawStop I might have had to replace two blades. Amortized over 45 years that’s insignificant.

 

[Alanbach]

I’m with Jim and Michael. Some people call this technology “destructive” . I would gladly “destroy” all my good blades in exchange for one (or more) of my fingers. We should all be grateful that this technology exists and is available in a high quality, competitively priced line of table saws. I cannot tell you how many older woodworkers I know that have lost fingers. They did not have the option of this tech when they had their accidents.

 

[Cheese]

I cannot tell you how many older woodworkers I know that have lost fingers. They did not have the option of this tech when they had their accidents.

It's often said that the two largest groups of people that are missing fingers are woodworkers & butchers.

Here's the solution for butchers, BladeStop™:

https://www.carnitec.com/en/bandsaw-bladestop-400/

[attachimg=1]

 

[mkasdin]

Speed of light = lasers that detect skin (Temperature) near the blade

 

[ChuckM]

Wait a minute...what if someone is cold-blooded? [big grin] [wink] [big grin]

 

[Cheese]

Speed of light = lasers that detect skin (Temperature) near the blade

Whoa...the light bulb just went on.  [big grin]

Ever since Felder made their announcement, I've been curious as to what technology they're using for their PCS system.

Differential temperature recognition...now that makes sense.

The BladeStop technology used in the meat industry uses color recognition differentiation to trigger the mechanism. The blue gloves used are a given in the industry and they trip the sensor when they enter the field of view.

But when it comes to woodworkers, all bets are off. Some are gloved but most are not. However a piece of oak at 90º will yield a different temperature signature obviously, than a finger at the same ambient temperature.

 

[Svar]

Speed of light = lasers that detect skin (Temperature) near the blade

No, PCS uses capacitive proximity sensor. Speed of light = electromagnetic wave propagation .

 

[Cheese]

No, PCS uses capacitive proximity sensor. Speed of light = electromagnetic wave propagation .

OK, please explain that...I seem to remember that while watching the videos of the PCS that the system was starting the shutdown process of the saw before the capacitive sensor was even within sensing distance. You've garnered my interest.

 

[Svar]

No, PCS uses capacitive proximity sensor. Speed of light = electromagnetic wave propagation .

OK, please explain that.

Wikipedia does it best:https://en.m.wikipedia.org/wiki/Capacitive_sensing
There are few great videos on YouTube. It's not expensive, you can make one at home.
It has to be calibrated because in theory it should sense wood or anything else for that matter.

 

[Steve1]

I don't see how it could be an external sensor.  So they must be making the blade as an element of the capacitive sensor.  Wood is a good insulator, a human hand not so much.  So the hand should be able to be detected before the finger actually touches the blade.

 

[ChuckM]

These interesting exchanges beg one question: How fool-proof is the PCS technology? For example, will it work in extremely cold or hot conditions? (My shop could easily be under -10C or lower in the winter.)

SawStop technology was easily explained and understood from Day 1. as of today, no one single failure of the SawStop technology (in protecting against serious injuries) has been documented.

I hope Felder will soon explain its technology and reliability in layman's term.

 

[threesixright]

Its in German, but it explains pretty clearly how PCS works


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[Gregor]

Simple technical explanation is that the felder detection works with the same principle as a Theremin and from this is able to easily detect the user (presence, distance and speed of change in distance).

That's very easy and cheap to implement, should be able to work error free for the lifetime of the machine.
The hardest part of it likely was to come up with the brilliant idea to repurpose a 90 year old music instrument as a safety detector.

 

[threesixright]

Simple technical explanation is that the felder detection works with the same principle as a Theremin and from this is able to easily detect the user (presence, distance and speed of change in distance).

That's very easy and cheap to implement, should be able to work error free for the lifetime of the machine.
The hardest part of it likely was to come up with the brilliant idea to repurpose a 90 year old music instrument as a safety detector.

Although the sensing was easily solved (curious where they placed the sensors), I do think the mechanical part of retracting the saw (@ full speed) was a little bit more of a challenge. Either way, it beats SawStop, when just looking the technology. And always works, which IMO is a big plus.

 

[Cheese]

Simple technical explanation is that the felder detection works with the same principle as a Theremin and from this is able to easily detect the user (presence, distance and speed of change in distance).

That's a very interesting read on the Theremin... [cool]

Thanks for that [member=53905]Gregor[/member] . 

Using 90 year old technology to save fingers. I wonder who came across this in the first place. It's not like it's on the radar screen of probably 99.995% of the population.

 

[threesixright]

@cheese

Watch more Big Bang

// ingenious device !


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[Gregor]

Although the sensing was easily solved (curious where they placed the sensors),

Simple: they use the blade as an antenna, basically it's having the function of one of the metal rods on a Theremin.

I do think the mechanical part of retracting the saw (@ full speed) was a little bit more of a challenge.

No, not really. It's a spring loaded linear guide that is held in normal position by the two electro magnets attracting each other. When the system fires one of the magnets gets polarized the other way, adding the repelling forces of th magnets to the energy stored in the spring. Likely the inverter controlling the blade motor also gets put in full-steam-reverse, that should actively break the blade quite rapidly (which might, depending on geometry, add additional momentum to the downward movement, similar to the sawstop but without destroying the blade in the process).

It's a relatively simple electromechanic system, the brilliance of it is in coming up with the detection.

How cheap electronics can be employed to prevent accidents with handheld tools can be seen in this video:
where you also you can get an idea on how fast breaking can be - I personally wouldn't use machine learning for this as the downsides (not being able to debug this, possibly train on the wrong stimulus without knowing) this approach brings are IMHO not worth using it for that application.