homemade pneumatic controled miter saw

[poorfarmer25]

Hello I am hoping to start some light manufacturing, And I came up for an idea of a miter saw controlled by a foot pedal that would make that cut and push off the board so the next one could be rapidly inserted.

My idea is to use a moveable stop clamped to the table, two of these Speedaire 6W159 Air Cylinder, 3/4 In Bore, 5 In Stroke inexpensive cylinders

a air constrictor Arrow ASP-2SC Speed Control Muffler, 1/4 NPT, 9/16 Hex to slow the downward stroke, and a foot pedal
to control the setup, my biggest hangup is with what type of solenoid should I get to cause a delayed push off?

Also any general air advice is appreciated most of my dealing has been with hydraulic.

[ger21]

Just my opinion, but I think that's extremely dangerous. I can easily see boards getting pushed off onto feet, and hands getting in front of the blade

We have a crosscut saw at work with a 24" blade. The blade is under the table, and lifts up into a fixed shroud, so you can't get your hands anywhere near the blade.

[poorfarmer25]

Well if I get it to work I plan to be several feet on the far side of it holding the end of the board up and feeding it in, that's why the kicker is needed.

I have thought about just using a table saw and pressing the butt of the wood up against the stop like most people, however I plan on making lots of similar cuts rapidly and would rather be as far from the blade as possible.

[poorfarmer25]

This might explain it a little better, also if you wonder why I used a storm trooper its because the model had the best pose-able joints, also he is wearing eye protection

[g7bee]

I am so old that I worked in pneumatics long before all these electro-pneumatic gizmo's were invented.
If you do not get replies using solenoids etc and I can wipe away the accumulated dust of time from my brain, I could work out a circuit for you using pure pneumatics. The only problem may be sourcing the components. I live in England and have probably got most, if not all the components you would need for such a circuit, in my shed.
Good luck with the project.

Mike.

[Christian Knüll]

You may not need a solenoid to push the part away. You can just use a mechanical valve that is actuated by the saw arm itself when it's in its lowest position. The cut usually finishes before the saw reaches its lowest position so the part will be completely cut through before the valve activates the pushing cylinder.

[TechGuy5002]

LOL! Storm Trooper cuttting Wood! I also noticed his rifle is on the table for easy access for shooting those pesky rebels! You never know when they show up for a fight!

You can't push down on the safety since its not designed to have force applied to it. It may work initially, but it will break over time.

You also need to add some parallel blocking on the outer edge (closest to the operator). Normally the operator applies force to keep the work piece square against the backside of the saw. The blocking will need to include rollers so you can easily move the board forward. You may also have to use rollers on the backside otherwise it may jam up since wood is rarely straight and true.

Overall I doubt this will be a time saver. Perhaps if you automated the board feed the saw can run unattended, but unless the cut pieces are very small, I don't think it will save much time since you'll still need to load new wood into the feeder fairly often. I think the risks exceed the gains you can achieve. I see a safety problem that once you start the cut its going to continue its action until it finishes it cycle. What happens if the cutting action occurs by accident and something in the way. Not just a hand but perhaps your swing a new board in to the saw. Or what if you hit the blade when moving a new board into position. Perhaps no when will get hurt but you make damage the blade or the saw. What if something falls on the foot switch. What if its triggered spontaneously (power surge, dirt, bad connection, etc).

[poorfarmer25]

its not designed to have the force applied to it. heheh

I think the risks exceed the gains you can achieve You might be right However this is just an idea in my mind at the moment and I'm still trying to make improvements on it.

I think that if I setup the solenoid properly so that it dose not auto cycle, and tighten the return spring on the saw that would alleviate most of the jamming problems.

[Al_The_Man]

It could be fairly easy to make it semi automatic, why not a clamp that engages when the work is placed in position at the end stop, the whole process could be initiated by the remote F.S.
And cycling each stage by simple relay logic and a couple of L.S's.
Even make an ejector!!
BTW, if you want the smoothness of a pneumatic without using a high pressure pump, look at air over oil?
Al.

[Geof]

look at air over oil?Al.

This is the correct suggestion. Pneumatic, even with a flow control valve, is not suitable. During the cut while there is some back pressure from the blade the air pressure builds up to drive the cut. Then when the blade is just breaking through and the back pressure diminishes the pressure is too much and the blade surges forward and can jam in the cut.

Air over oil with a hydraulic flow limiting valve, or an air cylinder with a hydraulic snubber in parallel is the safest approach. Also if the intent is to have something automatic and safe, clamp the work on both sides of the blade, stop the blade before retracting it from the cut then unclamp and eject.

[Al_The_Man]

For this application ones like it, there is a nice little sequencer call a Smart Relay and at present is made by around 8 companies in one form or another.
-Siemens Logo, Easy relay,smart relay,mini plc,programmable relay, xLogic, SuperRelay, Micro-Plc, Relay, PLC, crouzet,Moeller,Zelio,programmable logic controller, canbus,home automation, Automation, FBD, Function Block Diagram, ladder diagram, Intell
They started out as simple on/off control (boolean) logic, they now have counters/timers/latches, real time clock etc.
It can be programmed right on the unit or with PC S/W.
Also if using air over oil and use pneumatic cyclinders, if the type with the sensor ring on the piston is used then instead of having to use limit switches etc, the 2 wire magnet sensors can be used on the side of the cyclinder to register a position.
These cannot be used on hydraulic cylinders because of the steel construction.
Al.

[poorfarmer25]

During the cut while there is some back pressure from the blade the air pressure builds up to drive the cut. I can see what you are talking about it would not make a steady or fast cut at all.

For this application ones like it, there is a nice little sequencer call a Smart Relay and at present is made by around 8 companies in one form or another.
-Siemens Logo, Easy relay,smart relay,mini plc,programmable relay, xLogic, SuperRelay, Micro-Plc, Relay, PLC, crouzet,Moeller,Zelio,programmable logic controller, canbus,home automation, Automation, FBD, Function Block Diagram, ladder diagram, Intell
They started out as simple on/off control (boolean) logic, they now have counters/timers/latches, real time clock etc.
It can be programmed right on the unit or with PC S/W.

This looks VERY interesting I know in the school I was at they used plc controllers lots, But I never go a a chance to look at them I will do some research