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chuckknigh
10-06-2003, 01:38 AM
I know everyone here is well versed in rotary motion -- lead screws driven by stepper motors or servos -- that sort of thing.

Well, this weekend I found something neat at the flea market. A gigantic solenoid (maybe linear actuator...I'm still working on identifying it) that I'm thinking about using for a Z axis.

For a LOT of work, I don't require full 3D functionality -- I need X, Y, and pen up/down. Well, router up/down, really... So, when I saw this thing, I snatched it up. Wish I'd have picked up the pneumatic air cylinder, too, but alas, it got away.

Anyway, does anyone know how to control one of these? It's a 12VDC solenoid from Trombetta ElectroMagnetics.

The label says:
Trombetta +-
ElectroMagnetics
3921978
12VDC 0139

Yes, I have an email in to the company, but given the level of talent on this site, it never hurts to ask...anyone know anything about these devices?

-- Chuck Knight

chuckknigh
10-06-2003, 01:42 AM
Oh, their web site address is http://www.trombetta.com but nothing I found on the label corresponds to any current product listed on their site. In fact, there's nothing even close.

And, for reference, it's about 9" long, with the main body being around 4", and the diameter of the plunger rod being around 3/4". This is a big, beefy piece of equipment that *should* be useful on a router...if I can figure out how to use it!

-- Chuck Knight

balsaman
10-06-2003, 08:40 AM
It may work. They tend to rather violent in thier actuation tho. Could shake things up a bit.

Why not just stick to the stepper thing...no fancy gcode to actuate a solinoid required.

Eric

chuckknigh
10-06-2003, 11:31 AM
Why not just stick with steppers?

Well, let's see... Fun, experimentation, serendipity... All good reasons to try something new and/or different. I didn't go out searching for a solenoid -- I happened upon one at my flea market. For $1, I couldn't turn it down...

And besides, I don't have enough of the 100 oz-in steppers to do all 3 axes. I've got a 100 oz-in, a 67 oz-in, and a 45 oz-in, just lying around. No new printers have shown up, recently.

While these would likely be adequate for my vise conversion, I'd prefer something a little bigger. Trust me...this solenoid *is* bigger. :-)

-- Chuck Knight

Alan T.
10-06-2003, 11:46 AM
You might want to think this thru a bit before using it for a Z axis. Several of the older type CNC Engravers used an Air driven Solonoid for the Z-Axis, This was fine for them as they only used a tool depth of a couple of thou's using a V-tipped engraving bit turning at 15,000 plus rpm.s If you used this type of actuator it would probably at the very least bury the toolbit in the work before it could actually cut anything. You might even break the bit. These electronic accuators are usually pretty beefy and they are either all or nothing. You might shake the z-axis apart.

Just a word of caution. You might break more than the cost of a cheap stepper if you try to use this. Its entirely possible you might make it work but I would hate to see you tear up your machine before its time.

Not the good part. This actuator might actually be very good for something like an automatic tool changer for your machine. See, the dollar is not wasted.

Alan T.

HuFlungDung
10-06-2003, 11:51 AM
Chuck, can you always count on starting your cuts "in the air"? As Balsaman said, these devices are kind of "rammy" for machine axis control.

Also worth considering, is the fact that it will provide no "lock" on your vertical axis, unless you leave the current applied all the time. It may not be built to function that way without overheating.

If it is a one-way device, it will likely have spring return built into it, and you would need to check to see if it has enough strength.

They are very simple to work: just apply 12v to it and the plunger will ram in or out.

NeoMoses
10-06-2003, 02:26 PM
Every solenoid I've worked with "activated" when you energize the coils. They work by creating a magnetic field in the coils, which pulls the iron core in.

It apears that your solenoid may be a push/pull type. I would say that energizing 2 wires will make it pull, and the other 2 wires will make it push. Just try it out with a battery.

balsaman
10-06-2003, 07:28 PM
Don't let me discourage you. By all means play with the solenoid. I am a firm believer in experimentation! Let us know how it works out!

Eric

samualt
10-06-2003, 07:49 PM
chuckknigh:
I think your looking at this the wrong way. I don't think it would make a very good Z-axis device for a regular router. But it might make a good Z-axis for a punch-machine. What comes in sheets of material and needs a part/section knocked violently out of it? LOL. Perhaps some form of sheet plastic that is notched or something. ,or ??? Perhaps a small hammer head on the end of the solonoid would create a nice Hammer-machine for light metal.

A solonoid isn't going to make a good stepper. But that solonoid would make a great punch/hammer/stabbing motion! Just an idea!

:rainfro:

ehiebert
10-06-2003, 09:09 PM
I think this could be used for the Z-axis of a router, but it needs the correct companion hardware. I see this being applicable if the actuator is used to lift the router from the work piece.

The descent of the router into the workpiece whould be a slowly controlled freefall action when the solenoid is disengaged. This could be achieved using a small damper and spring combo. Maybe try a screen door damper.... you the type... it keeps the door from slamming and provides a smooth closure.

Of course a time delay must be provided in the toolpath for the router to descend before running.

Just a thought.

chuckknigh
10-06-2003, 10:40 PM
OOOH, I like the idea of a CNC punch or hammer, but I'm not entirely positive what I would use it for.

Though, the thought of embossed metal signs, etc, is very appealing...

-- Chuck Knight

samualt
10-06-2003, 11:58 PM
chuckknigh:
I think it would make a great hammer for metal embossing/3D Relief. Perhaps you could vary the voltage to the solonoid to get different levels of dent/deformation. A light cushion of foam or plastic underneath the metal sheet would keep you from bottoming out.

As to what it could be used for...how about a 4' by 4' embossed image of Elvis! LOL. Seriously, if anyone ever does this successfully I may have to add it to my machine. The image produced would be much better than a flat silhouette created by a torch. And, I've never heard of a machine like that. You might start a whole new industry!

:rainfro:

Mr.Ed
10-07-2003, 08:04 AM
One could make a nice daisywheel letter / cypher / number plotter (puncher) for metal sheet.

Instead of engraving letters, one could hammer them. Big fun for the neighbours too :D

Ed.

ToyMaker
10-07-2003, 09:47 AM
My dad makes "punched tin art" lamp shades and stuff by driving an awl into sheet metal with a hammer. A strong, fast-acting z-axis driving a shaped spike over a cnc x-y table could save him many, many hours.
But, on the other hand, he does this as a pastime. :)

robotic regards,

Tom
= = = = =
"These are the souls that time men's tries."
- - Sports Illustrated

jimbo
10-08-2003, 08:57 PM
Well have you tried it? I am curious.

What about using the solenoid to lift the router out of the workpiece under power. Then when power is removed a slow moving spring device (gas spring?) plunges the router at a more controlled rate.