Sherline spindle motor suggestions?

[vlmarshall]

Well, I just managed to smoke my Spindle controller board, a Puma SM. I was trying to add CNC4PC's C6 speed interface card, and missed the bit about using an isolated power supply. The C6 is dead, only putting out a constant 4.48 volts, and the Puma is no better, unresponsive to my old relay board, with the reset LED constantly lit.

I guess I'm in the market for another speed controller, any suggestions? Spindle monitoring and rigid tapping would be great, I'm not against the idea of switching out the 110VDC motor I'm using now, brushless would be nice, as would more horsepower.

[hoss2006]

Been there
Surplus Center no longer carries the replacement board I used but have another.
KB Electronic makes one too.

[vlmarshall]

Interesting...well, at least I know cheap replacements are available.

I wonder if anyone has used one of the 2000-4000watt brushless RC aircraft motors yet.
If I could find a way to control it, I'd do it. The idea of low-speed torque AND 10k spindle speeds is hard to ignore...but I'm spoiled by the Haas 10k spindle.

[valmet58]

the rc aircraft motors are controlled by a small module that requires as in input
a pulse that the width is varied from 0 to 2 msec. wide repeated about 30 times a second..that pulse driving circuit is very easy to implement with a pic microprocessor..Just a thought..

[escott76]

Originally Posted by vlmarshall Interesting...well, at least I know cheap replacements are available. I wonder if anyone has used one of the 2000-4000watt brushless RC aircraft motors yet. If I could find a way to control it, I'd do it. The idea of low-speed torque AND 10k spindle speeds is hard to ignore...but I'm spoiled by the Haas 10k spindle.

That may well be where I'm headed. I've seen pics of someone using an axi 28XX motor on one, and I have a 5330 or two kicking around, which top out around 2000 Watts. Why you'd need over 2 HP peak into a Sherline spindle I don't know, but I'd be willing to try
Controlling it shouldn't be that bad. I'd use one of the commonly available micro-controller boards from places like Parallax to build an "interpreter" to go from the 0-10v that the G540 puts out (or it could take step and dir if I wanted it to) and generate an appropriate pulse train for a hobby servo which is what the hobby ESC's use. It sounds bad, but the code is relatively simple to do.
There are a couple problems with this setup though. First is cost. If you have some of the stuff lying around it can be cheap, but if you have to find a power supply capable of the amperage these things demand to get to those power levels (you aren't getting 2000W without a PS that will put out ~60A). Add to that the cost of the motor and a good controller and you are right back to where you should have just gotten a cheaper VFD and been done with it.
The second big issue is cooling the motor. These kind of motors were designed to be placed in the nose of a moving airplane. They rely on cooling airflow to keep the magnets under their curie temp, so as to not lose magnetism. When you do things like use them in Helicopters, where they are relatively stationary you need to come up with ways to force air though them. This would be no different, you'd need to come up with a cooling solution, or your longer runs will end in disappointment.
I've actually built a couple of motors like this, using scrounged armature laminations from other motors, rewinding them to my liking, and redoing the magnet arrangement, switching from the stock ferrites to N45 neo's. I think the trick is to wind something like this so it will take power from a cheaper VFD, so your power supply and controller needs are handled in one box. It's the same kind of motor, 3 phase, so the base theory is sound. Once I've got my machine complete, that's my next challenge.

[escott76]

Originally Posted by valmet58 the rc aircraft motors are controlled by a small module that requires as in input a pulse that the width is varied from 0 to 2 msec. wide repeated about 30 times a second..that pulse driving circuit is very easy to implement with a pic microprocessor..Just a thought..

1-2ms wide repeated 50 times a sec, but you're in the ballpark

[vlmarshall]

Well, I just ordered a KBIC card, and sent an email off to the Puma's manufacturer to enquire about repair costs.

I've been wanting to get into PIC and BASIC stamp programing, maybe I'll pick up a Parallax experimenter board and play with one of my brushless ESCs in my spare time. I don't have anything big enough for a Sherline spindle, but the input for a small ESC, or even a servo, works the same way.

[escott76]

Originally Posted by vlmarshall Well, I just ordered a KBIC card, and sent an email off to the Puma's manufacturer to enquire about repair costs. I've been wanting to get into PIC and BASIC stamp programing, maybe I'll pick up a Parallax experimenter board and play with one of my brushless ESCs in my spare time. I don't have anything big enough for a Sherline spindle, but the input for a small ESC, or even a servo, works the same way.

Do yourself a favor, get the propeller board instead of the basic stamp. $20 buys the proto board with the chip and memory pre-soldered. It offers on board connectors pre-wired for keyboard and mouse input as well as TV out. Space for prototyping too. Easy to program too, with a USB programming cord. It's not only the cheapest option overall, but far more powerful in the end than a basic stamp. I like the language too, better than PBasic, but that's a personal preference.
It's the board I would use, and if you like I can help with programming, as I said I plan to do it myself at some time. I can also do PBasic, but I'm a little rustier in that.

[vlmarshall]

Nice, thanks for the tips

[Riceburner98]

We use Basic STAMP's all day here at work to run our test equipment. Super-easy to program (which is likely why we use them), but SLOW, inefficient code, and retardedly expensive. I've blown at least 6 of the $90 BS2P40's in the last few months. They don't like static charges. I'm changing to Cypress PSOC chips (they have tons of configurable devices embedded on the chips) since we use those in products we sell and so guys here know how to program them in C, but I use Atmel parts exclusively at home. I'd reccomend Atmel or PIC any day over Basic STAMPs, unless speed or cost doesn't matter and you need to have kids program it.

I've got the SurplusCenter control boards mentioned above (both the old plain aluminum one and the black anodized one) but haven't done much beyond spinning a motor with them. Hopefully they're easy enough to interface with. Lately I've been machining at 10k RPM / 120inches / minute and feel the need for more speed though. I like the idea of a nice high speed spindle with the RC motor attached. I could go for 20k RPM as long as it doesn't sound like a screaming Banshee. (Dremel tool.) It's fun watching a rooster tail of aluminum spit out of the cutter!

[Jason3]

Originally Posted by vlmarshall I wonder if anyone has used one of the 2000-4000watt brushless RC aircraft motors yet. If I could find a way to control it, I'd do it. The idea of low-speed torque AND 10k spindle speeds is hard to ignore...but I'm spoiled by the Haas 10k spindle.

Almost! I built a spindle with a 3 Hp Magmotor like the combat robot guys use. The spindle wasn't much good, but the motor was ferocious. I used a controller with a 5K pot, like the ones they have on electric scooters. Rated speed at 24v is 6000 rpm, and it has tons of torque.

If I could keep the motor cool, I would absolutely use it on something like the Sherline spindle.

You can control the brushless RC motor controllers with a servo tester - http://www.robotcombat.com/products/RL-SRVTST.html

Did you consider using a servo to drive the spindle? Everybody I've heard of doing that has been very pleased with their performance.

Best regards,

Jason

[vlmarshall]

Originally Posted by Jason3 Almost! I built a spindle with a 3 Hp Magmotor like the combat robot guys use...the motor was ferocious... Rated speed at 24v is 6000 rpm, and it has tons of torque. If I could keep the motor cool, I would absolutely use it on something like the Sherline spindle. You can control the brushless RC motor controllers with a servo tester - http://www.robotcombat.com/products/RL-SRVTST.html Did you consider using a servo to drive the spindle? Everybody I've heard of doing that has been very pleased with their performance. Best regards, Jason

Yes, I've thought about using a servo tester, I think I have one around here in my tons of RC stuff...
Hmmm... a servo spindle would give me instant rigid tapping ability...
Your 3hp combat 'bot motor sounds good, my current spindle setup is fan-cooled, but I guess I'd need more than just a fan... maybe a Peltier or water cooling?

Originally Posted by Riceburner98 We use Basic STAMP's all day here at work to run our test equipment. Super-easy to program (which is likely why we use them), but SLOW, inefficient code, and retardedly expensive. I've blown at least 6 of the $90 BS2P40's in the last few months. They don't like static charges. I'm changing to Cypress PSOC chips (they have tons of configurable devices embedded on the chips) since we use those in products we sell and so guys here know how to program them in C, but I use Atmel parts exclusively at home. I'd reccomend Atmel or PIC any day over Basic STAMPs, unless speed or cost doesn't matter and you need to have kids program it. I've got the SurplusCenter control boards mentioned above (both the old plain aluminum one and the black anodized one) but haven't done much beyond spinning a motor with them. Hopefully they're easy enough to interface with. Lately I've been machining at 10k RPM / 120inches / minute and feel the need for more speed though. I like the idea of a nice high speed spindle with the RC motor attached. I could go for 20k RPM as long as it doesn't sound like a screaming Banshee. (Dremel tool.) It's fun watching a rooster tail of aluminum spit out of the cutter!

Arrgh...I think I'll wait a bit on this one. When I get into PICs it'll be for robotics, I guess I won't torture them in my mill, at least not right away. Dealing with a learning curve AND a destructive environment sounds expensive.

Yes, running something like a 3/4" two-flute through aluminum at 10,000RPM and 100IPM is a lot of fun... but noisy.