DIY Spindle idea

[puurtsi]

Hi,

I read yesterday one diy spindle project on mycncuk.com and it did use rc airplane motor and speed controller for the spindle. There were also hard to build housing and needs to be machined. So I got my idea using same motor and flexible drill cable with some kind of diy coupling.

I don't have any glue if this works well for wood cutting or engraving but should work for pcb drilling. Positive thing is that motor speed can be adjusted. Though I don't know how it can done by EMC.

Any comments/suggestions about my idea? There is links where I got my idea...

http://www.hobbycity.com/hobbycity/s...idProduct=6461
http://www.hobbycity.com/hobbycity/s..._1400Kv_/_550w
http://www.mycncuk.com/forums/showth...spindle-design

http://www.amazon.com/Eazypower-30167-40-Inch-Flexible-Extension/dp/B0009XAFXU

http://www.amazon.com/Eazypower-30167-40-Inch-Flexible-Extension/dp/B0009XAFXU

[kawazuki]

Originally Posted by puurtsi Hi, I read yesterday one diy spindle project on mycncuk.com and it did use rc airplane motor and speed controller for the spindle. There were also hard to build housing and needs to be machined. So I got my idea using same motor and flexible drill cable with some kind of diy coupling. I don't have any glue if this works well for wood cutting or engraving but should work for pcb drilling. Positive thing is that motor speed can be adjusted. Though I don't know how it can done by EMC. Any comments/suggestions about my idea? There is links where I got my idea... http://www.hobbycity.com/hobbycity/s...idProduct=6461 http://www.hobbycity.com/hobbycity/s..._1400Kv_/_550w http://www.mycncuk.com/forums/showth...spindle-design http://www.amazon.com/Eazypower-3016.../dp/B0009XAFXU

Wouldn't bother with that flexible drive - they aren't accurate even when used with their intended drive - a hand drill ! and I seriously doubt they could handle 30k rpm! For a down and dirty PCB milling tool the motor should be ok but no one has ever confirmed their suitability for long periods of use - the planes fly for 7-10 minutes then get a cooling period - will they stand up to continued duty and without the prop air cooling?

[tskguy]

There has been a ton of discussion about building a spindle using a brushless rc motor. Check out this discussion it has a wealth of info.

http://www.cnczone.com/forums/showth...p=94477&page=5

I recently have built a spindle based off one of the design in this thread. I have chosen to use a belt reduction to get more torque but the bearing design is the same.

My design is similar to the previous design and this one combined.
http://www.metallmodellbau.de/Eigenb...salspindel.php

[diyengineer]

Originally Posted by kawazuki Wouldn't bother with that flexible drive - they aren't accurate even when used with their intended drive - a hand drill ! and I seriously doubt they could handle 30k rpm! For a down and dirty PCB milling tool the motor should be ok but no one has ever confirmed their suitability for long periods of use - the planes fly for 7-10 minutes then get a cooling period - will they stand up to continued duty and without the prop air cooling?

Those motors are not made for extended use.

[eSilviu]

Originally Posted by diyengineer Those motors are not made for extended use.

RC motor consist in 4..14 magnets, some wire on a iron core, 2 bearings and a shaft. If you don't overheat the motor until magnets or glue fail... what would fail?! Bearings can be changed. RC motor it's even simpler than DC motor (or universal motor) used in some hand-held drills. And in my opinion simpler means fewer components that can fail.
A... there is the controller and the power source too; if you use them at the nominal parameters it should work indefinitely...

[tskguy]

I agree....There is no reason why RC brushless motors wouldn't work very well as a spindle motor. Did anyone look at the high speed spindle thread? Other CNC zone members have very successful spindles designed around RC brushless motors and controllers. If the motor gets to hot cool the damn thing!! its pretty clear, look at all of the commercially available spindles out there. They are using brushless motors and are either air cooled or water cooled!

E

[CarveOne]

Originally Posted by tskguy I agree....There is no reason why RC brushless motors wouldn't work very well as a spindle motor. Did anyone look at the high speed spindle thread? Other CNC zone members have very successful spindles designed around RC brushless motors and controllers. If the motor gets to hot cool the damn thing!! its pretty clear, look at all of the commercially available spindles out there. They are using brushless motors and are either air cooled or water cooled! E

I agree too. If you look at the large R/C electric model aircraft (jets and other large scale models) and see how they are used you will gain a lot of respect for the brushless motors, controllers, and how many amps they routinely suck up with well designed air flow systems. A water jacket can be fitted around them or a fan can be installed on them for CNC use.

CarveOne

[Herbertkabi]

Look at my Spindle works - speed turned down because removed front screen and was the only way to keep camera clean, http://helicam.ee/cnc/CNC1.mov , wow-wow-sound because esc heli mode keeps choiced rpm, currently reduced down to ca 15k with 4.5mm endmill. This actual spindle makes up to 50k rpm, but very seldom I use more than 30k. There is two pole slotless motor I made myself. I have built several the same type spindles for friends and then used Lehner 2250 or chinese KB45-10XL 1200kv Brushless Inrunner http://www.hobbyking.com - also cood enough but first thing is changing bearings to the best(!!!) ones. You do not - you will have big problem later and this time comes surelly when you are very busy ;-) Water cooled ! In my mill the same cooling mix comes first into spindle and then to mill coolant nozzle. Look at Ampermeter - very low current when modest 15k rpm and 4.5mm endmill. Motor itself is able to several kw, in reality you never need this power but like that it is. The same story with ESC - Future 32/80 able for 80 amps. Much weaker one you cant use, when heavy cut then ampermeter shows (only)20A but you cant see peak amps - weaker ecs just will overheated and switshed off - the result - broken endmill and damaged part.
Motor and ESC are one story - second thing is collet chuck and BEARINGS, I use only super precision angular contact bearings. And sealing! And balancing!

cheers,
herbert

[tskguy]

Thanks for chiming in Herb!! All of my spindle is based of of you design.
I noticed you wind your own motors. Can you direct me to any threads or info on the web regarding your slotless winding methods. I have made many small outrunners in the past but mothing like your motor. All have been slotted stators
and standard magnet spaced on the inner side of the can.

Let me know.

Eric

[diyengineer]

Originally Posted by eSilviu RC motor consist in 4..14 magnets, some wire on a iron core, 2 bearings and a shaft. If you don't overheat the motor until magnets or glue fail... what would fail?! Bearings can be changed. RC motor it's even simpler than DC motor (or universal motor) used in some hand-held drills. And in my opinion simpler means fewer components that can fail. A... there is the controller and the power source too; if you use them at the nominal parameters it should work indefinitely...

I didn't mean to say they could not be modified to work, but you cant just slap a motor on and run it for very long is more what i was going for. You would either have to have a High velocity fan cooling it (in replacement for the air that would be introduced while flying through the cowl), or even better; which was already suggested a water-cooled jacket. It would be a very cool project indeed.

I've seen lots of smaller electric motors, but how big do they get? I bet the price jumps up a lot.

[diyengineer]

http://www3.towerhobbies.com/cgi-bin...?&I=LXXJW6&P=0

HOLY CRAP. Check this one out!! ^^

$269 bucks, but wow look @ the power.

Max. Continuous Power: 7500W

If my chinese spindle dies, im picking up one of those.. or larger?! haha

8500watt burst!


Thats like 10HP...

How would you power these without batteries though? And what is everyone using for a controller? Do you obviosuly use a belt drive attached to a spindle, or direct drive?

[rowbare]

Might be a good use for those massive surplus power supplies they were talking about last week on Hoss' thread.

bob