high speed ring gear application- help needed.

[fujimo]

hi,
i hope i have come to the place that can help me.
i have a round rod milling machine- very basically, it takes a square of wood and turns it into a dowel- i am wanting to make a different type of cutting head for it- as opposed to the fixed blades spinning around the wood blank as it is being fed into the machine.

these are my thoughts. to have a fixed ring gear on the stationary part of the housing, while the spinning head- will have two( opposite) gears traveling on the ring gear- these gears are directly attached to shafts terminating in a router cutting head attachment.
so as the head spins- the gears are rotated and the router bits cut longitudinally as they are simultaneously being spun.
my concerns are - the head spins at about 3 500 rpm . so depending on the ratio- the smaller gears running on the ring gear will be going at pretty high speeds- would like to get the sub shafts and router heads spinning at around 15 000 rpm

can these types of gears handle those rpm?
and if so- where to with an idea on gear shape, tooth pitch etc etc.

this is not very high load- as the heads will only be removing the corners on a 1/2" soft wood square.
this will have to be an open system-- lubrication? heat?

please note : this is for my own machine - this is not for commercial resale.
many thanks
wayne

 

[MikeHalloran]

You can't afford a ring gear that's precise enough for that duty.
... never mind the seal to keep sawdust out.

Better to mount 2...3...4 electric routers radially on a plate with a hole through it for the workpiece, and either rotate the workpiece or oscillate the plate in order to generate a cylinder. Oscillating instead of rotating the plate means you can use dangling electric cords to get power to the router motors, without using sliprings or rotary transformers.



Mike Halloran
Pembroke Pines, FL, USA

 

[fujimo]

good points - thanks

 

[fujimo]

what would be the best way to oscillate the plate-
and how many oscillations a minute would be easily attainable?
are there going to be any inertia issues with the mass of the routers on the plate- every time it changes direction?
probably 2 or 3 small trim routers on the plate- 3 might be better balanced!


good idea- am starting to like it!

 

[MikeHalloran]

A crank and a link would do it.
Maybe 3s per cycle or so.

OR, four routers with roundover bits, in a square array on a fixed plate, axially offset a bit so they don't collide, behind a square bushing, would slice off the corners as fast as you can push the sticks in. How many thousand feet per day do you need?


Mike Halloran
Pembroke Pines, FL, USA

 

[SwinnyGG]

It sounds to me like rotating the work is going to be much cheaper, safer, and simpler than rotating the tooling.

You're talking about rotating a wood dowel maybe a few feet long at most, vs rotating a bunch of heavy, imprecisely balanced, high powered electric equipment.

If you try to rotate or even just oscillate a giant tooling head with several router motors onboard, getting them all to cut precisely through their range of motion will require large and precise bearings and a relatively complicated arrangement to hold everything in place. All of that is expensive.