Can someone help me understand forced rotation?

[gofastman]

I was wondering, does the flex VRG have 2 axes of rotation? That is, does the spindle rotate and orbit around? Or is the pad locked in place and it only orbits around the center point?

I ask because I just bought a dynabrade for my rotary. It seems very well made, I guess I was sort of expecting a little more mechanical sophistication, like a planetary gear setup or something.
Are all forced rotation machines similar in the way they move?

[Setec Astronomy]

I know Todd Helme had done a good article (maybe working with Kevin Brown) about the action of the Flex, but I can't find it, this is all I could find:

Choosing the right style and type of DA polisher

Is pad rotation necessary for a DA polisher to correct paint?

[FUNX650]

Here's a parts list and exploded view of the
Flex 3401 that shows the direct drive gearing,
along with the orbital gearing's "offset-pinning"...
{I once had a (bad) habit of just calling them
concentric/eccentric drives.}

Parts for XC3401VRG | Powerhouse Distributing


Hope this helps out a little bit.


Bob

[VISITOR]

being forced rotation (gear driven) means that it will consistently spin/rotate (no matter how much pressure is applied), but you already knew that. as far as having the same rotation pattern/footprint like other 8mm throw traditional PC-style DA's, i have wondered that as well. it seems like it would be a little more refined in pattern (maybe less curvy). hopefully someone can chime who knows for sure as i have wondered this as well for quite some time. btw, the flex 3401 is a beast...

[Setec Astronomy]

as far as having the same rotation pattern/footprint like other 8mm throw traditional PC-style DA's, i have wondered that as well. it seems like it would be a little more refined in pattern (maybe less curvy). hopefully someone can chime who knows for sure as i have wondered this as well for quite some time. btw, the flex 3401 is a beast...

As I said in my previous post, Todd Helme (perhaps in conjunction with Kevin Brown) had a thread somewhere where he detailed the pattern (using a backing plate with pens or pencils stuck in it) of the Flex, but I can't find it.

Edit: I'm going to say it was an old TID thread, which would be somewhere in the Autopia archives.

[dlc95]

In the case of the Flex 3401, take a standard random orbit machine, like the PC 7424xp.

Then imagine a series of teeth inside the spindle housing, and a backing plate with a corresponding series of teeth.

These teeth engage as the spindle travels around the housing, thus preventing any slippage.

There was once a thread here asking if the PC could be converted to forced rotation. There is, but it would involve customization to the spindle housing, and backing plate. Basically, teeth would need to be added, and adjustments to accommodate space for such a modification, etc...

[gofastman]

So it would seem to me that the rotation of the spindle in indeed locked in place.
I was thinking it was sort of like the earth and sun, the earth rotates around its own axis and obits around the sun. I guess it's sort of like if the earth was locked in place facing one direction and it orbits the sun

[gofastman]

Here's a parts list and exploded view of the
Flex 3401 that shows the direct drive gearing,
along with the orbital gearing's "offset-pinning"...
{I once had a (bad) habit of just calling them
concentric/eccentric drives.}

Parts for XC3401VRG | Powerhouse Distributing


Hope this helps out a little bit.


Bob

That's perfect, thank you! Pictures are very helpful to me.