Another 4th axis build with Harmonic drive (CSF-25-50)

Hello,

I just received my Harmonic Drive CSF-25-50 that I'm intent to use for the 4th axis. Good thing with this type of HD is that it comes with a nice cross roller output bearing which allows easier mounting for the chuck. This is all I have at the moment. I mean I haven't done a design yet but I think I'll use a block of gray cast iron as housing. And I'll probably use the smallest size of Nema34 or biggest size of Nema23. I'll appreciate your recommendations on this.

The 25 size may be just a little oversize for a BF20 mill, but I don't know that yet too.

Anyway. Thanks.

harmonic drives have poor torsional stiffness, you won't be able to subject it to any high forces when machining so a cast iron housing might be an overkill.

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Originally Posted by ardenum2

harmonic drives have poor torsional stiffness, you won't be able to subject it to any high forces when machining so a cast iron housing might be an overkill.

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Hi,
Specs of the HD I have says the torsional stiffness is 14Nm where average torque is 55Nm. That's a little confusing for me.

Do you mean I need to use a softer metal like aluminium instead of cast iron on the housing, so that the housing can absorb the high force and help the gearbox not being damaged?

What are you wanting to machine? Wood? Alu? Steel?

Continuous 4th axis?
Or just 4th axis indexing (can then add a brake)

Hi,
The largest part I'll machine is a steel 100mm diameter turbine wheel.Attachment 494906

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Originally Posted by Azalin

Do you mean I need to use a softer metal like aluminium instead of cast iron on the housing, so that the housing can absorb the high force and help the gearbox not being damaged?

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no I mean you might not need the stiffness of cast iron, aluminium is also easier to machine. Iron will do a better job with damping though. do you have a low rpm high torque or high rpm low torque setup?

I have both.

Hi, For detailed product performance and parameters of CSF-25 bearings, you can refer to here https://lkpbearing.com/csf25-csg25-h...ller-bearings/