[irishjam]

Hi All,
I need a bit of help with harmonic drives.
I am modifying my 8x4 router to a 5 axis machine and before I finalize the dimensions I want to get 2 harmonic drives to confirm dimensions.
I have got a price for a 25 and 32 size which was pricey £3000 +20% vat
I have seen these on ebay and was wondering what you thought??
Big one for the c axis with through hole for cables etc and small one for b axis but it looks a bit tall.
Any other ideas or suppliers welcome.
Thanks
John

[hub]

I use these:
Sumitomo Drive Technologies: Home
They are not harmonic, but cycloid types. Similar in performance.
Hub

[irishjam]

Thanks Hub,

They look perfect
Any idea of prices as a guide

john

[hub]

Thanks Hub,

They look perfect
Any idea of prices as a guide

john

I got mine used. So I don't know retail prices. It also depends on what size, torque, ratio you need, etc etc.
A quick search on ebay:
Sumitomo Cyclo Drive CNVX-6125-5T-11 speed reducer | eBay
or
Sumitomo SM Cyclo Drive Gear Box | eBay
Just as examples....

Also, here on CNC zone is a DIY cyclo drive thread if you have the equipment to make one.

Hub

[darrengladysz]

I have a 4x7 cnc router with a 4th axis using r&p and servos. I'm using an 8 axis acroloop controller.

I am in the planning and sourcing for a 5 or 6 axis router - 5x8 or so since I will need space on either side.

I just picked up three harmonic drives from ebay. They were all new or at least there was no sign of use. I got a size 25, a size 40 and a size 25 gear.

Prices were as follows:

For the 25 with 160 ratio - $125 usd
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

For the 40 - 100 ratio - $250

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

and a harmonic drive with gearhead for $175

http://www.ebay.com/itm/330634859836?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I am planning to use these with kollmorgen servo discs.

I have managed to get some good prices on used servo discs with kxa drives (these are dc servos). The reason for these are that they are compact and light. They can be used with other drives but be careful as they are very low inductance and most drives will require an inductance (these are cheap however).

The 40 will be used with the B or C (where the spindle will be attached) and the 25 will be the axis that rotates around the z.

The 40 and 25 are component set so you need to machine the shafts and get bearings.

The gearhead will be for a rotary axis (like a lathe).

IMO wait a bit for a deal on ebay as the prices you are quoting are fairly high unless you do not mind. Shipping should not be a big issue. Also, don't hesitate to make a lowball offer as the harmonics are not fast moving items from what I see.

This is what I am planning for a 5x8:

[ame="http://www.youtube.com/watch?v=5vQVIjbBjcA"]Record 132 Prisma - Sphere - YouTube[/ame]

but with a 3-4 kw spindle without tool changer.

Biggest issue once all the components and weigth is factored in will be the x axis servos. I will be using ballscrews with a rotating nut although this may change.

[hub]

I would not have purchased those harmonics.. Just me though..
Well made harmonic drives will cost much more.. Because they are expensive to manufacture:
- Very high precision machining of the the gears
- Special material (the center 'gear' needs to be flexible & made out of metal to last)
- Special bearing

Also, they advertize as having 'reduced backlash'. So there is backlash, but how much?

Hub

[darrengladysz]

All are manufactured by harmonic drive. I did not see another manufacturer for harmonic drives.

Here is the spec sheet for the csf series. See page 47 for positional accuracy.

http://www.harmonicdrive.net/media/s...sg-catalog.pdf

The csf 40 series has a position accuracy within 1.5 x 10-4 arc-min. which is more than what I need. I'm also certain that any backlash and position errors will more probably result from my build than any backlash in the harmonics.

The other advantage of a harmonic over other gearing systems for a b or c axis is low mass. If you add mass you need to increase everything downstream. So it is probably worthwhile to pay a bit more to keep the mass down.

BTW the 40 series was brand new.

[hub]

1967:
Between the patentee USM Corporation (Boston) and Hasegawa Gear Works (Tokio) a licence agreement is concluded. The development of all-purpose units will be started in Japan.

1970:
The USM Corporation, Boston, and Hasegawa Gear Works, Tokyo, establish together two new companies: the Harmonic Drive System GmbH in Germany and Harmonic Drive Systems Inc. in Japan for the production and world-wide industrial marketing of the Harmonic Drive gear. New market requirements lead to the continuous further development of the Harmonic Drive gears in various types and sizes. The products are primarily used in industrial robots, machine tools and printing machines.

Today, there are a few..

[darrengladysz]

Thanks for the info.