Hello,
I have a stepper motor:
http://catalog.orientalmotor.com/item/i ... d&filter=0
being controlled by an arduino. I need to couple the 6mm diameter shaft of this stepper motor to a tube of diameter 30cm. The center axis of the tube is to rotate along the same axis as that of the stepper motor shaft. Right now I have been 3D printing a coupler for these two parts, but I need the axis of rotation of the tube to be very precisely aligned with that of the stepper motor. Can any of you recommend a set of parts I should use to make this work? I'm having trouble finding a part that can connect to the 6mm shaft of the stepper motor and the 30 cm diameter of the tube. Is a direct coupling not possible? Will I need to use some sort of belt-driven mechanism instead? As long as I can have a compact setup that rotates the tube along its center axis, then I'm very happy!
Thanks for the help!
part (or parts?) needed for stepper motor coupler
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Please be positive and constructive with your questions and comments.
- npp1993
- Posts: 2
- Joined: Wed Feb 26, 2014 5:20 pm
- adafruit_support_bill
- Posts: 88149
- Joined: Sat Feb 07, 2009 10:11 am
Re: part (or parts?) needed for stepper motor coupler
I don't know of anything off-the-shelf that will do that. If your 3D printer is not capable of the precision you need, a machine-ship should be able to turn something for you on their lathe.
- npp1993
- Posts: 2
- Joined: Wed Feb 26, 2014 5:20 pm
Re: part (or parts?) needed for stepper motor coupler
thanks, Bill! I'll look into that
- lyndon
- Posts: 281
- Joined: Tue Mar 29, 2011 5:28 pm
Re: part (or parts?) needed for stepper motor coupler
That's certainly doable, but it's a tall order and be prepared for sticker shock if you take it to a machine shop. They will basically need to cut out a 300+ mm round, bore it out partially to 300mm on one side, drill/ream a 6mm hole in the middle, turn it over and face off most of the other side, leaving enough material to make a hub for the shaft, possibly cross-drill and tap for a set-screw to hold the shaft in place.
That's a lot of operations. My guess is you're looking at around 2 hours of shop time. Expect to pay around $180 - $250 for it. Possibly more, since I can see some problems with workholding.
Is there any reason the motor shaft has to be co-linear with the tube? The simplest solution would appear to be a belt drive.
[edit]
This is a fun thought experiment. If you have been 3D printing this but the only problem is accuracy of a center hole, then that's much easier. You can 3D print what you have now and have a shop do the rest. Assuming the material can be held properly, it's simple to make the center hole and the hole for the 30cm tube concentric. That takes a lot less shop time. A quick shop can do that in a lot less than an hour. The biggest problem is still holding the work (it's amazing how many simple problems are made difficult because of workholding issues).
That's a lot of operations. My guess is you're looking at around 2 hours of shop time. Expect to pay around $180 - $250 for it. Possibly more, since I can see some problems with workholding.
Is there any reason the motor shaft has to be co-linear with the tube? The simplest solution would appear to be a belt drive.
[edit]
This is a fun thought experiment. If you have been 3D printing this but the only problem is accuracy of a center hole, then that's much easier. You can 3D print what you have now and have a shop do the rest. Assuming the material can be held properly, it's simple to make the center hole and the hole for the 30cm tube concentric. That takes a lot less shop time. A quick shop can do that in a lot less than an hour. The biggest problem is still holding the work (it's amazing how many simple problems are made difficult because of workholding issues).
- adafruit_support_mike
- Posts: 67485
- Joined: Thu Feb 11, 2010 2:51 pm
Re: part (or parts?) needed for stepper motor coupler
Based on your description, it doesn't sound like you actually need the stepper axis to be in precise alignment with the tube axis.
Precise axial alignment tends to be difficult and expensive. It's almost always better to design on the assumption there will be some amount of misalignment, and to use a coupler that compensates for it. That can be as simple as a piece of flexible tubing for low-torque applications, moving up to a U-joint in high torque applications.
Precise axial alignment tends to be difficult and expensive. It's almost always better to design on the assumption there will be some amount of misalignment, and to use a coupler that compensates for it. That can be as simple as a piece of flexible tubing for low-torque applications, moving up to a U-joint in high torque applications.
Please be positive and constructive with your questions and comments.