Stationary y-Axis motors

discussion of design changes / improvements / suggestions
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xtonyx
Posts: 22
Joined: Wed Jun 19, 2013 4:23 pm
Location: PCB, FL

Stationary y-Axis motors

Post by xtonyx » Thu Jun 20, 2013 5:04 am

Instead of mounting the y-axis motors on the gantry ends, why not mount them the the frame? It would save some weight from the moving assembly.

You'd just need to run your belts as a loop, where each end of belt is clamped to the gantry, and your motor is on one end of the y rail and you would have an idler/tensioner at the other end. This idler could be spring loaded to keep constant tension.

But I haven't even put my first one together yet.
tony

xtonyx
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Joined: Wed Jun 19, 2013 4:23 pm
Location: PCB, FL

Re: Stationary y-Axis motors

Post by xtonyx » Thu Jun 20, 2013 5:47 am

BJBSquared has done this, now I don't feel so clever.

http://www.shapeoko.com/forum/viewtopic.php?f=11&t=1510
tony

cvoinescu
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Re: Stationary y-Axis motors

Post by cvoinescu » Thu Jun 20, 2013 7:53 am

The main reason is that it's cheaper and simpler to have the motors move along an open belt. It also happens to be easier to extend. In CNC milling, where speed is not much of an issue and the gantry is fairly heavy anyway, the weight of two NEMA17 motors doesn't make that much of a difference, so simplicity wins. You have to remember that low cost was one of the goals when Edward created Shapeoko.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

bjbsquared
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Re: Stationary y-Axis motors

Post by bjbsquared » Thu Jun 20, 2013 12:15 pm

BJBSquared has done this, now I don't feel so clever.
I'm sure you are still clever. :D

The biggest advantage I think is that routing the wires for the Y motors was easy. Direct to the shield.

Weight difference = 2* (motor +motorPlate -carriagePlate)

Cost was more: An extra idler on each side and A LOT more belting.

The design is versatile size wise. Also stock can be slid in the X and Y direction
#1016 - 1M x 1M Y: Dual Motor Drive w/Looped Belts, X:Dual Rail with wlanfox blocks, Z: Stock, Spindle:DW660

xtonyx
Posts: 22
Joined: Wed Jun 19, 2013 4:23 pm
Location: PCB, FL

Re: Stationary y-Axis motors

Post by xtonyx » Thu Jun 20, 2013 1:29 pm

Thanks for the insight, I didn't consider that it might be easier/cheaper the way it was. :mrgreen:
tony

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