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(Probably) a new CoreXY-based design

Posted by roman_savchuk 
(Probably) a new CoreXY-based design
January 08, 2019 07:50AM
I wanted a small CNC router and at some point of researching my options decided to build shapeoko-like machine from scratch. I wanted it to be as simple as possible, and that brought me to mounting all of the machine motors on the X Carrier assembly, with xy belt drive arrangement like this.

Basically it's a non-crossing CoreXY like a D-bot used in some 3d printers, except for the belts are fixed and the motors are movable. I think it's a new design, but let me know if I'm wrong smiling smiley
Rest of the machine in Fusion 360

Test-running an unfinshed prototype
[www.youtube.com]


P.S. Posted this to r/hobbycnc earlier today
Re: (Probably) a new CoreXY-based design
January 08, 2019 07:50AM
Ok, I should've explained the point of this design in the opening post.
The gantry is based on existing aluminium profile machines like shapeoko or x-carve. All of them already have motors mounted on carriers, i.e. 2 motors to make Y-axis movement, 1 motor to make X-axis movement. So, it's already removing the mass of 1 motor from the moving assemblies.

The biggest advantage is actually addressing cable management issues. All NEMA motors, endstops and mainboard are located on a single rigid X carrier assembly. The only moving cables are power cable to mainboard, usb cable (or none if wifi shield is used) and power cable to spindle. So you can completely eliminate cable chains and distributor boxes.

Edited 2 time(s). Last edit at 01/09/2019 04:32AM by roman_savchuk.
Re: (Probably) a new CoreXY-based design
January 08, 2019 12:34PM
New ideas in these machines are very rare but bad, unsuitable ideas being quickly forgotten are regularly reinvented !
The CoreXY has been "invented" to have the motors fixed. Here you have the complexity without this advantage.

Edited 1 time(s). Last edit at 01/08/2019 12:35PM by MKSA.


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: (Probably) a new CoreXY-based design
January 08, 2019 12:40PM
I suppose the question to ask, is "what problem with Core-XY are you trying to solve?" or "what improvements does this configuration offer over the original design?"

At face value this appears to completely negate the purpose of the Core-XY design as already stated by MKSA above.
Re: (Probably) a new CoreXY-based design
January 09, 2019 03:41AM
At first sight, the shorter belts are a benefit, but the added gantry weight negates this. Except you have a really big spindle moving very slow. Then the stepper weight is neglectible.
Re: (Probably) a new CoreXY-based design
January 09, 2019 04:35AM
Added a short description in the post #2, hope it answers questions above
Re: (Probably) a new CoreXY-based design
January 23, 2019 01:10PM
Nice idea to shorten belts. Also, you may place motors on Y carriages instead of X. It may save X from weight load of motors and complexity of design but will keep weight on Y.
[Update] I was too fast to jump to conclusions. It won't work on Y sad smiley

Edited 1 time(s). Last edit at 01/24/2019 07:19PM by piper3d.
Re: (Probably) a new CoreXY-based design
January 29, 2019 05:53PM
Quote
MKSA
Here you have the complexity without this advantage.
Indeed, unless you consider that, in the provided drawing, the motors are still fixed, and that it is the whole belt and pulley system that moves (and remains lighter than the motors).

Then, you have the benefit of shorting belts...
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