smartrap core with aluminum extrusions?

hi guys, I was wondering why isn't the smartrap core designed with alu extrusions instead of the linear rods. If not else, at least the ALU extrusions are more readily available. I am thinking a 3-sides corexy stage left-right-back well clamped together as a way to reinforce the box underneath.

The motor supports and back bearing redirects could be attached with T-nuts and their position could be so easily adjusted. Even the Z-axis could be an extrusion instead of two linear rods.

What are the disadvantages of such an approach? Why are smooth rods+linear bearings still a solution of choice (hardness?) for an open source 3d printer that is supposed to be easy to replace parts or extend without the need for too many difficult to source or not easily available/specialized parts.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

Genuine question: is aluminum extrusion really easier to get than smooth rod? I am in the process of building a SmartCore and didn't have any trouble finding 8mm smooth rod (plenty of options on both Amazon and Ebay).

Of course a SmartRap Core using extrusion would no longer be a SmartRap Core (stating the obvious; there wouldn't be many pieces that would carry over). I am pretty sure I have seen corexy printers that use extrusions discussed on the corexy sub-forum.

Edited 1 time(s). Last edit at 08/11/2015 08:27AM by MichaelBrock.

Plenty of Aluminum Extrusion Core XY's out there... Just buy the bits and bolt it together. The SmartrapCore is meant to be made with wood and plastic in a simplistic design. It's not any worse, only different... You can use 6mm, 1/4", 5/16", or 8mm rods, printed, lmXuu bearings or bushings. It's just a different path to the same goal...

Instead of a wooden box, I'm using 19mm / 3/4" square aluminum tubing to build my box. 5/16 rods and bronze bushings. You could build your box with extrusions if you want...

Of course I can built however I can manage , my question was leaning more towards the choice of smooth rod over ALU extrusions. Granted, rod+bushing looks very clean and simple, while 15x15ALU+roller carriage looks a bit busier but it's not terribly complicated also but one gets the plus side of a sturdier box, many more options to use T-nuts and there will be no oscillations at higher speeds compared with the smooth rod. I have no idea if smooth rod oscillation is significant considering the relatively short rods (I know in Deltas it is a problem).

Thanks for your input.

Edited 1 time(s). Last edit at 08/11/2015 10:55AM by realthor.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

Madmike said is perfectly :-)

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madmike8
Instead of a wooden box, I'm using 19mm / 3/4" square aluminum tubing to build my box. 5/16 rods and bronze bushings. You could build your box with extrusions if you want...

Any pictures or maybe a thread showing it? I guess any such project needs to be shown somewhere at least to be a source of inspiration for others

PS: I didn't say rods are bad I aggree there are several ways to accomplish the same goal and having an open source project like this that offers custom openjscad interface and such a simple and easy to grasp concept is a great thing. Frankly, I would like to see an option for ALU extrusion instead of smooth rod

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

Mine is still a work in progress. I'm still working on a threaded Z axis. Here is Mandrav's though..

Mandravs SmartCore Build

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madmike8
Mine is still a work in progress. I'm still working on a threaded Z axis. Here is Mandrav's though..

Mandravs SmartCore Build

Pretty impresive indeed. Even Smartfriendz were surprised .

Is there any reason why you have ditched the wooden panels other than convenience? I can see how square ALU tube is very easy to put together while wood must be cut to size, screwed, etc. But although wood is affected by humidity over time isn't it more thermically stable than ALU ? It doesn't expand/contract as much I guess...

Edited 2 time(s). Last edit at 08/13/2015 09:10AM by realthor.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

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realthor
Is there any reason why you have ditched the wooden panels other than convenience?

I ditched the wood because of the noise it produced while the printer was working.
With the aluminum square tubes and the linear bushings instead of bearings, I can hardly hear it now when it's working next to me... it's hard to believe how quiet it came out