RailCoreII FAQ

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kraegar
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RailCoreII FAQ

Post by kraegar »

FAQ For the RailCoreII Corexy 3d Printer

What is the RailCore2?
RailCoreII is a CoreXY 3d printer designed and created by J. Steve White & Tony Akens. It was conceived via a discussion between us on the #reprap IRC in 2017. The primary considerations were to build a CoreXY with an enclosure integrated into the frames itself, use linear rails for all motion contraints, and make it as customizeable as possible. Once we built ours, we decided to release the design under an open source license.

The thingiverse link for all printable models is here:
Standard Parts: https://www.thingiverse.com/thing:2407174
Optional ZL Parts: https://www.thingiverse.com/thing:2765693

The entire project is available to download for Fusion 360 here:
Standard RailCore II (250mm^3) Build: http://a360.co/2z30VXH
RailCore II ZL (250mm^3 with Z leveling) Build: http://a360.co/2DoeHFu
RailCore II 300 (300mm^3) Build: http://a360.co/2BZLzTA (BETA LINK, USE AT YOUR OWN RISK)
RailCore II 300ZL (300mm^3 with Z leveling) Build: http://a360.co/2D5OryV (BETA LINK, USE AT YOUR OWN RISK)

What is CoreXY?
CoreXY is a type of Cartesian motion, where each of the X/Y motors is responsible for half the movement in X, and half in Y. Details are here: http://corexy.com/

Why CoreXY?
CoreXY is fast - almost as fast as a delta for FDM printing, and the bed only has to move in Z. This makes bed levelling easy. And the movement is simpler for a controller to handle than Delta Kinematics

Is there a BOM?
Yes! See here:
RailCore II: https://docs.google.com/spreadsheets/d/ ... sp=sharing
RailCore II ZL (250mm^3): https://docs.google.com/spreadsheets/d/ ... sp=sharing
RailCore II 300: https://docs.google.com/spreadsheets/d/ ... sp=sharing
RailCore II 300ZL (300mm^3): https://docs.google.com/spreadsheets/d/ ... sp=sharing


How much does it cost to build?
Roughly $1200 - $1350. Consider this a premium "self source" build. Approximately half of the cost is for the Electronics.

Is there a build guide?
Yes! The 250 standard is done See here: https://docs.google.com/document/d/1wBl ... sp=sharing
The 250ZL assembly guide is here: https://docs.google.com/document/d/1OoX ... sp=sharing
RailCore II 300: https://docs.google.com/document/d/1hC_ ... sp=sharing
RailCore II 300 ZL: https://docs.google.com/document/d/19Fu ... sp=sharing

Why 250mm^2?
This is the size that met the initial goals for us. It kept the printer small and portable, but is capable of printing the scale of models we typically print. There is also now a 300mm^3 version. We are looking into a 300x300x600 version as well.

Why use 1515 instead of <some other extrusion>?
1515 extrusions can use m3 hardware instead of T-Nuts. This means that the hardware is very cheap. We take advanatage of this in multiple ways throughout the design. It's also very space efficient, and, when combined with the side panels, the printer is more than rigid enough without needing a bigger extrusion.

Can I use <some other extrusion?
Sure! The design is open, feel free to modify it. However, most of the printed parts would have to change, and you could no longer use m3 hardware. The dimensions for the side panels would change, as well. The cost will increase quite a bit.

Can I use a different <hotend/extruder/bed/print surface/controller/firmware/Z-Probe/PSU>?
Yes! The design is very modular and easily customized. It's very easy to swap out components to suit your tastes.

Do you supply the sides?
The sides were originally planned to be the same Melamine MDF panels that SeeMeCNC uses in the Rostock Max v2 & V3. Due to availability concerns we're not sure if we can offer those. We have provided the DXF files, and any 1/4" rigid material can be used. (MDF, Plywood, HDPE, Delrin, Aluminum, whatever). I have also begun offering sides from HDPE at http://kraegar.com (You absolutely don't have to buy from me, it's still an open design). Two people used 1/8" aluminum for their side panels - the modified STL's for 1/8" panels will be made available as well.

Do you offer a kit?
No, but we've worked on the BOM to make self-sourcing as painless as possible. If you spot a broken link or have a question, let us know.

Do I have to use the suppliers from the BOM? I've found <random part> cheaper or better elsewhere.
Order from whatever supplier you want - the main purpose of the BOM is to list the specs of the parts you need, if you find a better supplier, go for it! We did not always choose the cheapest source, rather we focused on sources that wouldn't change their product or have links that constantly change.

How many RailCore printers have been built?
Steve built the "alpha" RailCore, and the first "beta" RailCoreII. Tony built the documentation version. After those three, we currently know of two other finished builds, and at least 3 that are in progress. If you've started a build, let us know!

Do all the parts have to be printed?
No! We teamed up with 713maker, who's cut some fantastic idler & stepper mounts for us from aluminum. These are totally optional - the printed parts do very well. But they look great, and are more rigid. Contact 713maker for more info.

Why didn't you test <insert your favorite printer thing here>?
Because we just built using the stuff we liked and knew. If you want to have us test a design for some other part, send one to us, and we'll do our best!
Last edited by kraegar on Wed Mar 28, 2018 2:43 pm, edited 7 times in total.
cluelessmaker
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Re: RailCoreII FAQ

Post by cluelessmaker »

quick question,

everything I've ever seen says that linear rails shouldn't span gaps without being mounted -- do you get away with it just because the extruder assembly is light enough, or is there something else that I'm missing? Would the 300mm version be worse off in this respect?
kraegar
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Re: RailCoreII FAQ

Post by kraegar »

The gap isn't enough for the rail to flex, so hasn't been an issue with the amount of weight we have on there.

The 300 should still be fine, there's a slight chance at faster speeds a MGN15 would do better than mgn12, or reinforcing the mgn12 with some 1515 extrusion may be needed, but from what we can tell it should be fine.
RanchRifle
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Re: RailCoreII FAQ

Post by RanchRifle »

Could you put up links to the Fusion360 projects for all four versions?
kraegar
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Re: RailCoreII FAQ

Post by kraegar »

RanchRifle wrote:Could you put up links to the Fusion360 projects for all four versions?
Added to all that are currently publicly available
RanchRifle
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Re: RailCoreII FAQ

Post by RanchRifle »

You are awesome! Sorry that you have to put up with such a demanding lot. :D
kraegar
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Re: RailCoreII FAQ

Post by kraegar »

Not a problem at all!
RanchRifle
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Re: RailCoreII FAQ

Post by RanchRifle »

I added the links to the 300 ZLT Fusion 360 model and BOM on the new Wiki.
https://railcore.org/doku.php?id=:en:start
Too bad than most of the action has moved to the facebook group. I guess I will have to learn how to book face. :(

Just as an aside, the more I think about it, the more I think it would look awesome to print the logo as an insert into the milled pockets you have been doing for the side panels. This may have to be investigated....
kraegar
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Re: RailCoreII FAQ

Post by kraegar »

Thanks for touching up the wiki!

And that's an interesting idea on the inserts. Others have mentioned doing some sort of a resin pour into them, but I don't know how well that'd stick with HDPE.
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