Help to find the best combination for CoreXY Machine

I am interested in making a COREXY machine, I have several parts of CNC machines that I have not finished putting together, and some special ones for 3D printers, the problem is that I have a lot of mix of things and I do not know how to combine them.

My idea is to do something as accurate as possible, since the idea is to print parts to assemble new machines.

I was thinking of using rectangular steel tube as main frame, and then MDF to weave the parts on the walls of the machine.

After reading several post about 3D printers. I have discovered that the Z axis is very important, which I would like to use a ballscrew with a nema 23 or nema 17 engine. I would use a DM542 driver with the Nema 17 or an AM882 driver if I use nema23.

My main doubt falls on the X and Y axis, since I do not have enough linear guides.

I have for example a guide type Hiwin MGR12, but I have only 1000mm, so I could use it for example for an X and Y axis, or for the Z axis using 3 cuts of 330mm each.

Then I have 3000mm of SBR16 but it does not have as much precision as Hiwin types.

Then I have 2000mm of original Hiwin HGR20 but I think it's a lot for a 3D printer. (Although I could use it for the Y axis)!

How do I recommend combining the guides?

Btw, have too Mk IV-B as head

Edited 1 time(s). Last edit at 01/28/2017 08:25PM by samsagaz.

If you have any double doors in your house, you could use the opening for the rails, and create a super large printer in whichever room has the double doors...but seriously, they are some seriously long rails(maybe a tall delta) cant you by some cheap shorter ones, save them for the future.

i think that dont have shorter rails, just dont know how to combine it, thats all
i have like 5meters in total

If you use ball screws for the Z axis, you run the risk that the bed will drop under its own weight. I can't see any advantage in using external drivers for the Z axis motor, because Nema 17 motors are easily driven by standard electronics, and some electronics can drive Nema 23 motors directly if you choose motors with an appropriate current rating.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

There's no way to figure the optimal cutting strategy for the rails if you haven't decided on the bed size or Z capacity.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I know you have said DD that they can be cut, it just seems such a shame to do so.

You are very lucky to have such resources to hand

Take a look at DD's current build log ( [forums.reprap.org] ). In particular, making a tall coreXY is a very efficient way to increase the build volume as the heated build plate is one of the major costs of a large build. However, Z is the slowest axis to print in, so perhaps you don't want to go to extremes on the Z to XY ratio.

Using the 12mm for XY would make sense if your target build volume is modest - 400mm X and 300mm x 2 for Y would work fine. A couple of pieces of the SBR16 would make for a good Z axis, either cantilevered or balanced like DD's. How tall to make it would be very much down to personal preference and expected usage.

If you want to go big things could be much more exciting. Use the 12mm (all of it) for the X axis, cut the SBR16 in half for the Y axis and the 20 in half for Z

Edited 1 time(s). Last edit at 01/29/2017 08:56AM by JamesK.

When it comes to deciding on the bed size, take a look around for heaters first. There are certain sizes that are very common and relatively inexpensive. Picking a bed size that isn't a whole number multiple of one of those common heater sizes is a sure fire way to drive up costs. Even if you aren't planning to heat the bed now, you may decide to later, so it's still a good idea to stick with a bed size that can be easily accommodated.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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dc42
Oh didnt know that, i just see some designs that use ballscrews on Z axis, but looks like you right.

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the_digital_dentist
i didnt think about the heater bed, but in my country i just can find 300x300mm ones i really dont need an big machine, think that 220x220 will be great too

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JamesK
Will search about DD Current build then And dont know if a tall design will be great for me, is my first machine, dont know if will find some use for tall parts :/
i Think that hiwin 20 needs preassure (move big weights) to works better :/

thanks all you guys...

Although there are a few standard sizes of heater available, you can order a silicone heater to your own size, power and voltage specifications inexpensively from Chinese suppliers. There is a link on my blog

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I'd go with 1m MGR12 for the X (least moving weight), 2x 1m HGR20 for the Y, and 3x 1m SBR16 paired with drive screws running close for the Z, with a set on either side in front, and the third centered in the back for optimum leveling.

Make a sweet 1 meter box, though your print size will be less natch. Probably around a 800mm cube, so you can use 4x 400mm square heaters for the bed.