Bigger X or Y axis - what's better choice

Hey everyone,

I'm about to configure my own Mendel90 and I will use a bigger print bed than the standard 200x200mm. At the moment, my first choice would be a 300x200mm heated bed.

So while configuring the whole printer size, I'm not quite sure which axis should actually be the larger one?

Should the X axis move the 300mm of the longer side of the bed, or should the Y axis with the heatbed itself move the full 300mm?

The most important part is the mass of the moving parts, so the longer axis should be the one with less weight. But which one is lighter? I never measured weight of a X axis with extruder and stepper motor, or the printbed.

What would you suggest? Is there anything I might have not considered so far?

The Y carriage is heavier than X on the existing machine but either way the bed will be 300 x 200 or 200 x 300 so it will be 50% heavier. The mass of the moving part of the X axis doesn't change.

If you make the X axis move 100mm more then the machine gets 100mm wider. If you make the Y axis move 100mm more then the machine gets 200mm deeper, so it is better to increase X.

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[www.hydraraptor.blogspot.com]

Quote
nophead
The mass of the moving part of the X axis doesn't change.

But the complete X axis assembly (including rods) that the z-axis must move increases due to the larger rods. Probably not a huge consideration as the overall mass that is moving isn't changing THAT much, but it is more.

One other consideration is that all the larger beds I've seen have the solder pads centered on the longer dimension. If you made the longer dimension the y-axis, you'd have to do some alterations of how the ribbon cable is ran, either moving it to the side of the bed or bending the cable to make a right angle turn.

It is only a little more mass but the Z axis has so much gear ratio that mass has very little effect.

It is easy to fold ribbon cable at 45 degrees to make a right angle bend on top of the Y carriage..

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[www.hydraraptor.blogspot.com]