Large CNC Router Construction

[kkilst]

I am a hobbyist of wood carving, and planning to build rather large CNC router of 1500X2000MM.
Attached are 2 photos of the alternative construction of X-axis assembly.
I am not sure what is the more solid configuration, to put it in "vertical" or "horizontal" ?
Four of 0.5kW spindle motors are going to be used on this X-axis slide.
I would appreciate to get opinion and criticism from the community of this field.
Thank you and best regards,
kkilst@cbn.net.id

[andy_ck87028]

I have built the second; i.e. horizontal as it seems to be logically the more stable; less potential for twist in construction and flex under load

It is more complex and more thought needs to go into spindle size, spindle access, etc but I remain convinced it is the best approach.

Andy

[fatal-exception]

you will still have flex in the y direction.

You need to show how your spindle will be attached to the rest of the machine.

[LeeWay]

Style two would be my choice as well. I call that a bridge type gantry. The Z axis runs across it like a bridge. That is the type gantry I used and it is a solid machine and can mill and route aluminum.
The rails you picture are hopefully the supported type. It would seem that this type would work best being bolted on at the bottom rather than the side or upside down.
I would consider spreading the gantry rails apart some. Enough to get a Z axis hanging down in between the two. I would leave the gantry screw mount up top, but off to the back side of the Z axis. This will give you more room for Z travel. You can use heavy end plates with gussets to raise the gantry up a little as well.
On the x table, I would consider putting the screws underneath as well. They are less likely to catch on anything and this will help narrow the footprint and keep the screws cleaner. A little more difficult to build, but worth the effort. Good luck with this and keep it coming along.

[kkilst]

I appreciate for the comments and opinions.
All the round-shaft (Rails) are fully supported. My intention is to use standard parts as far as possible.
I do not have machining shop myself, some parts have to be subcontracted for the CNC machining.
By spreading the rails wider for accommmodating the Z-axis asssembly,
I am still figuring out of how the construction of the Z-axis would be like for
multiple spindles.
Can I get some pictures from existing design as a reference.
Thank you in advance.

[ger21]

Originally Posted by kkilst By spreading the rails wider for accommmodating the Z-axis asssembly, I am still figuring out of how the construction of the Z-axis would be like for multiple spindles.

Here's my ideas for a two spindle machine.

http://www.cnczone.com/forums/showthread.php?t=45844

[LeeWay]

I think multiple spindles would better lend itself to a more open design rather than the bridge type I mentioned. You could still use the bridge style and gain the proper support from the rails. The rails will work mounted on the side like you show in the first image, but only half of the bearings would be used until it's under load from the spindle.
Ger's design looks pretty cool. Here is a video of a 4 router head design. Pretty neat for lots of narrow parts.

http://www.youtube.com/watch?v=48B1Zs7pOOI

http://www.youtube.com/watch?v=48B1Zs7pOOI