[Woodphizeau]

First post, here goes...

I've been looking at a build of a 48x48 machine, have plans and I'm sure lots of questions I'll research to follow, but the one that's burning in my mind right now is simple - is it reasonable and/or rational to think about a build with the bed of the machine vertical (think X & Y are traveling parallel to the wall).

The issues that come to mind are 2 fold - 1 is steppers moving the gantry weight vertically... I'm looking at a machine that's flying gantry with dual 5 start acme drives from steppers in the 320oz variety.

Second concern is workpiece placement/generally fixturing.... I plan on a thin vacuum table for part of the bed, and a "standard" t slot/clamp surface for the rest, and given that it's fixture not gravity that holds the piece I see the only concern being basic material handling TOO the work area, not holding it.

So folks - what am I missing as I think about this?

WHY would I consider this? Space. Eating a 60" wide section of full-height wall is something my current space allows for Much more easily than the footprint of a horizontally placed machine, potentially delaying my much anticipated build...

Looking forward to your wisdom.


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[ger21]

One, you move the gantry left to right, not vertically. Then you're only lifting the Z axis, rather than the entire gantry. Depending on your performance goals, you might need a bigger motor for this axis (Y?).

You want to mount it at a 5°-10° angle, as it'll make it a bit easier to work with.
I've seen at least one commercial machine like this, and maybe 1 or two homebuilt ones.

[Woodphizeau]

Ha! Didn't think of turning it 90 degrees... That's a perfect addition to the master plan - thanks!

What's the calculation on the "weight of z to cutter weight/stepper strength required.

I was also thinking that a slight angle would in fact help, so that's for the validation there.

I did see a kit that's vertical... But what fun is a kit when I can build it myself

Thanks for the input, hope there's others out there with feedback!


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[adprinter]

Gravity is a powerful force to be reckoned with. When you start mounting things like the linear rails, and the trucks for your gantry, it's best to have things oriented as near to perfectly level as you can achieve. Then, the only force your steppers are fighting is the actual weight of the gantry (and whatever tool you are using, such as a Router). Linear rails which are NOT mounted perfectly level, will introduce a strain on the steppers, when driving the gantry in whichever directly is "up hill". And then tend to cause the gantry to "coast" when traveling in the opposite direction. This would make motor tuning the stepper motors a nearly impossible nightmare! The best results are achieved, when "all things being equal" is applied (particularly where motor tuning is concerned). Just my 2 cents worth....

[louieatienza]

Gravity is a powerful force to be reckoned with. When you start mounting things like the linear rails, and the trucks for your gantry, it's best to have things oriented as near to perfectly level as you can achieve. Then, the only force your steppers are fighting is the actual weight of the gantry (and whatever tool you are using, such as a Router). Linear rails which are NOT mounted perfectly level, will introduce a strain on the steppers, when driving the gantry in whichever directly is "up hill". And then tend to cause the gantry to "coast" when traveling in the opposite direction. This would make motor tuning the stepper motors a nearly impossible nightmare! The best results are achieved, when "all things being equal" is applied (particularly where motor tuning is concerned). Just my 2 cents worth....

There shouldn't be a problem. The Z ram on some commercial 5-axis machines can weigh a half-ton (the A/C head alone can weigh over 300lbs with spindle.) Horizontal milling machines are still prevalent in the metalworking field. Sizing the motors right, plus using a balancing mechanism, whether spring, gas shock, or counterweight, can help relieve the stress on the motor.

[Woodphizeau]

I'll look into adding a counterweight as that should help the coasting, and I plan to rather oversize the motors as well.

I was thinking of the build on at oration table level and then angle mounting for production, at which point the counterweight would be applied and motor retuned - sound about right?


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