sliding gantry or sliding Base ?

[Ricardoco]

Thanks for your answer,
so, if space wouldn't be an issue for you, you would opt for the fixed gantry, right ?

Now that you ask i suspect i would, assuming the size didnt bring its own considerations then yes i would.. I think you would gain accuracy and greater versatility of materials...

I suspect there will be some more input shortly...

Rick

[Jonathan]

With a fixed gantry you can make the gantry as strong as you want without worrying about its mass too much, since it's not moving. Clearly since the rails now need to be bigger it's likely to cost more, so you're using more space and money to get better rigidity which is nothing new. Also the motors now have to move the mass of the bed and whatever you cutting, which could add up to a considerable amount with an aluminium bed. Clearly this means you may have to spend more on the motors, although since the bearing blocks can be spaced out a lot, you should only need one ballscrew so that saves a bit compared to a moving gantry.

It will be significantly cheaper to use steel for the main frame, instead of extrusion. With a fixed gantry you can afford to get some big box section...