sliding gantry or sliding Base ?

[JohnJ]

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

Regarding my experiences,
i only know a few industrial Milling Machines that are built with a bridge design,
for example the Datron Machines, which are good worthy Mills, have a bridge design, but they have a moving gantry and fixed table, which is probably due to size, as size is a big sales argument for industrial machines.

You are right, all the bridge type machines I can think of, have either no load at the tool tip, or only light load.
I can just think of industrial machines, as thats where my experience is from.

For now i will complete a 3D Design of a fixed gantry type machine, lets see if I like it at the end.

Nevertheless, i would love some more people to join the discussion and share their experiences.

Regards,
Clemens

[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...