One ring to rule them all?

[Rufe0]

Indeed indeed, so just brainstorming what my options are now. Thinking the height adjustment on the bed is abit of a hassle I could do without. But I still want to be able to work on tall items. So that leaves me with a very tall machine, would have to use waste boards or something to space the work up, maybe a hassle maybe not. Something like this.


I'm wondering if there would be a better way though. I had an idea... it's basically a fixed gantry except the bed is fixed and the gantry moves(not shown but bed would sit on supports at both ends). I think it would look really cool, like some sort of scanner out of a sci-fi movie. Would offer better access aswell and I think I could make it significantly lighter. * not a proper drawing just an artists interpretation * shown with spindle hanging out the front for ease of drawing, obviously it would be a dual gantry with centralized spindle.


I think both would suffer from strength issues, especially as there is no diagonal support to stop skewing.

Any thoughts?

[njhussey]

Why don't you put the Z axis between the gantry uprights? It would put the C of G much closer to the center of the gantry bearings and you'd lose much less cutting area at the back end of the bed.

[Rufe0]

Why don't you put the Z axis between the gantry uprights? It would put the C of G much closer to the center of the gantry bearings and you'd lose much less cutting area at the back end of the bed.

Thanks which one are you referring to? Can you do a drawing?

[Rufe0]

Why don't you put the Z axis between the gantry uprights? It would put the C of G much closer to the center of the gantry bearings and you'd lose much less cutting area at the back end of the bed.

Ah I think I get you, in the real design the spindle would be centralized to the gantry, not hanging out the front.

[njhussey]

Yes, that's what I meant

[Rufe0]

Just easier to draw it hanging out the front so you can see where it is

[Robin Hewitt]

I may have misread this but the two rails under the bed seem to give total support to the outside edges and none in the centre? As most of the cutting will actually tend towards the centre do you think this is a good idea?
I have never quite figured out the optimum separation but there must be one

[Rufe0]

I may have misread this but the two rails under the bed seem to give total support to the outside edges and none in the centre? As most of the cutting will actually tend towards the centre do you think this is a good idea?
I have never quite figured out the optimum separation but there must be one

Mmm as pictured the bed would be made of 100x100 square hollow section so shouldn't flex too much. However liear rail is cheap so wouldn't hurt to add one in the middle.


Just doing the numbers, using 100x100x5 shs @ 14.7kg per meter. The traveling 0 shape fixed but moving gantry design reqires 4.2m of tube per 100mm width. So for a 200mm wide traveling 0 it would weigh 120kg, heavy but just managable .


The very tall normal machine of the same size would need 15m of tube which would weigh 220kg.