[strangetanks]

I'm beginning a new cnc router build. I am really contemplating using an articulated arm arrangement for the z axis instead of the standard slider. Similar to the new Bosch Articulated Arm Miter saw. Wondering if anyone else has any thoughts on doing things this way, drawback sect.

Some of the reasons I wanted to switch to this arrangement is mostly I really don't like the linear slides on my current machine. If I tighten them up there is more resistance than I like, if I let it out a little there is a small movement in the slide. I also found that the bearings get full of super fine dust. Everything works fine on my current machine, but I want to make a machine that is more rigid and needs less maintenance.

Any thoughts would be welcome.

[ger21]

Use Profile linear bearings like THK or Hiwin. Much more rigid, far simpler, and more compact then any type of articulated arm setup would be. With Proper seals, they are very dust resistant.

[LeeWay]

The arm, like what you see in that saw, is just kinda neat. It is not as accurate vertically as you might think. It does well in the Y axis, but not as well for Z.
Not really what you want for a Z axis.
Better bearings and ways are the answer as Gerry mentioned.
The Z axis drive would be a second source to upgrade.
That tried and true design can be incredibly accurate even with a lot of weight on it.It's how the big boys do it.

[aarggh]

Google articulated arm + problems + saw, not as cool or robust in commodity equipment as you'd think.

cheers, Ian

[strangetanks]

Thanks for your thoughts everyone. Just getting parts ordered to get started on the x axis, so I have a ways to go till I finalize designs for the z. I'm still really on the fence. Also considering an arrangement of linkages similar to how a pantograph machine works. I have a big old one in my shop that's converted to make mortise and tenon joints for fabricating doors.

Pretty much like this one https://www.apexauctions.co.uk/aucti...tm?lotId=55686

I can tell you its rigid as all get out and is so smooth the whole mechanism wants to move to one side because my shop floor is slightly out of level. Of course its all cast iron and heavy as heck.