Build Log: 3-4 Axis Mill/Router

[JAZZCNC]

Hi Ian,

Ok I can give you a solution that is perfect answer to all your issues but it's a bit off the Norm and cost's a bit more, will also mean a redesign. . . BUT. . . The plus,s are many and well worth the trouble if your cutting Ali and Odd sized material.?

Make it so the gantry lifts up and down not the Z axis.? Infact you don't have a Z axis the Gantry becomes it. The spindle is fixed on a plate that just moves across the Gantry.
There are only a couple of advantages to this design but they are BIG ones.?

Finish is improved massively because you only have the tool extension from spindle extending down from Gantry so stiffness and resonance is improved massively so tool chatter is far less, it's about good as it gets in tool rigidity and therefore finish.

There's virtually no restriction in material size that can be machined and still have Ultimate Tool strength has the tool Extension doesn't change only height of gantry. The Only limiting factor is how high you build the Columns that the gantry run up & down on. The flex and rigidity of tool will never change whether you machining 2mm Ali or Top of an Engine block has the distance form gantry to spindle never changes because spindle is fixed to plate running across it. Only gantry goes up an down doing the job of a normal Z axis giving the absolute minimum amount of flex, which can only come from the tool it's self.

This design will need ballscrew down each side to lift gantry up and down but could be driven with single motor connecting screws with belts across top. The Columns can be braced across the top so still very strong and rigid and provide perfect mounting for motor/belts etc. If heavy gantry then counter balance down side each column will neutralise the weight so won't need massive motors.

In your position with your needs then this would be my route without shadow of a doubt.!!

Hope this helps.

[John S]

The flex and rigidity of tool will never change whether you machining 2mm Ali or Top of an Engine block has the distance form gantry to spindle never changes because spindle is fixed to plate running across it. Only gantry goes up an down doing the job of a normal Z axis giving the absolute minimum amount of flex, which can only come from the tool it's self.

?????????

So if the gantry is mounted on spindly rails both sides this will not be transmitted to the tool. ?

A Z axis usually has twin rails close together on one plate.
You are proposing two Z axis so 4 rails well spaced apart ?