Z-Plunge advice sought...

[Wal]

Hello all,

I'm in the latter stages of my mini-mill design - just looking to finalise the placement of the Z-Axis on the frame.

Have a look at the attached diagram - you can see that my Z has a plunge of 150mm. In the diagram the plunge bottoms out with the spindle touching the machine bed - probably not something that you'd want to see in the real world - so my question is: how much clearance would you recommend leaving between the spindle at it's bottom-most position and the machine bed? I know that this is one of those questions where the answer is influenced by further factors (machine use etc.) but is there a good clearance distance to start with?



Thanks for any advice you can offer!

Wal.

[Jonathan]

The closest you want it to the bed is close enough to leave room for the shortest cutter and thinnest material. The nearest I can think of would be milling PCBs - so maybe 10mm. Realistically you can generally just put a spacer between if you can't get the spindle close enough, so I wouldn't worry too much.

If you put the spindle mounts closer together, you can slide the spindle up and down in the mounts and it becomes a moot point...

[Wal]

>If you put the spindle mounts closer together, you can slide the spindle up and down in the mounts and it becomes a moot point...

Yep, true enough - I've included 4 sets of holes for the spindle brackets so that should give me a fair bit of room for manoeuvre - just wanted to be sure that I wasn't missing something obvious!

Cheers Jonathan.

Wal.

[JAZZCNC]

I just have holes in back plate for adjustabilty so between these and sliding spindle up and down brackets makes finding the best or ideal position easy.

Like this (Only showing 1 brackets but there's two) If mostly cutting thin material then the holes at the bottom are the Ideal position has the distance from lower Spindle main Body to collet is a constant overhang so here the Z axis is extended the least it needs to be.
Spare holes can be used for other things like holding air or Vacuum shoes/pipes etc.