Re: Crazy Ideas Vol 1 - home switches

I am using simple micro switches with rollers on the levers.

in Turbo-CNC the home command sends the signal past the switch
closeure and then slowly reverses until the switch opens.

most of these micro switches seem to be very repeatable.






--- In CAD_CAM_EDM_DRO@yahoogroups.com, Stephan Kotzé <stephank@c...>
wrote:

> Hi All
>
> Been busy with my first mill. I decided on a arch type ("fixed

Gantry" with moving table) after reading a book on high speed milling
and high speed mill design. Working volume is 300x300x300mm. This is
no router as I expect to do all metals including superalloys. I got
bits and pieces from ebay and is now busy with construction. I also
did some FEM analysis for errors etc. (I am a mechanical/production
engineer). The drivers and steppers are sorted, now the integration.

>
> First problem I face is leadscrews. I did not buy commercial units,

instead settling on normal M10x1.25 thread (cheap). I read on a
website (about optical equipment) about lapping these to give an
accurate thread. That is now done. Next problem is mounting them. I
got a bicycle axis and split this in 2, giving me 2 adjustable
angular contact units. I noticed that they did not run very smooth,
and after investigation I saw that they have a very rough torque nut.
Setting up a Dremel and fitting these units onto bearings, I ground
them smooth and accurate (pictures available for those that want to
see). They now run extremly smooth even when overtorqued. Next
problem is the nut. I have seen various designs on the net for these,
but none to my satisfaction. The roller screw nut design in the files
section is very interesting and i think i will go for that. Problem
is I do no have my lathe yet, so I might have to settle for a Delrin
or oil impregnated Nylon nut, tapped long enough to take up any
backlash.

>
> Couple of questions:
>
> Anyone have a recommendation for homing switches. They obviously

need to be fairly repeatable. (optical, mechanical)

>
> I need an idea for cheap bellows to protect the linear guides and

leadscrews

>
> Vol 2 will follow soon with ideas for DRO's
>
> Stephan
>
>
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