Re: ACME or Ball?

Hello,

Commercially available PCB milling machines by companies such as LPKF
and T-tech use acme screws and a/b nuts with success, so the
questionn seems easily answered...

In short, Yes. Acme will work fine. Most of these commercial machines
use 3200 or 4000 steps/inch and have top feedrate of 60/90
inches/minute. Steppers are used, and sometimes the homing is against
a fixed stop, with no switch. This takes advantage of the steppers
ability to stall without problems...

Machines I've seen use Kerk or BS&A nuts. And Jan R is right about
ballscrews and dust/grit. Acme is MUCH more forgiving.

Hope this helps,

Ballendo


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "ghidera2000"
<ghidera2000@y...> wrote:

> I'm looking at putting together a small mill/drill for PCBs and
> doing cutouts of plastic or sheet metal enclosures and front panels
> ( <= 1/4" thick). The mill working area would be a maximum of about
> 18" by 18". Traces would be pretty fine, between 0.0125" and 0.01"
> and drilling for all the through-hole parts.
>
> Think an ACME screw setup would do ok at this or are ball a must

for

> this level of precision?
>
> Also, think the small ballscrews would be good here? In the reid
> catalog I was looking at the TBS-17 screw and the precision nuts

for

> them. Would these be strong enough? I just can't see my application
> requiring much in the way of brute strength...