Ah! Yeah, that would be great, thanks! -Pete
On 06/14/2011 01:29 PM, doug metzler wrote: > I did roll my own - let me know if you want me to send the Eagle PCB files > and BOM. > > DougM > > On Tue, Jun 14, 2011 at 1:20 PM, Peter Loron<pet...@standingwave.org>wrote: > >> On 06/14/2011 08:53 AM, Kirk Wallace wrote: >>> On Mon, 2011-06-13 at 13:47 -0700, Peter Loron wrote: >>>> Hello, folks. Can anybody comment on using hall effect switches on a 3 >>>> axis mill for limit / home switches? Seems like they would have some >>>> possible advantages over physical contact switches. >>>> >>>> Thanks. >>>> >>>> -Pete >>> My Hardinge lathe uses Hall limit and home sensors. The Z axis target >>> magnet is small and mounted such that there is minor protection from >>> chips. There is a small gap between the magnet and sensors when aligned. >>> If chips are in the magnet area, they get wiped off, but not too small >>> such that small chips don't bind in the gap. the magnets are weak enough >>> to have largesh chips fall off. The trip location accuracy only needs to >>> be within about 2 or 3mm because, in my case, the home sensor is used in >>> conjunction with the screw encoder index, which should be accurate >>> to .002mm or better. What I like about Hall sensors is that they are >>> machining fluid proof and will practically never wear out or change the >>> trip point or behavior over time. I tend to think using mechanical >>> micro-switches is silly, but a lot people use them to good effect. The >>> Hardinge Z axis uses a Hall sensor with magnet in a micro-switch >>> housing: >>> >> http://sensing.honeywell.com/index.cfm?ci_id=154286&la_id=1&Ne=7&sid=1308EB555700&ci_id=154286&N=3591+4294966517&la_id=1 >>> Short URL: http://alturl.com/v2jzu >>> >>> These are mounted in a location well protected from chips, but the area >>> is not sealed from coolant, which is fine because the sensors don't mind >>> fluids. >>> >>> The Z sensors are in an aluminum threaded barrel similar to this one: >>> >> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=480-3256-ND >>> Short URL: http://alturl.com/netsd >>> >>> They tend to be expensive, but it should not be too difficult to machine >>> a barrel and pot an IC sensor with leads into it >> Yeah, I'm going to roll my own...I have a pile of Allegro sensors here. >> Also, retail on the Honeywell sensors is probably more that I've got >> invested into the whole mill... :-) >> >> -Pete >> >> ------------------------------------------------------------------------------ EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
