most commercial cncs have encoder home morks ( Z phase) and they have what users often miss-call a 'home' switch
its really a 'close to home, slow down you fool' switch so the velocities during the home 'stretch' ( between 'nearhome' and home) are always controlled the distance between those should be governed by distance, max velocity + safety margin btw proxes have trip distance and trip time, see specs from mfctr want really good switches? look for swiss My-com guaranteed 1um seem Baumer owns them now ( Baumer is big prox company in Euro-tania ) tomp On 02/16/2016 10:05 AM, Gene Heskett wrote: > On Monday 15 February 2016 19:11:10 Jack Coats wrote: > >> I saw some prox sensors ebay (china trash) that folks on 3D printers >> are using for automatic bed leveling compensation. They are about >> $2.50/ea delivered, others are $10 if you want a better quality. >> >> Their repeatability is good, > But hows the velocity vs trip point? Do they lag at the higher speeds, > or pre-trip at higher speeds? Never played with any, but could be > cajoled if these elcheapo's turn crappy before their time. >> If using switches, please check the brand. Microswitch and possibly >> Cherry make great switches. Some others are 'problematic' to be kind. >> >> Enjoy. >> >> On Mon, Feb 15, 2016 at 5:57 PM, Gene Heskett <ghesk...@wdtv.com> > wrote: >>> On Monday 15 February 2016 18:44:00 Bertho Stultiens wrote: >>>> Hi, >>>> >>>> I'm looking for an on-the-cheap way to do reasonable homing. Usual >>>> switches for the purpose cost a lot. The machine only has a >>>> repeatability of 0.02mm, so it may just be a waste to use too >>>> accurate (expensive) switches. >>>> >>>> Has anyone numbers on the repeatability of "normal" >>>> micro-switches? >>>> >>>> Micro-switches are (relatively) cheap and mostly not too shabby, >>>> but I have a not seen any hard data on repeatability (other than >>>> datasheets saying that they are made for repeatability). >>> I am using some micro-mini roller lever junk I got for 6 bucks a bag >>> of 10 from ebay. Repeatability according to my dials is well within >>> .001" even with crap switches. Its a "dry' circuit, so as long as >>> the contacts are clean, there's very little other wear. MMMV after >>> a long time, but its not beem noticable in 6 months now. >>> >>> Cheers, Gene Heskett >>> -- >>> "There are four boxes to be used in defense of liberty: >>> soap, ballot, jury, and ammo. Please use in that order." >>> -Ed Howdershelt (Author) >>> Genes Web page <http://geneslinuxbox.net:6309/gene> >>> >>> >>> -------------------------------------------------------------------- >>> ---------- Site24x7 APM Insight: Get Deep Visibility into Application >>> Performance APM + Mobile APM + RUM: Monitor 3 App instances at just >>> $35/Month Monitor end-to-end web transactions and take corrective >>> actions now Troubleshoot faster and improve end-user experience. >>> Signup Now! >>> http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 >>> _______________________________________________ >>> Emc-users mailing list >>> Emc-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/emc-users > > Cheers, Gene Heskett ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
