On 02/16/2016 07:53 AM, Nicklas Karlsson wrote: > I heard rumors here a while ago about micro meter accuracy switch but > I guess it might be a little bit expensive.
Well, yes. The "real" switches which are /specified/ with repeatability values of about 0.005mm are in the order of $200...$300 per unit from what I found. The ones specified at 0.001mm are about an order of magnitude more expensive. Even specified 0.010mm repeatability switches are in the $100 class range. This is a cheapo - not-too-good, not-too-bad - used router (bought for $1500). Using expensive homing switches is like upgrading your bicycle to run a formula 1 race ;-) It looks like micro-switches will do just fine if the speed is controlled. Maybe it would be a good idea to have a two-stage trip, as mentioned. Proximity to home and then a home switch. Then you can control the mechanics a bit better. On 02/16/2016 03:00 AM, John Alexander Stewart wrote: > I did some tests, plotted the results, etc, at: > http://cnc-for-model-engineers.blogspot.ca/2015/06/home-switch-repeatability.html Those numbers are not /that/ good if you think about it. At least not in comparison to /significantly better than 0.001"/, what others report. I had seen you graph while searching the net, but asked the question here anyway because you already said that there might be some problems with the measurement. > I think my major issue was the mounting for my dial indicator, and > if you do read the article, I did some tests with my new mill, and > results are the same or better. I was *totally* surprised at how well > they worked. Your graph does seem to indicate some kind of bias. However, it is hard to tell whether it is a mechanical feature or your measurement setup (as you mention). However, when we get into these kinds of distances, simple temperature and moisture changes are a factor too. Especially with (mechanical) electronics involved. It seems that the micro-switches are well suited for the purpose, but I guess some hard (unbiased) data has yet to be gathered (outside of a mill). -- Greetings Bertho (disclaimers are disclaimed) ------------------------------------------------------------------------------ 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
