I understand your situation. In light of what you said you might want to go with Prox switches and forget about mechanical microswitches. My reason is this: Small cheap mechanical microswitches are very easy to break and hard to mount, protect and adjust. Prox switches are just the opposite. Most are even waterproof. Prox switches are becoming very cheap. Someplace is trying to sell me some for about $10 each with a cable. I've used Prox switches on very expensive machines for homing and limits and they just work. No call backs.
Dave On 2/17/2016 11:10 AM, Bertho Stultiens wrote: > On 02/17/2016 04:28 PM, Dave Cole wrote: >> The other approach to take is to forget about home switches and do a >> touch off on the work or the stops by using a probe. > Yes, you are right. That would be a good solution. > > I may just want to clarify... The whole discussion is not about the > correct or best way to do this. My implementation target is a cheap > router and a lot of not-so-experienced operators. > > However, the speculative and inquisitive mind got hold of me when > thinking about the switches and started to question the switches. The > micro-switches for themselves are actually interesting how they behave. > > My thoughts here were more like, why pay a lot of money if cheap stuff > can do the trick. Is there data on the cheap stuff as to prove that the > expensive stuff is better. If the cheap stuff works well, or works > badly, then that would be a nice insight if documented with data. > > >> Mount the probe in in the spindle and touch off on the stops or the >> workpiece to obtain a zero position. >> There are some relatively inexpensive probes for sale. >> Most homing systems I have used on machines are not that accurate. >> Homing only positions the spindle or carriage to the machine, and not >> the workpiece. > The point of homing, in the application at hand, is not about perfect > accuracy. It is to make sure that the machine is in a known state. > > The mounting/unmounting of a probe in the spindle will be a challenge > for non-experienced operators. > > >> If you clamp the workpiece against a stop and there is a spec of grit or >> a rough edge or interference then super accurate homing becomes useless. >> Referencing to the workpiece is usually what people usually really want > You are right that the work-piece is the actual reference and that it > takes precedence when actually performing the work. However, from what I > saw on the old router at the hackerspace, we want to automate the > machine boundaries. At least we can make the machine not run past its > ends. Having a (home-) side more accurate than simple end-stops is just > a bonus. > > Doing proper touch-off on the work-piece or calibrating the work-piece > position is a story that merits a whole thread for itself, I guess. > > ------------------------------------------------------------------------------ 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
