On Thu, Aug 16, 2012 at 04:07:10PM +0200, andy pugh wrote: > On 16 August 2012 15:58, SourceForge.net <[email protected]> wrote: > > > Emc could benefit from a tapping cycle that does not rely on a spindle > > encoder but instead uses floating taping heads. > > How does that work? Do you have to assume that spindle speed is > approximately correct, and not care too much about the tapping depth? > > Or is this for use with the friction-reversing heads? (though I still > wouln't know how to control depth)
For a tension/compression tapping head, the cycle would need to reverse the spindle at the bottom, and the feed and speed would need to be matched proportionally according to the pitch. It's tricky to track during the reversal, especially if your spindle doesn't accelerate very fast. For a reversing tapping head, they are much more forgiving. You can always feed too slowly, and the clutch in the tapping head slips. The spindle doesn't reverse. The forward and reverse gearings in the tapping head are different (but the ratios are different on different models of head), so on reversal you can feed faster by some ratio. Both styles give very approximate depth control and you really ought not use them on blind holes if you need to get close to the bottom. They are both tricky to use. I recommend writing a subroutine that takes the pitch and depth as an argument, and handles all the magic ratios for one's particular tapping head. I suppose you could fake the encoder feedback and use the rigid tap cycle with a T/C head, but I haven't tried this. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
