On Wed, Oct 29, 2008 at 11:55:22PM +0000, Chris Morley wrote: > IMHO -CSS should always wait > for an up to speed signal before STARTING feed otherwise the surface > feed might not be even close.
Are you talking about constant surface speed or feed per rev? I am not entirely sure which thing you think needs improvement because of language imprecision - please spell out exactly what you mean. I think you might mistakenly believe that the FEED per rev will be too large if the spindle is not up to speed, but I am not sure this is what you mean. Even if the spindle is still coming up to speed, the FEED per rev will be right with the current EMC behavior already (for lathes with spindle feedback). It's true the surface SPEED could be too low if the spindle just started. When radius changes abruptly you have the same problem with speed. I don't think you should stop feed in all these cases. That could be a disaster with some materials or tooling. It is often better to cut at a slightly wrong speed than to stop feed and rub the work with the tool. It's a compromise either way. EMC's current solution to that compromise is "let the user control it" (even if he just programs G4 once in a while). > The threading should only feed hold when it's not synced in my > opinion. Thats they way the Okuma was- If you hit feed hold (in the > middle of a pass) it would hold after the current thread pass was > finished. EMC2 already does this. > As for the spindle brake/reverse problem sort of the same thing- EMC > should not go from m3 to m4 (or vice versa with out stopping first and > it should know if it did stop. I disagree. Many spindle controls (all VFDs??) handle this perfectly fine. My lathe is one. For machines with reversing contactor spindle control, you may want to stop before you reverse. I agree with Stephen that you can handle this in HAL. I have all sorts of machine-specific stuff in classic ladder on my lathe. You cannot open the collet or change gears with the spindle running, etc etc. I think it's an adequate way of handling these machine-specific peculiarities. > What we need to do this safely is a feed hold that cannot be > by-passed . the current feed hold can be overridden. This seems contrary to what you said two paragraphs up. Can you clarify? Chris P.S. Please wrap your text at 70 columns; it is very difficult to quote and reply to your messages with unwrapped paragraphs and have it remain coherent. ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
