The ramps are essential for full strength as they remove the need for a safety groove
Dave Caroline On 19/05/2014, Steve Blackmore <[email protected]> wrote: > On Sun, 18 May 2014 12:45:08 -0700, you wrote: > >>I'm still not seeing why G76 has a entry and exit ramp. I believe the >>intent was to deal with Z acceleration time where the helix is not valid >>at the start (and I assume the end) of synchronized motion. Normally, >>one would start the thread off the part enough to have the Z and spindle >>locations synchronize in air. > > Absolutely. You start the thread in air so the tool is at correct > feed/speed combination when it contacts the material. > > A good CAM program can work this distance out for you. Normally in the > machine setup you tell it what the max feeds and acceleration are and > you are able to enter a tolerance value so you have a little leeway. > > Otherwise you guess. > >> For threads that need to start in the >>material rather than air, ramping may be used to ease into the thread >>until the helix is correct. But the way I see it, either way there will >>be a bit of bad helix at the start and end of the thread. Ramping-in >>cuts less material, so may get in the way more than plunge-and-go. >>Channeling before threading, so any material left will only have valid >>helix, seems better. I would like to know if there is any situation >>where ramping would be better than channeling or plunging. > > If the thread starts in the job, often parts are designed so there is a > clearance groove in, out or both on the thread, a plunge can be made as > long as the tool can accelerate to the correct feed within that groove. > If that's not possible or desired a ramp in move in/out can be done, but > the tool has to be at the correct feed when it hits the work - as long > as the pitch of the thread doesn't alter, it's fine. > > > Steve Blackmore > -- > > ------------------------------------------------------------------------------ > "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE > Instantly run your Selenium tests across 300+ browser/OS combos. > Get unparalleled scalability from the best Selenium testing platform > available > Simple to use. Nothing to install. Get started now for free." > http://p.sf.net/sfu/SauceLabs > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
