Hi Stuart, I'd like to offer some general observations and thoughts.
Tapping requires a very close coordination of spindle rpm and axis feedrate. MPG axis feedrate by it's nature varies constantly as the operator rotates the MPG slightly faster or slower. Attempting to create a system where the spindle rpm's could be adjusted in real time to match the constantly varying feedrate caused by the inconsistent rpm of MPG input would be a significant challenge if it is doable. If it is doable, what happens when the operator inadvertedly reverses direction with the MPG? The spindle would have to stop instantly and reverse direction. Current rigid tapping cycles usually get the spindle rotating at a fixed rpm and then match the axis feedrate to the rpm. When the tap reaches the programmed depth (first peck or final) the spindle rpm and axis feedrate decelerate together, stop and then accelerate together as the spindle direction and axis direction are reversed. Hope this helps. Have a good day, Jim Fleig CNC Services 585 975-9618 On Sep 30, 2010, at 9:41 AM, Stuart Stevenson <stus...@gmail.com> wrote: > Gentlemen, > I am working on a project on the Enshu. I am not sure how valuable > it will > be but I sure want to try it. I want to tap threads using the MPG. > The spindle drive is a full servo. The spindle motor has a resolver > for > feedback to the spindle drive. The EMC2 DAC signal to the spindle > drive is > +-10V. I have found a quadrature signal out of the spindle drive. This > spindle drive uses the resolver feedback to generate this quadrature > signal > (A and B). The spindle has a prox and amplifier that feeds a signal > into a > daughterboard on the spindle drive for spindle orientation during tool > change. The daughter board has a pin that outputs a pulse once per > revolution corresponding to the radial position of the spindle. I > intend to > use the A and B as encoder feedback into EMC and the orientation > pulse as an > index pulse into EMC. This will allow full servo control of the > spindle as a > C axis. > I would like ideas on the best way to implement this. I would like > to have > the spindle set up as a C axis but without a C axis display on the > screen > (unless I am using the C axis as an actual C axis but that is another > project). I don't think I NEED any display for the spindle for this > project. > I think I would like to be able to command a G code to engage the > spindle > and an F code for feedrate to move the C and Z in a coordinated > fashion. > Maybe I am thinking backwards. Maybe driving the Z axis with the MPG > and the > C (spindle) coordinated with the Z is the best way. > Since I am thinking 'manual' then maybe a button is better than a G > code. > If I had a button how would I tell the machine the pitch of the > thread? > Maybe a screen display like the FO/SO/MV displays. This would adjust > in > proper increments per the chosen units and allow the MPG to set the > pitch > prior to engaging the coordination button. > thoughts - comments - ideas > thanks > Stuart > > -- > dos centavos > --- > --- > --- > --------------------------------------------------------------------- > Start uncovering the many advantages of virtual appliances > and start using them to simplify application deployment and > accelerate your shift to cloud computing. > http://p.sf.net/sfu/novell-sfdev2dev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
