Gentlemen, A little progress on the handwheel tapping project. The spindle motor encoder has pulses of 7200 per revolution in low gear. This gives 20 pulses per degree. Not enough to be a real C axis. The number of pulses may be limited by the spindle drive so I may try to tap into the sign wave feedback from the spindle motor. There are two sign wave signals from the spindle motor to the spindle drive. I have not looked at these with a dual trace scope to determine their orientation to one another. Jon E - will this allow use of your resolver to encoder converter board? I have it tuned per revolution rather than per degree. I have the max velocity set to 5. This should allows 300 rpm max. with the handwheel. A fast/tiring spin with your hand. Slower may just be better. I have the accel set to 2. This allows a lot of Pgain. The spindle holds position VERY tight like this. I may go back to the XYZ to try tuning with this method. I like the halscope traces for the spindle better than for the XYZ. I have not tried to home the C axis. I do have an index pulse from the spindle. This will allow the orientation of the spindle to the encoder after every gear change. I have not tried to use the index to orient the spindle to the encoder. I had just accomplished the spindle tuning as explained when the shop said 'Is this ready? We have a job for it'. This will go to weekend project status now. This may be of interest to someone during our meet here. I will continue to work on this but I am sure I won't be complete by then. I need to determine how to set up the MPG tapping cycle. How do I set the feed/rev ratio? What kind of screen feedback? etc? The most important finding is the ultimate usefulness of tapping this way. It seems novel but is it a useful tool? Putting it on the Cinci or Viper for 5 axis MPG tapping would be killer! Ken Lerman - thanks for the link - I have some AB encoders that look as if they are steppers. These may be exactly what I need. I think detenting MPG/steppers would give a very good tactile feedback to a hand. As the current in the motor increases the detent resistance increases. This should be very interesting. thanks Stuart
On Sat, Oct 2, 2010 at 11:22 AM, Kenneth Lerman <kenneth.ler...@se-ltd.com>wrote: > Stuart, > > See: > > http://deepblue.lib.umich.edu/bitstream/2027.42/60859/1/paulgrif_1.pdf > > Figure 2.1 > > > Ken > > On 10/01/2010 09:32 PM, Stuart Stevenson wrote: > > Hi Ken, > > That is a good idea!!! Isn't it possible to use a stepper motor as a > pulse > > generator? If so, wouldn't it be possible to variably bias that same > stepper > > to achieve the haptic feedback? > > thanks for the idea > > Stuart > > > > On Fri, Oct 1, 2010 at 7:45 PM, Kenneth Lerman<kenneth.ler...@se-ltd.com > >wrote: > > > > > >> Hi Stuart, > >> > >> If you are going to do some computer assisted hand tapping, you might > >> want to add some haptic feedback. If you measure the spindle current and > >> use that as a measure of load, you could drive a small servo connected > >> to the mpg and use it as a brake. If you make the braking force > >> proportional to the spindle load, that might let you "feel" when the tap > >> gets dull or jams on chips. > >> > >> Regards, > >> > >> Ken > >> > >> On 09/30/2010 09:41 AM, Stuart Stevenson 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 > >>> > >>> > >>> > >> > >> > ------------------------------------------------------------------------------ > >> 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 > -- dos centavos ------------------------------------------------------------------------------ Beautiful is writing same markup. Internet Explorer 9 supports standards for HTML5, CSS3, SVG 1.1, ECMAScript5, and DOM L2 & L3. Spend less time writing and rewriting code and more time creating great experiences on the web. Be a part of the beta today. http://p.sf.net/sfu/beautyoftheweb _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
