I really can't understand why they use a stepper for this task. There is no need for expensive stepper drivers and mucking about with allowing for lost pulses. A DC motor works easily as well if not better. Here is a video of an Emco conversion I did. <http://www.youtube.com/watch?v=D4PrCejPbZ8> All you need is a relay output and a simple encoder with one pulse per tool. With the relay off the motor is driven in reverse through a current limiting resistor. This holds the turret firmly in place against the pawl. With the relay energised it runs the motor at full power forwards. To change tool you work out how many tools you need to index then turn the relay on and count pulses from the encoder. When you reach the desired count, turn off the relay and it locks in place. In the above conversion I used a simple hexagonal cam and a microswitch as the encoder.
If you want to do a really good job of it, add an index signal to find tool 1. At startup you rotate the turret until you see the index. I never bothered. I just set it up to remember the current tool number when you restart. Les On 26/07/10 02:27, Steve Stallings wrote: > Sorry, but the pawl is essential to how it operates. > > The counter rotation is limited by the pawl to the > exact position where the tool should rest. These > tool turrets will only work with the spindle rotating > in the normal direction, pushing the tool back against > the pawl, but they do work well for such a simple > design. They were used by Southbend, Emco Maier, > and many others. > > Steve Stallings > > > ------------------------------------------------------------------------------ The Palm PDK Hot Apps Program offers developers who use the Plug-In Development Kit to bring their C/C++ apps to Palm for a share of $1 Million in cash or HP Products. Visit us here for more details: http://ad.doubleclick.net/clk;226879339;13503038;l? http://clk.atdmt.com/CRS/go/247765532/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
