Hi Dave,
for the Moment i am 'flirting' with two Solutions:
1st chinese spindle Controller (Manual attached)
i have servo Motors and Controller from this compnay on all my machines,
they are working without any Problems. still waiting for a offer for this Controller.
pro
-gives me all posibilities
-modern,standard equipment
contra
-maybe cost
-Need's to be rewired
-will take some time to get
2nd i call it dogcatcher
-will be a sloted plate (5mm makronlon, because i am getting scared to drive metal against metal)
-driven by a 20mm pneumatic cylinder
-8mm proximity will give the Trigger for drive in
-8mm proximity detect dog
pro
-have all the material laying around
-cheap
contra
-part's to make will also take time
-not sure i will work
i am just brainstormin, all comments wellcome.
Thomas
I dont think this problem is a big as you think with sensorless vector VFD, I once built a pump with that kind of VFD and it ran reliably down to 18 rpm with a load, or 1/100 of base speed. My machines also had to stop and line up with rails that plugged in. Taper your drive dogs as much as you can too, so you dont need to be perfect. Run the motor at the lowest possible speed and tell it to stop on the sensor. Worse that will happen is that it will overshoot a bit. As long as the overshoot is reliably consistent you can adjust sensor position to accomodate.
i have tryed this solution, but was not able to get the stopping Point good enough.
Another thought about this issue. Things like this work much better when they are designed to be extremely tolerant of misalignment rather than being very accurately made. So I htink a better approach here is to have the tool gripper mounted to be spring loaded upward. You press it against the spindle and if the dogs are not lined up the compressing of the spring triggers a limit switch that causes the spindle to rotate until the dogs drop into the slot and the limit switch then indicates that the alignment has been achieved, fasten the tool and retract the gripper. No spindle switch needed.
i have a 'umbrella' toolchanger witch drives in/out, and uses zhe Z-axis for tool Change, so no way.