Good afternoon,
We are in the process of installing a R2000iA/125L (RJ3IB controller) on an injection molding machine. We are looking for a method of matching the robots motion speed during one linear move to the ejectors that push the part out of the mold. This speed is not always constant through the part cycle or from part to part.
It is possible to put an encoder on the ejectors and feed that thru the PLC running the press to the robot (Ethernet IP) as a reference. We would prefer to keep any logic within the robot to limit additional variables so this option is less than desirable.
We also thought of monitoring the torque on a given motor and increasing or decreasing the speed if the motor torque is above or below a given value. This is the option we like the best but we are not sure where to start with the programming or if it is even possible.
Our main concern is damage to the robot. These are old molding machines and once you start the eject cycle there is no stopping it other than an e-stop. With 12" of ejection stroke if we overload an axis and stall the robot in the first inch of travel the molding machine will continue to push the robot the remaining 11" without hesitating. The robots we are replacing (gantry style) have this same issue and we have blown out bearings with one mistyped number.
Thanks in advance for any advice,
Matt