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I am studying automating a process which may include removing parts from a cardboard carton and either placing them on a transfer nest (for further handling by another system) or placing them in the final location directly (if this is feasible). I intend to have someone else (a robot integrator) perform the system design and installation (it sounds like fun, but I don't have the time). I have not personally been involved in a project exactly like this one before, and I am looking for some suggestions which may help me evaluate ideas. The sort of information I am looking for is: A) I believe there are special material handing robots which are intended for this application, but what are their limitations (speed, accuracy, repeatability, etc.)? The working volume is larger than the robots that I am used to are capable of. B) I believe the scenario I am envisioning (see below) would seem to be fairly simple, but there may be problems I am overlooking. Is there anything I am considering which is likely to cause trouble? C) To avoid vision guidance, I believe we could have the operator push each box to a particular position (e.g. up against a set of stops). However, the system must accomodate different size boxes for different models (in different batches). Are there any *simple* but *reliable* methods of ensuring the operator has positioned the box correctly? I would rather not use rams to push the box into position. A set of sensors (e.g. ultrasonic) to detect each box is in position may work. A set of manually operated locking bars to hold the box in position (they won't close if the box is out of position) is another possibility. The locking bars would have to be adjustable for different models of dunnage though. D) Is some sort of collision sensing advisable to avoid crashing too hard into an unexpected obstruction (i.e. some foreign material was left in the cell)? For example, someone may forget to remove the lid from a box before loading it into the enclosure. E) Is there any particular brand of robot which is especially widely used for this type of application? What robots are used for this application? How fast are they? What are the typical costs? I don't need to point out that I want it to be cheap, simple, reliable, minimal maintenance, run for years needing only occasional lubricating, etc. The robot controller should have no moving parts (no fans, hard drives, etc.), and should be capable of withstanding a typical factory floor enviroment. The system would have the following general requirements: 1) The parts to be handled are plastic and are approximately 300mm to 600mm across, and no more than 25mm thick. Each part weighs no more than a few hundred grams. The parts are quite rigid, and all models could be picked up by a common suction gripper (or some such similar means) at the centre of the part. 2) The dimensions vary according to the part number (within the above mentioned range), but only one model needs to be handled during a batch (i.e. the parts are not mixed). 3) The parts are oriented horizontally in piles (i.e. stacked one atop the other) in the cardboard cartons. Each 'pile' is separated from the rest by cardboard dividers. There are different numbers of columns of parts in each box for different part numbers, but each part number has a specific known way it is packed. The robot would have to reach up to one metre down into the box (with the dividers in place) to retrieve parts. Some sort of sensor will likely be necessary for the robot to know the correct height to unload each part. 4) The boxes range in approximate size from approximately 0.5m x 1m x 1m high, to 1.5m x 1.5m x 1m high, with the larger ones being more common. The smaller containers could quite likely be eliminated, as they are intended for easier manual handling. 5) There are two scenarios. In one scenario, the system must unload one part every 20 seconds. In the second scenario, the system must unload two parts in succession for a total of two parts in 20 seconds. 6) The application may require the robot to drop the part onto a transfer nest to allow another mechanism to operate on it. In this scenario, an accuracy of plus or minus several millimetres should be good enough. 7) If accuracy (or perhaps more appropriately, repeatability) of roughly a few 10ths of a millimeter is possible for the entire system (not just the robot), then it may be feasible to avoid the transfer nest, and allow the robot to place the part in the final location directly. The robot would likely need to accomodate vision guidance for this to work. I am envisioning having a guarding enclosure containing a gantry robot, with interlocked access doors allowing an operator to push full cartons into the enclosure, and remove empty ones. The robot would be disabled while the doors are open. There is the possiblity of having a partitioned enclosure, with the robot allowed to work in one side, while the other side is being loaded. The working enclosure would probably be a metre or so deep, and several metres long, so that several boxes could be worked on in succession before needing attention. ********************** Michael Griffin London, Ont. Canada [email protected] **********************