spin drier function with robot

    Hello guys, I'm too new in robots so am sorry if my case is not properly described...


    In my application wet parts (1,8 kg each) come out in a stack of 15 parts high on a conveyor belt.

    I'm thinking of using articulated(anthropomorphous) robot to pick-up the stack of 15 parts with a gripper and by rotating Axis 6 at max speed through the gear box (need at least 800 rpm) for some 5-6 sec to spin dry parts (like in centrifuge) and put them in the pallet afterwards.

    Single part weight: 1,8 kg + 40-60g residual water.


    Before diving deeper into details I'm kindly asking for an expert opinion does it sound doable with modern robots / grippers?

    Thanks,

    RK

    Quote from HawkME

    but the 800 rpm is not achievable with J6

    Thanks for your reply HawkME.

    Do you mean because of torque/inertia/gripper/balance issues or just because J6 has not enough rotation speed?

    I was thinking to apply 1:10 gearbox between J6 and gripper (from Sumitomo or Spinea for example)

    A 1:10 gearbox could give you 800 rpm, but has a few issues.

    • You now need a robot large enough to handle the weight of the gearbox and the parts
    • You Need to specify a continuous turn J6 axis
    • How would you even mount the gear box? the gearbox only works if the case is held still while the shaft rotates. This means you would need to fix the gearbox case to J5, which would be sketchy.
    • Your J6 kinematics will be screwed up by doing this, which could make linear moves behave oddly.

    You have a couple of realistic options. 1, you can have a stand-alone centrifuge separate from the robot. 2, mount an additional motor and gearbox on the end of J6 to handle the spinning (more payload needed though). Personally, I think using a stand-alone centrifuge is the simplest and best option. I would not recommend using J6 directly for this application.

    Yeah, I have to mostly agree with Hawk. The one real alternative I could see to a standalone centrifuge would be to build an end effector with the spin motor between the body of the end effector and the J6 mounting flange. If selected properly, you might even be able to use a servo motor and make it an external axis of the robot. This would probably be necessary in order to ensure that the end effector was rotated properly for the pick/drop positions -- using a regular AC motor and VFD, for example, would make it easier to control the speed, but harder to control the position. And you need both.


    However, you're still going to need either a big, fast servo, or a smaller servo with a gearbox. Either way, you're going to end up with an end effector that weighs a lot more than the payload it's carrying, which drives you towards a bigger robot.

    A company I know already mass produce molds/shells using the Kawasaki and they utilize the built in spin function purely for the removal of excess material (not drying), albiet, they do not and could never achieve those sort of speeds.

    Also, a ceramic company manufacturing mugs, use the Arc Weld weave method to aggressively shake the mugs (up to 5 in total and securely gripped), prior to loading onto a moving conveyor through a kiln.


    However, if you are looking at those speeds, you also need to consider the safety implications:

    - Securing of parts under rotation.

    - Emergency stopping in the event of malfunction or user intervention.

    - Sufficient safe guards to prevent ejection of parts.

    - Stopping under normal running conditions inclusive of equipment errors.

    Have a look over stop categories for your robot as most have selectable options now to change the stop category.


    It maybe worthwhile considering a heating system (if you're material allows for it) that the robot could rotate the parts around at a safe speed.

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