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X-Z pick and place gantry robot using PLC

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Omila

Student
Jul 7, 2021
2
Design an x-z axis pick and place gantry robot for my Mechanical Engineering final year project. Any help is highly appreciated.

The project scope involves the design, fabrication, and installation of the pick and place gantry for the transfer of clay roofing tile from conveyor to rack using vacuum suction gripping. The robot is to be programmed using PLC. I require assistance in the selection and design of suitable actuation for arm movement and programming the PLC for accurate results. Any assistance in this matter is highly appreciated. Thank you!
 
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We don't do the work for you... tell us what you've tried and we will help with guidance, but we don't do the basic research.

Dan - Owner
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Thank you for your input! The specific functional requirement is as follows, the extruded clay block is brought beside the hydraulic press which presses the clay block to the required shape. This must then be removed from the mould and transferred to a separate tray which is then taken for drying. The automation involves the transfer of the clay block to the pressing machine and then, simultaneously transferring the already pressed tile onto a separate tray. So far I have designed a gantry robot with two overhanging carriages for pick and place. As seen in the attached image, I have designed two carriages that maintain a fixed distance from each other which simultaneously pick the clay block from the conveyor and the pressed tile from the pressing machine.
Certain barriers were designed to make sure the pick and placement take place in a single 2D plane. Namely the X and Z axes. The gripping mechanism is by means of suction cups for which calculations have already been done.
For the vertical movement of the robotic arms, I thought of using a single pneumatic actuator (since required displacement is only 1 inch) to lift the 15kg load (both carriages loaded condition) for which actuation speed can be controlled using flow valves.
The horizontal movement is designed to be done using a ball screw drive powered by a servo motor. And controlled via limit switched.

If anyone could kindly read this, I would appreciate any comments on the decisions I've taken so far. Particularly the actuation mechanisms used.
Also if anyone has any experience in this field I would really appreciate a discussion on the topic.
Thank you!
Omila
 
 https://files.engineering.com/getfile.aspx?folder=a81eb1cd-e560-42be-b705-883f9f5c51c9&file=Capture2.PNG
Pneumatic actuator for lifting will tend to give a jerky motion as the piston moves against its stops (though there are methods to limit the shock, and yes flow controls may help), you need to test that the suction cups don't lose suction under that shock loading condition. I'd have a backup plan if that doesn't work, something with a more controllable motion profile perhaps.

Ball screw and stepper motor sounds...slow.
 
I would consider replacing a pick-n-place machine with simple flippers... easier to control, no need for vacuum (and cleaning equipment), etc. Conveyer on one side brings block to press into shape, flipper on conveyer moves un-compressed block into press, block gets pressed, a flipper underneath flips it onto conveyer on opposite side, flipper resets, new block is flipped on top from conveyer belt on other side. Rinse and repeat, no human intervention required.

Dan - Owner
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Guided Ball screw actuator with stepper motor for the X axis and Pneumatic Guided cylinder for the Z axis. The vacuum suction with 4 cups connected to a Vacuum ejector. You need to work from here. Cycle time, cup diameter and MOC, Stroke length of the Z cylinder and the vacuum ejector, sequencing the operation in the PLC with controls.
 
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