CNC Machining - Tending 2

Created by Rico Stodt, Modified on Mon, 07 Feb 2022 at 03:44 PM by Rico Stodt

This page provides detailed information of the tending a CNC lathe machine application.


Contents


Application – Video




Scenario


  • Pick a part from one of two possible rows in a presentation fixture.
    • The second row contains extra parts in case the first row becomes empty.
    • If the first row contains parts, always pick from the first row.
  • Wait for the machine door to open (signal sent to robot from machine).
  • Move into the machine.
  • Grasp the finished part and trigger the chuck to release.
  • Move to place the new part, use a force push to ensure the part is correctly seated and trigger the chuck closed.
  • Move to place the finished part and trigger the machine to start.
  • Place the finished part to allow a human operator to perform final inspection.
  • Repeat the process continuously.

Gripper Information


Notes:

  • End of arm tooling is a customer dual pneumatic gripper that was designed and built by a 3rd party. The PSG was not available when this application was created but would be a good option for similar tasks.
  • Center of mass and tool center point details were obtained using SolidWorks model of EOAT.
  • Two different subtools and tool center points are used to define each gripper endpoint location.
  • When training a pick or place Move To, the associate subtool is selected as the tool center point for the pose.

 

Gripper Image


3.1 CNC Machine Tending EOAT.PNG


Tool Settings

  • Tool Center Point
    • Subtool 1 = (X)=0mm, (Y)=49mm, (Z)=164mm
    • Subtool 2 = (X)=0mm, (Y)=-49mm, (Z)=164mm
  • Mass = 2107g
  • COM = (X)=0mm, (Y)=0.3mm, (Z)=48.5mm


3.1 CNC Machine Tending Tool Settings.PNG

Task Overview


Note: This task was created using Intera 5.1. Some differences may be seen if you are using newer versions of Intera.


3.1 CNC Machine Tending Task Overview.PNG

 


Create and Set Up Signals and Variables


Signals


Signal Name

Type

Line

Pick 2 Ready

Input

DI_0

Pick 1 Ready

Input

DI_1

Machine Ready

Input

DI_2

Start Machine

Output

DO_1

Open-Close Chuck

Output

DO_2


All of the signals are configured with a default value of 0 (or false). The image below shows the configuration of one of the signals.


3.1 CNC Machine Tending Signal.PNG

 

Variables


No custom variables used in the task.


Key Task Elements


Task Work Flow


3.1 CNC Machine Tending Task Workflow.PNG


Initialize


Notes:

  • The robot moves to a home position and then sets the valves in the controller to the proper configuration to ensure both grippers are open.
  • The robot moves to and re-registers all landmarks.


3.1 CNC Machine Tending Initialize.PNG

 

Pick from Tray


Notes:

  • Before picking, a Wait Until node is used to ensure parts are present at one of the two pick locations using input signals.
  • When picking, the first row is the priority. If this row has available parts, the robot will pick from the first location every time.
    • If no parts are available in the first row, the robot will pick from location 2.
    • This logic is controlled using a Priority node with two Do If nodes.


3.1 CNC Machine Tending Pick From Tray.PNG

 

Move to Machine and Wait


Notes:

  • Wait Until node is used to prevent the robot from entering the machine until an input signal is received from the machine.
  • A delay is required after the Wait Until node in order to allow time for the door to open as the signal is sent when the process is complete, not when the door is open.
    • The length of this delay was adjusted to decrease cycle time once the application was running successfully.


3.1 CNC Machine Tending Move to Machine.PNG

 

Pick Finished Part


Notes:

  • No miss pick logic is used in the application. If a miss pick occurs, the robot will continue running without stopping or displaying an error.
  • Before moving to the retract point, an output signal must be sent to open the chuck holding the part.


3.1 CNC Machine Tending Pick Chuck.PNG

 

Place New Part


Notes:

  • Apply Force is used in the Contact Mode to ensure the part is flat against the back of the chuck before triggering the chuck to close.
  • While still in the Contact Mode, a short delay is applied to give the robot time to start applying the force and then a signal is sent to close the chuck. Another delay is used after the signal is sent to ensure the chuck closes fully before the force is no longer applied.
  • Standard Move To nodes are used before an after the force is applied to ensure the robot is stable at the beginning and end of the force push. This is a best practice when using apply force.


3.1 CNC Machine Tending Place Chuck.PNG

 

Trigger Machine While Exiting


Notes:

  • A series of four Joint moves are used for to exit the machine.
  • The Start Machine signal is sent while the robot is exiting the machine in order to optimize cycle time.
    • This is done by placing a Set To node in the middle of the series of joint moves.
    • A series of joint moves are treated as a path during motion planning and a Set To node will not break up or pause this motion. This allows for the signal to be sent while the robot is moving without pausing or slowing the robot motion in any way.


3.1 CNC Machine Tending Exit Machine.PNG

 

Place Finished Part


3.1 CNC Machine Tending Final Place.PNG

 

 


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