[leem2209]

Hi All,

Seeking support with getting the right settings for RoboDK curve following as per the examples of the propeller polishing and the canoe polishing.

I have a wooden seat that is "bum" shaped, so not flat. The seat is made on a CNC machine so we have the CAD file available.

I have a sander on the end of a UR10e robot that I want to do the sanding of the seat with.

I've created a sanding toolpath in Solidworks, the process is similar to the canoe example that uses Inventor (https://www.youtube.com/watch?v=NoefxDYIwFA) 

Exported that to RoboDK and using the curve follow feature, I can have the robot follow the path, but the sanding head stays parallel to the table, rather than keeping the tool face flat to the surface of the seat.

I've attached images which will hopefully help.

I'm nearly there with this, it's taking me ages to get here as I've had to do it in bits here and there! I just want to get this running now and finish it off.

I'm not sure though, whether I need to do more in Solidworks before exporting the toolpath, or if it's wrong settings in RoboDK. 

Any ideas or pointers would be greatly appreciated!

M

[Sergei]

Exported that to RoboDK and using the curve follow feature, I can have the robot follow the path, but the sanding head stays parallel to the table, rather than keeping the tool face flat to the surface of the seat.

Make sure that the appropriate surfaces are selected when importing curves from SolidWorks. This is necessary to calculate the appropriate normals for the curves.

If you can share with us your station and part model with trajectory (in STEP format), we can help you better.

[Albert]

If you are using the RoboDK plugin for SolidWorks you should select the curve AND the surface to have the curve normals perpendicular to the surface.

Another option if you want to calculate the curve normals with respect to a surface within RoboDK is to use this script.

1. Select Tools-Run Script
   
2. Select the script Curve Project 2 Surface
   
3. Select the object with the curves as a first step
   
4. Select the object with the surfaces as a second step
   

You'll obtain a new object with the curves projected on the surface and normals perpendicular to the surface for each point.

[leem2209]

I missed out the key point of selecting the face of the object when exporting my curve.

Thank you both!

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Another question on this....

As the robot follows the curve, it stops at each point and at the arcs in the path it stop/start/stops very quickly at each point. Which isn't good for the robot or for sanding!

As per the canoe video, I've changed the rounding value:

Curve Follow Project - Program Events - Set Rounding

I've tried from 0.5mm to 30mm and it doesn't seem to make any change at all. I can see in the instruction list that the top command "Smooth" changes as per my setting, but the robot still stops at each point.

Any ideas?

---

Update:

If I select "run on robot" then "run" - it does the stop/start juddering.

If I select "send program to robot" it is smooth.

Is this normal?

[Albert]

How smooth the path is depends on many factors such as the robot controller, programmed speeds, tool weight, application, ... When you use the driver, some robot controllers can't buffer multiple commands so you'll notice more jerky movements, whereas when using the post processor, the controller can look ahead to smooth the path better.

You can try different values for rounding to see the result:
https://robodk.com/doc/en/Robot-Programs.html#InsSmooth