11-19-2020, 03:25 PM
Hello there,
I also happen to work with a Fanuc robot for 3D printing (M-20ib/25, with R-30ia controller). Here's the way I managed to work around this problem :
1. First, I made a python script which calculates the angle between the vectors created by the current point and the last 2 points (in the plane of the vectors). Depending on the angle, I apply a CNT value (rounding) interpolated from 0 to 100 (or any other values depending on your process) for every linear instruction.
2. Secondly, you need to buy Fanuc's package option called "TCPP", which stands for Tool Center Point Prediction. This option allows you to send an AO signal which is linked to your TCP speed. This enables the live modification of the extrusion flow rate. You can even send the signal a few hundreds of milliseconds in advance.
So for your application, when you print a circle, all the angles of the "set of 3 points" vectors are pretty wide and greater than 90°, which allows for a fat CNT value. And in case you robot's still slows down, you have the TCPP AO signal to prevent overextrusion.
Hope this helps. Cheers,
JF
I also happen to work with a Fanuc robot for 3D printing (M-20ib/25, with R-30ia controller). Here's the way I managed to work around this problem :
1. First, I made a python script which calculates the angle between the vectors created by the current point and the last 2 points (in the plane of the vectors). Depending on the angle, I apply a CNT value (rounding) interpolated from 0 to 100 (or any other values depending on your process) for every linear instruction.
2. Secondly, you need to buy Fanuc's package option called "TCPP", which stands for Tool Center Point Prediction. This option allows you to send an AO signal which is linked to your TCP speed. This enables the live modification of the extrusion flow rate. You can even send the signal a few hundreds of milliseconds in advance.
So for your application, when you print a circle, all the angles of the "set of 3 points" vectors are pretty wide and greater than 90°, which allows for a fat CNT value. And in case you robot's still slows down, you have the TCPP AO signal to prevent overextrusion.
Hope this helps. Cheers,
JF