Universal Robots Forum

G-code for simultaneous milling operations

Hi all,

I am working with the new g-code URcap and I seem to have run into a limitation. Some of our CNC machines are capable of doing simultaneous operations. One case of this is keeping the tool perpendicular to the direction of the toolpath (see attached image). The current version of the URcap does not seem capable of this, as it keeps the tool’s orientation fixed with respect to the part’s frame for all axes (doc=6) or all axes except the z-axis (doc=5).

Is there a workaround to still achieve the movement as specified in the g-code?
Or are there maybe plans to add this feature in the future?

Thanks in advance,


1 Like

For simulation of this you can use RoboDK trial version. We tried something like this and found same problem.

Hello Karin! Would you mind sharing the G-code file that you generated for this application?

Which CAM software and post-processor did you use?

The FAQ article on the UR Support Site includes the following:

Note: For G00 and G01, it is recommended to create multiaxis toolpaths using head axes instead of turntable axis. In terms of G-code, this means only using B and C axes for motions.


Hi ypan,

Thank you for your reply. The generated g-code (generated by HyperMill for an Okuma machine) did indeed use the A-axis for motions. However, changing the code to only use the B and C axes had no effect.

I worked around the problem by writing a script that translates the g-code into mc_add_linear() commands (for the e-series) or servoj commands (for the CB-series). I needed a script either way because some important lines of the g-code are not supported by UR, such as changes in coordinate systems. The disadvantage for the CB-series is that it cannot make use of the “doc=5” option in the processpath module, which would allow the orientation around the z-axis to change. This would be helpful in avoiding joint limits.

Kind regards,

Hello Karin,

Unfortunately, I don’t have access to HyperMill, so I am not able to check which post-processor works with UR.

I used the Multiaxis Contour operation in Autodesk Fusion 360 to generate the G-code file based on what you described in the first post: https://a360.co/31P5YJV. Fusion 360 offers a 30-day free trial if you want to give it a try.

Here is the G-code file that I generated using the post-processor for Hurco in Fusion 360:

Toolpath_Hurco.zip (12.4 KB)

The Hurco post uses the i,j,k convention for defining the tool orientation. Please make sure to use the “doc=5” option.

If HyperMill has a post for Hurco, you may want to give it a try as well.

Let me know how it goes.