How do I setup a 5 axis mill?

Hello. I've been using LinuxCNC for a while to control a 3 axis mill. The spindle moves along Z, and the table moves along X and Y. I just ordered a 4th and 5th axis setup that will bolt to the table, and discovered that I can't use the stepconf wizard to set it up. From what I've read here, it seems that I need to select the XYZA configuration, then edit the config files to duplicate the A axis and rename it to C, specify the right pins, etc... I could use some help with this.

I'm also concerned about where I will specify things like the distance between the A axis and my table surface, the fact that my C axis is attached to the A axis. Will I have to edit a kinematics file? Is the 5axiskins file intended for this style of machine? Where are these files located?

I am using Fusion 360 for CAM, and I'm hoping to do some indexed 5 axis machining. I hope someone who has done this before can point me in the right direction.

The setup wizards are for simple configurations only. Yes, you could make a XYZA and copy the A.

JT

5-axis machines are complicated. You need to work out what you want the A and B G-code words to mean.

They _can_ just refer to the angles of the rotary axes, or they can alternatively refer to the angle that the tool-tip is aligned to the work at the current XYZ point.

I have attached a rather detailed document on the subject (I hope the author does not mind). Depending on your mathematical background you will find this somewhere between fascinating and baffling. If you fall in the latter camp then be reassured that you don't need to understand all this, but you do need to know what you want your 5-axis machine to be.

Thank you for the replies. I have made some progress, but I still have a lot of learning to do. My first idea to duplicate the A axis seemed to have worked, but I did encounter some problems. After selecting an XYZA mill and editing the .ini file, I was able to move the A and C axes position in the DRO, but I would often get a joint following error. Then after I attempted to edit the .hal file in the same way, duplicating the A axis and renaming to C/5, LinuxCNC failed to start with the error "pin does not exist." I am curious about why this didn't work, or how to add a pin. My next thought was that I was having this problem because I am testing this in simulation mode on my regular PC that doesn't have a parallel port. My 4th/5th axis won't arrive for another week. I edited sim_hardware.hal and was able to get different errors. That's where I stopped trying this method. Maybe instructions/explanations for modifying these files exist somewhere?

I wish I had come across that .pdf at the beginning of my search. It was very helpful. Thank you. I did take all that math in school, but it's been many years since I've used it.

From what I've read, I think that I need to use RTCP positioning to be compatible with Fusion 360, and most 5 axis CAM software. Is that the case? Since Fusion isn't able to generate tool paths from .stl files, I'm thinking about Deskproto. Any other 5 axis CAM recommendations in that (<1000$) price range?

I was using trivkins for those first attempts. I found that 5axiskins is intended for a machine with a tilt/rotate spindle, so then I found XYZACkins. I was able to compile and run it, and it is working pretty well. It has the table moving along Z instead of the spindle. I'm not sure if that is set in the kinematics or is just the way it is displayed in the vismach file. I don't think it will cause any problems for me to use it as is after I replace the offsets for the rotary axes, but I would like to change it to reflect the way my mill is configured. Any advice or links to helpful info would be appreciated.

Yep, the instructions are here linuxcnc.org/docs/2.7/html/
And specific instructions for the ini file are here linuxcnc.org/docs/2.7/html/config/ini-config.html

I can't look at your file from this Windoze computer it doesn't know what a tar file is. A more universal compression is zip.

Did you increase the number of axes?

JT

The file I attached is the XYZAC configuration I found at:

wiki.linuxcnc.org/cgi-bin/wiki.pl?Contri...or_a_milling_machine

This setup is a lot closer to what I would like to use than the XYZA mill. I think it will be easier to start with this and modify it to suit my machine. Here it is as a .zip